TRÉCUL, _Comptes rendus de l’Académie_, t. lxxv. p. 1169, November 11, 1872. A proof of M. Trécul’s carelessness in experiments of this kind is the fact that in studying the fertility of an impregnated wort, he often obtains different productions. Our experiments give opposite results. If we sow nothing, we obtain nothing. If we sow a plant, we obtain a similar plant; or, should there be any difference, the change may be traced, beyond question, to its origin in the plant sown, and is the consequence of some alteration in the conditions of our experiment. Footnote 61: _Comptes rendus des Séances de l’Académie des Sciences_, t. lxxv. p. 1220; Nov. 18, 1872. Footnote 62: Since writing the above we have experienced some doubt as to whether the forms of development represented in Fig. 20 are actually those of the _aspergillus glaucus_, which we supposed our fungoid growth to be. In some of the later sketches of our observations we find similar forms, which belong to a bluish kind of _penicillium_, with rather large spores. Fortunately, this doubt affects our argument in no essential particular. It matters very little what variety of fungoid growth it is that gives rise to alcoholic fermentation attended by peculiarities of shape that only occur in the development of its spores when air fails it. Footnote 63: By the term _conidia_ is meant certain chains of cells, which are in reality mycelial spores. Footnote 64: See PASTEUR, _Études sur le Vin_, 1st Edition, pp. 20 and following. Footnote 65: Since writing this paragraph, we have found in M. Ch. Robin’s _Journal d’Anatomie et de Physiologie_, an article signed by that gentleman, and entitled _Sur la Nature des Fermentations_, &c. (July-August, 1875), in which the learned microscopist says:—“The _torula cerevisiæ_ is derived from the _mycoderma cerevisiæ_. My observations leave no doubt on my mind that _penicillium glaucum_ is one of the forms evolved from spores or ferments that have preceded it, as M. Trécul showed a long time ago, and that, moreover, the spores of _penicillium_, germinating in suitable media, give us the sporical form termed _mycoderma_.” We take the liberty to observe that these assertions of M. Robin’s are purely gratuitous. Up to the present time it has been impossible to discover a suitable medium for the proof of these different transformations or polymorphisms. From the time of Turpin, who firmly believed that he had observed these changes, to our own, none of the microscopists who have affirmed these transformations have succeeded in adducing any convincing proof of them, and M. Trécul’s latest observations, especially as regards _penicillium_ and its transformation into ferment or into the _mycoderma_ of beer, have been positively disproved by ours, supported, as they are, by proofs that we consider irrefutable. Footnote 66: