84 Manual of Veterinary Microhiology. 



become eliminated in various ways, are no longer re- 

 placed by fresh additions. Recovery is not complete 

 when the elimination of these substances is ended. 

 Besides the weakness of the patient, local troubles 

 more or less important may persist, recovery from 

 which will take place gradually now that the cause 

 which engendered them is removed. 



But the disease, having attained its height, may 

 terminate in death, the manner in which this is 

 brought about varying in different cases. 



Microbic diseases maybe acute or chronic, epizootic, en- 

 zootic of sporadic. The gravity of some, at least, of 

 these diseases is subject to variations, whilst others of 

 them are almost invariably fatal ; charbon and rabies 

 for example. Indeed, from the knowledge which we 

 have gained in regard to receptivity, immunity, and 

 the resistance of the organism we should expect all 

 degrees of intensity in such diseases. In epizootics of 

 great severity it is observed that the first animals at- 

 tacked are more severely affected than the last, and 

 that the number of the individuals attacked, consider- 

 able at the beginning, rapidly diminishes toward the 

 end of the attack. This is probably due to the fact 

 that the virus fixes itself upon individual animals by 

 reason of their special susceptibility. The least refrac- 

 tory will be first attacked, will be severely affected, 

 and the virus will rapidly multiply, thus increasing 

 the chances of infection for all those which are sus- 

 ceptible to the disease. On account of this dissemi- 

 nation of the virulent germs the less susceptible will 

 also be finally stricken, but, by reason of the fact that 

 they do not offer a very favorable field, the microbic 

 pullulation will in these be less extensive, the disease 



