298 BIOLOGY AND ITS MAKERS 



treatment the precise culture and capacities which he has 

 brought to bear upon them." 



In 1857 Pasteur went to Paris as director of scientific 

 studies in the Ecole Normale, having previously been a 

 professor in Strasburg and in I.ille. From this time on his 

 energies became more and more absorbed in problems of a 

 biological nature. It was a momentous year (1857) in the 

 annals of bacteriology when Pasteur brought convincing 

 proof that fermentation (then considered chemical in its 

 nature) was due to the growth of organic life. Again in i860 

 he demonstrated that both lactic (the souring of milk) and 

 alcoholic fermentation are due to the growth of microscopic 

 organisms, and by these researches he developed the 

 province of biology that has expanded into the science of 

 bacteriology. 



After Pasteur entered the path of investigation of microbes 

 his progress was by ascending steps; each new problem the 

 solution of which he undertook seemed of greater importance 

 than the one just conquered. He was led from the discovery 

 of microbe action to the application of his knowledge to the 

 production of antitoxins. In all this he did not follow his 

 own inclinations so much as his sense of a call to service. In 

 fact, he always retained a regret that he was not permitted 

 to perfect his researches on crystallography. At the age of 

 seventy he said of himself: "If I have a regret, it is that I did 

 not follow that route, less rude it seems to me, and which 

 would have led, I am convinced, to wonderful discoveries. 

 A sudden turn threw me into the study of fermentation, fer- 

 mentations set me at diseases, but I am still inconsolable to 

 think that I have never had the time to go back to my old 

 subject" (Tarbell). 



Although the results of his combined researches form a 

 succession of triumphs, every point of his doctrines vras the 

 subject of fierce controversy; no investigations ever met 



