BACILLUS TYPHOSUS. 441 



In the febrile cases in 17 the presence of typhoid bacilli, 

 often in great numbers, was demonstrated. Thus in 

 these carefully followed cases the statistics show over 

 80 per cent, of the febrile cases positive. The bacilli 

 were isolated from these cases as early as the sixth day, 

 and as late as the thirtieth day, and in a case of relapse 

 on the forty-seventh day of the disease. The conval- 

 escent cases gave uniformly negative results, the earliest 

 examination having been made on the third day after 

 the disappearance of the fever. The bacilli seemed to 

 be more numerous in the stools from about the tenth or 

 twelfth day on. These observations, with regard to the 

 appearance of the bacilli in the stools during the febrile 

 stage and their usually quick disappearance after the 

 defervescence, have been confirmed by others. In 

 several cases in which no Widal reaction was demon- 

 strated the bacilli were isolated. From private sources 

 between the seventh and twenty-first day of the disease, 

 experience thus far obtained seems to indicate that the 

 bacilli may be obtained from about 25 per cent, of all 

 cases on the first examination and from about 75 per 

 cent, after repeated examinations. In some samples of 

 feces typhoid bacilli die out within twenty -four hours; 

 in others they remain alive for days or even weeks. 

 This seems to depend on the bacteria present in the 

 feces and upon its chemical formation. Probably the 

 presence of typhoid bacilli in some stools and their ab- 

 sence in others must be explained largely upon the 

 characteristics of the intestinal contents. The short 

 life of the typhoid bacillus in many specimens of feces 

 suggests that stools be examined as quickly as possible. 

 In fact, unless the physician wishes to take the 

 trouble to have the sample of feces sent immediately 



