We are compelled here to admit that vibrios frequently abound in liquids exposed to the air, and that they appropriate the atmospheric oxygen, and could not withstand a sudden removal from its influence.  Must we, then, believe that such vibrios are absolutely different from those of butyric fermentations?  It would, perhaps, be more natural to admit that in the one case there is an adaptation to life with air, and in the other case an adaptation to life without air; each of the varieties perishing when suddenly transferred from its habitual condition to that of the other, whilst by a series of progressive changes one might be modified into the other. [Footnote:  These doubts might be easily removed by putting the matter to the test of direct experiment.] We know that in the case of alcoholic ferments, although these can actually live without air, propagation is wonderfully assisted by the presence of minute quantities of air; and certain experiments which we have not yet published lead us to believe that, after having lived without air, they cannot be suddenly exposed with impunity to the influence of large quantities of oxygen.

We must not forget, however, that aerobian torulae and anaerobian ferments present an example of organisms apparently identical, in which, however, we have not yet been able to discover any ties of a common origin.  Hence we are forced to regard them as a distinct species; and so it is possible that there may likewise be aerobian and anaerobian vibrios without any transformation of the one into the other.

The question has been raised whether vibrios, especially those which we have shown to be the ferment of butyric and many other fermentations, are in their nature, animal or vegetable.  M. Ch.  Robin attaches great importance to the solution of this question, of which he speaks as follows:  [Footnote:  Robin, Sur la nature des fermentations, &c. (Journal de l’Academie et de la Physiologie, July and August, 1875, P. 386).] “The determination of the nature, whether animal or vegetable, of organisms, either as a whole or in respect to their anatomical parts, assimilative or reproductive, is a problem which has been capable of solution for a quarter of a century.  The method has been brought to a state of remarkable precision, experimentally, as well as in its theoretical aspects, since those who devote their attention to the organic sciences consider it indispensable in every observation and experiment to determine accurately, before anything else, whether the object of their study is animal or vegetable in its nature, whether adult or otherwise.  To neglect this is as serious an omission for such students as for chemists would be the neglecting to determine whether it is nitrogen or hydrogen, urea or stearine, that has been extracted from a tissue, or which it is whose combinations they are studying in this or that chemical operation.  Now, scarcely any one of those who study fermentations, properly so-called,