256 NATURE STUDIES. 



accounted for ? It seemed, in truth, as if the one 

 outbreak had little or nothing to do with the other. 

 The infected animals which had died, or had been 

 killed, whilst suffering from the fever, were duly 

 buried, and that very deeply, in the soil. Such a 

 method of interment would seem to obviate all risk of 

 infection. But the possibilities of nature are illimit- 

 able, and no man knew this better than Pasteur. If 

 the poison had been buried in the soil, why should it 

 not be there still ? And, further, why should it not 

 be conveyed upwards to infect the fresh flocks that 

 fed on the graves of their predecessors ? With a gift 

 of scientific divination, Pasteur sought in the earth- 

 worm, the type of the " middle-man " betwixt the 

 living and the dead. He now examines the bodies of 

 the worms which live in the soil wherein the bodies of 

 the animals infested with splenic fever, years before, 

 were entombed. By experimental means, he solves 

 his problem. He makes a preparation of the contents 

 of the digestive system of the worms. This he 

 .administers in the food of healthy animals, entirely 

 removed from the pastures. And once again a 

 scientific principle dawns in view. The rabbits and 

 guinea-pigs which devoured the matter obtained from 

 the worms at once developed splenic fever, whilst in 

 their blood the rods were seen developing in full 

 force. Once again Pasteur had sown the fever, and 

 had argued thus from the result, backwards to the 

 cause. It has also been proved, that even grain may 

 convey the subtle "rods" to healthy animals, and 



