454 PATHOGENIC MICROORGANISMS 



sole incitant of cystitis. Among such cases rare instances have been 

 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 to those of the Friedlander 

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

 pneumonia by Mallory and Wright,' which is strongly pathogenic foi 

 mice, guinea-pigs, and rabbits. 



BACILLI OF THE PROTEUS GROUP 



The bacilli of this group have little pathological interest, but are im- 

 portant because of the frequency with which they are encountered in 

 routine bacteriological work. They may confuse the inexperienced 

 because of a superficial similarity to bacilli of the colon-typhoid group. 

 In form they may be short and plump or long and slender, staining easily 

 with anilin dyes and decolorizing with Gram's method. They are 

 actively motile and possess many flagella. The individuals stain irreg- 

 ularly, often showing unstained areas near the center. The type of the 

 group is found in the so-called Bacillus proteus vulgaris described by 

 Hauser ' in 1885. 



Bacilli of this group are widely distributed, being found in water, 

 soil, air, and wherever putrefaction takes place. In fact, proteus is one 

 of the true putrefactive bacteria possessing the power to cause the cleav- 

 age of proteids into their simplest radicles. 



Bacillus proteus vulgaris grows best at temperatures at or about 

 25° C. and develops upon the simplest media. It is a facultative anae- 

 robe and forms no spores. 



In broth, it produces rapid clouding with a pellicle and the forma- 

 tion cf a mucoid sediment. 



In gelatin, the colonies are characteristically irregular, giving the 

 name to this group. 



Gelatin is rapidly liquefied. Liquefaction, however, is diminished 

 or even inhibited under anaerobic conditions. 



■ Mallory and Wright, Zeit. f. Hyg., xx, 1895. 



2 Hauser, "Ueber Faulniss-Bakt.," Leipzig, 1885. 



