350 ' ANTHKAX 



The Pathology of Anthrax.— Various theories were formerly 

 held as to the mode jn which the anthrax bacillus produces its 

 effects. One of the earliest was the mechanical, according to 

 which it was supposed that the serious results were produced by 

 extensive blocking of the capillaries in the various organs by the 

 bacilli. According to another, it was supposed that the bacilli 

 used up the oxygen of the blood, thus leading to starvation of 

 the tissues. In modern times there has been a tendency to 

 attribute the effects produced to toxic action. That toxic effects 

 do occur in anthrax is probable, for frequently while the bacilli 

 are still locally confined, there may occur pyrexia and oedema 

 spreading widely beyond the pustules. All attempts, however, 

 to throw further light on the toxic process have hitherto been 

 unsuccessful. In the opinion of some, the anthrax bacillus 

 shows a special tendency to be broken up in the infected tissues, 

 and substances derived from its protoplasm may thus be readily 

 distributed throughout the body. According to Bail there is in 

 anthrax an aggressin intoxication, and in support of this he 

 states that the protective action of an anthrax immune-serum is 

 due to its containing anti-aggressins. It may be stated that 

 the alleged aggressins have been obtained by centrifuging the 

 oedematous fluid from the point of inoculation or the pleural 

 exudates occurring in infected animals, and killing any remaining 

 bacilli by shaking the fluid with toluol. 



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 the serum of the susceptible rabbit 

 is capable of killing the organism. Again, the properties 

 of the serum of immunised animals have been much dis- 

 cussed. 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, and holds the view 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 



