Other evidence which is so much vaunted by M. Pasteur and his supporters, as to the possibility of inducing fertility in previously sterile flasks, by the addition of a portion of asbestos containing the solid particles filtered from the atmosphere,[80] is also equally valueless for confirming the proposition that fermentation is only capable of being initiated by living ferments. The same asbestos which _may_ contain living spores or organisms (“germs”), does undoubtedly contain many decomposable particles and fragments of organic matter.[81] The previously barren solution may therefore be rendered fertile by the mere addition of those portions of unstable organic matter, whose molecular mobility has not been impaired by the agency of heat, and which are therefore capable of initiating fermentations. This view is strengthened, as M. Pouchet has pointed out, by the fact that in these cases, instead of meeting some of the _various_ kinds of organisms which are supposed to have representatives in the air, and whose spores or ova may be supposed to have been sown, it is often merely _Bacteria_ which are encountered,--differing in no respect from those that may present themselves in a somewhat similar infusion, which has undergone change in a closed flask without any such hypothetical sowing of living spores or germs. It is more especially important to bear in mind this consideration, when portions of organic matter can always be easily demonstrated amongst such atmospheric dust; whilst living _Bacteria_, or other organisms, such as are first produced as a result of the supposed sowing of spores, either cannot be demonstrated, or would seem, from other evidence, to be at least very sparingly distributed.[82] [80] Loc. cit., p. 40. [81] Speaking of experiments in closed flasks, in which the air has been either calcined or filtered, Gerhardt (‘Chimie Organique,’ t. IV. p. 545) says:--“Si dans les premières expériences l’air calciné ou tamisé s’est montré beaucoup moins actif que l’air non soumis à ce traitement, c’est que la chaleur rouge ou le tamisage enlève à l’air non seulement les germes des infusoires et des moisissures, mais encore les débris des matières en décomposition qui y sont suspendues, c’est-à-dire les ferments dont l’activité viendrait s’ajouter à celle de l’oxygène de l’air.” [82] On what other supposition can one explain the results of experiments LVII.-LXV., and of others alluded to on p. 100?