372 Anthrax 



made by cutting away a little of the hair from the abdomen of a 

 guinea-pig or rabbit, or at the root of a mouse's tail, making a little 

 subcutaneous pocket by a snip with sterile scissors, and introducing 

 the spores or bacilH with a heavy platinum wire, the end of which is 

 flattened, pointed, and perforated. An animal inoculated in this 

 way dies, according to the species, in from twenty-four hours to 

 three days, suffering from weakness, fever, loss of appetite, and a 

 bloody discharge from nose and bowels. There is much subcutane- 

 ous edema near the inoculation wound. The abdominal viscera 

 are injected and congested. The spleen is enlarged, dark in color, 

 and of mushy consistence. The hver is also somewhat enlarged. 

 The lungs are usually shghtly congested. 



When organs which present no appreciable changes to the naked 

 eye are subjected to a microscopic examination, the appropriate 

 staining methods show the capillary and lymphatic systems to be 

 almost universally occupied by bacilli, which extend throughout 

 their meshworks in long threads. Most beautiful bacillary threads 

 can be found in the glomeruli of the kidney and in the minute capil- 

 laries of the intestinal villi. In the larger vessels, where the blood- 

 stream is rapid, no opportunity is afforded for the formation of the 

 threads, and the bacteria are relatively few, so that the burden of 

 bacillary obstruction is borne by the minute vessels. 



Death from anthrax seems to depend more upon the obstruction 

 of the circulation by the multitudes of bacilli in the capillaries, and 

 upon the appropriation of the oxygen destined to support the tissues, 

 by the bacilli, than upon intoxication by the metabolic products 

 of bacillary growth. 



Virulence. — The anthrax bacillus maintains its virulence almost 

 without modification because of the prolific formation of spores and 

 their remarkable resisting powers. By artificial means, however, 

 the formation of spores can be inhibited and the bacilli attenuated. 

 This was first achieved by Pasteur* by cultivation at temperatures 

 above the optimum, at which no spores were formed. Toussaintf 

 found that the addition of i per cent, of carbolic acid to blood of 

 animals dead of anthrax destroyed the virulence of the bacilli; 

 ChamberlandJ and Roux found the virulence destroyed when 0.1-0.2 

 per cent, of bichromate of potassium was added to the culture 

 medium; Chauveau used atmospheric pressure to the extent of six 

 to eight atmospheres and found the virulence diminished; Arloing§ 

 found that direct sunlight operated similarly; Lubarsch, that the 

 inoculation of the bacilh into an immune animal, such as the frog, 

 and their subsequent recovery from its blood, diminishes the virulence. 



Vaccination. — Pasteur || early realized the importance of some prac- 



* "Rec. de M6d vet.," Paris, 1879, p. 193. 



t " Compte-rendu Acad, des Scl. de Paris," xci, 1880, p. 135. 



i "Ann. de I'lnst. Pasteur," 1894, p. 161. 



§ "Compte-rendu de I'Acad. des Sci.," Paris, 1892, cxrv, p. 1521. 



II "Rec. de M6d. vet.," Paris, 1879, p. 193. 



