ANAEROBIC LIFE OF AEROBIC SPECIES 201 



mycelial filaments are slender, branching, and inter- 

 twined, but when it becomes a ferment as the result of 

 an insufficient supply of air, the hyphae segment, sepa- 

 rate, enlarge, and finally are transformed into chains 

 of large, round, or slightly oval cells (Fig. 16) which, 

 in reality, resemble large cells of yeast. Bail had be- 

 lieved in their transformation, but Pasteur shows that 

 when these supposed yeasts are introduced into aerated 

 must of beer they do not produce alcoholic fermenta- 

 tion: they reproduce the Mucor. There has not, there- 

 fore, been any transformation of species; there has 

 been only an adaptation to a new life, with a change of 

 form corresponding to change of functions. 



When he had reached this point, Pasteur might recall 

 that there are analogous changes in the mycoderma of 

 wine when submerged in a sugar solution. The cell 

 becomes more turgescent, its protoplasm less granular 

 (Fig. 13). The mucor and the mycoderma, so different 

 in form, resemble each other, therefore, in their nature. 

 In the case of both, and of a certain number of other 

 lower species, the fermenting property, that is to say 

 the ability to break up sugar into alcohol and carbonic 

 acid, appears to us, therefore, not as a specific property 

 but as a transitory faculty related to the conditions of 

 existence, and we may briefly sum up the foregoing by 

 saying that fermentation is life witJiout air. 



When Pasteur gave utterance to these facts before 

 the Academy of Sciences, he was not understood at 

 first, and his opponents shouted cries of victory. This 

 modification of form accompanying a modification of 

 properties was transformation, as much as that of 

 Hoffmann, or Turpin, or that of Darwin. No, Pasteur 

 unceasingly repeated, it is not a question of a trans- 

 formation of species but of a general physiological law 

 which is applicable alike to all living species and respects 



