236 BACTERIOLOGY. 



Under favorable conditions of oxygen, nutrition, and 

 temperature its growth is rapid. 



Under 12° 0. and above 45° C. no growth occurs. 

 The temperature of the body is most favorable to its 

 development. The spores of the anthrax bacillus are 

 very resistant to heat, though the degree of resistance is 

 seen to vary with spores of different origin. Esmarch 

 found that anthrax spores from one source would read- 

 ily be killed by an exposure of one minute to the tem- 

 perature of steam, whereas those from other sources 

 resisted this temperature for longer times, reaching in 

 some cases as long as twelve minutes. 



Staining. — The anthrax bacilli stain readily with 

 the ordinary aniline dyes. In tissues their presence 

 may also be demonstrated by the ordinary aniline stain- 

 ing fluids, or by Gram's method. They may also be 

 stained in tissues with a strong watery solution of dahlia, 

 after which the tissue is decolorized in 2 per cent, soda 

 solution, washed in water, dehydrated in alcohol, cleared 

 up in xylol, and mounted in balsam. This leaves the 

 bacilli stained, while the tissues are decolorized ; or the 

 tissues may be stained a contrast color — eosin, for ex- 

 ample — after the dehydration in alcohol, and before the 

 clearing up in xylol. In this case they must be washed 

 out again in alcohol before using the xylol. In the 

 preparation treated in this way, the rod-shaped organ- 

 isms will be of a purple color, and will be seen in the 

 capillaries of the tissues, while the tissues themselves 

 will be of a pale-rose color. 



Inoculation into Animals. — Introduce into the 

 subcutaneous tissues of the abdominal wall of a guinea- 

 pig or rabbit, a portion of a pure culture of the bacillus 

 anthracis. In about forty-eight hours the animal will 



