this he subjected the flasks to a heat of from 212° Fahr. to over 400° Fahr. After being left a few days under favorable situations, and then examined, they were found to contain the living creatures we have described. The only remaining question is, Could these organisms or their germs survive this degree of heat? The alternative to which the opponents of spontaneous generation seem to be driven, by these investigations, is thus pointedly stated by Mr. Alfred Russell Wallace, in a late review of Dr. Bastian's book, in Nature. He says: "The only way of escaping from the results of such a series of experiments as that here recorded is by asserting that, although the organisms which are produced in the flasks are killed by a temperature much below that
Fig. 5.
Transformation of a Mass of Chlorococcus Corpuscles into the so-called "Winter-egg" of Hydatina senta. (x 250.)
a, Ovoid mass of bright-green Chlorococcus Corpuscles, about 1/300 in long diameter: b, Such a mass after its transformation into a brown granular body, without distinct bounding wall (should have been intermediate in tint between a and c); c, A similar body at a later stage, when a limiting envelop has made its appearance, upon which villous outgrowths had been produced; d, Later stage, constituting the so-called "winter-egg" of Hydatina; e, Hydatina senta which is produced from such a body—almost adult.
to which the flasks have been subjected, the germs from which they have been produced are not so killed. We are asked, therefore, to accept as facts three pure suppositions: first, that such excessively minute and simple organisms as bacteria, whose only mode of multiplication is by fission or gemmation, have germs which possess different physical properties from themselves; secondly, that these germs, as well as many others, are omnipresent in the atmosphere; and, thirdly, that they are not injured by an exposure for four hours to vapor heated to over 300° Fahr.; and, finally, we are to accept all
