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Chapter IX

Communicable Diseases, Table of Contents

CHAPTER IX

SMALLPOX

The most important fact disclosed by an investigation of the records of occurrence of smallpox in the United States Army during the World War is, as might be anticipated, the demonstration on a gigantic scale, of the importance and value of vaccination as a preventive measure. Appreciation of the value of vaccine virus as a preventive agent presupposes a knowledge of the history of smallpox and the toll of human lives it took in prevaccination days, and, for that matter, in recent times, in populations not adequately protected. For example, history tells us that all the inhabitants of Greenland died during the course of one epidemic and the country was not repopulated for 300 years; that in 1707 one-third of Iceland's population of 50,000 succumbed to the disease;1 that from 1701 to 1800 an average of 1 of every 12 persons dying in London each year died of smallpox;2 that in 1752 during an epidemic of smallpox in Boston, with a population of about 10,000 people not immune to smallpox, about 2,000 were rendered immune by inoculation with smallpox, the only method of immunization then known, approximately 2,000 fled the city, and of the remaining 6,000 nonimmunes more than 5,500 suffered attacks of smallpox;3 and that in two Indian (Moqui) villages in Arizona with a total population of 900 individuals, smallpox in epidemic form attacked 590 and killed 184.4 These are a few of innumerable instances that will serve to illustrate the havoc that smallpox has wrought.

The history of military medicine of prevaccination days is replete with reports of epidemics of smallpox comparable in nature and severity with the examples cited for civil populations.

When Jenner, in 1798, gave to the world the method for controlling and preventing this disease-vaccination-this measure gradually was adopted by all civilized countries. With the passage of time and with additions to scientific knowledge, it has been possible constantly to improve the methods of preparation of the vaccine virus and to develop better and more satisfactory methods of administration, with the result that to-day the procurement of a potent, purified virus is, as compared with 30 years ago, a simple matter in all civilized communities.

In so far as military medicine is concerned the prevalence of smallpox in the French forces as compared with the German forces during the Franco-Prussian War (1870-71) offers very striking evidence of the value of vaccination. Perhaps the most conservative and most reliable statistics of the reactive prevalence of the disease in the opposing military forces are those recorded in the official German Medical History of the War of 1870-71. These figures are as follows:

 


Total cases

Rate per 1,000 strength

Total deaths

French Army

14,173

540

1,963

German Army

4,835

61

278

aUnless otherwise stated, all figures for the World War period are derived from sick and wounded reports sent to the Surgeon General.-Ed.


358

General vaccination of the military forces was a matter of custom in the German Army at that time,5 whereas in the French Army such was not the case.

During the Russo-Japanese War the Japanese forces were well vaccinated and of the million men engaged in that conflict only 362 contracted smallpox (4 per 10,000 of strength), of which number only 35 died.6

OCCURRENCE IN THE ARMY PRIOR TO THE WORLD WAR

A brief reference to the trend of the smallpox rates in the United States Army during the past few decades and a comparison of its prevalence during war periods are considered desirable and will bring more clearly into relief the very excellent results obtained through the application of protective measures during the World War. The admission and death rates for white enlisted personnel, United States Army, 1840 to 1919, inclusive, are given in Table 54 and shown graphically in Chart XLI.

TABLE 54.-Smallpox-Admissions and deaths, white enlisted men, United States Army,1840 to 1919-Rates per 1,000 of strength

Year

Admissions

Deaths


Years

Admissions

Deaths

Years

Admissions

Deaths

Years

Admissions

Deaths

1840

0.40

0

1862

4.68

1.36

1882

0.48

0.05

1901

1.27

0.30

1841

0

0

1863

4.71

1.44

1883

.14

.05

1902

1.02

.17

1842

1.70

.20

1864

8.08

3.21

1884

0

0

1903

.50

.05

1843

.30

0

1865

4.62

1.75

1885

0

0

1904

.32

.05

1844

.12

0

1866

3.37

.70

1886

.23

0

1905

.11

0

1845

.12

0

1867

1.07

.17

1887

.05

0

1906

.17

.02

1846

.55

0

1868

.84

.05

1888

.22

.04

1907

.10

0

1849a

7.22

.87

1869

1.02

.10

1889

.13

0

1908

.19

0

1850

2.23

0

1870

.93

.07

1890

.05

0

1909

.01

0

1851

1.19

.43

1871

.56

.07

1891

.33

.10

1910

.18

.01

1852

1.20

.22

1872

1.65

.25

1892

.05

0

1911

.07

0

1853

1.31

0

1873

1.58

.36

1893

.09

0

1912

.08

0

1854

2.59

0

1874

.16

.04

1894

.04

0

1913

.11

.03

1855

3.74

0

1875

.51

.05

1895

0

0

1914

.09

.01

1856

.21

.07

1876

.22

0

1896

0

0

1915

.05

0

1857

.63

0

1877

.83

.28

1897

0

0

1916

.06

0

1858

1.10

0

1878

.28

0

1898

.66

.16

1917

.21

0

1859

.90

0

1879

.78

.05

1899

3.38

.85

1918

.20

0

1860

0

0

1880

.28

0

1900

1.91

.79

1919

.07

.01

1861

3.36

.15

1881

.24

.05

 

 

 

 

 

 

aNo record for the years 1847 and 1848.

The interesting points shown in Chart XLI are two in number: First, the highest admission and death rates since 1840 occurred in 1864 during the Civil War, since which time the general trend of the smallpox admission and death rates in the Army have been downward, except for the period of the Spanish-American War and the Philippine insurrection. Second, prior to the World War the Army had always experienced a sharp increase in smallpox admission and death rates during war periods, whereas during the World War the admission rate was but little higher than for the years immediately preceding, and the death rates for smallpox were essentially the same.

A somewhat more detailed analysis of the admission and death rates during war periods discloses information of importance. The comparative admission and death rates for the Civil War, Spanish-American War and Philippine insurrection, and for the World War are incorporated in Table 55.


359

CHART XLI

TABLE 55.-Smallpox-Admissions and deaths, United States Army in the Civil War, Spanish-American War, and Philippine insurrection, and the World War-Absolute numbers and ratios per 10,000

 

Total mean annual strengths


Admissions

Deaths

Case mortality


Absolute numbers

Ratios per 10,000

Absolute numbers

Ratios per 10,000 strength


CIVIL WAR

 

 

 

 

 

 

White troops May 1, 1861, to June 30, 1866

2,193,427

12,236

55.8

4,417

19.5

36.10

Colored troops July 1, 1863, to June 30, 1866

183,395

6,716

366.2

2,341

122.1

34.85


SPANISH-AMERICAN WAR AND PHILIPPINE INSURRECTION

 

 

 

 

 

 

Total Army, white and colored, 1898-1901

446,221

825

18.5

258

5.8

31.27

Army in United States, 1898-1901

212,658

126

5.9

4

.2

3.17

Army in Cuba and Porto Rico, 1898-1900

48,686

20

4.1

4

.8

20.00

Army in Philippine Islands, 1898-1901

177,542

674

38.0

249

14.0

36.94


WORLD WAR
(Apr. 1, 1917, to Dec. 31, 1919)

 

 

 

 

 

 

Entire Army

4,128,479

853

2.1

14

.03

1.64

Army in United States

2,235,389

780

3.5

1

.005

.13

Army in Europe

1,665,796

24

.1

5

.03

20.83

Army in Philippinesb

21,451

11

5.1

3

1.4

27.27

Army in other countriesc

22,620

10

4.4

3

2.1

30.00

Transports

108,033

4

.4

2

.2

50.00

Native troops, Philippine Islands

18,576

23

12.4

---

---

---

Native troops, Porto Rico

11,831

1

.8

---

---

---

aSource of information: (1) Medical and Surgical History of the War of the Rebellion, Part First, Medical Volume, pp. 640 and 710. (2) Annual reports of the Surgeon General, 1899, 1900, 1901, 1902. (3) Statistical tables, Office of the Surgeon General, 1917-1919.
bIncludes troops in China. 
cNot including Hawaii, Panama, and native Hawaiians; including 8,388 officers.


360

The rates in Table 55 are based on the total of the mean annual strengths for the periods covered. The table shows a marked decrease in rates for each war period as compared with the immediately preceding war period. Based on a rate per 10,000 of strength for each war period, the rates were as follows: Civil War (white troops) 56, Spanish-American War, 19; World War, 2. During the Civil War vaccination as a protective measure was not well carried out for a number of reasons; and while no epidemics occurred, there was a considerable number of sporadic cases.7 The colored enlisted men incorporated in the Union Army during the Civil War were protected only in small measure by protective vaccination, with the result that the rate per 10,000 of strength for colored enlisted men during the period was 366 as compared with a rate of 56 for white enlisted men in the same army.7

An examination into the geographical distribution of the cases of smallpox that occurred during the Spanish-American War and Philippine insurrection is illuminating. Table 55 shows that whereas there was a total of 825 admissions for smallpox during the period referred to, 674 of these cases occurred in troops on duty in the Philippine Islands. The comparative rates per 10,000 of strength were as follows: Total Army, 19; troops on duty in United States, 6; troops on duty in the Philippine Islands, 38. The high rates in the Philippines caused the comparatively high rate for the Army as a whole during this period, and the high rates in the Philippine Islands were due to lack of protection by vaccination and inability to secure a potent vaccine virus for troops on duty in those islands during the first year or more of the occupation.8

The first expeditionary forces sent to the Philippine Islands during the Spanish-American War were dispatched hurriedly, and our present knowledge of the keeping qualities of vaccine warrants the statement that many of the individuals when called to active service were vaccinated with an inert virus. On arrival in the Philippines, these forces immediately came in contact with virulent smallpox in epidemic form. It is a matter of record that under the Spanish régime and for a few years subsequent to American occupation more than 40,000 Filipinos died each year of smallpox.9 American troops gradually came to occupy many small and large towns throughout the islands, with consequent intimate exposure to virulent smallpox. There was the further complication that there were no adequate provisions for the production of the virus in the Philippines, and supplies brought from the United States frequently were not adequately protected by cold storage en route, with the result that they proved to be inert when used. There was the still further complication that even when a potent vaccine became available in Manila itself, no ice was available in which to pack it for shipment to military garrisons in the Provinces. These were the factors that account for the high rate of incidence in the early days of our occupation of the Philippines. The principal factor militating against the protection of our forces, the nonavailablility of potent vaccine


361

virus, soon was overcome by the establishment of a laboratory, under Government supervision, for the production of the vaccine virus. When and as such a vaccine became available the admission rates immediately dropped, as is shown in Chart XLI. When locally produced vaccine virus became available steps were taken to protect the civil population, with the result that the disease in epidemic form disappeared in the wake of the vaccinating squads. As an example of the striking influence of this protective measure may be cited the fact that the deaths from smallpox in the native population in the Provinces adjacent to Manila were reduced from 6,000 annually to zero and in Manila itself not 1 death from smallpox was recorded for the 7 years prior to 1914.9

Subsequent to 1914, as a result of relaxation in administrative control and inefficiency and incompetency on the part of subordinate Filipino health officers charged with the administration of smallpox vaccine, a large unprotected population-young children-came into being. The result was that in 1918 and 1919 the population of the Philippine Islands suffered the greatest smallpox catastrophe of modern times.9 Incomplete statistics show that more than 60,000 persons died of smallpox during this period and more than 90 per cent of the deaths occurred in unvaccinated children.10

Notwithstanding the fact that smallpox in widespread virulent epidemic form attacked the Filipino population during the period of the World War, the military forces (American and Filipino) on duty in the Philippines during the same period were singularly free. In a military force of approximately 40,000 men only 3 deaths from smallpox occurred. Reduced to approximately comparable figures, the statement is justified that the ratio of recorded deaths from smallpox during the epidemic in the native population as compared with that in the military population was as 40 is to 1. The senior writer of this chapter has been informed by those conversant with the situation that, as a matter of fact, it may conservatively be estimated that 100,000 Filipinos died during the course of the 1918-19 epidemic, in which case the comparative ratio would be about 80 to 1, rather than 40 to 1.

The actual results accomplished in the prevention of smallpox in the American military forces during the past 75 years probably can best be expressed in the statement that for every 1 case of smallpox occurring during the World War, 9 occurred during the Spanish-American War and Philippine insurrection and 28 occurred during the Civil War (white enlisted men only). The case fatality rate during the Civil War was 39 per cent; during the Spanish-American War and Philippine insurrection, 31 per cent; and during the World War it dropped to the extraordinarily low figure of 1.6 per cent. (See Table 55.) This low mortality rate is probably accounted for in minor degree by the fact that the type of smallpox prevailing in the United States during the World War was of low virulence; however, the principal factor responsible for the low death rate was the high degree of protection afforded by vaccination.


362

TABLE 56.-Smallpox-Admissions and deaths, by countries of occurrence, officers and enlisted men, United States Army, April 1, 1917, to December 31, 1919-Absolute numbers and ratios per 1,000

 

 

Total mean annual strengths


Admissions

Deaths

 


Absolute numbers

Ratios per 1,000 strength

Absolute numbers

Ratios per 1,000 strength

Total officers and enlisted men including native troops

4,128,479

853

0.21

14

0

Total officers and enlisted men American troops

4,092,457

829

.20

14

0

Total officers

206,382

11

.05

1

0

Total enlisted American troops:

 

 

 

 

 

    

White

3,599,527

612

.17

9

0

    

Colored

286,548

204

.71

2

.01

    

Color not stated

---

2

---

2

---

         

Total

3,886,075

818

.21

13

0

Total native troops enlisted

36,022

24

.67

---

---

Total Army in the United States including Alaska:

 

 

 

 

 

    

Officers

124,266

9

.07

---

---

    

White enlisted

1,965,297

573

.29

1

0

    

Colored enlisted

145,826

198

1.36

---

---

         

Total enlisted

2,111,123

771

.37

1

0

         

Total officers and men

2,235,389

780

.35

1

0

U.S. Army in Europe, excluding Russia:

 

 

 

 

 

    

Officers

73,728

1

.01

1

.01

    

White enlisted

1,469,656

16

.01

2

0

    

Colored enlisted

122,412

5

.04

---

---

    

Color not stated

---

2

---

2

---

         

Total enlisted

1,592,068

23

.01

4

0

         

Total officers and men

1,665,796

24

.01

5

0

Officers, other countries

8,388

1

.12

---

---

U.S. Army in Philippine Islands:

 

 

 

 

 

    

White enlisted

16,995

11

.65

3

.18

    

Colored enlisted

4,456

---

---

---

---

         

Total enlisted

21,451

11

.51

3

.14

U.S. Army in Hawaii:

 

 

 

 

 

    

White enlisted

16,161

---

---

---

---

    

Colored enlisted

3,319

---

---

---

---

         

Total enlisted

19,480

---

---

---

---

U.S. Army in Panama: White enlisted

19,688

---

---

---

---

U.S. Army in other countries not stated:

 

 

 

 

 

    

White enlisted

---

9

---

3

---

    

Colored enlisted

---

---

---

---

---

    

Color not stated

---

---

---

---

---

         

Total

14,232

9

.63

3

.21

Transports:

 

 

 

 

 

    

White enlisted

97,498

3

.03

---

---

    

Colored enlisted

10,535

1

.09

2

.19

    

Color not stated

---

---

---

---

---

         

Total

108,033

4

.04

2

.02

Native troops enlisted:

 

 

 

 

 

    

Philippine Scouts

18,576

23

1.24

---

---

    

Hawaiians

5,615

---

---

---

---

    

Porto Ricans

11,831

1

.08

---

---

OCCURRENCE DURING THE WORLD WAR

As stated above, smallpox played a very minor part as a cause of sickness and death in the United States Army during the World War. The total mean annual strength of the Army for the period April 1, 1917, to December 31, 1919,


363

was 4,128,479, and during this period only 853 cases of smallpox were recorded as primary admissions. The admission rate per 1,000 of strength for the period was therefore 0.2, or 2 men in every 10,000. Of those who had the disease only 1.6 per cent died (14 deaths), and the death rate expressed in terms of strength was only 3 deaths in every 1,000,000 men. It will be noted that the expression "primary admissions" is used in referring to the total number of cases. In all the basic tables presented in this chapter the absolute numbers used will be primary admissions unless otherwise specified. Only one disease was used in statistical tabulations, and this was the primary admission. It occasionally happened that an individual admitted for one disease (primary admission) contracted some other disease-for example, smallpox-before release from hospital. This concurrent disease, or complication, was tabulated separately, and the tables of concurrent diseases show that in addition to the primary admissions (853) a total of 126 cases of smallpox were concurrent with other diseases, making a grand total of 979 cases (.24 per 1,000 of strength).

GEOGRAPHICAL DISTRIBUTION

The geographical distribution of smallpox during the World War is shown in Table 56.

Briefly, the facts of interest disclosed by this table are as follows, the admission ratios per 1,000 being converted into ratios per 100,000 of strength that they may be expressed in whole numbers:

 

 


Admissions

Deaths

 


Absolute numbers

Ratios per 100,000

Absolute numbers

Ratios per 100,000

United States (including Alaska), American troops, commissioned and enlisted

780

35

1

0

Europe (excluding Russia), commissioned and enlisted

24

1

5

0

Philippine Islands, American troops, enlisted

11

51

3

14

Philippine Islands, Filipino troops

23

124

0

0

Hawaii, American troops, enlisted

0

0

0

0

Hawaii, Hawaiian troops

0

0

0

0

Porto Rican troops

1

8

0

0

Panama, American, enlisted

0

0

0

0

In order of importance the occurrence geographically was the Philippine Islands, United States, Porto Rico, and Europe. As will be explained below, a large proportion of the 780 cases encountered in troops in the United States occurred in nonprotected individuals reporting for duty at mobilization camps in the incubationary stages of the disease.

IN THE UNITED STATES

Mobilization of the military man power of the United States for the World War was accomplished in large mobilization camps and the occurrence of smallpox in 39 of the larger of these camps is tabulated in Table 57. The rates per 1,000 of strength are based on the total mean annual strength for the period.


364

TABLE 57.-Smallpox. Admissions by camps of occurrence, white and colored enlisted men, United States Army, April 1, 1917, to December 31, 1919. Absolute numbers and ratios per 1,000

Camp

Total mean annual strengths


White admissions

Colored admissions

Total admissions


Absolute numbers

Ratios per 1,000 strength

Absolute numbers

Ratios per 1,000 strength

Absolute numbers

Ratios per 1,000 strength

Beauregard, La.

20,625

3

0.15

1

2.37

4

0.19

Bowie, Tex.

26,193

13

.52

---

---

13

.50

Cody, N. Mex.

22,636

3

.13

---

---

3

.13

Custer, Mich.

37,631

12

.33

6

4.43

18

.48

Devens, Mass.

47,921

1

.02

---

---

1

.02

Dix, N. J.

49,786

3

.07

1

.21

4

.08

Dodge, Iowa

39,032

39

1.17

28

4.82

67

1.72

Doniphan, Okla.

26,747

32

1.20

---

---

32

1.20

Fremont, Calif.

15,414

2

.13

---

---

2

.13

Funston, Kans.

56,222

69

1.38

20

3.24

89

1.58

Gordon, Ga.

44,871

7

.18

8

1.17

15

.33

Grant, Ill.

49,256

12

.28

14

2.02

26

.53

Greene, N. C.

29,710

6

.23

1

.28

7

.24

Greenleaf, Ga.

11,959

1

.08

---

---

1

.08

Hancock, Ga.

37,994

3

.08

---

---

3

.08

Jackson, S.C.

42,011

5

.14

---

---

5

.12

Kearny, Calif.

25,472

1

.04

---

---

1

.04

Lee, Va.

57,635

13

.25

8

1.21

21

.36

Lewis, Wash.

47,792

12

.25

---

---

12

.25

Logan, Tex.

27,734

4

.15

2

1.87

6

.22

McArthur, Tex.

25,271

10

.41

1

1.05

11

.44

McClellan, Ala.

28,664

3

.11

3

1.41

6

.21

Meade, Md.

50,033

---

---

2

.25

2

.04

Mills, N. Y.

24,197

5

.22

5

3.98

10

.41

Pike, Ark.

49,587

6

.15

44

5.05

50

1.01

Sevier, S. C.

27,786

9

.34

1

.62

10

.36

Shelby, Miss.

30,432

1

.03

6

3.63

7

.23

Sheridan, Ala.

26,507

1

.04

---

---

1

.04

Sherman, Ohio

42,750

2

.05

6

1.04

8

.19

Taylor, Ky.

46,962

19

.45

4

.91

23

.49

Travis, Tex.

44,264

19

.51

7

1.06

26

.59

Upton, N.Y.

44,871

4

.10

4

.86

8

.18

Wadsworth, S.C.

31,809

3

.10

---

---

3

.09

Wheeler, Ga.

25,726

1

.04

1

.55

2

.08

Others

339

---

---

1

2.95

1

2.95


     Total (all camps in U.S.)

1,270,068

324

.28

174

1.57

498

.39

Examination of Table 57 shows that in only four of the camps-Camps Dodge, Iowa; Doniphan, Okla; Funston, Kans.; and Pike, Ark.-did the rates of occurrence exceed one case per 1,000 of strength. In only 10 of the remaining 35 camps did the admission rate exceed 0.25 per 1,000 of strength. It is evident, therefore, that smallpox occurred only sporadically during the mobilization of our forces. Furthermore, the historical records of the various camps and hospitals on file in the Surgeon General's Office indicate that a large proportion of the cases arising in the camps occurred in individuals already in the incubationary or acute stage of the disease on arrival at camp and to a considerable extent in individuals soon after the arrival at camp and before protection could have been afforded by vaccination. The following evidence in support of this statement has been epitomized from these historical records:

CAMP BOWIE, TEX.

Of the 13 cases occurring in this camp, no evidence could be adduced that contact played any part. Three recruits reported at camp in the prodromal stages of the disease and one case was contracted through exposure while on furlough.11


365

CAMP DEVENS, MASS.

Only one case occurred at this camp and he contracted the disease prior to induction into active service.12 The low rate at this camp as well as at all other camps located in the northeastern section of the United States is a reflection of the thoroughness with which protective vaccination is carried out in the civil communities of the States concerned.

CAMP DODGE, IOWA

A total of 67 cases occurred at this camp.13 In six instances the disease occurred in one organization and was attributed to contact. Twenty of the cases were admitted to hospital within a period of 14 days after arrival in camp, most of them having acquired the disease prior to arrival, and in 30 other instances the disease developed within less than a month after arrival. Smallpox is known to have been unduly prevalent in the States-Iowa, Minnesota, and Illinois-from which this camp drew its quota for training, and the prevalence of smallpox at Camp Dodge was merely a reflection of the prevailing conditions in civil communities.

CAMP FUNSTON, KANS.

A total of 89 cases occurred at this camp, and the troops in training in this camp were drawn from an area in which smallpox was known to be uncommonly prevalent in the civilian population.14

CAMP PIKE, ARK.

Of the 50 cases arising at this camp, 29 were admitted to hospital within 14 days of their arrival at camp and 1 individual reported at camp in the eruptive stage of the disease.15 The training quota for this camp was drawn from the States of Alabama, Arkansas, Louisiana, and Mississippi, and the occurrence of smallpox at Camp Pike was a reflection of the undue prevalence of smallpox in some of those States.

CAMP TAYLOR, KY.

Of the 23 cases at this camp, it is stated that 13 were in the incubationary stage of the disease at the time of arrival at camp.16

From what has been said in preceding pages, the inference may be drawn that the greater prevalence of smallpox in some mobilization camps, as compared with others, was attributable to the more extensive prevalence of the disease in certain States or groups of States than in others. In support of this statement a statistical analysis is offered in Table 58.


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TABLE 58.-Smallpox. Numbers of admissions and ratios per 1,000 enlisted men (white and colored), United States Army, by States and groups of States, and comparable ratios per 1,000 among the civilian population of these States and groups, April 1, 1917, to December 31,1919a

aSource of information: (1) Sick and wounded reports made to the Surgeon General, U.S. Army. (2) Public Health Reports-Notifiable Diseases, Prevalence in States, 1917, 1918, 1919. Government Printing Office, Washington, D. C.

The data in Table 58 are assembled by groups of States in conformity with the grouping adopted by the United States Bureau of the Census. It will be noted in the statistics covering the civilian population that certain States have been omitted. The principal reason for this is that such States had not been admitted to the registration area and authoritative figures were not available. It should also be explained that the rate in the civilian population for each group of States is an average of those rates available for the States comprising the group rather than for all States comprising the group; for example, the rates for the New England group are based on the rates for four States rather than six.

Analysis of this table lends adequate support to the statement that the rate of occurrence of smallpox in military personnel in mobilization camps during the World War was dependent on its rate of occurrence in the civilian population in near-by States and was a reflection thereof. This can best be appreciated by inspection of Chart XLII.


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CHART XLII.-Smallpox in the United States Army and civil population, April 1, 1917, to December 31, 1919. Occurrence by groups of States. Ratios per 1,000 of population


368

Leake and Force,17 who reviewed the prevalence of smallpox in the United States during recent years (1915-1920), found that the disease is markedly increasing in certain sections. In general, it may be said that the increase is occurring in the southern and central groups of States and in practically all States west of the Mississippi River. In the New England and Middle Atlantic groups the rates are very low and have remained so for years. In the Pacific group, the rates are increasing rapidly. A correct interpretation of this condition presupposes a knowledge of the laws and customs governing preventive vaccination in the United States. There are no Federal laws governing this matter, the formulation and enforcement of protective measures of this nature being left to each State. The result is that in some States the laws are effective and well administered and there is practically no smallpox, whereas in others they are loosely drawn or inefficiently administered, or both, with the inevitable result-increased occurrence of the disease. In New York State, for example, the law provides that vaccination against smallpox shall constitute a condition requisite for school attendance in cities of the first and second class, and for other children residing in the State when smallpox is declared epidemic by the State commissioner of health. The public health organization of the State is a strong one and vaccination is efficiently administered. It is not surprising, therefore, that during the period, April, 1917, to December, 1919, the reported incidence rate for smallpox was only 14 cases in every 100,000 of population. On the contrary, the vaccination laws in the State of Kansas are most ineffective, and it occasions no surprise to learn that the reported rate of incidence for that State for the same period (April, 1917, to December, 1919), was 158 cases in every 100,000 of population. In the State of Indiana, for example, it is lawful for health officers to order compulsory vaccination of school children upon pain of exclusion from school for noncompliance. The Indiana State Board of Health, however, advises its health officers to be very chary in issuing such orders on account of the opposition exhibited by the citizens of the State. The reported smallpox morbidity rate for Indiana for the period under discussion (April, 1917, to December, 1919), was 40 per 100,000 population.18

IN EUROPE (RUSSIA EXCEPTED)

During the period, April, 1917, to December, 1919, there were 24 primary admissions for smallpox in the American forces in Europe, with 5 deaths. The admission rate was 1 in every 100,000 of strength. The cases were of sporadic occurrence except for 5 cases arising in January and February, 1919, in Base Hospital No. 103, at Dijon, France.19 The original of this small group of cases was an enlisted man of Company K, 52d Infantry, admitted to hospital with what at first appeared to be chicken-pox. A correct diagnosis was not arrived at until a short time prior to the death of the individual, when a confluent hemorrhagic eruption appeared. As a result of contact with the original case, a nurse and three attendants developed smallpox. The nurse had the disease in highly virulent form and died; the three enlisted attendants recovered. As soon as the true condition was recognized, all military personnel in Dijon were revaccinated with a fresh "green" vaccine virus obtained from Paris, and no further cases arose. In the interim between admission of the case to


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hospital and final diagnosis of smallpox no revaccinations were carried out, and the three individuals who later contracted the disease through exposure had not therefore been revaccinated. The important lesson to be deduced is that in all cases suggestive of a diagnosis of smallpox it is wise to consider them as such, at least administratively, and to revaccinate all persons exposed.

IN THE PHILIPPINE ISLANDS

The comparatively high admission rate in the Philippine Islands, as has been explained in previous pages, coincided with a devastating epidemic of virulent smallpox in the native population of the Philippine Islands. Though 34 cases of smallpox occurred in approximately 40,000 American and Filipino troops in the Philippine Islands, the influence of protective vaccination is evidenced in the fact that only 3 of these cases resulted in death.

IN OTHER COUNTRIES WHERE OUR TROOPS SERVED

No cases occurred in Hawaii. Among the Porto Rican troops, 1 case occurred and the individual recovered. In Panama, there were no cases. In Siberia, 9 cases, with 3 deaths, occurred among our expeditionary forces there.

IN THE ALLIED ARMIES AND IN THE MILITARY FORCES OF GERMANY AND AUSTRO-HUNGARY

An effort was made to secure information as to the occurrence of smallpox in the military forces of all the European nations (Russia excepted) engaged in the World War. Though incomplete, the information obtained is of sufficient importance to warrant its inclusion here.

FRENCH ARMY

During the four years of the war only 28 cases of smallpox occurred in the French Army, and among French colonial troops 44 cases were reported, with 4 deaths.20 Vaccination was a compulsory measure in the French Army and it is understood that a "green," rather than a "ripe," glycerinated vaccine was used. Vaccines of the "green" type, though containing more pyogenic organisms, are undoubtedly more potent, and this doubtless accounts for the exceptional freedom of the French forces from smallpox.

BRITISH ARMY

British forces serving in France were exceptionally free of smallpox.21 During 1914 and 1915 no cases were reported; during 1916, 4 cases; 1917, 2 cases; and in 1918, 6 cases, with 3 deaths. Prior to 1914, the British Army was well protected by vaccination. In January, 1916, the Army Council issued instructions authorizing the enlistment of men who refused vaccination ("conscientious objectors"). The promulgation of these instructions resulted in the dissemination of a considerable number of these "conscientious objectors" throughout various commands in the different theaters of war. These nonimmunes created no trouble in France, as all the armies operating on the Western Front were well protected, as was also the case with the population of France


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in general. In the Near East, however, conditions were quite different, smallpox prevailed in the civil populations, supplies of potent vaccine were difficult to obtain, and very considerable numbers of nonimmune military personnel were incorporated in the various commands. It is not surprising, therefore, that difficulty was encountered with smallpox. The disease appeared in the forces in Mesopotamia, and gradually spread, with the result that 1,908 cases were reported between December, 1916, and October, 1918. Great difficulty was encountered in stamping out the disease because of the considerable numbers of military nonimmunes, the impossibility of making vaccination compulsory, the widespread prevalence of smallpox in the civil population, and the inability to secure adequate supplies of a potent vaccine virus. As a matter of fact, the epidemic was only finally brought under control by the establishment of a vaccine-producing laboratory on the ground. In two regiments with a combined strength of 1,749 men there were 204 men unprotected by vaccination. In the unprotected group 25 cases of smallpox (123 per 1,000) occurred, with 5 deaths (20 per cent), whereas in the remaining protected group there were only 5 cases (3 per 1,000), with no deaths. During the period March 31, 1918, to March 29, 1919, 1,068 cases were reported in Mesopotamia with the following death rates:21

 


Admissions

Deaths

Mortality (per cent)

British troops

516

86

17

Indian

552

56

10

The records of protective vaccination in these groups indicate that the admission and death rate in the unprotected group was far greater than in the protected group. The matter is summed up in the following words:21

The lessons taught by the war on the subject of smallpox stand out clearly. If compulsory vaccination is not permitted, and men unprotected from smallpox by vaccination are sent to a war area where the disease is endemic, a sharp epidemic may flare up, as happened in the French Army during 1870-71. It was unfortunate that in Mesopotamia the one great essential in combating smallpox was denied to the medical services, namely, compulsory vaccination. If similar conditions should occur in future campaigns, the authorities concerned should realize how great a source of weakness must be present in the event of a smallpox endemic area becoming a theater of war. Attention should be devoted to the training of all medical officers in the diagnosis of the disease and the operation of vaccination. Further research in lymph suitable for a hot country is required. Careful plans for the proper distribution of lymph are essential, and the medical arrangements of a force will not be complete without adequate means for distributing the lymph in thermos flasks or other suitable containers. If resistance is to be offered against a severe outbreak, well-equipped isolation hospitals with modern and effective methods for disinfection will also be necessary.

BELGIAN ARMY

No cases were reported in the Belgian Army.22

ITALIAN ARMY

In the Italian Army 695 cases of smallpox were reported (1915, 79 cases; 1916, 148 cases; 1917, 139 cases; 1918, 329 cases).23 Military regulations provided for compulsory vaccination. No information is available as to the


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thoroughness with which the regulations were complied with nor as to distribution of cases with respect to the vaccinated and the nonvaccinated status of the personnel.

GERMAN ARMY

During the four years of the European war there were reported in the German military forces 434 cases of smallpox, with a case mortality rate of approximately 5 per cent.5 This speaks well for the thoroughness with which vaccination was carried out in the German Army, as their forces were exposed to smallpox both on the Russian front and in the Balkan States.

AUSTRO-HUNGARIAN ARMY

Vaccination was not effectively carried out in the Austro-Hungarian Army, particularly as regards those forces serving in Galicia; as a consequence 25,000 cases had been reported by the end of 1915, and during 1916 an additional 18,000 cases were reported.24 Doctor Morawetz, Vienna, who was in charge of a large smallpox hospital during the war, in a personal communication, has furnished the following information relative to smallpox in the Austro-Hungarian Army:24

Smallpox was a rare disease in the army before the war, and was only occasionally seen among civilians in Vienna. Although in the absence of epidemics, vaccination was not strictly compulsory, it was customary among civilians, and a high percentage of immunes were thus created. However, this was not universally true in Galicia, where vaccination was not carried out to the same degree and many persons were susceptible to the disease. During the war, vaccination became careless and many children were not protected. It was compulsory in the army, but as time went on the supply of lymph became inadequate on account of the scarcity of animals, and it was not uncommon to find many men in the service without vaccination scars. There are no statistics available to show occurrence of smallpox, either in the army or in the country as a whole. Such records have been misplaced or destroyed. However, for Vienna, the first case was reported in October, 1914, a soldier returning from the battle fields of Russia, where smallpox was prevalent. This case was followed by three others among soldiers. From that time, there was a rapid increase in the number of cases, and during the last three months of 1914, 112 cases were recorded. During the following year, 1915, 1,566 cases were reported, after which there was a decrease. In 1914, 7.4 per cent of the cases reported were among the military population; in 1915, 4.2 per cent; in 1916, 39.9 per cent; and in 1917, 64 per cent. In the civil population, the occurrence was chiefly among babies or children under the school age. The disease was brought under control by compulsory vaccination; but following the conclusion of hostilities, there was an increase due largely to fugitives from Poland.

RACIAL DISTRIBUTION, AMERICAN TROOPS (WHITE AND COLORED)

The detailed statistics showing prevalence of smallpox in our white and colored enlisted men are in Table 56. The rate for colored enlisted men was considerably higher than for white enlisted men, both in the United States and in Europe; admission rates for the Army as a whole having been 17 cases per 100,000 of strength for white, as compared with 71 per 100,000 for colored enlisted men. Vaccination for the colored population of the United States is not so complete as for the white population, and this accounts for the comparatively high rates in the colored group.


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RELATIONSHIP OF SMALLPOX TO LENGTH OF SERVICE AND TO PREVIOUS VACCINATION

In previous pages it has been stated that a large proportion of the smallpox occurring in mobilization camps in the United States was not chargeable to the Army, but was traceable rather to exposure in civil communities just prior to reporting at camps.

Prior to the World War, Army Regulations provided that certain data relative to all cases of smallpox in military personnel were to be reported to the Surgeon General of the Army, and these regulations were continued in force during the war. The data to be reported are shown on the following form:

INFORMATION DESIRED BY OFFICE OF THE SURGEON GENERAL IN CASES OF SMALLPOX AND SUSPECTED SMALLPOX

1. Name of patient:
2. Rank and organization:
3. Date of enlistment:                             Where mustered in:
4. Age:
5. Last station and date of joining present station:
6. Date taken sick:                                 Where:
7. Date admitted to sick report:              Where:
    By whom:
8. Has patient been vaccinated against smallpox? If so, give dates and names of places where administered (from records available, consult service record); also the result-i. e., immune reaction, vaccinoid, vaccinia, or unsuccessful. (See F. 81 M. D.: "The immune reaction appears as an areola after 24 hours and disappears in 72 hours. In a case of vaccinoid there is a small pustule which appears and disappears more quickly than in vaccinia. These reactions are evidence of protection. The term "protected" will not be used.)
9. Soldier's statement regarding vaccination, where obtainable:
10. Medical history of present attack (to accompany on regular form):
11. Whether cases of smallpox exist in the post or neighborhood among soldiers or civilians:
12. Diagnosis:
13. Remarks:
Date - - - - - - - - - - - - - - - - - - -
Station - - - - - - - - - - - - - - - - - -

Signed - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

It was possible to analyze 422 of these reports pertaining to the World War, from the viewpoint of the interval between the date of reporting at camps and the appearance of symptoms of smallpox, the following information being obtained:

 


Interval between date of reporting at camps and appearance of symptoms of smallpox


Number of cases


Per cent of total

 

Active smallpox on arrival at camp

 

2

1

 

1 to 3 days after inoculation

 

69

16

 

4 to 14 days after inoculation

 

82

19

 

15 to 30 days after inoculation

 

88

21

 

1 to 3 months after inoculation 

 

50

12

 

3 to 12 months after inoculation

 

93

22

 

More than 1 year after inoculation

 

6

1

Time interval unknown

32

 

8

 


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In this analysis of the special reports on smallpox it will be noted that two of the cases arrived at camp with smallpox. These special reports, however, cover only about one-half of the cases that occurred during the World War, and unfortunately include only a small percentage of such cases, for the historical records of the various camps of mobilization indicate that a very considerable number of men had smallpox on arrival at camp. Thus at Jefferson Barracks there were 4; Camp Pike, 14; Columbus Barracks, 5; Camp Funston, 9; Camp Dodge, 14; Camp Lee, 31; Camp Taylor, 13; Camp Sherman, 2; Camp Travis, 3; Fort Thomas, 15; Camp Upton, 2.

Since the incubation period of smallpox is usually 14 days, and 153, or 36 per cent, of the above group of 422 cases came down with smallpox within 14 days of their arrival at mobilization camps, it may be stated very definitely that somewhat more than one-third of the individuals of the group contracted the disease prior to their entry into the service. Only six individuals (1 per cent of the total in this group) with more than one year of service contracted smallpox. More adequate protection, as a result of revaccinations, accounts for the freedom from smallpox of the group of individuals with service in excess of one year. Three per cent of the cases occurred in Medical Department personnel nursing cases of smallpox.

PREVENTIVE MEASURES

VACCINATION

Needless to say, the principal, and for practical purposes the only, measure on which the United States Army has relied for the prevention of smallpox is vaccination.

For many years prior to the World War a considerable number of manufacturers of biological products were engaged in the manufacture of vaccine virus, the methods of manufacture being regulated by and under the supervision of the United States Public Health Service. The United States Army has never produced its vaccine virus, but has obtained all such products from firms accredited by the United States Public Health Service.

The following regulations governed the administration of vaccine virus to military personnel during the World War:25

34. Smallpox.-Any case of smallpox occurring among persons subject to military control will be isolated, and contacts not protected by recent successful vaccination will be revaccinated.

35. Vaccination.-Vaccination being recognized as an effective means of preventing smallpox, all recruits upon enlistment and all soldiers upon reenlistment will be vaccinated. When the first vaccination of a recruit is ineffective, it will be repeated at the end of eight days.

All the personnel of a military command, station, or transport, including civilians connected therewith, will be vaccinated when in the opinion of the medical officers responsible for sanitation it is necessary as a means of protection against smallpox. Civilians refusing to be vaccinated when so directed by proper authority may be excluded from the military reservation or station.

Officers should be vaccinated at least once in a period of seven years. Troops under orders to perform overseas journeys or field service will be inspected by the responsible medical officer with respect to their protection against smallpox, and those who in his opinion require it will be vaccinated.


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Technique.-The skin of the selected site must be clean. Washing with warm water, followed by alcohol, is usually sufficient, the alcohol being permitted to evaporate before proceeding. Scrubbing with soap and water is necessary for a dirty skin, but needless irritation of the skin is to be avoided.

The procedure, described as follows, is preferable to "scarification," which will no longer be used:

Incision is the method of choice, and should be made with the point of a sterile needle, producing a "scratch." A sterile scalpel may be used, but is more likely to cause bleeding. The incision or scratch should preferably not draw blood. There should be at least two incisions, three-quarters of an inch long and one inch apart; after exposure to smallpox four incisions will be made. The virus is then placed upon the abraded surface and gently rubbed in, unnecessary irritation being avoided.

The wound is allowed to dry thoroughly and can be left without dressing, though several layers of gauze may be applied with adhesive plaster. Any dressing that retains heat and moisture is bad. Shields will no longer be issued.

A number of different methods of administering vaccine virus were subjected to trial by individual medical officers during the World War, the purpose being to develop a more satisfactory technique, to increase the percentage of positive reactions, and to reduce complicating pyogenic infections.

Two of the most promising methods subjected to trial and results obtained are summarized below.

De Lanney,26 at Fort Crook, Nebr., reported as follows on a multiple puncture technique used by him in vaccinating 508 soldiers.

I have maintained for a number of years that the American method of vaccination was defective in its technique because of the variety of local results, some of which are very severe. Nor could they all be due to individual susceptibility, because bad arms often occurred in those previously vaccinated; neither could they be blamed to the operator because, no matter how careful he was, bad arms were sure to follow. Shields and protectors were often to blame, but bad arms would occur where nothing in the way of protection had been used. What, then, was the cause of those large, sloughing, painful sores with their necrotic cores and sharply defined edges, which later filled up with redundant granulation and still later became glazed over instead of covered with normal epithelium?

During a smallpox epidemic, I had, as city physician to an industrial city, to have about 4,000 laborers vaccinated. The best virus procurable was used and the strictest precaution was practiced, but, in spite of all, a large number of very sore arms developed, with resultant suffering and loss of time to laboring men who could least afford it.

It was noticed that a large number of men of foreign birth had well-formed scars on their arms, and it was learned from them that they nearly all had been vaccinated from scabs removed from another person's arm, as is still the practice in some communities. It was also noticed that when "scab vaccination" had been used, a larger number of places on the arms had been vaccinated, often as many as five or six to each arm. The question then came up: Does not the number of vaccination incisions play an important part in determining the severity of the local reaction? Following these observations, I then proceeded to experiment with multiple vaccination, but the epidemic having been controlled and nearly every one being vaccinated, no large number of unvaccinated could be gotten together for vaccination, observation, and tabulation of results; but from the few that we were able to observe it seemed that the reaction was very much less severe, and that fewer sore arms resulted from the multiple vaccination than in the single ones.

During the mobilization of the National Guard in 1916, I tried again to confirm what had then become a conviction, but the hurry, incident to rapid mobilization, did not permit of statistical report.

In the February 10, 1917, British Medical Journal, Capt. H. W. Hill, D. P. H., described a method of vaccination by the subdermal method, and an opportunity to try it out came when 520 truck company personnel came to Fort Crook, to be equipped and prepared for


375

oversea service. I then had an opportunity to try out the speed with which this method could be used, an essential point when a large number has to be vaccinated, also the percentage of primary and secondary "takes" and the results, both local and systemic. These results are tabulated below, and justified statistically our previous conviction, that multiple affords far less local reaction than single vaccination and that the diffusion of the area of inflammatory reaction prevents local death of tissue.


Number of men vaccinated

Not previously vaccinated

Previously vaccinated

Number of men vaccinated

Not previously vaccinated

Previously vaccinated

508

116

387

Successful, per cent

85

28

Successful

99

109

Unsuccessful, per cent

15

72

Unsuccessful

17

278

Number of dressings required

1

0

Had smallpox

3

2

 

The time actually consumed in vaccinating each man was about 15 seconds; there was no time lost in waiting for arms to dry, no after treatment, and in no case was any man excused from duty for more than three days. The method was practically that described by Hill, which I here copy:

(1) The sleeve is rolled up. (2) Orderly 1 washes the arm with soap and water. (3) Orderly 2 washes the arm with rectified spirit. (4) Orderly 3 washes the arm with ether. (5) Orderly 4 breaks the capillary tube of glycerinized vaccine, and sets the rubber bulb or other method of expelling contents, handing it to orderly 5. (6) Orderly 5 expels the vaccine at three or four points on the arm in a triangle or square having not less than 2 inches between the points. (7) Orderly 6 sterilizes an ordinary sewing needle, and hands it to the medical officer. (8) Medicial officer punctures the arm through the drops of vaccine; six tiny punctures, drawing no blood, are made through each drop, each set of six occupying a space of not more than one-sixth inch square; the needle is held almost parallel to the surface; not over one one-thousandth of an inch enters the epithelial layer, a peculiar little "snick" being felt as the needle goes in. (9) Orderly 7 wipes the vaccine. (10) The sleeve is pulled down.

The only difference in the technique I used was, that all the needles were mounted on a handle, either a hemostat or pushed into penholders, to facilitate handling. This was found a great help, for when the needle was held in the fingers alone they became very tired and the needle hard to hold.

Of the 508 men vaccinated, not one had a bad arm. There was redness and swelling, differing in degree with each case, but no suppuration or large scabs or large area of necrosis. One case had to be dressed once because of multipustular vaccinia around the points of vaccination. These pustules resembled confluent smallpox, and covered the outer surface of about half the arm, but they soon dried without bad results. In previously vaccinated cases a typical local reaction resembling a von Pirquet reaction appeared at the side of puncture, usually accompanied by itching which subsided in a few hours; this was not an indication that the vaccination was or was not going to "take."

That which is hard to explain is the great variation in the number of successful points of vaccination in different arms; in some cases all four took, in others three, two, or one- this in both primary and secondary cases. It was noticed, however, that the relative number increased in the unvaccinated, while in those with only one "take" it was always a very weak "pock," with very little systemic reaction, as though the individual had a relative high degree of immunity.

The vaccinial "pocks" were typically umbilicated, and dried up in 15 to 20 days in the form of hard black buttons which readily dropped off, leaving a typically vaccinial scar.

*    *    *    *     *    *    *

It would seem from observation of this series that the method described by Hill has many advantages: (1) It protects the arm from external infection, for as soon as the arm is wiped off the punctures are practically sealed; this also obviates the necessity of waiting for the arm to dry or to be dressed. (2) The numerous vaccination points diffuse the area of inflammation over a large surface, thus preventing the formation of a necrotic center, as in the single method, at the same time increasing the percentage of "takes." (3) It is painless and


376

bloodless. (4) It is rapid enough for any requirement. The saving in suffering, time, bandages, and dressing by this method will be appreciated by those who have had an opportunity to compare this with other methods now used, or who have had to spend whole mornings dressing suppurating arms.

The puncture method of vaccination used by De Lanney and described by Hill27 was tested on 500 individuals at the Army Medical School, Washington, D. C., during the fall of 1917, and the medical officers making the test were very favorably impressed with the results obtained.28 The principal advantages were that the vaccination could be more expeditiously done than by the method of linear incision (routine Army method) and the further fact that no dressings or after treatment of any nature were necessary.

The intradermal method of vaccination gave most excellent results as carried out by Wright,29 at Camp Upton, N. Y. He reported on this method, in part, as follows:

Importance of successful vaccination -To-day the importance of the successful vaccination and revaccination of troops is appreciated by the medical officers of all armies. In the 367th Infantry, with which regiment I am serving, the regimental medical officers found large numbers of men on whom repeated revaccinations, and in many cases primary vaccinations, by the prescribed incision method gave negative results. The question immediately arose as to whether or not these men were immune to smallpox. According to their histories, very few of them had ever had smallpox, while arm examinations for vaccination scars showed that the majority of them had been successfully vaccinated in civil life-in most cases from 10 to 15 years previously. Some were found who had never been successfully vaccinated against smallpox and had never been through an attack of the disease. Therefore, it seemed reasonably clear that most of them were not immune, and that those who were immune possessed only partial immunity. At the same time it was evident that their failure to give "takes" was not due to the virus used, because with it we were daily getting a large number of "takes" on other men. Then it occurred to me that intracutaneous injections of vaccine virus might prove to be a more satisfactory method of virus transference than the one that we were using; therefore it was for the purpose of reducing to a minimum the number of unsuccessful vaccinations in the regiment that this work was undertaken.

The method used was as follows: Virus treated with a glycerol-phenol solution was used. The composition of the glycerol-phenol solution was: Phenol (carbolic acid), 1 part; glycerin, 49 parts; and water, 50 parts. The virus was diluted with equal parts of sterile distilled water immediately before using, although in a few of the first cases undiluted virus was used. Dilution of the virus was made solely to avoid waste, because I soon discovered that the diluted virus gave just as good results as the undiluted; and sterile distilled water was used for dilution instead of glycerin because it was feared that further dilution with glycerin might cause too much attenuation of the virus. One-tenth cubic centimeter of the diluted virus was injected intradermally by means of a sterile tuberculin syringe and a relatively fine needle, which was also sterile. I used needles size 26 according to the English standard wire gauge No. 189. The site of injection was the skin area covering the insertion of the deltoid muscle. In some of the cases only one insertions was made, but in most of the cases two injections were made, one being separated from the other by a distance of about 1 inch. Two injections are preferred because of the larger area of vesicle formation that results, thereby affording one a better sense of protection, if not actual protection. Control vaccinations by the incision method, as described above, were made on all men vaccinated by the intradermal method; they were made on the same arm, on the same day, and the same virus was used in the two methods. Control injections of the virus-free glycerol-phenol solution, of exactly the same percentage composition as the fluid medium in which the virus was preserved and as shown above, were made on 60 of the men who volunteered. Two-tenths cubic centimeter of this solution was used for each injection, which was also made intradermally.

Results.-Intradermal vaccinations and controls by the incision method were carried out on a total of 227 men. All of these men during the preceding four months had been


377

unsuccessfully vaccinated by the incision method a number of times, the number varying from two to eight. ''Takes'' were obtained in 160, or 70.48 per cent of the cases by the intradermal method, whereas "takes" were obtained in only 19, or 8.3 per cent of the same cases by the incision method. All of the 19 cases that showed a "take" by the incision method also showed a "take" by the intradermal method. There were 67 cases that failed to show a "take" by the intradermal method; in all but 4 of these cases, however, the vaccination site showed either an "immunity reaction" or "vaccinoid." The "immunity reaction" occurred in most instances. The 208 cases that did not give a "take" by the incision method exhibited "immunity reactions" and "vaccinoids" in but few instances.

In Table 1 the number of unsuccessful vaccinations by the incision method during the past four months is detailed as well as the results obtained by myself with both methods.

TABLE 1.-Unsuccessful vaccinations by incision method, and results with incision and intradermal methods

Number of times unsuccessfully vaccinated in Army


Total number vaccinated

"Takes,"
 intradermal method

"Takes," incision method

Unsuccessful intradermal method

Unsuccessful incision method

1

6

6

0

0

6

2

34

23

2

11

32

3

68

51

8

17

60

4

44

31

3

13

41

5

44

29

3

15

41

6

17

12

1

5

16

7

12

7

1

5

11

8

2

1

1

1

1

     


     Total

227

160

19

67

208

Table 2 shows the results obtained in the case of men who had never been successfully vaccinated in their lives, as compared with the results obtained on men who had been successfully vaccinated at some time prior to their entry into the military service.

TABLE 2.-Results according to success of previous vaccinations

 

Total


Intradermal "takes"

Incision "takes"

Intradermal unsuccessful

Incision unsuccessful

Men never successfully vaccinated before

50

44

9

8

43

Men successfully vaccinated before

175

116

10

59

165

Of the 8 men who had never been successfully vaccinated, and whose results by the intradermal method were unsuccessful, it was found by inquiry into their histories that 7 had had smallpox, 3 of them having had it five years before, 1 one year before, 1 four years before, 1 eight years before, and 1 eighteen years before. Of the 59 unsuccessful cases by the incision method in this same group, a history of smallpox was obtained in only seven instances.

The course of the eruption as it occurs in primary vaccination by the intradermal method is similar in every way to the course as it occurs by all other methods except for the arrangement of the vesicles, which form a circle around the site of virus deposition. The vesicles appear, as a rule, on the sixth day and become pustules on the seventh or eighth day. The vesicles are multicolor. The center of the circle of vesicles is depressed and shows early scab formation. On the eighth or ninth day the circle reaches its maximum diameter, at which time it measures from 0.5 to 1.4 centimeters. After the ninth or tenth day the vesicles begin to dry up, and at the end of from 12 to 14 days the vaccinated area is marked by a dark brown scab that is sharply circular in outline. This scab falls off in from 18 to 24 days and leaves a sharply circumscribed reddish, circular depressed scar, which may or may not show foveation.


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In revaccination "takes" by the intradermal method the vesicles become pustules on the sixth or seventh day, and the size of the circle of vesicles is smaller-their maximum diameters measuring from 0.4 to 0.9 centimeter-than the size circles obtained in the primary vaccination cases.

One circle of vesicles surrounds each site of virus injection.

It is seen that the circular arrangement of the vesicles around the site of virus injection is a constant and characteristic feature of the method, and is the only difference to be noted. The virus produced evidence of its activity by vesicle formation only at points where the skin layers were but slightly separated, which explains the circular arrangement of the vesicles; the actual site of virus deposition is marked by the dark depressed central scab, which is due to the local necrosis produced by the mechanical and chemical injury to the skin at that point.

In none of these cases did any infection occur, and the local reactions in the severest cases were relatively mild as compared with the severe reactions that so often follow vaccination by the incision method.

In the cases of primary vaccination with no history of smallpox, the circle of vesicles was the same size in practically all of the cases, measuring approximately 1 centimeter in diameter. In the cases with a history of smallpox, and also in the revaccination cases, the size of the circle or area of vesiculation varied in a most remarkable way according to the time that had elapsed since the attack of smallpox or the previous vaccination; the more recent the smallpox attack or revaccination, the smaller the circle of vesicles-a result that is not at all surprising because in all of these cases exactly the same amount of virus was introduced, and it seems only reasonable that the size of the area of vesiculation should vary in direct proportion to the immunity against smallpox that the person vaccinated possesses.

With this method it is possible to deposit a definite amount of virus of known strength in each instance; and after having observed that a definite relationship exists between the size of the reaction area and the immunity to smallpox the injected person possesses as shown by his history, I am convinced that intradermal injections of vaccine virus will prove to be a most satisfactory and reliable method for the estimation of the relative immunity of individuals to smallpox, if a sufficient number of observations are made.

The arms of the 60 men on whom control injections of 0.2 cubic centimeter of the glycerol-phenol solution were made showed at the end of 24 hours a small area of erythema, measuring about 2 millimeters in diameter; while at the end of 48 hours all traces had disappeared. It is apparently clear, therefore, that the results obtained were due not to the irritant action of the glycerol-phenol solution on the skin, but rather to the activity of the virus itself, and also that pressure necrosis is not to be considered a factor in their production.

The amount of time required for vaccinating a large number of men by this method is slightly less than the amount required for vaccinating the same number by the incision.

The only disadvantage of the method is the relatively large amount of virus used in comparison with other methods. With 1 cubic centimeter of virus it is possible to vaccinate from 16 to 20 persons, while by most other methods 1 cubic centimeter is a sufficient amount of virus for 40 or 50 vaccinations.

It is evident that Wright attributed a large proportion of failures, or unsuccessful vaccinations, to the routine technique used throughout the Army. There is, however, ample justification for the statement that in so far as the Army as a whole was concerned many of the failures were attributable to other factors, the most important of which doubtless was nonpotent, or weakly potent, virus. The virus routinely used in the Army was a "ripe" glycerinated virus, and whereas such virus will retain its potency for a considerable length of time if kept in cold storage at low temperatures, it loses it more or less rapidly when exposed to the high atmospheric temperatures that prevail in this country during the summer months. Producers of vaccine virus will not guarantee the potency of their glycerinated products if exposed for any length of time to atmospheric temperatures during the hot summer months. The methods of


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handling and storing vaccine virus at mobilization camps during the World War were not always ideal; there is no doubt, therefore, that much of the vaccine virus was nonpotent, or only slightly potent, at the time it was actually used. This factor accounts to a considerable extent for the failures obtained.

That the linear incision technique of itself fails to account for a considerable proportion of unsuccessful vaccinations was clearly shown during the course of a small outbreak of smallpox at Dijon, France, in January and February, 1919, referred to above. The technique followed in revaccination was the linear incision method described on page 374. Notwithstanding the fact that all personnel presumably had been protected by vaccination or revaccination prior to departure from the United States, a large percentage of the personnel revaccinated gave positive reactions (vaccinia or vaccinoid). A few hours after revaccination a considerable number of the vaccinated individuals noted a mild inflammatory reaction apparently due to a staphylococcus infection. This subsided and the virus reaction appeared on the fourth to sixth day. Bacteriological examination of the vaccine showed numerous staphylococci, and a laboratory specialist was sent to Paris to inspect the institute from which the vaccine was being obtained. The following pertinent information is abstracted from the report of the inspecting officer:30

The smallpox vaccine purchased in France for use by the American Army is prepared at the Institute de Vaccine Animale, 8 Rue Ballu, Paris. * * *

The Institute de Vaccine Animale is over 50 years old and vaccinia virus is its sole product. This institute is at present the only one of its kind in Paris, though there are several other laboratories for the production of the virus in France.

The institute was strikingly clean in all particulars. On the ground floor, in addition to offices and reception room, there is an open court for receiving animals and supplies. This court was in excellent condition. Off to one side from the court was the stable with eight cows. The stables are well lighted by natural and artificial light. The construction was such as to permit complete and thorough flushing of the walls and floor. The animals were clean. They had been inoculated and only the belly of each was used. The inoculated areas of the animals were excellently protected from dust and dirt.

Only animals free from tuberculosis, as proved by rigid tuberculin tests, are brought to the institute. They are also quarantined to assure the absence of other diseases. After collection of the virus, the animals are kept for some days to insure the absence of any other disease, then killed and a careful post-mortem examination made.

The second floor of the institute is the laboratory proper, and here grinding of the pulp is done. The apparatus for this purpose is such as to exclude air during the process. A 50 per cent glycerin is used with such an amount of pulp as to give a final dilution of about 40 per cent glycerin in the virus ready for use. Great reliance is placed on the germicidal properties of glycerin, as proved by tests. As a routine, no bacteriological examinations are made, for the absence of dangerous organisms is accepted, as shown by numerous tests in the past.

The vaccine is ready for use after the following tests: First, the autopsy; second, the test on rabbits for virulence, by inoculation of the entire shaven backs with a dilution of 1 to 1,000 dilution of the virus. This inoculation must give a confluent cowpox; third, tests on the uninoculated human must give 100 per cent of "takes." No attempt is made to rid the vaccine of all but spore-bearing bacteria. It is accepted that bacteria are present in large quantities in the pustules of cowpox, and the director insists that an attempt to ripen the vaccine to such a point would render the vaccine virus itself relatively inactive, and to such a degree as to make the vaccine of little value.

The vaccine, therefore, is not a "ripe virus." On the other hand, inasmuch as glycerin is used, it is not a green virus. It may be described as partially ripened by the addition of glycerin.


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The director of the institute lays great stress on the actual results, on the complete absence of accidents in the vaccination of millions of French soldiers and civilians, on the fact that 40 per cent of vaccinations in the French Army during the great war resulted in "takes," and, finally, on the fact that only 10 cases of smallpox occurred during the same period and these of a mild type.

The following figures on the vaccination of 108 individuals at the central Medical Department laboratory are recorded: The figures are small, but these individuals had all been vaccinated within the past two years and none with positive results. Out of these 108 vaccinations, 18.5 per cent gave a normal positive "take" (vaccinia); 26 per cent additional gave a modified positive "take" (vaccinoid).

Vaccination against smallpox as practiced in the United States Army during the World War was highly successful as a preventive measure, as has been pointed out in preceding pages.

We should not be content, however, with the extraordinarily good results obtained but should strive rather to eliminate the disease altogether. In so far as the military service is concerned an approach to this ideal is contingent primarily on two factors: The development of a vaccine virus that will retain its potency for a considerable length of time after exposure to continuously high atmospheric temperature, and perfection of a vaccination technique that will assure a higher percentage of positive results.

DISCHARGES FOR DISABILITY RESULTING FROM VACCINATION

The basic tables in the statistical volume of this history (Vol. XV, Part II, Table 50, p. 166) indicate that four men were discharged as a result of vaccination against smallpox. The clinical records of these cases have been reviewed and the following pertinent information is made of record to prevent misrepresentation. Of the four individuals presumably discharged on account of disability resulting from vaccination, one was discharged in Europe and three in the United States. One of the four cases was complicated by erysipelas, the end result of which was a peripheral nerve paralysis, and it was for the latter condition that discharge was effected. Two other cases tabulated as being discharged as a result of vaccination were actually discharged for defects that had existed prior to their enlistment and their vaccination had no bearing. The reason for the discharge of the fourth and last case was not made a matter of record.

GENERAL MEASURES

No special hospitals were provided for the care of smallpox cases. These cases were segregated in special wards or separate rooms in the sections of hospitals allotted for the care of acute infectious diseases. Medical personnel (attendants and nurses) caring for such cases were vaccinated at frequent intervals.

On the occurrence of a case of smallpox in a command, regulations provided for immediate vaccination of the command or such parts of it as might be considered necessary by the medical authorities. Revaccination of large groups and the establishment of a so-called working quarantine (confinement to the limits of the area occupied by the group for a period of 14 days) occasionally were practiced when secondary cases arose.


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Usually, however, the command had been vaccinated recently, and the cases were of sporadic occurrence without secondary infection. Under such conditions no attention was paid to the matter except revaccination of contacts who recently had not been vaccinated successfully.

Individuals with smallpox were held in isolation until scaling was complete. The average duration of hospitalization of cases of smallpox during the World War was 29 days.

ETIOLOGY

No contributions were made to the elucidation of the etiology of smallpox by Army medical investigators during the World War.

SYMPTOMS

In general, the cases occurring in the United States were mild, in Siberia the infections were usually severe (hemorrhagic and confluent types), and in the Philippines and in France the disease was more severe than in the United States, but not so severe as in Siberia. Of 236 cases concerning which clinical histories are available for study, 166 (70 per cent) were admitted to hospital after the eruption was established. In a few instances patients with headache and fever remained in barracks for several days before smallpox was suspected. Headache was recorded in practically all cases. In 19 instances the records show that at no time did the patient feel ill. Backache was recorded in 42 per cent, and pains in the bones and joints in 33 per cent. Chills were noted in 32 per cent, nausea and vomiting in 21 per cent, and vertigo in 8 per cent. Abdominal pains were complained of in 22 cases (7 per cent), and in 2 of these the pain was located in the right inguinal region, was accompanied by rigidity of the abdominal muscles, and simulated appendicitis. Chest pains occurred in 3 per cent, and bronchitis frequently was noted. Three cases presented marked nervous symptoms, positive Kernig's sign and Babinski's reflex, stiffness of the neck muscles, diplopia, and convulsions. These cases so strongly simulated meningitis that lumbar puncture was performed. Pharyngitis was present in 91 cases (27 per cent).

In but two cases was a prodromal rash noted. This was a morbilliform eruption simulating measles. Distribution of the smallpox rash was that usually seen; i. e., more commonly on exposed surfaces of the body, especially the forehead, palms of the hands, and soles of the feet. The usual induration or "shotty" feel to the papules was recorded in nearly all cases. Scarring was noted in but one case, which occurred in Siberia.

Elevation of temperature was not of constant occurrence. A review of 139 clinical histories shows the temperature during the first week in hospital to have been afebrile in 50 cases (36 per cent); it ranged between 99° F. and 100° F. in 28 (20 per cent), and exceeded 100° F. in 61 cases (44 per cent).

In 87 cases, in which the eruption was more or less fully developed on admission to the hospital, 6 cases were in the macular; 4, maculopapular; 28, papular; 15, papulovesicular; 10, vesicular; 15, vesiculopustular; 22, pustular stage. It will be seen from the above statements that patients were admitted to hospital during all stages of the disease except incrustation. This apparent delay in sending cases to hospital was due principally to the fact that


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many arrived in camp in the eruptive stage. This was not confined to camps in any one locality, but was common throughout the United States.

Secondary rise of temperature was practically always absent. Itching frequently was noted and often manifested itself early in the course of the disease. Albumin and casts in the urine were of frequent occurrence but evidently cleared up, as a diagnosis of nephritis was but rarely made.

The following extracts from clinical histories serve to illustrate some of the more important phases of the disease.31

A. H. R. (white), Pvt., Company 1, V. T. S., Camp Lee, Va. Length of service, three months. Vaccinated three times unsuccessfully in July and August, 1918. November 1, 1918, without prodromal symptoms, the eruption appeared on the forehead. Lesions so few in number that it was not until they became scattered all over the body, on November 5, that the patient was sent to hospital. Even then he did not feel ill. Temperature and pulse were normal during the evolution and decline of the eruption. Diagnosis: Smallpox. On November 25, headache, backache, slight cough, and elevation of temperature were noted. Following these prodromes an eruption appeared which was diagnosed as chicken pox. Neither disease was severe and the patient was returned to duty after 41 days in hospital.

G. K. (white), Pvt., B. H., Camp Dodge, Iowa. Length of service, three months. Successfully vaccinated February 28, 1918. On duty in isolation ward with smallpox cases. March 18, 1918, with prodromes, an eruption appeared on face, body, and extremities, thickest on forehead. When entered on sick report two days later (March 20) the eruption was described as "a number of small pustules on indurated bases." Temperature 104.4° F., but returned to normal on March 22, and 19 days after admission, desiccation being complete, the patient was discharged from the hospital to resume his duties as attendant in the smallpox ward.

A. L. H. (white), recruit unassigned, 163 D. B., Camp Dodge, Iowa. Length of service, one day. Never vaccinated. Several days before coming to camp the patient noticed an eruption on the forehead. He did not feel sick at the time. Smallpox was present in his home town. He was admitted to hospital on the day of his arrival in camp, May 28, 1918, because of a pustular eruption all over his body. He did not feel sick. On June 3 the pustules were dry and scaling had commenced. By June 8 scaling was complete, and the patient returned to duty on the 10th without any elevation of temperature during his stay in hospital.

C. R. (colored), recruit unassigned, Camp Lee, Va. Length of service, one day. No record of previous vaccination. There was one case of smallpox in his home town at the time of his departure. He was taken sick April 10, 1918, while at home, with a severe headache and backache. There was a history of some fever, in bed four days, sore throat, and a few "bumps" on his face, April 15. He arrived at camp April 17, and was admitted to hospital with normal temperature and a discrete, shotlike, pustular eruption over the face, chest, abdomen, back, arms, and legs. There were a few pustules in the palms of hand and on the soles of feet; also slight umbilication. The eruption was diagnosed as smallpox, and the patient was discharged from hospital after 25 days.

The case histories summarized above are typical of many cases occuring in the United States. One relates to a patient repeatedly vaccinated, with negative results; another to a patient recently successfully vaccinated; the third to a patient who had never been vaccinated; and the fourth to a patient concerning whom there was no record of vaccination status. The first case shows both smallpox and chicken-pox, the disease which is most commonly confused with mild smallpox. In the second case, the question might arise as to whether the case was one of a generalized vaccinia. The belief held by many observers is that generalized vaccinia is a rare disease. The fact that many cases came into camp with active lesions of smallpox and others gave a


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history of contact while at home and arrived in camp within the incubation period, throws the weight of evidence in favor of a diagnosis of mild smallpox rather than vaccinia. This was the consensus of opinion among medical officers stationed in the larger hospitals. The mild character of the disease is evidenced by the fact that 22 per cent of the cases were diagnosed varioloid.

DIAGNOSIS

The diagnosis of smallpox is neither simple nor certain prior to the appearance of the eruption. Even then it may offer considerable difficulty if the number of lesions is small. In mild cases, occurring sporadically, the difficulty is increased. This was the experience of the Army during the World War. With universal vaccination in effect, the cases generally were mild, as is shown by the very low case-fatality rate. In but few instances, for example, at Dijon, was it possible to trace the source of infection to persons in the military service, and it but seldom was feasible personally to verify histories of exposure to civilian contacts. The general symptom-complex of a more or less sudden onset, generalized pains, headache, backache, chills, fever, nausea, and vomiting, is not peculiar to smallpox. Most of the eruptive diseases, as well as influenza, present such signs and symptoms in varying degrees of intensity. It was a matter of differential diagnosis and each stage, from the prodromal to the well-marked pustular or scab stage, offered new difficulties. During the prodromal stage the following symptoms were most common, and in the order named: Headache, backache, pains in bones and joints, fever, chills, nausea and vomiting, vertigo, and chest pains. This syndrome necessitated consideration of a diagnosis of influenza, meningitis, and the pneumonias. The differential diagnosis between smallpox and influenza was difficult and sometimes impossible until appearance of the eruption. If no eruption was present by the fourth day, a diagnosis of influenza was considered safe. There were 30 cases in which a tentative diagnosis of influenza was later changed to smallpox. In several instances the resemblance to meningitis led to lumbar puncture. Pneumonia and bronchitis were not uncommon complications, especially among severe cases; pneumonia was reported in five of the more severe cases. These cases were admitted to hospital as pneumonia and the diagnosis of smallpox subsequently was made. In such instances there is a question whether the pneumonia was a complication or whether smallpox was merely a concurrent disease. The clinical records of World War cases do not indicate that typhus or the typhoid fevers caused any particular concern in differentiation from smallpox, though several cases were under observation for typhoid fever over a period of several days before the final diagnosis of smallpox was made.

Since the prodromal rash may be either morbilliform or scarlatinaform, measles, German measles, and scarlet fever were of necessity given consideration. There were 6 admissions to hospital with an original diagnosis of measles, 1 of German measles, and 5 of scarlet fever in which the diagnosis was changed to smallpox after further observation.

Measles was of very common occurrence, and it is not surprising that some confusion was encountered in differentiating it from smallpox. There were 5 cases of smallpox in which measles was diagnosed as a concurrent disease and 6


384

of measles where an additional diagnosis of smallpox was made. There were 8 cases, with 1 death, in which scarlet fever was a concurrent disease. The case in which death resulted was one of hemorrhagic smallpox contracted in Siberia. It ended fatally after eight days in hospital.

The angina commonly seen in smallpox occasionally led to the consideration of diphtheria. As a concurrent disease, diphtheria was recorded in one case, and, in addition, the clinical records not uncommonly showed the results of repeated cultural and bacteriological examinations for the Klebs-Loeffler baccilus. Drug rash occasionally presented difficulty in diagnosis. This was especially true for iodide and copaiba rashes. The former drug is in common use in the Army and the records show one case sent to hospital as "drug rash" (iodide) in which the final diagnosis was smallpox.

During the vesicular and pustular stages differential diagnosis ordinarily offers no great difficulty to persons conversant with smallpox when the rash is typical. But few medical officers in the Army were clinically conversant with smallpox in atypical form as noted during the World War and there was difficulty in diagnosis.

The clinical records show that cases of smallpox in the United States usually were afebrile unless accompanied by some condition other than smallpox that could account for the elevation of temperature. During the vesicular and pustular stages, syphilis and chicken-pox caused the greatest concern in differential diagnosis. The former was common in the Army. Where discrete lesions occurred, irrespective of type, especially when of recent onset and accompanied by fever, there was a tendency to make a presumptive diagnosis of syphilis. The clinical records indicate that not infrequently consultants from the venereal services were called in before a final diagnosis of smallpox was made. The Wassermann test, consultation, study of vaccination status, general signs and symptoms, especially of the skin and mouth, with observation, were the methods used in arriving at a diagnosis. Even after the use of all available methods in large base hospitals, several cases were sent to duty and recorded as smallpox in which doubt is expressed in the records as to the true diagnosis.

It was with chicken-pox, especially, that difficulty was encountered in differential diagnosis. An analysis of 100 clinical records of smallpox cases shows that 47 per cent were admitted to hospital during the vesicular or pustular stage, and that 9 per cent were thought to be chicken-pox. There were two cases of chicken-pox in which smallpox was diagnosed as a concurrent disease and three cases of smallpox in which chicken-pox was recorded as an additional disease. One case was discharged from hospital after 23 days in isolation, during which time both diagnoses had been considered and no decision was reached as to what the real diagnosis was.

COMPLICATIONS AND SEQUELÆ

The complications and sequelæ of smallpox are usually due to secondary pyogenic infection, and are dependent on the severity of the skin lesions. As the type of disease occurring in military personnel was mild, except in Siberia and in the Philippines, it is not surprising that the complications and sequelæ were also mild in character.


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Among the diseases recorded as secondary or concurrent diseases were: Erysipelas, carbuncle, furunculosis, abscesses, and impetigo. There were four cases of erysipelas and two of impetigo. One case with multiple abscesses and one with impetigo ended fatally. Eye and ear complications were uncommon.

The most important complications were those of the respiratory tract, which included 12 cases of bronchitis with recovery, 2 of bronchopneumonia with 1 death, and 4 of lobar pneumonia with 1 death.

Of the 780 primary admissions in the United States, only 1 ended fatally, and that case was complicated with scarlet fever.

Among the total primary admissions, 126 complications and associated diseases were recorded, with 8 deaths. The remaining deaths, 6 in number, show no other diagnosis than smallpox or toxemia. There were no cases of tetanus following vaccination or associated with smallpox.

REFERENCES

(1) Spalding, Heman: Smallpox (Variola) and its Prevention. The Chicago Medical Recorder, Chicago, 1917, xxxix, No. 11, 490.

(2) Macaulay, History of England, Vol. IV, 53.

(3) Rosenau, M. J.: Preventive Medicine and Hygiene. D. Appleton & Co., New York and London, 1927, fifth edition, 28.

(4) Annual report of the Surgeon General, U. S. Army, 1899, 250.

(5) Handbuch der Ärztlichen Erfahrungen im Weltkriege, Band iii, Innere Medizin, Leipzig, Johann Ambrosius Barth, 1921, 265.

(6) Osler, Sir William: The Principles and Practice of Medicine. D. Appleton & Co., New York and London, 1914, eighth edition, 315.

(7) Medical and Surgical History of the War of the Rebellion, Part third, Volume I, Medical History, Washington, Government Printing Office, 1888, 625.

(8) Annual Report of the Surgeon General, U. S. Army, 1899, 207.

(9) Heiser, V. C., and Leach, C. N.: Vaccination in the Philippines Still Effective. Journal of the American Medical Association, Chicago, 1922, lxxix, No. 1, 40.

(10) Philippine Islands, Health Service Annual Reports, 1918, 1919.

(11) History of Medical Department activities, Camp Bowie, Tex., prepared under the direction of the camp surgeon. On file, Historical Division, S. G. O.

(12) History of Medical Department activities, Camp Devens, Mass., prepared under the direction of the camp surgeon. On file, Historical Division, S. G. O.

(13) History of Medical Department activities, Camp Dodge, Iowa, prepared under the direction of the camp surgeon. On file, Historical Division, S. G. O.

(14) History of Medical Department activities, Camp Funston, Kans., prepared under the direction of the camp surgeon. On file, Historical Division, S. G. O.

(15) History of Medical Department activities, Camp Pike, Ark., prepared under the direction of the camp surgeon. On file, Historical Division, S. G. O.

(16) History of Medical Department activities, Camp Taylor, Ky., prepared under the direction of the camp surgeon. On file, Historical Division, S. G. O.

(17) Leake, J. P., and Force, J. N.: The Essentials of Smallpox Vaccination. Smallpox in Twenty States, 1915-1920. Weekly Public Health Reports, U. S. Public Health Service, Government Printing Office, Washington, August 19, 1921, xxxvi, Part 2, No. 33, 1975, 1979.

(18) Public Health Reports, U. S. Public Health Service, Government Printing Office (The Notifiable Diseases, Prevalence in States in 1917, 1918, 1919). Reprints Nos. 505, February, 1919, 551, August, 1919, and 643, February, 1921.

(19) Letter from the director of laboratories, A. E. F., to the commanding officer of troops stationed at Dijon, February 5, 1919. Subject: Smallpox. Copy on file, A. G. O., World War Division, chief surgeon's files, 710-Smallpox.


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(20) Dopter, M.: Les Maladies Infectieuses pendant la Guerre. Librarie Félix Alcan, Paris, 1921, 163.

(21) History of the Great War, Based on Official Documents, Medical Services, Hygiene of the War. His Majesty's Stationery Office, London, 1923, Vol. II, 438.

(22) Health Statistics for the Belgian Army. On file, Historical Division, S. G. O.

(23) Health Statistics of the Italian Army. On file, Historical Division, S. G. O.

(24) Morawetz, G.: Die Blattern wahrend des Krieges 1914-1918 in Oesterreich. On file, Historical Division, S. G. O.

(25) Special Regulations No. 28, W. D., August 10, 1917.

(26) Delanney, E. L.: The Army Method of Vaccination. The Military Surgeon, Washington, 1918, xlii, No. 1, 84.

(27) Hill, H. W.: Acupuncture the Best Method of Vaccination Against Smallpox. The Canadian Medical Association Journal, Montreal, vi, March, 1916, n. s., 193.

(28) Letter from the commandant, Army Medical School, to the Surgeon General, U. S. Army, dated December 21, 1917. Subject: Smallpox Vaccination by Puncture. On file, Historical Division, S. G. O.

(29) Wright, Louis T.: Intradermal Vaccination Against Smallpox. The Journal of the American Medical Association, Chicago, 1918, lxxi, No. 8, 654.

(30) Report from Major P. A. Schule, M. C., to the Director of Laboratories, A. E. F. Subject: Preparation of Vaccines and Sera in Paris Laboratories, February 25, 1919. On file, Historical Division, S. G. O.

(31) Case records on file in the Office of the Surgeon General, U. S. Army.