NOT DESCRIBED IN PREVIOUS SECTIONS. 513 



a longer or shorter course, from forty -eight hours to eight or ten days, in 

 direct proportion to the amount of the culture introduced. The animals do 

 not seem to suffer any inconvenience, as a rule, and after the abscess is 

 opened suppuration ceases. The organism is found aggregated in small and 

 large, irregular clumps in the pus, many of them lying in the pus corpuscles. 

 It seems to form metastatic abscesses only under exceptional circumstances, 

 such as when injected directly into the blood. Otherwise the abscess remains 

 strictly confined to the seat of inoculation in rabbits, white rats, and gray 

 mice." 



152. BACILLUS VENENOSUS. 



Obtained by Vaughan from water. 



Morphology. Bacilli with rounded ends, two to four times as long as 

 broad. 



Biological Characters. An aerobic and facultative anaerobic, non- 

 liquefying, actively motile bacillus. Spore formation not mentioned. Grows 

 rapidly in the usual culture media at the room temperature also at 38 C. 

 On gelatin plates small, white, spherical colonies sometimes slightly yel- 

 low; the superficial colonies are elevated above the surface of the gelatin. 

 In gelatin tubes an abundant growth occurs along the line of puncture and 

 slowly extends upon the surface. In cultures from the spleen of an inocu- 

 lated animal the growth upon the surface is less marked. On agar a thin, 

 white layer is formed. On potato a light-brown, moist growth. In recent 

 cultures from the spleen of an inoculated animal the growth upon potato 

 may be invisible. Grows abundantly both in Parietti's solution and in Uf- 

 felmann's gelatin. 



Pathogenesis. Pathogenic for rats, mice, guinea-pigs, and rabbits. 



153. BACILLUS VENENOSUS BREVIS. 



Obtained by Vaughan from water. 



Morphology. Short, thick bacilli, about twice as long as broad; in old 

 cultures grows out into threads. 



Biological Characters. An aerobic and facultative anaerobic, non- 

 liquefying, actively motile bacillus. Spore formation not mentioned. 

 Grows rapidly in the usual culture media at the room temperature also at 

 38 C. On gelatin plates forms small, round colonies with concentric rings; 

 the deeper colonies are generally yellowish or brown ; the surface colonies 

 are elevated and spread but little. In gelatin tubes grows along the line of 

 puncture and spreads slowly upon the surface, finally reaching the sides of 

 the tube. Upon agar a thin, white layer is formed. On potato a thick and 

 moist, light-brown growth. When kept for fourteen days or longer at 40 C. 

 there is an invisible growth upon potato. Grows abundantly in Parietti's 

 solution and slowly in Uffelmann's gelatin. 



Pathogenesis. Pathogenic for rats, mice, guinea-pigs, and rabbits. 



154. BACILLUS VENENOSUS INVISIBILIS. 



Obtained by Vaughan from water. 



Morphology. A slender bacillus with rounded ends, from two to four 

 times as long as broad. 



Biological Characters. An aerobic and facultative anaerobic, non- 

 liquefying, motile bacillus. Spore formation not mentioned. Grows slowly 

 in the usual culture media at the room temperature also at 38 C. On gela- 

 tin plates small, granular, yellowish colonies are developed ; the superficial 

 colonies are coarsely granular and very irregular in size and outline. In 

 gelatin tubes grows slowly both on the surface and along the line of punc- 

 ture ; scarcely visible at end of three days. On agar a very thin, white 

 3 



