Vaccination 409 



few. so that the burden of bacillary obstruction is borne by 

 the minute vessels. The condition is thus a pure bacteremia. 



Death from anthrax seems to depend essentially upon 

 the obstruction of the circulation by the multitudes of 

 bacilli in the capillaries, upon the appropriation of the 

 oxygen destined to support the tissues, by the bacilli, 

 leaving the tissues to be poisoned by the carbon* dioxid, 

 rather than upon intoxication by metabolic products of 

 bacillary growth. 



Vaccination. Pasteur * early realized the importance 

 of some practical measure for the protective vaccination 

 of cattle against the disease, and devoted himself to inves- 

 tigating the problem. He found that the inoculation of 

 attenuated bacilli into cows and sheep, and their subse- 

 quent reinoculation with mildly virulent bacilli, afforded 

 them immunity against highly virulent organisms. Loffler, 

 Koch, and Gaffky, however, found that these immunized 

 animals were not absolutely protected against intestinal 

 anthrax. 



The means of diminishing the virulence of the anthrax 

 bacillus are numerous. Toussaint f first produced im- 

 munity in animals by injecting them with sterile cultures of 

 the bacillus, and found that the addition of i per cent, of 

 carbolic acid to blood of animals dead of anthrax destroyed 

 the virulence of the bacilli ; Chamberland J and Roux found 

 the virulence destroyed when 0.1-0.2 per cent, of bichro- 

 mate 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 bacilli into immune 

 animals, such as the frog, and their subsequent recovery 

 from its blood, diminishes the virulence of the bacilli mark- 

 edly. 



The protective inoculations prepared by Pasteur consisted 

 of two cultures of increasing virulence, to be employed one 

 after the other, rendering the vaccinated animals more and 

 more immune. The cultures were prepared, that is, at- 



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



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



t "Ann. de 1'Inst. Pasteur," 1894, p. 161. 



\ "Compte-rendu de 1'Acad. des Sci.," Paris, 1892, cxiv, p. 1521. 



