194 LOUIS PASTEUR. 



the bacteria by compressed oxygen, and yet the viru- 

 lence had continued. 



Were there, then, two kinds of virus? What 

 escape was there from this darkness ? A new light 

 suddenly began to dawn. Pasteur had already some 

 years previously demonstrated that the animal body 

 is sealed against the introduction of lower organisms 

 that in the blood, the urine, the muscles, the liver, 

 the spleen, the kidneys, the brain, the marrow, and 

 the nerves, in a normal state, no germ is found, or 

 particle of any kind, known or unknown, which could 

 be transformed into bacteria, vibrios, monads, or mi- 

 crobes. The intestinal canal alone is filled with 

 matters associated with a host of germs and living 

 products in process of development, and in divers states 

 of physiological action. Not only is its temperature 

 favourable to the life of infusoria, but it receives in- 

 cessantly matters charged with the germs of these mi- 

 croscopic organisms. To the upper portions of the 

 canal the air still has access, so that even in the 

 stomach aerobic microbes may be found, but in the 

 lower parts of the intestinal canal oxygen is absent, 

 and only anaerobic microbes can be developed there. 

 Although the life exerted in the mucous surface of the 

 intestines opposes itself to the passage of those little 

 organisms into the interior of the body, this ceases 

 to be the case after death. There is no longer any 

 obstacle to arrest or prevent them from acting accord- 



