504 PATHOGENIC AEROBIC BACILLI 



tin is transparent, and a deposit of thick, granular masses accumulates at the 

 bottom of the tube. Upon the surface of agar a thick, white layer is formed, 

 which later is wrinkled and after a time gives off a putrefactive odor. Gela- 

 tin cultures give off an odor of sulphuretted hydrogen. Upon potato a soft, 

 white or pale-yellow layer is formed, which in places is made up of small 

 granules. The potato around the growth has a bluish-brown color. 



Pathogenesis. Subcutaneous injection of a small quantity (0.1 cubic 

 centimetre) of a liquefied gelatin culture is fatal to mice in about six hours ; 

 the animals become comatose before death, and at the autopsy putrefactive 

 changes are already observed ; the bacillus can be recovered from the blood 

 in cultures. Sterilized cultures also prove fatal to mice. Pathogenic also 

 for guinea-pigs, which die in, about twenty hours after receiving a subcuta- 

 neous inoculation. 



130. BACILLUS VARICOSUS CONJUNCTIVE. 



Obtained by Gombert (1889) from the healthy conjunctival sac of man. 



Morphology. Large bacilli with round ends, from two to eight n long 

 and about one JJL broad; the shorter bacilli are often constricted in the 

 middle. 



Stains with the usual aniline colors. 



Biological Characters. An aerobic and facultative anaerobic, liquefy- 

 ing, non-motile bacillus. Grows very slowly in nutrient gelatin at 22 C. ; 

 rapidly in agar and upon potato at 37 C. In gelatin stick cultures, at the 

 end of twenty-four hours, a circular layer haying a grayish- white centre is 

 developed upon the surface, and a scarcely visible grayish- white thread along 

 the line of puncture. Liquefaction extends gradually from the surface 

 without clouding or changing the gelatin, so that at the end of two weeks 

 the gelatin is entirely liquefied without giving any other evidence of the pre- 

 sence of the microorganism. Upon agar plates, at 37 C., the deep colonies 

 have a diameter of about four millimetres by the end of the fourth day; 

 under a low power they are seen to be covered with minute, irregular, thorn- 

 like projections, which subsequently increase in size ; the centre of the colony 

 is granular and opaque. The superficial colonies, under a low power, are seen 

 to have an opaque central nucleus surrounded by a yellowish, finely granu- 

 lar, transparent peripheral zone; later the central portion is irregular and 

 semi-opaque, surrounded by a broad marginal zone which consists of twisted 

 and bent tapering offshoots having a dark contour. Upon the surface of 

 agar a thin, white, dry, very adherent film is formed ; a thick, white film 

 forms upon the surface of the condensation water. Upon potato develop- 

 ment is rapid at 37 C., forming at first a dry, white layer, which at the end 

 of ten days covers the entire surface ; it then has an irregular surface and 

 fringed margins, is smooth, dry, and after a time has a reddish-brown color. 



Pathogenesis. When inoculated into the cornea of rabbits a grayish- 

 white cloudiness is developed in twenty-four hours, around which the cornea 

 is highlv vascular ; the animal recovers without the formation of an abscess. 

 Injected into the conjunctiva it causes an intense hyperaemia. 



131. BACILLUS MENINGITIDIS PURULENTJE. 



Obtained by Neumann and Schaffer (1887) from pus from beneath the pia 

 mater in an individual who died of purulent meningitis. 



Morphology. Bacilli about two u long and 0.6 to 0.7/* broad; often 

 grow out into long filaments, especially in gelatin cultures. 



Stains with the usual aniline colors, but not by Gram's method. 



Biological Characters. An aerobic and facultative anaerobic, non- 

 liquefying, motile bacillus. Does not form spores. Grows in the usual 

 culture media at the room temperature better in the incubating oven. Upon 

 gelatin plates the deep colonies, under a low power, are homogeneous, round 

 or oval, pale brown, and with a smooth contour; the superficial colonies are 



