NOT DESCRIBED IN PREVIOUS SECTIONS. 491 



Pathogenesis. In Hauser's experiments filtered cultures (two to six cubic 

 centimetres), injected into the circulation or into the cavity of the abdomen 

 in rabbits, caused fatal toxaemia. 



100. PROTEUS ZENKERI. 



Obtained by Hauser (1885) from putrefying animal substances. 



Morphology. Bacilli which vary greatly in length average about 1. 65 //, 

 and about 0.4 ju broad. 



Biological Characters. An aerobic and facultative anaerobic, non- 

 liquefying, motile bacillus. Spore formation not observed. Grows in the 

 usual culture media at the room temperature. Upon the surface of nutrient 

 gelatin a laminated mass forms about the point of puncture, from the peri- 

 phery of which offshoots are given off, at the extremities of which colonies 

 are formed, as in the case of Proteus mirabilis. Gradually a rather thick, 

 grayish-white, opaque layer is formed, which covers the entire surface of the 

 gelatin and is easily detached from it. This species is distinguished from 

 the two preceding by the fact that it does not liquefy gelatin or blood serum 

 and does not give off a decided putrefactive odor when cultivated in these 

 media. 



Pathogenesis. Considerable quantities injected into small fl.tmna.1a give 

 rise to local abscesses and to symptoms of toxaemia. 



101. PROTEUS SEPTICUS. 



Obtained by Babes (1889) from the mucous membrane of the intestine and 

 the various organs of a boy who died of septicaemia. 



Morphology. Bacilli about 4/z broad and varying greatly in length; 

 slightlv curved rods or flexible filaments, often associated in loose chains. 



Stains by the usual aniline colors and by Gram's method. 



Biological Characters. An aerobic, liquefying, motile bacillus. Spore 

 formation not observed. Grows in the usual culture media at the room 

 temperature. In gelatin plates centres of liquefaction are quickly formed 

 and rapidly extend. The spherical, liquefied places have at first a wavy or 

 dentate outline, and are surrounded by a branching, transparent, granular 

 margin which rapidly extends in advance of the liquefaction. In stick cul- 

 tures in nutrient gelatin liquefaction of the entire con tents of the tube may 

 take place within twenty-four hours, or a broad, liquefied sac is formed 

 along the line of puncture. Gelatin cultures give off a very disagreeable 

 odor. Upon the surface of nutrient agar, at 37 C., a peculiar, thick net- 

 work extends over the surface in the course of a few hours. Upon potato an 

 elevated, brownish-white, shining layer is formed. Blood serum is lique- 

 fied by this bacillus. 



Pathogenesis. Pathogenic for mice, less so for rabbits. In mice death 

 occurs in from one to three days after the subcutaneous injection of a small 

 quantity of a pure culture ; the bacilli are present in the blood in small 

 numbers. 



102. PROTEUS LETHALIS. 



Synonym. Proteus bei Lungengangran des Menschen (Babes). 



Obtained by Babes (1889) from the spleen and gangrenous portions of the 

 lung of a man who died of septicaemia. 



Morphology Short rods with round ends, from 0.8 to 1.5 >u thick ; often 

 swollen in the middle, like a lemon or a flask ; forms short, flexible filaments 

 which also present similar swellings. 



Stains with the usual aniline colors and also by Gram's method. 



Biological Characters. An aerobic and facultative anaerobic, non- 

 fying, motile bacillus. Not observed to form spores. Grows in the 

 usual culture media at the room temperature. In gelatin plates forms hemi- 

 spherical, elevated, whitish, translucent colonies, which later send out 



