THE GERM THEORY. 805 



represented it formerly in one of the plates of my work on the diseases 

 of silk-worms. Little by little all connection between them disappears, 

 and presently they are reduced to nothing more than germ-dust. If 

 you make these corpuscles germinate, the new culture reproduces the 

 virulence peculiar to the thready form which has produced these cor- 

 puscles, and this result is seen even after a long exposure of these 

 germs to contact with air. Recently we discovered them in pits in 

 which animals, dead of splenic fever, had been buried for twelve years, 

 and their culture was as virulent as that from the blood of an animal 

 recently dead. Here I regret extremely to be obliged to shorten my 

 remarks. I should have had much pleasure in demonstrating that the 

 anthracoid germs in the earth of pits in which animals had been buried 

 are brought to the surface by earth-worms ; and that, in this fact, we 

 may find the whole etiology of disease, inasmuch as the animals swal- 

 low these germs with their food. A great difficulty presents itself 

 when we attempt to apply our method of attenuation by the oxygen 

 of the air to the anthracoid microbes. The virulence establishing it- 

 self very quickly, often after twenty-four hours, in an anthracoid germ 

 which escapes the action of the air, it was impossible to think of dis- 

 covering the vaccine of splenic fever in the conditions which had 

 yielded that of chicken-cholera. But was there, after all, reason to be 

 discouraged ? Certainly not ; in fact, if you observe closely, you will 

 find that there is no real difference between the mode of the generation 

 of the anthracoid germ by scission and that of chicken-cholera. We 

 had, therefore, reason to hope that we might overcome the difficulty 

 which stopped us by endeavoring to prevent the anthracoid microbe 

 from producing corpuscle-germs, and to keep it in this condition in 

 contact with oxygen for days, and weeks, and months. The experi- 

 ment fortunately succeeded. In the ineffective (neittre) bouillon de 

 poule the anthracoid microbe is no longer cultivable at 45 Cent. 

 Its culture, however, is easy at 42 or 43, but in these conditions the 

 microbe yields no spores. Consequently it is possible to maintain in 

 contact with the pure air, at 42 or 43, a mycUienne culture of bac- 

 teria entirely free of germs. Then appear the very remarkable results 

 which follow : In a month or six weeks the culture dies that is to 

 say, if one impregnates with it fresh bouillon, the latter is completely 

 sterile. Up to that time life exists in the vase exposed to air and 

 heat, If we examine the virulence of the culture at the end of two 

 days, four days, six days, eight days, etc., it will be found that long 

 before the death of the culture the microbe has lost all virulence, al- 

 though still cultivable. Before this period it is found that the culture 

 presents a series of attenuated virulences. Everything is similar to 

 what happens in respect to the microbe in chicken-cholera. Besides, 

 each of these conditions of attenuated virulence maybe reproduced by 

 culture ; in fact, since the charbon does not operate a second time (ne 

 recidive pas), each of our attenuated anthracoid microbes constitutes 



