In neither case did we obtain alcoholic fermentation, nor was there any appearance of lactic fermentation, or bacteria, or _vibrios_, properly so called. The flasks remained in the oven, at a temperature of about 25° C. (77° F.), until the end of January, 1873, when we made a microscopical examination of their deposits, exercising greater care and precaution than we had adopted in the case of those examinations which we had made from time to time in the course of the experiment to assure ourselves of the nature of the organisms present.[74] The result was that we never found anything besides the _mycoderma aceti_, which had developed, although with great difficulty, on the surface of the liquids neutralized with carbonate of lime. The beaded filaments had, under these circumstances, only become a little larger than they had been in the unsweetened acid liquids. _Mycoderma aceti_, then, grown on sweetened acid or neutral liquids, grown in the absence or in the presence of carbonate of lime, undergoes no transformation into bacteria or vibrios or yeast, if only we operate with pure germs, free from the dust floating in the air, and from that which, unknown to the operator, may be introduced by means of the vessels and materials employed. It may be asked, do we, therefore, absolutely, reject the theory of the polymorphism of _mycoderma aceti_? 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 efforts have been directed to ascertain if _mycoderma aceti_ might be, for example, the _aërobian_ 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 anything 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. Béchamp 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.