M. Béchamp (_Comptes rendus_, November 18th, 1872) asserts that _the air has no direct influence on the production of ferment or on the process of alcoholic fermentation_. That experienced chemist deduces this erroneous assertion from experiments on sweetened water, to which bunches of grapes, petals of corn-poppies and petals of _robinia pseudo-acacia_ had been added. As may be seen in our “Studies on Wine” (p. 7, 1st edition, 1866), these experiments conducted by M. Béchamp in 1872 were merely a reproduction of those made long before with vine leaves, petals of elder-flowers, leaves of sorrel, &c., by the Marquis de Bullion, Fabroni, and other experimentalists. M. Béchamp has modified his later experiments by not adding the bunches of grapes, leaves, &c., to the sweetened water before having introduced carbonic acid gas into the liquid. Fermentation having still taken place in spite of this change, M. Béchamp wrongly concluded that _air has no direct influence on the production of yeast on an alcoholic fermentation_. The introduction of the carbonic acid gas could not remove all the air imparted to the sweetened water by the objects placed in it, and it was this air which remained adhering to these objects that permitted the production of fermentation. We may avail ourselves of the opportunity here presented to add that, in this same Note of November, 1872, M. Béchamp commences by making various assertions concerning the forms assumed by cells of the alcoholic ferment of the grape when in process of fermentation. This question was discussed by us ten years before, and our conclusions supported by sketches, in a Note which appeared in the _Bulletin de la Société chimique de Paris_, for 1862. Footnote 98: The germs of ferments are less widely diffused than M. de Bary supposes, as may be seen from our observations in Chap. III. See, too, our Memoir of 1862, _Sur les Générations dites Spontanées_, p. 49. It is only in a laboratory devoted to researches on fermentation, or places such as vaults, cellars, and breweries, that the air holds appreciably in suspension cells of ferments, ready to germinate in saccharine media. If we except these particular circumstances, ferment is not very largely diffused, save on the surface of fruits and the wood of the trees which bear them, and perhaps, also, on some other plants. The particles of dust held in suspension in any atmosphere whatever rarely produce fermentation in pure must even when we take all possible precautions, so that the action be not overlooked; for true fermentation may be hidden by fungoid growths, when there is much air and but a small quantity of saccharine liquid present. Footnote 99: