(a) There is more acute respiratory disease among rural than among urban troops. Men from rural districts have not acquired immunity to these diseases in childhood as have the city men. Southern troops come largely from sparsely settled rural districts.

(b) Southern troops appear physically less robust than those from other sections, doubtless due in part to the widespread dissemination among them of such debilitating diseases as hookworm, malaria, and pellagra.

(c) Southern troops are relatively less familiar with the fundamental elements of personal hygiene and sanitation than are those from other sections of the country.

As protective measures against these diseases, the Army has followed the policy of frequent medical inspections of troops, isolation and quarantine of the sick, segregation of contacts, and determination of disease carriers and their isolation. The supreme importance of a natural protective immunity against disease is demonstrated by the failure to curb disease among Southern troops, where immunity did not exist and yet where the several measures of control referred to above were in effect.

The most promising measures for combating respiratory diseasesthe diseases of crowded communities-is in the development of protective vaccines or sera and in the education of the soldier, or, better still, of the man before he becomes a soldier, in the elements of selfcare, personal hygiene, and community sanitation. A vaccine for pneumonia has been prepared and is being used with promising results among volunteers.

The statements made above are an assurance to the public that the control of the group of respiratory diseases, now such a menace to the southern soldier, is by no means hopeless. With our present knowledge, strengthened by this study of our experience during the past year, the solution will, it is hoped, be found in continued study and experiments now going on. A board of medical officers has been appointed by the War Department to make an intensive study of pneumonia and important results are looked for.

Dust as a predisposing factor in the causation of respiratory diseases in certain camps has frequently been reported and has been considered of sufficient importance to justify recommendations for the oiling of roads and camp sites as a preventive measure. It has been the experience of medical officers of the Army that pneumonia has been unduly prevalent when there has been a large amount of dust at a station where troops were congregated. At one dusty camp in this country, two severe dust storms were followed on each occasion by a rapid increase of influenza, a great many cases of which were complicated by streptococcus pneumonia.

Contact infection by droplet transmission is of the greatest importance in the spread of the respiratory diseases, and detailed instructions to medical officers were issued by this division requiring the adoption of the cubicle system in the isolation wards and other wards of hospitals which were used for the treatment of respiratory infections. Cubicles were improvised by means of sheets suspended between the hospital beds, and aseptic methods, including face masks,. were practiced by medical officers, nurses, and other attendants engaged in treating these patients. In barracks wide separation of the heads of the sleepers and free ventilation have been advocated as one measure to prevent droplet infection.

The occurrence of communicable diseases in camps and cantonments leads to an appreciation of the necessity of having in each camp & medical officer who could be free to devote his entire time and energy to the control of these diseases. This was in line with the modern methods of public health organizations in progressive communities and so the position of camp epidemiologist was established. It has been possible to select especially well-trained and well-informed officers for this duty and to assign them to all camps in which communicable diseases were at all frequent. Practically all of the large camps now have such an officer on the medical staff and these epidemiologists have been able to relieve division and camp surgeons of a large amount of important detail work, and to give intensive study to disease problems. Some division commanders and their surgeons have been so impressed with the utility of these specialists that they have developed for their division officers capable of carrying on the work after the departure of the division overseas. The study of epidemics has been further extended to certain States whose chief executives have requested the assignment of medical officers to duty with State boards of health whose special function is to act as liaison officer between the State officials and the camp authorities, keeping the latter informed of the prevalence of communicable diseases in communities from which men are being sent into the Army camps.

A most careful study of the incidence of infectious disease in the large camps has been made by the chief of the section of communicable diseases. This report will be published in full. The following abstract of a report is of much interest:

15. REPORT ON COMMUNICABLE DISEASES IN THE ARMY DURING THE WINTER MONTHS OF 1917 AND 1918.

[Statistics all from weekly telegraphic reports.]

The mobilization of such a large army as has been accomplished during the year is of special interest to the sanitarian and the epidemiologist. During the past 12 months more than a million men have been assembled in our camps, held together for intensive training, and sent over the sea. At present another million is being assembled and will go through a like process of training and join their comrades on the battlefields of France. These men have come from every section of the great country, from every class, without reference to previous social status, educational qualification, or personal habits. They have come from infected and uninfected localities. Immunes, susceptibles, infected have been brought together in the close contact which is a necessity in every military organization. To accomplish this great task without more or less spread of infection is an impossibility. Fortunately advances in general sanitation, in water purification, and in garbage and sewage disposal, in protective measures against typhoid fever by vaccination, have largely eliminated from armies the intestinal diseases. If the morbidity from typhoid fever had been as great in the army during the months covered by this report as it was during the same time in certain civilian populations, there would have been more than 50,000 cases of this disease in the Army; whereas, in fact, there were less than 200 cases all told and less than 10 deaths in a million and a half of men. The unsanitary conditions as seen at Camp Alger and at Jacksonville and Chickamauga in 189 do not exist in this country to-day.

A. DEATHS IN THE ARMY.

It was seen long before the assembly of troops was begun that the acute respiratory diseases would be the greatest factors in morbidity and mortality. With this in view the Surgeon General has insisted that at least 45 square feet of floor space and 500 cubic feet of air space should be allowed each soldier. It has been necessary, however in some camps and during certain portions of the time to fall below these individual limits, and there have been camps in which the floor space per man has been reduced

to two-thirds and even to one-half that mentioned above. Crowding is a military necessity, and by crowding we do not mean altogether the amount of space allowed in sleeping quarters. In fact, crowding during the hours of sleep, undesirable as it is, is less likely to aid in the dissemination of diseases, especially the acute respiratory diseases, than is crowding during the waking hours. During the day time men are coughing, sneezing, expectorating and otherwise discharging bacteria from their respiratory passages, and these are being inhaled by those in close contact with them. By these means the acute respiratory diseases are disseminated. Take, for instance, an assembly hall which accommodates several thousand. If every man in this hall, when all the seats are occupied, sits perfectly upright, the greatest distance possible hetween his nose and that of the man in front or behind him is 26 inches, while the distance between his nose and those of the men on each side of him is not more than 16 inches. With men thus placed and many of them coughing and sneezing it will be easily understood that the air is constantly filled with a spray laden with bacteria. The death rate in the Army should be compared with that for the same age period in civil life. The comparisons should be made on the records for the same season of the year and so far as practicable for the same year. Through the courtesy of the health and vital statistics departments of certain States and cities, it has been possible to make this comparison. The greater number of enlisted men are between 21 and 31 years of age. The period corresponding to this available in civil statistics is the age from 20 to 29 years.

The following points should be borne in mind:

(a) The death rate of the group 20 to 29 years is lower than that of the present draft age 21 to 31.

(b) The death rate in these age groups is greater among males than among females. In fact, the death rate from pneumonía during this age is 40 per cent greater among males than among females.

(e) The Army includes more above than below the draft age.

In all these respects comparison is to the disadvantage of the Army. The following table gives a comparison of the annual death rate in the Army, with that of certain cities for the same period and for the same age group. The figures are based on weekly telegraphic reports.

TABLE NO. 146.-Annual death rate per 1,000 in Army, compared with leading cities, United States (age 20 to 29 years; time, October, November, December, 1917, January, February, March, 1918).

It is a striking fact that the death rates in the different camps show wide variation as is indicated in Table 147.

TABLE NO. 147.-Annual death rates per 1,000 in United States Army within cantonment limits of United States, based on period Sept. 29, 1917, to Mar. 29, 1918.

It will be seen from Table 147 that five National Guard camps (Sheridan, Hancock. Wadsworth, McClellan, and Logan) have shown lower death rates than New York City, St. Louis, New Orleans, Pittsburgh, and Chicago for the age group 20 to 29 years. Two more National Guard camps (Shelby and Kearney) show lower death rates than New Orleans for this age group. Six National Army camps (Custer, Lewis Meade, Grant, Devens, Dix) show lower death rates than any of the above mentioned cities. Two other National Guard camps (Sherman and Upton) are about on a level with New York City, St. Louis, and Chicago, and below Pittsburgh and New Orleans, Three more National Army camps (Dodge, Taylor, and Gordon) are below New Orleans. These facts demonstrate that camp life may be made as safe as that of some of our best health-guarded cities, and indeed may show a lower death rate in the corresponding age group. This is the goal which should be striven for. Of course the death rate among selected soldiers should be lower than among the population at large of the same age groups.

The great differences in death rates in the various camps have furnished a sanitary problem worthy of the most serious and detailed study. The following facts stand out most prominently:

(a) The location of the camp, whether in the South or in the North, the camp site. and the surroundings, have not been predominant factors in the causation of disease. (b) Crowding, lack of clothing, fatigue, improper food, lack of heat or ventilation, and dust in camps have not played the most important rôle in morbidity or mortality. (c) Men from rural communities are more susceptible to the acute respiratory diseases, and especially to pneumonia, than are those from urban life.

(d) On the whole the Southern soldier is much more susceptible to these diseases than his Northern comrade.

Pneumonia is an urban or a crowd disease in both civilian and military life. Our camps are the most crowded cities in our country, and consequently they furnish the highest rates for the respiratory diseases. The man who has lived in a densely populated area is more resistant to these diseases because he has been exposed to the same bacteria before, probably many times, and has acquired more or less immunity, or at least an increased resistance. For a converse reason, the man who has lived in a sparsely settled community is the more susceptible, because he has never before, or has not recently, harbored these bacteria. As previously stated, location of the camps has had nothing to do with the diseases prevalent in them, or at most, but a little to do therewith. There are certain geographical areas in which both good and bad camps are situated. However, when a map is made and the camps are placed not where they actually exist but each camp in the center of the population from which its troops came, then all the healthy camps are in one area. This area is included in lines drawn down the Atlantic coast from Maine to about the northern border of Maryland, to the Mississippi River, then north to the western end of Lake Superior. From this region came the healthiest soldiers in our camps, and they were the healthiest because they had greater resistance to those organisms which caused the acute respiratory diseases. There are possibly other factors involved in this problem. The Southern soldier is more susceptible largely because he has never, or but rarely, been brought in contact with the bacteria causing these diseases, and when contact does occur he displays but little resistance. Measles is much more common in the Southern States than in the northeastern district where we find the most robust soldiers coming from. The farther south one goes the more deadly is pneumonia. It is the more deadly because it is rare, and when introduced it falls upon virgin soil and the organism grows with greater intensity, and acquires marked virulence.

In the Civil War pneumonia was more prevalent and more fatal among Southern than among Northern troops. Among the former this disease annually affected 103 men out of every 1,000, while the corresponding rate for Federal white troops was 34. and the cases reported as acute bronchitis and catarrh numbered 415 per 1,000 among Southern troops as against 192 in the Union ranks. The death rate from pneumonia in certain divisions of the Confederate Army was 20.6 per 1,000, while in divisions of the Union Army, it was 7.8 per 1,000.

Measles prevailed in the Confederate Army, especially in new regiments, so greatly that it interfered with their organization. It so diminished the effectiveness of the troops and became so fatal in some camps that companies, battalions, and even whole regiments had to be disbanded for a time and the men sent home.

B. SPECIFIC CAUSES OF DEATH AMONG THE TROOPS.

As has already been indicated the diseases responsible for the great number of deaths in the Army during the winter of 1917 and 1918 are those generally known as the acute respiratory diseases. They are thus designated because they are trans

mitted from the respiratory organs of one man to the corresponding organs of another. While pneumonia, either primary or secondary to measles, and meningitis have exacted the greatest toll of life, they have not been the most potent factors in incapacitating troops, and in this respect they have been greatly surpassed by measles. The causes for admission to hospital or to quarters are stated in Table 148.

TABLE NO. 148.-Percentage relations of causes for admission to sick report in United States Army, within United States limits, based on period from Sept. 29, 1917, to Mar. 29, 1918 (weekly telegraphic report).

This disease prevailed in epidemic form in all but three camps. These were Hancock, Wadsworth, and Upton, and were occupied almost solely by soldiers from Philadelphia, and New York. Measles appeared within a few weeks after the opening of the camps in September and persisted throughout the greater part of the winter. Camps Pike, Bowie, Wheeler, Sevier, Beauregard, and Jackson suffered most severely with this disease. At Beauregard the annual morbidity rate per 1,000 reached 2,700 during one week. A study of measles according to the nativity of the soldier shows that the United States may be divided into the following groups so far as susceptibility to this disease as displayed among soldiers is concerned. The first group, showing the greatest susceptibility to this disease, includes the following States: Texas, Florida, Alabama, Mississippi, Arkansas, and Tennessee. Although there are no records, Oklahoma probably comes in this group. Group No. 2 includes Louisiana, Georgia, and Kentucky. Group No. 3, includes North and South Carolina, Indiana, Missouri, Iowa, Wisconsin, Nebraska, and Kansas. Group No. 4 includes the rest of the United States.

Measles was present to an excessive degree in the same camps that experienced the most trouble from pneumonia. Southern troops suffered more severely from this disease. The mortality from uncomplicated measles is a minor factor when compared to that from pneumonia, either primary or secondary to measles.

B. PNEUMONIA.

Pneumonia, primary or secondary to measles, has caused more deaths than any other disease. It occurred in epidemic form in many camps, especially in those occupied by southern troops. The highest pneumonia morbidity rates were at Camps Bowie and Wheeler. The highest mortality rate from this disease was at Camp Pike. Clinically, pneumonia has been reported as lobar and broncho. It is not easy in all cases to differentiate these forms. However, accepting the diagnosis numbers as reported, lobar pneumonia was the more prevalent in most camps. In some camps it is reported that the dominant form of pneumonia changed with the arrival of new troops. Most of the camps, not all, report that broncho pneumonia has been more fatal. At Camp Pike the case mortality is reported at 57 per cent in broncho and 35 per cent in lobar. At Camp Cody the cases showed slightly higher rate in the lobar form. It is generally agreed that broncho-pneumonia is more frequently a secondary infection. A more important matter is the prevalence of a pneumonia in which the streptococcus hemolyticus appears as the causative agent. This organism is reported as causing both lobar and broncho pneumonia, and the pneumonia caused by it appears to be more frequently complicated with empyema and more fatal than that due to the pneumococcus.

In order to prevent the spread of pneumonia, as well as other communicable diseases, each patient in hospital has been inclosed in a cubicle formed by hanging sheets on frames between the beds. In addition to this all patients carried to hospitals, and while out of cubicle in hospitals, wear masks consisting of three or four thicknesses of gauze. These measures have undoubtedly been of value and should be continued hereafter. In fact there is no reason why shelter tents should not be used for the formation of cubicles in barracks.