In 100 cases of enteric fever treated at No. 6 Military General Hospital, Naanw poort, South Africa, the death-rate among the inoculated was 23 per cent. lower than that among the non-inoculated; the average temperature among the in oculated was 0.9 degree lower for the first ten days; but in the inoculated the temperature was fifty-four days longer, on the average, in returning to the nor mal. Parker (Lancet, Aug. 25, 1900).
According to Pettenkofer, the condi tion of the soil has much to do with the causation of the disease. It is more prev alent when the ground-water is low after a dry season, and an outbreak of the dis ease frequently follows a heavy rain storm after a period of drought. The disease may be more readily conveyed in dust during the dry season (Baumgarten).
Typhoid fever sometimes occurs far away from human habitation. One form of what is called is es sentially typhoid in character. The cause of the disease may exist in canned meats and milk, which are the principal food of miners and prospectors. This planation does not seem sufficient, be cause, in some district of the Rocky Mountains, almost every newcomer is liable to take the disease. The bility of the wide distribution of the typhoid germ in the soil and in inferior animals has been given as an explanation for such cases.
Typhoid fever is a very widely dis tributed disease. It is endemic in Eu rope and North America. In America it prevails equally from Hudson Bay to the Gulf of Mexico and from the At lantic to the Pacific.
Individual immunity may be either hereditary or acquired from a previous attack. It is quite probable that the individual when weakened by overwork from unhealthy surroundings or from a previous disease is more liable to an at tack of typhoid. In a large proportion of eases, however, the previous health of patients has been good.
The Bacillus Typhosus.—Pathologists have been for many years of the opinion that typhoid fever was caused by a dis tinct virus. Flint, in the second edition of his work, published in 1S67, wrote as follows: "Assuming these statements to be correct, typhoid fever is one of the diseases the special cause of which may be generated without the body and re produced within the body." The bacillus discovered by Eberth, a short, thick, straight or very slightly curved, rod-like body with rounded ex tremities is now looked upon as the cause of the disease. It is found especially in
the intestinal and mesenteric glands and in the spleen and occasionally in many other parts of the body, as well as in the blood.
After the first ten days these organ isms are found in large numbers in the passages from the bowels. They can be readily differentiated from the b. coli communis, with which they were at first confounded. These organisms are found in all cases of typhoid fever, and they can be cultivated outside the body. For some years all attempts to inoculate ani mals failed. Abbott reported a case in which the disease had been communi cated to rabbits by inoculation. The typhoid bacilli were found in enlarged mesenteric glands and in the spleen. More decided cases of the communica tion of the disease to inferior animals have recently been reported.
If these conclusions are confirmed by further experiments, the three require ments of Koch's law will be amply satis fied and the bacillus of Eberth will be as conclusively proved to be the cause of typhoid fever as Koch's bacillus of tuberculosis.
So far as is known in the great major ity of cases, the port of entry for the bacillus is the alimentary canal.
The most frequent source is the drink ing-water, but it may be taken in milk and other articles of diet. Bacilli may be inhaled in the form of dust into the mouth and pharynx and afterward swal lowed. It is possible that the organism may be inhaled into the lungs and may invade the system in that way. Cases of pneumonic typhoid have recently been reported which demonstrated the possi bility of this mode of invasion.
Many local epidemics have resulted from the pollution of drinking-water, and one especially which occurred in Plym outh, Penna., in 186', demonstrated positively this mode of the introduction of bacilli into the system. Plymouth was supplied from a reservoir into which ran several small streams. During January and February a case of typhoid fever oc curred in a house on the bank of one of the streams. The dejecta were thrown out upon the snow and became frozen. About the end of March, a thaw and rain-fall took place, which carried the impurities into the reservoir. Toward the middle of April typhoid fever ap peared in different parts of the city sup plied with water from the reservoir. Twelve hundred cases occurred in a town with a population of eight thousand.