RESEARCH IN MEDICINE 7 



is necessary to fix contemporary events more definitely I may introduce 

 the fact that two years later Pasteur quotes Professor Biot as referring 

 to his recent discoveries in crystallography as " a very California." 



Now, this work of Pasteur on the tartaric acids not only opened a 

 new field in crystallographic studies, hut, of far greater importance, 

 led to the discoverer's studies in fermentation. In the course of his 

 work on the tartaric acids he found that if salts of the inactive acid 

 were acted upon by a mould (PenicMum glaucum) the right-handed 

 constituent was destroyed, but the left-handed remained unchanged; 

 and from this he concluded that the change from an optically inactive 

 to an optically active fluid, under such experimental conditions, could 

 be due only to the presence of living matter causing the destruction of 

 one component. This was the beginning of his studies of fermentation, 

 and from this time his labors were those which eventually established 

 the sciences of bacteriology and immunity. 



The opportunity to study alcoholic fermentation came at Lille in 

 1854, at a time when Pasteur was professor of chemistry and dean to 

 the faculty at that place. The manufacturers of the region had met 

 with disappointment in the making of alcohol from beets, and one of 

 them came to the new professor of chemistry for advice. Pasteur 

 undertook daily visits to the factory and from these visits came the 

 idea of studying the fermenting beet juice in the laboratory. 



Fermentation, at the time Pasteur entered the field, was a subject 

 involved in great obscurity, with only here and there a ray of light. 

 Cagnaird-Latour, in 1836, had studied that ferment of beer called yeast, 

 and had observed that it was composed of cells " susceptible of repro- 

 duction by a sort of budding, and probably acting on sugar through 

 some effect of their vegetation." Schwann and Kiitzing a few years 

 later reached the same conclusion, but were opposed at once by Liebig, 

 who enunciated a theory of mechanical decomposition and denied in 

 its entirety the theory that fermentation was a biological process. Also 

 Berzelius, second only to Liebig as an authority, believed fermentation 

 was due to contact, and elaborated a theory of catalytic force. With 

 such weighty opposing opinion the observations of Cagnaird-Latour and 

 Kiitzing were neglected and fermentation was regarded by all as a 

 strange and obscure process and was so characterized by Claude Ber- 

 nard in 1850. 



Uninfluenced by these views, however, Pasteur, having recognized 

 that living matter is essential for alcoholic fermentation, adhered 

 strictly to the experimental method, and taking up the problem of lactic 

 acid fermentation (the souring of milk), discovered that the same 

 budding and multiplying of a cell went on in it as in alcoholic fermen- 

 tation, but that the cell of lactic acid fermentation was different from 

 that of alcoholic fermentation. He observed also that the form of the 



