INTRODUCTION. xxxiii 



animals which had died of splenic fever. But they 

 were quite unconscious of the significance of their 

 observation, and for thirteen years, as M. Eadot informs 

 us, strangely let the matter drop. In 1863 Davaine's 

 attention was again directed to the subject by the 

 researches of Pasteur, and he then pronounced the 

 parasite to be the cause of the fever. He was opposed 

 by some of his fellow-countrymen ; long discussions 

 followed, and a second period of thirteen years, ending 

 with the publication of Koch's paper, elapsed, before 

 M. Pasteur took up the question. I always, indeed, 

 assumed that from the paper of the learned German 

 came the impulse towards a line of inquiry in which 

 M. Pasteur has achieved such splendid results. Things 

 presenting themselves thus to my mind, M. Eadot 

 will, I trust, forgive me if I say that it was with 

 very great regret that I perused the disparaging 

 references to Dr. Koch which occur in the chapter 

 on splenic fever. 



After Koch's investigation, no doubt could be en- 

 tertained of the parasitic origin of this disease. It 

 completely cleared up the perplexity previously existing 

 as to the two forms the one fugitive, the other per- 

 manent in which the contagium presented itself. I 

 may say that it was on the conversion of the per- 

 manent hardy form into the fugitive and sensitive one, 

 in the case of bacillus subtilis and other organisms, that 

 the method of sterilising by ' discontinuous heating ' 



b2 



