Susceptibility. Pathogenesis. XI 



those which are more used to hardship. Shedding of teeth 

 as well as pre-existing catarrh and digestive disturbances 

 render the animal particularly susceptible to anthrax. 



Susceptible animals acquire a long lasting immunity against 

 later infections after a recovery from the disease (see immuniza- 

 tion). 



Pathogenesis. The spores taken into the digestive tract 

 germinate there and grow into bacilli. They then pass through 

 the mucous glands and lymph follicles into the lymph spaces 

 of the mucous membrane and submucosa, while spores which 

 directly enter the connective tissue through injuries in the 

 skin or mucous membrane germinate at the point of entrance. 

 In the lymph spaces of the tissues the bacilli multiply by fission, 

 although they are more or less inhibited and even partly de- 

 stroyed by the hostile anthracocide substances which are pres- 

 ent in the tissue fluids. The final result of the infection de- 

 pends then on the one hand upon the resisting power of the 

 infected organism, and on the other hand, upon the virulence 

 of the anthrax bacilli. This again depends principally upon 

 their capability of forming capsules. According to the investi- 

 gations of Preisz, which correspond with the results obtained 

 by Gruber & Futaki and also by Weil, the virulence of the 

 anthrax bacilli depends first of all upon the character of their 

 capsules, that is, the virulence of the different strains of bacilli 

 is more or less dependent upon the density and solubility of 

 the capsules, inasmuch as dense capsules protect the bacilli 

 against the destructive action of the dissolved hostile substances 

 and the engulfing action of the phagocytes. 



In immune animals even bacilli capable of producing dense 

 capsules are quickly destroyed by the numerous anthrax de- 

 stroying substances which are present in the tissue fluids, be- 

 fore they have time to form protecting capsules. Consequently 

 an infection in such animals remains ineffective. On the other 

 hand, in susceptible animals which possess a smaller quantity 

 of anthrax destroying substances a greater or lesser number 

 of the bacilli remain active, form capsules and become more 

 resistant, producing also capsuled progeny. In this manner 

 the capsule forming bacilli multiply at the point of infection, 

 but in the meantime their destruction is also in progress, part 

 of them being taken up and digested by the migrated leucocytes. 

 A part of the destroyed extracellular bacilli are dissolved, and 

 in this way the capsule substance, which has been named 

 anthracomucin by Preisz, on account of its' mucin-like action 

 against reagents, reaches the circulation of the body fluids. 

 Hereby the anthracocide substances are gradually weakened. 

 They are further affected by the capsule substance which results 

 from the bacilli entering the blood circulation in the earliest 

 stages there to be destroyed and dissolved. Finally, the bac- 

 tericidal substances of the body fluids are completely or almost 



