670 Proteus Infection 



younger colonies, which have not yet reached the surface of 

 the gelatin, are more compact, rounded or nodular, later 

 covered with hair-like projections, and becoming radiated 

 like the superficial colonies." 



If the culture medium be concentrated, or the culture 

 has been frequently transplanted, the phenomenon is less 

 marked and may not occur. 



Gelatin Punctures. Puncture cultures in gelatin are not 

 characteristic. A stocking-like liquefaction of the gelatin 

 extends so rapidly that the entire gelatin is liquefied in a few 

 days. Anaerobic cultures do not liquefy. 



Agar-agar. Upon agar-agar the bacillus forms a moist, 

 thin, transparent, rapidly extending layer which rarely 

 reaches the sides of the tube. Upon agar-agar plates ame- 

 boid movement of the colonies may also occur. 



Potato. Upon potato the growth occurs in the form of 

 a smeary patch of soiled appearance. 



Milk. Milk is coagulated. 



Metabolic Products. The bacillus usually produces 

 alkalies. Indol and phenol are formed from the peptone of 

 the culture media. Nitrates are reduced to nitrites, and 

 then partly reduced to ammonia. In most culture media 

 not containing sugar the bacillus produces a very disagree- 

 able odor. 



In culture media containing either grape- or cane-sugar 

 fermentation occurs both in the presence and in the absence 

 of oxygen. Milk-sugar is not decomposed. 



Pathogenesis. It is a question whether or not Bacillus 

 proteus is to be ranked among .the pathogenic bacteria. 

 Small doses are harmless for the laboratory animals ; large 

 doses produce abscesses. A toxic substance resulting from 

 the metabolism of the organism seems to be the cause of 

 death when considerable quantities of a culture are injected 

 into the peritoneal cavity or blood-vessels. The bacilli do 

 not seem able to multiply in the healthy animal body, but 

 can do so when previous disease or injury of its tissues has 

 taken place. 



Bordoni-Uffreduzzi has shown that the proteus quite 

 regularly invades the tissues after death though it ap- 

 pears unable to maintain an independent existence in the 

 tissues during life, and is probably of importance only when 

 present in association with other bacteria. It at times 

 grows abundantly in the urine and may produce primary 



