ANTHRAX. 9 341 



lungs may be slightly congested, but otherwise no 

 changes are to be found. 



When the various organs, which present no appreciable 

 changes to the naked eye, are subjected to a microscopic 

 examination, the appropriate staining methods bring out 

 a most remarkable and beautiful change. The capil- 

 lary system is almost universally occupied by bacilli, 

 which extend throughout its meshworks in long threads. 

 Most beautiful bundles of these bacillary threads can, at 

 times, be found in the glomeruli of the kidney and in 

 the minute capillaries of the intestinal villi. In the 

 larger vessels, where the blood-stream is rapid, the bac- 

 teria are relatively few, so that the burden of bacillary 

 obstruction is borne by the minute vessels. The con- 

 dition is thus seen to be one of pure septicemia, and 

 bacilli can be secured in pure cultures from the blood 

 and tissues. 



The susceptibility of the anthrax bacillus to the influ- 

 ence of heat, cold, antiseptics, etc. not only permitted 

 Buchner, Behring, and others to produce biological curi- 

 osities in the form of bacilli unable to bear spores and 

 robbed of their pathogenic powers, but also suggested 

 to Pasteur the important practical measure of protective 

 vaccination. Pasteur found that the inoculation of non- 

 virulent bacilli into cows and sheep, and their reinocula- 

 tion with slightly virulent bacilli, gave them the ability 

 to withstand the action of highly virulent organisms. 

 Iv6ffler, Koch, and Gaffky, however, found that these 

 immunized animals were not absolutely protected from 

 intestinal anthrax. 



The methods of diminishing the virulence of the 

 anthrax bacilli are numerous. Toussaint, who was cer- 

 tainly the first to produce immunity in animals by inject- 

 ing them with sterile cultures of the bacillus, 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 and Roux found it removed when 

 o. 1-0.2 per cent, of bichromate of potassium was added to 



