BACILLI OF THE COLON-TYPHOID-DYSENTERY GROUP 639 



observed in which it has formed gas in the bladder (pneumaturia). 

 When this occurs the urine is not ammoniacal but remains acid. 



Different strains of this bacillus vary much in their pathogenicity 

 for animals. Wilde claims that it is more pathogenic for white mice and 

 guinea-pigs than is the bacillus of Friedlander. He speaks of it as the 

 most virulent member of this group. Kraus, writing in Fluegge's 

 "Mikroorganismen," rates its pathogenicity less high. 



Closely related to this bacillus, as well as those of the Friedlander 

 group, is an encapsulated bacillus isolated from a case of broncho- 

 pneumonia by Mallory and Wright, 20 which is strongly pathogenic for 

 mice, guinea-pigs, and rabbits. 



B. ACIDI-LACTICI. This organism, like the others, is a Gram- 

 negative, non-liquefying, non-sporulating bacillus. Just like the B. 

 aerogenes, it has no motility. It differs from the Colon bacilli proper 

 in not fermenting dulcite. It differs from the Lactis aerogenes in 

 failing to ferment saccharose. Like the Lactis aerogenes, it is non- 

 motile. It forms indol, reduces nitrate, and coagulates milk. 



It is commonly present in milk and may be present in water. It is 

 often found in the intestinal canal but as far as we know has no patho- 

 genic significance. 



BACILLUS FECALIS ALKALIGENES. In 1896 Petruschky 21 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 in the large 

 intestine. This organism, which he called Bacillus fecalis alkaligenes, 

 is of little pathogenic importance, 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 cannot 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 

 flagella. 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 sufficiently 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- 



20 Mallory and Wright, Zeit. f. Hyg., 20, 1895. 



21 Petruschky, Cent. f. Bakt., I, ixix, 1896. 



