206 TRANSACTIONS OF THE [MARCH 29^ 



consider that every culture in general modi6es the medium in 

 which it is effected; a modification of the soil in the case of or- 

 dinary plants; a modification of plants or animals when it relates 

 to their parasites; a modification of our culture liquids when it 

 relates to mucedines, vibrionicns, or ferments, . . . If one sows 

 chicken bouillon with the microbe of fowl cholera, and after 

 three or four days filters the liquid to remove every trace of the 

 microbe, and afterwards sows anew this parasite in the filtered 

 liquid, it will show itself totally impotent to resume the most 

 feeble development. Perfectly limpid after filtration, the liquid 

 retains this limpidity indefinitely. How is it possible to doubt 

 that by the culture of mitigated virus in the fowl, we place its 

 body in the state of our filtered liquid, which can no longer sus- 

 tain the microbe?" — Comptes Renilus Acad, des Sciences, 

 XC, 975. 



First then, his statements are correct, but the analogy is more 

 apparent than real. 



For this theory requires a peculiar substance for each disease, 

 or at least for every disease which protects against subsequent 

 attacks. Of what nature is this substance ? According to the 

 examples given by Pasteur, it appears as an alimentary sub- 

 stance. If so, it must be present in the body in considerable 

 amounts, for the germs, though infinitely small, are infinitely 

 numerous, and the proportion of inorganic matter extracted 

 from the soil by a particular plant, like tobacco, which requires 

 frequent rotation, or the amount of organic matter removed 

 from solution in chicken bouillon, is very large. Whatever we 

 consider this to be, multiply it by the number of infectious dis- 

 eases not inhibiting one anotiier, and we obtain a conception of 

 tlie amount of these substances required. 



Again notice that these substances, whatever their character 

 or comi)Osition, are bodies having no office that we know of in the 

 nsual economy of the system. If they were, a man, after an 

 attack of a certain disease, and while possessing immunity from 

 it, would be deprived of a substance necessary to the system, 

 which would speedily show its defective organization. 



Still again, we know of the speedy elimination from the- 

 system of -all bodies not figuring in the general economy, except 

 in those cases where some morbid action induces at tlie same 

 time a constant supply to meet this drain. 



Considering these facts, is it not strange that such a variety of 

 substances, foreign to the normal working of the system, should 

 be formed in it, and that, contrary to the usual rule, these sub- 

 stances should be able to withstand the natural tendency of the 

 system toward tlie removal of effete matter until such time as 

 the disease germ by its multijilieation removes them ? 



