tion, alcoholism and insanitary surroundings are important predisposing causes. But in addition to all this there must be an exciting cause. A careful study of the seasonal prevalence shows that pneumonia, like tuberculosis, bronchitis and congestion of the lungs is very much influenced by temperature, humidity and prevailing winds. The following chart of the Health Department shows deaths from pneumonia during 1906, arranged by months, compared with the average monthly deaths for the past ten years. This chart shows that the disease is especially prevalent during the colder months of the year, and reaches a minimum in June, July, August and September. It is well known that cold, and especially damp cold, winds are often the cause of catching cold, probably because they abstract bodily heat in proportion to their velocity, and if this takes place to an unusual degree, or with great abruptness, the capillaries of the skin contract, the blood is driven into the internal organs, and congestion results, usually in the weakest spot. As an additional effect of sudden changes in temperature, we have the suppression of the cutaneous function and consequent retention of effete matter in the blood. We can readily appreciate how all this may be aggravated by the habitual presence of alcohol in the blood current, which diminishes oxidation of the waste products, and also by overcrowding, because the effect of deficient air supply is not only to reduce the quantity of carbonic acid by expiration, but also to diminish the normal oxidation of effete matter. In any event, the conditions referred to favor the accumulation of effete matter, render the blood current sufficiently impure to lose its germicidal properties, and thus constitute a suitable fluid for the rapid multiplication of the pneumococcus invader. It is also evident that other depressing influences, such as previous illness, especially an attack of measles or of influenza, vastly increase the vulnerability of the tissues and chances of infection.

This disease is doubtless communicable from sick to well persons, as shown by the occurrence of epidemics in prisons, institutions, etc.; indeed, its infectiveness is no longer a matter of doubt, and calls for prompt disinfection of the sputum and avoidance of close contact, in the manner already described in the care of tuberculous patients.

While precautionary measures for the destruction of the germs are of great importance in stamping out the sources of infection, our aim must also be directed towards the correction of predisposing and exciting causes. This we can do by clothing adapted to climate and seasons, proper housing conditions as regards heating and ventilation, proper food and temperate habits. The disease, unfortunately, is increasing in this country, and the increase is doubtless influenced by the increased

Deaths from Pneumonia during 1906, by months.
Average deaths from Pneumonia, by months, for 10 years.

Reproduced from Report of the Health Officer, District of Columbia, 1907.

MONTHLY DEATHS FROM PNEUMONIA DURING 1906, COMPARED WITH AVERAGE MONTHLY

DEATHS FOR PAST TEN YEARS.

consumption of alcohol.

We have already emphasized the fact that

pneumonia is vastly more fatal among the topers.

We may also lessen the harmful effects of abrupt changes in temperature by systematic hardening of the skin, remembering always that a normal function of the skin depends largely upon cleanliness, and a proper tone of the cutaneous vessels and nerves, secured by bathing.

INFLUENZA. "LA GRIPPE."

Influenza or epidemic catarrh is also an infectious disease, caused by a very small bacillus, discovered by Pfeiffer in 1892. This organism is constantly found in the bronchial and nasal secretions of the affected persons and, as in tuberculosis and diphtheria, is largely disseminated by close contact with the sick. The disease often assumes pandemic proportions, because all ages are susceptible to infection, and no precautions are taken to guard against its contagious nature. As early as 1173 the disease is reported to have appeared in different parts of Germany, Italy and England, and since then over sixty epidemics have been recorded, of which fifteen were very extensive. The disease in the United States was first recognized in New England in 1627, and a number of epidemics, notably those of 1807, 1815, 1824, 1847-48, 1851, 1857-58, 1874-75 have been recorded. The most extensive epidemic occurred in 1892 to 1897, and during the census year 1900 there were no less than 16,645 deaths from the disease in this country. During the past 12 years 808 deaths were reported in the District of Columbia. It is by no means a trivial affection, as it carries off a number of persons, chiefly from pneumonic complications, and wrecks the health of many more by affections of the nervous system, heart, kidneys, eyes and ears. In the prevention of the disease the same general rules which have been urged in tuberculosis and pneumonia are clearly indicated.

TYPHOID FEVER.

Typhoid fever carries off annually over 35,000 victims in the United States. According to the records of the Health Department there were during the ten years ended December 31, 1906, 1,693 deaths from this disease in the city of Washington: 968 white and 725 colored. Based upon an estimated mortality of 10 per cent, it is within reason to assume that there were not less than 16,930 cases during the same period. If we calculate the average cost for care, treatment and loss of work to be $300.00, and the average value of a human life $5,000, we have a total loss in the vital assets of this community of $13,544,000 from one of the so-called preventable diseases.

Typhoid fever is essentially a filth disease, caused by a specific bacillus,

which is constantly found in the intestinal discharges, and almost always in the blood and urine of typhoid fever patients. The invasion of the microbe most likely takes place through the alimentary tract, as evidenced by the location of the disease in the intestines, and the frequent dissemination of the germs through the water and milk supply. The possibility of transmission through the air should not be excluded, for, as in tuberculosis, so in this disease the infectious material may have become dried and pulverized, and with particles of dust may gain access to the food or the mouth, there to be swallowed or inhaled.

The principal source of transmission, however, is through the water supply, infected milk, food and infected hands. In all such instances the virus proceeds primarily from the stools and urine of typhoid patients, and gains access through sewers, or otherwise, to the water supply, or contaminates vegetables and fruit which are eaten raw, through the medium of night soil or washing them with infected water. Milk and food may be contaminated by washing the utensils with infected water or by handling it with unclean or infected fingers. The writer, in his investigation of the typhoid fever situation in 1895, also pointed out how flies may carry the germs on their feet, from typhoid stools and infected sources, to the food and milk supply. There is special danger from infection of the fingers in handling or washing soiled patients, or their clothing, bedding and utensils, as the germs from the soiled parts may cling to the fingers and be conveyed to the mouth during eating, or infect the food and milk of others, in handling it, unless the hands have been thoroughly washed after every unclean act. Moreover, it has been shown within the last ten years that some persons after recovering from typhoid fever may continue to carry the germs, and spread them through the urine and feces, although the persons themselves apparently enjoy good health. From the statistics of Lentz, Klinger and V. Drigalski, Goldberger estimates that about 3 per cent of typhoid fever patients become "chronic bacillus carriers," and thus constitute an important source of infection, chiefly in handling milk and food. Those who are familiar with the average dairy employee or cooks will have no difficulty in surmising how the fingers may become infected by careless toilet habits. Indeed, it is very evident that the Mosaic law of ablution of the hands after every unclean act can not be too strongly urged in the light of our knowledge concerning the transmission of disease germs.

Notwithstanding the different modes of dissemination of the germs it should be remembered that typhoid fever is a typical water-borne disease. The infection of a water supply is either direct or indirect; the former includes all instances where the water is contaminated by