CONDITIONS FATOURINQ FERMENTATION. 



73 



thinking of as an interpretation, tlie problem, to his inind, is, of 

 course, a simple one. 



It is true, however, that the course of events between the period 

 of the publication of Prof. Tyndall's first and that of his second 

 paper did give to his explanation of these second results some 

 semblance of support — although they were, at the same time, in 

 rather flagrant contradiction with the uniformly negative results 

 of his first five hundred trials. 



The new point of view introduced in the mean time through 

 the labours of Professor Cohn, in conjunction with those of Dr. 

 Eidam and Dr. Koch, w^as thus brought about. 



Dr. Eidam* carried out some researches in 1875 under Prof. 

 Cohn's direction as to the exact death-point of Bacterium termo. 

 He ascertained that this organic form always disappeared in fluids 

 heated to a temperature of 113° F. (45° C), though Bacilli were 

 found growing and multiplying rapidly therein. In the following 

 year these researches were continued in regard to Bacilli, and the 

 results are given by Prof Cohnf in his own memoir on these 

 organisms, which was published in the autumn of 1876. The 

 points of most significance therein recorded are (^) that Bacilli 

 are the organisms which commonly make their appearance when 

 previously boiled fluids undergo fermentation ; (jb) that at a tem- 

 perature of 37° C, or thereabouts, when the infusions are exposed 

 to air through a cotton-wool plug, these Bacilli grow into threads 

 which accumulate in the form of a pellicle on the surface ; (6) 

 that in twenty-four to forty-eight hours a number of highly re- 

 fractive particles appear at short distances from one another 

 within the threads, which are to be regarded as "spores"; and 

 (^d) there is a certain amount of evidence, but not of a conclusive 

 character, to show that these " spores " in a dry condition may 

 resist heat much better and for a longer time than their parent orga- 

 nisms. This latter evidence is inconclusive, principally because no 

 sufficient precautions were taken to show that what was attribu- 

 ted to survival of germs might not have been really due to a still- 

 continuing germinality of the fluids, though also in part because 

 the possible action of mere chemical ferments was not duly con- 

 sidered. 



These points w^ere reenforced in tlje same number of Prof. 

 * Beitrage zur Biologie dcr Tflanzen, 1" Bd. 2'« Heft, p. 208. 

 t Ibid. 2er Bd. 2'«^' Heft, p. 268. 



