STUDIES ON FERMENTATION. 127 



On the contrary, we have endeavoured to prove the existence of 

 this polymorphism again and again in a variety of ways. We 

 have been mostly concerned with physiological polymorphism ; 

 that is, our eflforts have been directed to ascertain if mijcoder))ia 

 aceti might be, for example, the aerobian form of a ferment from 

 which it differed physiologically, as, for instance, lactic ferment, 

 which, in shape, sometimes bears a striking resemblance to 

 mycoderma aceti. "We have not succeeded in discovering any- 

 thing of the kind up to the present time. 



What, in view of the positive proofs to the contrary, we do 

 absolutely reject in the matter of this mycoderma, is the theory 

 of polymorphisms, advocated by M. Bechamp and other authors, 

 which, in our judgment, can only be founded on incomplete and 

 erroneous observations, 



§ IV. — Growth of Mucor Racemosus in a state of Purity 

 — Example of Life more active and lasting when 

 removed from the influence of Air. 



Side by side with the facts explained in the last para- 

 graph, the study of varieties of the genus mucor, grown in 

 natural or artificial saccharine liquids, is of great importance to 

 the establishment of the physiological theory of fermentation, 

 which we shall explain later on. There is a ver}^ remarkable 

 work on the subject of this mucedinous fungus by a German 

 botanist, M. Bail, who, in 1857, declared that mucor mucedo 

 caused alcoholic fermentation, and could change into ordinary 

 yeast. The first assertion, relating to the alcoholic fermentation 

 that this fungoid growth which is everywhere so abundant may 

 cause, is quite correct ; the second which relates to its faculty of 

 changing into yeast is erroneous.* 



* Ever since the year 1861 (see p. 92), this question of the possible 

 transformation of the ordinary fungi, especially peniciUium and mucor 

 mucedo, into yeast has engaged our attention. The results attained have 

 been entirely negative ; but hitherto only the conclusions of our work 

 have been published, some account of which was given at the meeting of 

 the Societe PMlomatliique of March 30th, 1861. The following extract is 



