80 MECHANISM OF INFECTION 



cessfully resist destruction and each successive generation 

 will be more resistant to bacteriolysis. At the same time 

 the compounds of the bacterial products with antibodies 

 will cause the formation of more and more severe lesions. 

 Infections, at first local, may become generalized and the 

 animal may die. 



The numerous experiments of Loeffler, Behring, Metchni- 

 koff and others on anthrax in rats do not give us a sufficiently 

 accurate explanation of all the conditions of the evolution 

 of this disease in animals, because all their experiments 

 were in reply to other questions which need not occupy us 

 here. But such as they are, they permit us to conclude that 

 hypersensitization of the white rat to anthrax, by one or 

 several inoculations which may be considered as vaccina- 

 tions, is not in contradiction to the principle of vaccination 

 which makes no exception for anthrax in animals nor for 

 any other known septicemic infection. 



Relapses in typhoid, auto-reinfections in tuberculosis 

 and syphilis, reinfections in cyclic diseases (malaria, try- 

 panosomiasis) and all the chronic infections in which attacks 

 alternate with more or less prolonged remissions (gonorrhea, 

 influenza) are all phenomena of the same category. They 

 all presuppose a certain reciprocal adaptation or a symbiosis 

 of the parasites and the organism: The difference in the 

 observed results, that is to say, the increase or diminution of 

 resistance or of sensitization of the parasite or the organism, 

 the final destruction of one or the other are determined only 

 by secondary factors, notably: By the degree of reciprocal 

 adaptation of the parasite and the organism at the moment 

 of infection; by the infecting dose; by the general condition 

 of the organism before the infection and the severity of 

 the lesions which are produced during the period of disease 

 or during the attacks. The mechanism of these reactions 

 will be under all circumstances the same. 



RESUME AND CONCLUSIONS. 



1 . A pathologic state can be caused only by : 

 (a) The penetration into the interior of the organism of 

 bacteria or of bacterial products in a colloidal state. 



