282 BACTERIA. 



dence at all that it has been the point of entrance of the 

 bacilli, but in the human subject there very frequently 

 occurs at the point where the bacilli enter a wound, a 

 marked local reaction, the result apparently of an effort 

 on the part of the tissues to prevent the further advance 

 of the bacilli. There is first irritation at the point of in- 

 oculation, this usually occurring in from one to three days 

 after the inoculation ; about a day later a minute vesicle 

 surrounded by a zone of inflammatory redness and swelling 

 makes its appearance. The serum in this vesicle becomes 

 brown, and gradually a kind of mortification is set up ; 

 other vesicles, forming a ring, appear around the original 

 point ; these in turn become brown or black, until 

 gradually an extensive black scar is formed. If these 

 little pustules, with the surrounding tissue, be freely 

 excised and the wound well cauterized with strong carbolic 

 acid, there may be no return of the disease ; in fact, if the 

 removal be free enough, this result is most certainly ob- 

 tained ; but if the inflammation be allowed to go on 

 unchecked, there is gradual extension of the vesication, 

 sloughing, and blackening, until a very considerable area 

 is affected, the bacilli sooner or later making their way into 

 the blood vessels and giving rise to general anthrax. In the 

 vesicles, and also in the tissues around the point of inocula- 

 tion, anthrax bacilli can usually be found in considerable 

 numbers, the tissues are somewhat cedematous, and there is 

 an increase of leucocytes in the inflamed area. When the 

 blackening commences there are usually found along with 

 the bacilli, or in some cases in the centre of the ulcer re- 

 placing them, chains of micrococci ; these are seldom seen 

 in the very early stages, but in the later stages they are 

 almost invariably present. 



The animals most susceptible to this disease are sheep, 

 mice, rabbits, guinea-pigs, and, according to Fliigge, horses, 

 hedgehogs and sparrows, all of which die or are very 

 ill when the organism is inoculated directly into the sub- 

 cutaneous tissue. Most birds are not readily inoculated, and 

 for a long time it was found impossible to kill fowls by means 

 of anthrax. White rats, old dogs, and amphibians are ex- 

 ceedingly resistant to the disease in almost any form ; cattle, 

 too, which are readily infected through the alimentary canal, 

 are but slightly susceptible to anthrax introduced by direct 



