In 1707, Spallanzani found it possible, eleven times in succession, to suspend the life of rotifers submitted to desiccation, and to call it back again by moistening this organic dust with water. A few years ago Doyere brought to life some tardigrades that had been dried at a temperature of 150 deg. and kept four weeks in a vacuum. If we ascend the scale of beings, we find analogous phenomena produced by diverse causes. Flies that have been imported in casks of Madeira have been resuscitated in Europe, and chrysalids have been kept in this state for years. Cockchafers drowned, and then dried in the sun, have been revived after a lapse of twenty-four hours, two days, and even five days, after submersion. Frogs, salamanders, and spiders poisoned by curare or nicotine, have returned to life after several days of apparent death. Cold produces some extraordinary effects. Spallanzani kept several frogs in the center of a lump of ice for two years, and, although they became dry, rigid, almost friable, and gave no external appearance of being alive, it was only necessary to expose them to a gradual and moderate heat to put an end to the lethargic state in which they lay. Pikes and salamanders have at different epochs been revived before the eyes of Maupertuis and Constant Dumeril (members of the Academy of Sciences) after being frozen stiff. Auguste Dumeril, son of Constant, and who was the reporter of the committee relative to the Blois toad in 1851, published a curious memoir the following year in which he narrates how he interrupted life through congelation of the liquids and solids of the organism. Some frogs, whose internal temperature had been reduced to -2 deg. in an atmosphere of -12 deg., returned to life before his eyes, and he observed their tissues regain their usual elasticity and their heart pass from absolute immobility to its normal motion. There is therefore no reason for doubting the assertions of travelers who tell us that the inhabitants of North America and Russia transport fish that are frozen stiff, and bring them to life again by dipping them into water of ordinary temperature ten or fifteen days afterward. But I think too much reliance should not be put in the process devised by the great English physiologist, Hunter, for prolonging the life of man indefinitely by successive freezings. It has been allowed to no one but a romancer, Mr. Edmond About, to be present at this curious operation. Among the mammifera we find appearances of death in their winter sleep; but these are incomplete, since the temperature of hibernating animals remains greater by one degree than that of the surrounding air, and the motions of the heart and respiration are simply retarded. Dr. Preyer has observed that a hamster sometimes goes five minutes without breathing appreciably after a fortnight's sleep.