284 BACTERIA PATHOGENIC TO MAN 



well as our own indicate that the typhoid bacilli are not apt to be 

 found in the urine until the beginning of the third week of the fever, 

 and may not appear until much later. From this on to convalescence 

 they appear in about 25 per cent, of the cases, usually in pure culture 

 and in enormous numbers. Of 9 positive cases examined by Richard- 

 son 1 2 died and 7 were discharged. At the time of their discharge 

 their urine was loaded with typhoid bacilli. We have observed similar 

 cases. In one the bacilli persisted for five weeks. Undoubtedly in 

 exceptional cases they persist for years. When we think of the chances 

 such cases have to spread infection as they pass from- place to place, 

 we begin to realize how epidemics can start without apparent cause. 

 The more we investigate the persistence of bacteria in convalescent 

 cases of disease, the more difficult the prevention of their dissemina- 

 tion is seen to be. The disinfection of the urine should always be 

 looked after in typhoid fever, and convalescents should not be allowed 

 to go to places where contamination of the water supply is possible r 

 without at least warning them of the necessity of great care in disin- 

 fecting their urine and feces for some weeks. Richardson made the 

 interesting discovery that after washing out the bladder with a very 

 weak solution of bichloride of mercury the typhoid bacilli no longer 

 appeared in the urine. 



Paratyphoid. A few of the cases of " typhoid " heretofore described 

 as giving no Gruber-Widal reaction were undoubtedly due to the para- 

 typhoid bacilli. As has been already stated, this is the name by which 

 we now, in conformity with Schottmuller, designate a bacillrs which 

 stands about midway between B. typhosus and B. coli. It has been 

 found necessary to distinguish two varieties, type A and type B, which 

 differ also in their agglutinating property. It remains to be seen whether 

 we shall have to differentiate any additional types. There are no certain 

 distinguishing features to separate the clinical pictures of abdominal 

 typhoid and paratyphoid. Many cases of paratyphoid present all the 

 classical symptoms of typhoid. According to Conradi, von Drigalski, 

 and Jiirgens the fever curve of paratyphoid is characterized by a fairly 

 sudden rise, an irregular course of the temperature with almost always 

 an absence of the continua. Besides this, the disease has a better 

 prognosis and a slow convalescence. According to other authors, 

 enlargement of the spleen is quite often absent (de Feyfer and Kayser 

 missed it in 42 per cent, of the cases), whereas an involvement of the 

 upper portions of the intestinal tract (gastric fever!) is more common. 

 Further than this, it is unwise to lay much stress on peculiarities in the 

 course of the disease, for we know that true typhoid runs a variable 

 course. We have only to think of the vast difference between a mild 

 or abortive typhoid and a fully developed or, better still, a complicated 

 case. It will almost always be impossible to separate a case of true 

 typhoid from a paratyphoid by the symptoms alone. At the most, 

 during an epidemic the general course of the disease, when it agrees 



1 Journal of Experimental Medicine, May, 1898. 



