264 POPULAR SCIENCE MONTHLY. 



of the epidemiology of typhoid fever. The most original and valuable 

 work of the board is the proof that the infection of typhoid fever is 

 spread in camps by the common fly, and by contact with patients and 

 infected articles, clothing, tentage and utensils, as well as by contam- 

 inated drinking water. 



In June, 1900, Major Eeed was sent to Cuba as president of a board 

 to study the infectious diseases of the country, but more especially 

 yellow fever. Associated with him were Acting Assistant Surgeons 

 James Carroll, Jesse W. Lazear and A. Agramonte. At this time the 

 American authorities in Cuba had for a year and a half endeavored to 

 diminish the disease and mortality of the Cuban towns, by general 

 sanitary work, but while the health of the population showed distinct 

 improvement and the mortality had greatly diminished, yellow fever 

 apparently had been entirely unaffected by these measures. In fact, 

 owing to the large number of non-immune foreigners, the disease was 

 more frequent than usual in Havana and in Quemados near the camp 

 of American troops, and many valuable lives of American officers and 

 soldiers had been lost. 



Eeed was convinced from the first that general sanitary measures 

 alone would not check the disease, but that its transmission was prob- 

 ably due to an insect. The fact that malarial fever, caused by an ani- 

 mal parasite in the blood, is transmitted from man to man through 

 the agency of certain mosquitoes had been recently accepted by the 

 scientific world ; also several years before, Dr. Carlos Finlay, of Havana, 

 had advanced the theory that a mosquito conveyed the unknown cause 

 of yellow fever, but did not succeed in demonstrating the truth of his 

 theory. 



Dr. H. E. Carter, of the Marine Hospital Service, had written a 

 paper showing that although the period of incubation of yellow fever 

 was only five days, yet a house to which a patient was carried did not 

 become infected for from fifteen to twenty days. To Eeed's mind this 

 indicated that the unknown infective agent has to undergo a period of 

 incubation of from ten to fifteen days, and probably in the body of a 

 biting insect. * Up to this time the most generally accepted theory as 

 to the causation of yellow fever was that of Sanarelli, who claimed that 

 the Bacillus icteroides discovered by him was the specific agent of the 

 disease. Major Eeed, in association with Dr. Carroll, had, however, 

 already demonstrated that this bacillus was one widely disseminated in 

 the United States, and bore no special relation to yellow fever. 



In June, July and August, 1900, the commission gave their entire 

 attention to the bacteriological study of the blood of yellow fever 

 patients, and the post-mortem examination of the organs of those dying 

 with the disease. In twenty-four cases where the blood was repeatedly 

 examined, as well as in eleven carefully studied autopsies, Bacillus 

 icteroides was not discovered, nor was there any indication of the pres- 

 ence in the blood of a specific cause of the disease. 



