348 ANTHRAX 



method than with the Sobernheim procedure, where the 

 presence in the animal's body of the protective serum might tide 

 it over the stage when the action of the vaccine was lowering 

 its resistance. 



The effects of the b. anthracis have been much studied with 

 a view to the shedding of light on the processes obtaining in 

 resistance and the development of immunity. Many puzzling 

 facts have long been known ; for example, in the dog, which 

 shows great natural resistance, the serum has little if any 

 bactericidal action, while in the susceptible rabbit ther.e is 

 present a serum capable of killing the organism. Such observa- 

 tions have hitherto been without explanation. Again, the 

 properties of the serum of immune animals have been much 

 discussed. Sobernheim and others have been unable to detect 

 in it any trace of special bactericidal action. Sclavo found that 

 the serum when heated to 55 C. did not lose its protective 

 properties; as the serum might have been complemented (see 

 Immunity) by the serum of the animal into which it was injected, 

 he simultaneously introduced an anti-complementary serum and 

 found that the heated serum was still effectual. From this he 

 deduces that in the action of the serum substances of the nature 

 of immune body and complement are not concerned. Many 

 have thought that the serum had a stimulating effect on the 

 leucocytes, but Cler has brought forward ground for supposing 

 that its effect is a sensitising one on the bacteria, and that thus 

 the effects are to be traced to opsonic action. With regard to 

 the formation of the protective substances, it is stated that the 

 spleen and bone-marrow are richer in these than the blood fluids. 

 In this connection an interesting fact may be mentioned, namely, 

 that Roger and Gamier found evidence of the liver and spleen 

 having special capacities for killing anthrax bacilli ; an otherwise 

 fatal dose could be introduced into the portal vein or the splenic 

 artery' without causing death. It has been thought that the 

 capsule frequently developed by the anthrax bacillus is a defen- 

 sive mechanism against bactericidal and bacteriolytic capacities 

 in an infected animal. It is stated that capsulation renders the 

 bacillus less susceptible to phagocytosis. Opinion on the signific- 

 ance of capsule formation is at present divided. 



Methods of Examination. These include (a) microscopic 

 examination ; (b) the making of cultures ; and (c) test in- 

 oculations. 



(a) Microscopic Examination. In a case of suspected 

 malignant pustule, film preparations should be made from the 

 fluid in the vesicles or from a scraping of the incised or excised 



