T11K TYPHOID BACILLUS 285 



with the above points, may cause one to suspect paratyphoid. Schott- 

 miiller and Kurth, from a total of 180 cases which had been looked 

 upon as typhoid, were able in 12 cases to isolate a paratyphoid 

 bacillus. 



llfmermaim observed a whole epidemic in which typhoid-like bac- 

 teria, which he regarded as the cause of the disease, were found in 

 the blood. The Gruber-Widal reaction 1 : 100 was positive in only 42 

 per cent.; the newly found bacillus was always agglutinated. Similar 

 reports concerning an epidemic of 14 cases in Holland are made by 

 de Feyfer and Kayser; and Sion and Negel report one from Roumania. 

 Formerly none of these cases would have been differentiated from true 

 typhoid. 



Detection of Typhoid Bacilli in Water. There is absolutely no doubt 

 that the contamination of streams and reservoirs is a frequent cause 

 of the outbreak of epidemics of typhoid fever, but the actual finding 

 and isolation of the bacilli is a very rare occurrence. This is often 

 due to the fact that the contamination has passed away before the 

 bacteriological examination is undertaken, and also to the great 

 difficulties met with in detecting a few typhoid bacilli when they are 

 associated with large numbers of other bacteria. The greater the 

 amount of contamination entering the water, and the shorter the time 

 which elapses between this and the drinking of the water, the greater is 

 the danger. 



Differential Diagnosis. The typhoid bacillus and the bacilli of the 

 colon group resemble each other in many respects. It is necessary to 

 remember that there are many varieties of bacilli differing in both cultural 

 and agglutination reactions which are grouped under the general name 

 of the colon bacillus. By comparing what has been said of the 

 bacillus coli and the bacillus typhosus it will be seen that while certain 

 varieties of each simulate each other in many respects, the character- 

 istic varieties of each still possess individual characteristics by which 

 they may be readily differentiated: 



1. The motility of the B. coli is, as a rule, much less marked than 

 that of the B. typhosus. Tne cobn bacillus is also shorter, thicker, and 

 has fewer flagella. 



2. In gelatin the colonies of the colon bacillus develop more rapidly 

 and luxuriantly than those of the typhoid bacillus. 



3. On potato the growth of the colon bacillus is usually rapid, luxuri- 

 ant, and visible, though not invariably so; while that of the typhoid 

 bacillus is ordinarily invisible. 



4. The characteristic colon bacillus coagulates milk in from thirty- 

 six to forty-eight hours in the incubator, with acid reaction. The 

 typhoid bacillus does not cause coagulation. 



5. The colon bacillus is conspicuous for its power of causing fer- 

 mentation, with the production of gas in media containing glucose. 

 The typhoid bacillus never does this. 



6. In nutrient agar or gelatin containing lactose and litmus tincture, 

 and of a slightly alkaline reaction, the color of the colonies of the colon 



