Plate IV. represents in its two halves the condition of the _mycoderma vini_ at two different and unequal periods after its submersion. In the left-hand semi-circle, it is evident that many of the figures are swollen, that modification of their protoplasm has taken place, and incipient budding is going on in several of them. A budding of this kind would not wither; the buds would grow and, detaching themselves, would form new cells capable of budding in their turn. We should have under our eyes all the characteristics of a yeast, which, beyond doubt, would give rise to a very active fermentation, inasmuch as it would belong to the order of phenomena of nutrition and vital energy of which we are speaking. Instead, however, of insisting upon the acceptance of our interpretations, based on a few facts merely, let us go on to accumulate facts, varying the conditions as much as possible. Our examples, taken singly, may seem insufficient to establish the theory that it will be our endeavour to substantiate, but taken together we trust that they will secure our readers’ confidence. We may now, perhaps with advantage, introduce two new expressions to embody the preceding facts, by the help of which we may often shorten our subsequent explanations. Since life can continue, under certain conditions, away from contact with the oxygen of the air, and since the altered nutrition is accompanied by a phenomenon which is of great scientific as well as industrial importance, we may divide living beings into two classes, _aërobian_, that is those which cannot live without air, and _anaërobian_, which, strictly speaking, and for a time, can do without it; these latter would be ferments, properly so called. Again, since we can conceive, in an entire organism, some organ or even a cell capable of existing, at least momentarily, apart from the influence of the air, and endowed at a given moment with the character of a ferment, we may, in like manner, make use of the expression _anaërobian_ cell, in opposition to a cell that is _aërobian_. As long ago as 1863, in our work on putrefaction, we proposed to adopt the preceding expressions, and since then we have had the satisfaction of seeing them used by different authors in France and other countries. One of the principal assertions in this paragraph relates to the non-transformation of _mycoderma vini_ into other moulds or into yeast.[69] [Illustration: Plate 4. Mycoderma Vini functioning as an Alcoholic Ferment.—Right Half, showing Appearance of Spores just Sown; Left Half, their Appearance after an Interval of Submerged Life.]