108 ESSENTIAXS OF BACTERIOLOGY 



Potato. A dry, creamy layer, and when placed in incu- 

 bator, rich in spores. 



Staining. Readily take the anilin dyes with the ordinary 

 methods. To bring out the cup-shaped concave extremities, 

 a very weak watery solution of methylene-blue is best. 

 Gram positive. 



Spores are stained by the usual method. When several 

 bacilli are joined together, the place of their joining looks like 

 a spore, because of the hollowed ends. Double staining will 

 differentiate the spores. (See Fig. 42.) 



Sections of tissue are stained according to the ordinary 

 methods, taking Gram's method very nicely. 



Pathogenesis. When mice are inoculated with anthrax 

 material through a wound in the skin, they die in twenty- 

 four hours from an active septicemia, the point of inocula- 

 tion remaining unchanged. 



On autopsy will be found: 



Peritoneum. Covered with a gelatinous exudate. 



Spleen. Very much swollen, dark red, and friable. 



Liver. Parenchymatous degeneration. 



Blood. Dark red. The bacilli are found wherever the 

 capillaries are spread out, in the spleen, liver, intestinal villi, 

 and glomeruli of kidney, and in the blood itself. Only when the 

 capillaries burst are they found in the tubules of the kidney. 



Mode of Entrance. The bacilli can be inhaled, and then a 

 pneumonia is caused, the pulmonary cells containing the 

 bacilli ; when the spores are inhaled, a general infection occurs. 



Feeding. The cattle graze upon the meadows, where the 

 blood of anthrax animals has flowed and become dried; the 

 resistant spores contaminate the grass and so enter the ali- 

 mentary tract; here they then cause the intestinal form of the 

 disease, ulcerating through the villi. Cattle are also in- 

 fected by w r ading in streams which tannery washings have 

 contaminated. 



Local Infection. In man usually only a local action occurs; 

 by reason of his occupation woolsorter, cattle-driver, 

 tanner, etc. he handles the hides or wool of animals that 



