BACTERIUM TYPHI. 237 



Chantemesse and Vidal (A. P., 1892, 755) and Sana- 

 >lli (A. P., 1892, 721) were able, on the contrary, to so 

 icrease the virulence by all sorts of artificial means that 

 ley obtained varieties which are truly pathogenic for 

 dmals. Chantemesse (H. R., 1897, 1103) was even able 



produce sickness in rabbits and monkeys by highly 

 irulent cultures introduced into the stomach, and the 

 limals died with typhoid symptoms (clinical and ana- 

 >mical). Thus the Bact. typhi becomes acclimated to 

 le animal body.. 



special Methods for the Demonstration of the Bact. 

 typhi. 



It is usually easy to cultivate them from the spleen and 

 lymph-glands of a fresh typhoid cadaver ; still, not infre- 

 quently more colonies of the Bact. coli are obtained than 

 typhoid. The case is different when the bacteria are to be 

 sought for in water, feces, etc. The fact that the demon- 

 stration of the Bacterium typhi when in mixtures with 

 other bacteria appears to be very difficult for all investi- 

 gators 1 has led to numerous suggestions to replace the 

 simple gelatin plate method by better ones. A great dis- 

 trust is aroused against all of these suggestions, since every 

 new author criticizes the suggestions of his predecessor and 

 usually discards them. 



The two principal methods which have been employed 

 are : 



1. Preliminary Culture. — The suspicious water is placed 

 in nutrient media which contains an antiseptic, and kept 

 twenty-four to forty-eight hours in the incubator. Water 

 bacteria, especially a number of liquefying varieties, die, 

 while the Bact. typhi and coli, which are more resistant 

 to disinfectant agents, multiply in the incubator. Unfor- 

 tunately, the rapidly growing forms of Bact. coli, besides 

 Bact. vulgare, streptococci, and oidium, multiply more in- 

 tensely than the Bact. typhi, and when plates are prepared 



1 An idea of the difficulty is given by the fact that many authors 

 were not able at all to isolate typhoid bacteria from typhoid stools, 

 and that Nicolle, Grimbert, and Chantemesse declare it to be impos- 

 sible to recover typhoid bacteria from water, containing abundant 

 Bact. coli, to which they had been added. 



