BACILLUS OF TYPHOID FEVER 427 



has applied this method to human beings. Gay * has also prepared a 

 sensitized dead typhoid vaccine which he has already used in a consid- 

 erable number of cases. It will take some time, however, before a 

 statistical estimation of the superiority of this method over the older 

 vaccination with dead bacteria will be possible. 



Attempts have recently been made to treat active typhoid fever by 

 intravenous injections of sensitized vaccines. The cases are as yet too 

 few to permit final judgment. 



BACILLUS PECALIS ALKALIGENES ' 



In 1896 Petruschky 2 described a bacillus which is a not infrequent 

 inhabitant of the human intestine, being found chiefly in the lower 

 part of the small intestine and the large intestine. This organism, 

 which* he called Bacillus fecalis alkaligenes, is of little pathogenic im- 

 portance, although Neufeld states that he has seen a case of severe 

 gastroenteritis in which the watery defecations contained this bacillus 

 in almost pure culture. As a rule, however, this organism can not be 

 regarded as pathogenic, and is important chiefly because of the ease 

 with which it may be mistaken for Bacillus typhosus. 



Bacillus fecalis alkaligenes is an actively motile, Gram-negative 

 bacillus, possessing, like the typhoid bacillus, numerous peritrichal fla- 

 gella. On the ordinary culture media it grows like the typhoid bacillus. 

 It does not coagulate milk. It produces no indol, and on sugar media 

 in fermentation tubes produces no acid or gas. On potato, its growth, 

 while somewhat heavier than that of the typhoid bacillus, is not suf- 

 ficiently so to permit easy differentiation. It differs from Bacillus 

 typhosus in that it produces no acid on any of the sugar media, and is 

 therefore easily differentiated by cultivation upon Hiss-serum-water 

 media or on pepton waters containing sugars. On the Hiss semi- 

 solid tube-medium Bacillus fecalis alkaligenes, while clouding the 

 medium throughout, grows most heavily on the surface where, eventu- 

 ally, it forms a pellicle. 



1 Gay, Arch, of Int. Med., 1914. 



* Petruschky, Cent, f, Bakt., I, xix, 1896, 



