148 NON-PATHOGENIC BACTERIA. 



antly at either the incubator or room temperature. Gelatin 

 is liquefied rapidly. The growth on gelatin or agar is white 

 or creamy, red on potato. It does not sporulate. 



Vibrio berolinensis : This bacterium is found in water, and 

 because of its resemblance to the spirillum of Asiatic cholera 

 is of importance. It is not pathogenic for man, but guinea- 

 pigs succumb rapidly when inoculated with pure cultures. 

 Its morphology is exactly like that of the cholera germ, but 

 in culture the difference between the two is quite apparent. 

 It gives the nitroso-indol or cholera-red reaction very strongly. 



Several other non-pathogenic organisms resembling the 

 cholera germ are found in water, and they will be considered 

 in connection with that organism. 



The non-pathogenic bacteria which bear a resemblance to 

 any of the pathogenic bacteria, so that they may be mistaken 

 for them, will be described together with such organisms, so 

 that their differentiation will be understood more clearly. 



