382 BACTERIOLOGY. 



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, sodium 

 carbonate solution, washed in water, dehydrated in alco- 

 hol, 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 

 example 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 inocula- 

 tion 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 oedematous. 

 Here and there, scattered through this oedematous 

 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 red 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 



