The so-called reanimation of Rotifera has very recently again been made a subject of lively discussion, since observations have been conducted with more exactness and subjected to a stricter criticism. Baker affirmed that in 1771, he had revived paste-eels which Needham had given him in the year 1744! Franz Bauer saw his _Vibrio tritici_, which had lain four years in a dry state, move on being moistened. The remarkably careful and experienced observer, Doyère,[JS] draws the following conclusions from his beautiful experiments: that Rotifera revive, i.e. pass from a motionless state to one of motion, after being exposed to a cold of 11°.2 Fahr., or to a heat of 113° Fahr.; that they preserve the property of reviving in dry sand up to a temperature of 159° Fahr.; but that they lose this property and remain immoveable if warmed in _moist sand_ to 131° Fahr. only;[JT] and that the possibility of this so-called revivification is not prevented by their being exposed to desiccation for twenty-eight days in barometric tubes, in vacuo, even should chloride of lime or sulphuric acid be employed.[JU] Doyère has also seen Rotifera slowly revive after being dried without sand, (desséchés à nu,) a fact which Spallanzani denies.[JV] “Desiccation conducted in an ordinary temperature might be open to many objections which are not perhaps wholly obviated by the employment of a dry vacuum; but when we observe that the _Tardigrades_ irrevocably perish in a temperature of 131° Fahr. if their tissues are permeated with water, whereas they can, when dried, support a temperature that may be estimated at 248° Fahr., we are disposed to admit that the sole condition required for _animal_ revivification is the perfect integrity of organic structure and continuity.” In like manner, the sporules, or germinating cells of cryptogamic plants, which Kunth compares to the propagation of certain phanerogamic plants by buds (bulbillæ), retain their power of germination in the highest temperature. According to the most recent experiments of Payen, the sporules of a small fungus (Oïdium aurantiacum), which invests the crumb of bread with a reddish feathery coating, do not even lose their vegetative powers by being exposed in closed tubes for half an hour to a temperature of 183° to 208° Fahr. before being strewn on fresh, unspoilt dough. May not the newly discovered and wonderful monad (Monas prodigiosa), which causes blood-like spots in mealy substances, have been mixed with this fungus?