232 PASTEUR: THE HISTORY OF A MIND 



the ideas of Virchow in pathology. If Fate had willed 

 that he should not finish his task, that he should suc- 

 cumb to the hemiplegia which attacked him at the time 

 of his studies on silkworms, some other scientific man 

 would have come, a Koch for example, for whom Pasteur 

 would have been a precursor because he would have 

 pointed out the way and left behind him the means of 

 following it. His pathological work was the develop- 

 ment and the compliment of his work upon the fermen- 

 tations. But Pasteur had no precursor in the proper 

 sense of this word, that is to say, he did not develop 

 and extend the ideas of anyone else. He remains the 

 equal of many when he demonstrates the bacterial origin 

 of anthrax or of other diseases. Where he is without 

 equal is when he discovers the attenuation of viruses, 

 and when he introduces into science that fertile no- 

 tion which allows us to act upon a disease by acting, 

 not upon the sick person, as up to that time one had 

 been in the habit of doing, but upon the pathological 

 bacterium. 



What renders his history particularly interesting at 

 this period, is that we can follow the stages of his 

 progress. As we have seen, he had had for a long time 

 the desire to enter into pathology. He was led to it 

 by that secret force of things the elements of which we 

 have just analyzed. He showed himself an eager student 

 of medical works and after having borrowed from them 

 certain words, as we have seen, at the beginning of his 

 studies upon the disease of silkworms, he began to pene- 

 trate into things. From this stage his choice was nar- 

 rowly restricted. He had read and meditated on the 

 works of Jenner upon vaccine, those which Coze 

 and Feltz had just published. But what interested him 

 most of all were the studies which Davaine was pursuing 

 at this time upon the anthrax bacteridium. 



