184 Veterinary Medicine. 



They take aniline colors readily, and iodine slightly, assuming in 

 the last case a violet tint. The staining is unaffected by heating 

 in melted balsam. The bacillus grows readily in ordinary cul- 

 ture media, (peptonized gelatine, bouillon, milk, etc.), but, being 

 anaerobic, only under the surface in stick cultures, or under a 

 neutral gas or vacuum. It grows most rapidly at a temperature 

 of 36 to 37 C. but also as low as 15 C. The bouillon at 37 

 C. becomes milky and opaque in 24 hours, and later it clears up, 

 the microbes being precipitated as a free white powder. In gela- 

 tine cultures liquefaction takes place in three days, and in twenty 

 days the whole mass may be dissolved and the microbes precipi- 

 tated to the bottom. Spores may form in the living body and as 

 these are set free by the granular degeneration of the bacilli, the 

 virulent exudate and cultures usually show the microbe in three 

 different forms : 1st ; the straight, motile bacillus of one thick- 

 ness throughout its whole length ; 2d ; club-shaped or fusiform 

 bacilli, the thickening of the end or median part being due to the 

 endogenous formation of a refrangent spore or spores ; and 3d ; 

 the free refrangent spores which have been set free by the de- 

 generation and destruction of the sporulating bacilli. The mi- 

 crobe is not found on the surface of the living animal, nor in the 

 blood, for in both the supply of oxygen is too abundant ; it forms 

 its colony under the skin, in the tissues, and above all, in the 

 mass of extravasated blood or gelatinoid exudate which its irrita- 

 tion has produced and where air is lacking. 



The most marked differential features of the microbes of an- 

 thrax and emphysematous anthrax are contrasted in the following 

 table :— 



Bacillus Anthracis. Bacillus of Emphysematous 



Anthrax. 



5 to 20/x X 1.25/u. 3 to 10/i X 0.5 to o.6,u. 



Ends square or cupshaped. Ends rounded. 



Occurs singly in the living body. Often in pairs or threes in body. 



Long filaments in cultures. No long filaments. 



Nonmotile. Motile (sluggishly). 



iErobic. Anaerobic. 



No spores formed in living body. Sporulates in living body. 



Sporulates in air ; in surface soil. Sporulates in vacuo ; deep in soil. 



Bacilli only. Bacilli ; sporulating bacilli ; free spores. 



Multiplies freely in blood stream. Dies in blood stream unless charged 



with toxins. 



Rabbit very susceptible ; man less so. Rabbit, pigeon and man immune. 



Produces no gas. Gas producing. 



Inoculation swelling very restricted. Inoculation swelling very extensive. 



Bacillus destroyed by putrefaction. Not destroyed by putrefaction. 



