Pasteur and his Work, 
Davaine or his opponents were in the right : and he adopted in 
his investigation the methods which had led him to such 
splendid results in his previous studies. He resolved to isolate 
the organism from infected blood, cultivate it, as Koch had done, 
in artificial media, and then to test its action upon animals. 
In this investigation he was assisted by M. Joubert, as, owing 
to his paralysis, he could not carry it on by himself. 
In 1877, he reported to the Academy of Sciences that the 
bacilli were the only agents in producing anthrax. A little 
drop of splenic-fever blood sown in urine or in yeast- water, 
previously " sterilised " (rendered imputrescible by contact with 
air free from germs), in a few hours produces myriads of them ; 
a drop of this first cultivation sown in a similar manner and 
with the same precautions, proves as fertile ; and this process 
being repeated for ten or twenty times, it may be taken for 
certain that all the substances which the first drop of blood 
might have carried with it, have been completely got rid of. 
Yet , Pasteur found that if a very small quantity of the final culti- 
vation were injected beneath the skin of a rabbit or a sheep, it 
killed them in two or three days with all the symptoms of the 
natural disease. In order to satisfy himself and others that there 
was nothing else than the bacillus at work in producing this 
effect, he had his cultivation-fluids kept at an absolutely uniform 
temperature, which allowed the organisms to be deposited at the 
bottom of the tubes. When he inoculated with the clear upper 
fluid, or the deposit — the bacilli — he found that the latter alone 
caused disease and death. 
But it was necessary to explain the discrepancy between the 
results obtained by himself and Davaine, and those of Jaillard 
and Deplat. These latter had speedily killed rabbits with 
blood from a cow that had died of splenic fever, and their 
blood was also so virulent as to kill others, and yet no bacilli 
could be found in it ; while Bert maintained that he had de- 
stroyed the bacilli by compressed oxygen, and still the blood 
retained its virulence. It might be surmised that there were 
two kinds of destructive agents operating in this blood, and 
Pasteur had the good fortune to demonstrate that this was 
actually the case. Some years previously he had ascertained 
that in none of the tissues or fluids of the body, except in the 
intestinal canal, are there any germs ; that canal alone contains 
them, as they readily find access to it along with the food and 
water, and its temperature is favourable to their development. 
In the commencing portions of the intestine, in which there is 
air, aerobic microbes can exist ; but toward the terminal divi- 
sions oxygen is absent, and only anaerobic microbes can live. 
During life the latter can do no harm, as the vitality of the 
