B. ANTHRACIS: INOCULATION INTO ANIMALS. 363 



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 

 be found dead. Immediately at the point of inoculation 

 but little or no reaction will be noticed, but beyond 

 this, extending for a long distance over the abdomen 

 and thorax, the tissues will be markedly cedematous. 

 Here and there, scattered through this cedematous 

 tissue, small ecchymoses will be seen. The underlying 

 muscles are pale in color. Inspection of the internal 

 viscera reveals no very marked macroscopic changes 

 except in the spleen. This is enlarged, dark in color, 

 and soft. The liver may present the appearance 

 of cloudy swelling ; the lungs may be pale or pale-red 

 in color ; the heart is usually filled with blood. There 

 are no other changes to be seen by the naked eye. 



Prepare cover-slip preparations from the blood and 

 other viscera. They will all be found to contain short 

 rods in large numbers. Nowhere can spore-formation 

 be detected. Upon microscopic examination of sections 



