We append drawings of the _torulæ_ found in the six laboratory basins (see Sketches I., II., III., IV., V., VI. of Fig. 12). The abundance of the germs of these organisms in our laboratory is very striking, and is doubtless due to the nature of the work carried on there, as well as to the power of endurance peculiar to the germs, or the minute vegetative cells of these microscopic plants—a tenacity of life which prevents them from losing their reproductive powers, even after being dried up into dust. But varied as are the formations represented in Fig. 12—and it will be observed that in IV. and VI. we have shown four distinct forms, marked _a_, _a_; _b_, _b_; _m_, _m_; _n_, _n_ respectively—it must not be supposed that they correspond necessarily to distinct species. From the ends of a compound organism like those in No. III, a little spherical cell may detach itself and then, by a process of budding, give rise to a series of other minute spherical cells reproducing the form shown in Nos. I. and II. The forms figured in No. III. represent one of the types of _mycoderma vini_, which is often found in this branching arborescent state; but it frequently also occurs in short forms, and it is in this shape that it is generally met with on the surface of wines. It is true that the nature of the substratum has a great influence on the changes of aspect in the organisms which we are describing, but this is not the sole cause of their morphological modifications. We are strongly inclined to believe that each of the cells, or vegetating forms so represented, differing so greatly as they do in aspect, and begotten, all of them, spontaneously in certain appropriate liquids, in a laboratory where researches on fermentation are pursued, is capable of furnishing a distinct variety. In fact, there is not a single one of the cells in the six varieties in Fig. 12, which, taken alone, has not its own peculiar characteristics, which, by hereditary transmission, it can impart, in a greater or less degree, to all the individuals of the generations that succeed it. We may remark, on the other hand, that nothing can be more favourable to the isolation of different varieties of _torulæ_ or _mycoderma vini_ than the spontaneous impregnations to which we submit our liquids. For when suitable liquids contained in flasks exhausted of air are impregnated with the particles of atmospheric dust, by opening the flasks for a moment and then immediately re-sealing them, it must generally happen that we admit only one species of reproductive organism, so that we shall have a vegetation exclusively of one kind, as being derived from the same mother-cell. If we could take from a crowd composed of men and women separate couples, and forthwith transport each couple to a separate isolated and unpeopled island, they would, in the course of time, beyond doubt form so many distinct tribes.