80 BACTERIA. 



cillium occurred so frequently in his cultivations, and, as 

 Brefeld and others pointed out, however complete Hallier's 

 isolation apparatus might be in itself, he did not take sufficient 

 care to prevent the entrance of the spores of these various fungi 

 when he introduced the micrococci and bacteria which he 

 wished specially to study, so that, although nothing fresh 

 might be added after he had introduced the seed material, 

 his seed material itself might be a mixture of various kinds, 

 and along with it he could not be sure that the spores of the 

 larger fungi had not entered. It was a case, said Brefeld, of 

 covering with a waterproof a man already drenched with 

 rain. So faulty, indeed, were these experiments considered 

 to be by Burdon Sanderson in this country, by Hoffmann, 

 Rindfleisch, Manassein, and Ferdinand Cohn abroad, that 

 these observers undertook various experiments to prove 

 that not only was there no connection between bacteria and 

 the higher fungi, but that there were actually cases in which 

 the micrococci did not develop into the longer rod-shaped 

 bacteria. Moulds could only be developed in artificially pre- 

 pared food solutions when the seeds or spores of moulds 

 were sown ; whilst bacteria seeds or germs, when obtained 

 free from the germs of moulds, would in similar solution 

 give rise to the development of bacteria only. There 

 was soon a reaction against the whole of Hallier's teaching, 

 and it was now pointed out that he had seldom or never 

 been able to reproduce any disease by inoculating cultiva- 

 tions of the organisms that he grew, and the theory of living 

 contagion fell into discredit, though the fact must not be 

 ignored that Salisbury's and Hallier's work led to further 

 consideration of many points associated with the relation 

 of bacteria to disease, and that eventually it exerted a 

 marked influence on the germ theory of disease. Hallier 

 undoubtedly laid great stress on the fact that a micro- 

 coccus was the cause of certain diseases, and he pointed out 

 that its extreme minuteness was in favour of its being able 

 to enter readily and retain firmly its position in the body. 



In 1868-9 Davaine and Chauveau succeeded in demon- 

 strating that in all probability the infectious element 

 in anthrax blood (Davaine), and in glanders pus and 

 vaccine lymph (Chauveau), and in vaccine lymph (Burdon 

 Sanderson) was not merely a soluble poison, but some 

 solid material, such as a leucocyte, and probably a 



