tremely difficult to separate them without rupture. "If the grain has been some hours infused in water, and the extremity adroitly cut off, without injuring the interior, and then pressed with pincers, a parcel of minute eels are seen passing through the hole, just like a bit of paste drawn into a thread. When dropped into water, they scatter; and, falling to the bottom, are extended as so many straight lines, or a little curved, and remain in this position until revival. "Such variety has occurred in the time for revival, computing from the moment of humectation, that I have never seen the same thing twice. The anguilla of some grains were re-animated in three hours, or less; and others in four or five. Some required twenty hours or more; and some complete days. All those of the same grain were not re-animated at once; sometimes two days intervened between the animation of the first and last. The whole do not revive: some are disfigured and lacerated; part are always so; but some apparently entire and unhurt remain motionless. Resurrection is affected by the state of the weather: it is accelerated by heat, and retarded by cold; but here also are irregulari ties. "It may be useful to describe the symptoms which announce the revival of the eels. The first indication of returning life is a deviation from the straight lines their dead bodies formed: the head and tail begin to curve, though the rest of the body continues in a straight line. Sometimes the two extremities do not bend: the body only becomes a little arched in the middle. One will gently oscil late, while the other does not move: sometimes they approach each other until a circle is formed by the extremities touching. One extremity will rest on the other, or glide over it, or both are entwined together: sometimes the whole body is rolled into a spiral in more or fewer, in wider or narrower volutions. These bendings, arcs, oscillations, circles, twinings, glidings, volutes; these contortions are formed and destroyed, and repeated at first very languidly, then in a manner more lively and perceptible. This strange variety of motions, with others which it is unnecessary to describe, continues during all the time they live: whence it appears they have nothing that may properly be called progressive motion, which constitutes a difference between them and the other resurgent animals. They never rise in the water, nor do they crawl on the sides of the vessel; they constantly remain at. the bottom, appearing like a pel licle or spot darker or lighter, according as they are more or less numerous. "If the water fails, whether by evaporation or otherwise, the eels gradually become lifeless, and motion ceases when there is no more water. The other three kinds of resurgent animals have the prudence to fly the places where the water dries; but the eels continue in the same spot, without attempting to escape. "In several hours, they become very dry, and adhere to the substances below so tenaciously, that it is difficult to separate them without breaking: when wet, they separate easily, especially with the point of a needle. They soon soften, and, becoming pliant, it is evident they are of a gelatinous consistence; consistence; and an iron instrument cannot touch them without injury. This, at least, happens while alive: when dead some days, they are still very fragile, yet have more cohesion than one would think they resist the point of a needle, and do not suffer from a drop of water let fall from a considerable height. If dry only a quarter of an hour, the contact of water re-animates them, and in a little they become as vivacious as before. Urine, salt water, and vinegar, produce similar effects, though fatal in other circumstances, as we shall see. When dry during some days, they require a full hour for revival. If one has patience to wet them, and allow them to dry, death and resurrection will be seen in an important limitation; which is, the oftener humectation is repeated, the less the number of resurgents will be, and the longer time required for revival. I had a number of lively eels in a watch-glass, the first time they were revived: one thousandth part did not revive the eleventh time, and the seventeenth there was not one. I have often repeated this important fact, and always with the same consequence, except that the reviving eels either went beyond the seventeenth time, or died before attaining it. Not only wheel animals, sloths, and the minute eels of roofs, but also those of blighted corn, enjoy the property of resurrection circumscribed within certain limits, beyond which it is lost. The body to revive must be entire. Eels, cut into two or more parts, though often wet, and remaining long in water, never exhibit any sign of motion. All sensation is lost on division in two, after a slight universal vibration or convulsion of the body. "I have subjected the eels, as well as wheel animals, to different experiments, and first to electricity, using Franklin's battery. Those alive died instantaneously, and those dead at the time lost the property of resurrection. This did not surprise me; for almost all were broken or disfigured by the traversing shock. There was a difference in the results, if the blighted corn was subjected to the same experiment: few revived when the grains had been previously macerated; if the grains were dry, many recovered life. "As salt water, urine, and vinegar are unfit for reviving the anguillæ, at least if they have been only a short time dry, so are they fatal to them when revived; not so instantaneously, however, as to other animalcula, for eels will move in them some hours after immersion. "A vacuum does not prejudice their resurrection, whether the first time after proceeding from the grain, or in future: only resurrection is not so soon accomplished as in the open air. "The heat of the sun or the fire at 140° kills them in several hours: motion and life are almost immediately destroyed at 144° or 119o. Heat is a more powerful agent on wet grains than on dry. The observer will commonly have many eels from grains that have suffered 138°: most part are killed at that degree, if the grains are wet. "When freezing water becomes solid, the eels cease to move. Cold 8 below 0 does not destroy the resurgent property, and life returns on melting of the ice. "Plants "Plants are beings so analogous to animals, that he may be excused who has defined them rooted animals. In the works of Vallisneri, Buffon, Bonnet, and, lastly, of the abbé Corti, may be seen the numerous and various traits of analogy between these two classes of organised beings. The subject of which we treat presents a new analogy: for as different animals revive after death, so do many plants spring again after they have perished. It would be departing from my plan, was I to say as much of them as I have said of animals; and I shall be content with mentioning two, the nostoc and tremella. The nostoc, so named by Paracelsus, is a terrestrial plant, whose sudden appearance in places where there was no sign of it before was considered by the ancients rather as a prodigy of heaven or earth than as a plant. Thus they denominated it heaven's flower and earth's flower. It is seen in all seasons, but particularly in summer, after heavy rains. Though it springs in every soil, it prefers meadows, arid lands, and sandy valleys. The colour is a brownish green, the figure irregular, and resembling a leaf carelessly folded. When separated with the fingers, some resistance is felt, such as one feels on tearing a young leaf. If a sudden drought happens, the nostoc contracts and dries, remaining only a shrivelled, fine, thin skin. If a sudden and heavy rain falls, it again becomes green, and resumes its original size. Therefore the nostoc, as Réaumur, who has furnished me with this intelligence, observes, is a plant of a singular kind, since it recovers life after being in a state which to others would be permanent death. "The same privilege is possessed by the tremella, which is an aquatic plant, placed by botanists in the class conferva. If it chance to be in a vessel where the water fails, it dries, and loses its verdure; but water being supplied, it soon recovers its original state. Nature does the same as art. I have seen, from the beginning of July till the end of October, a ditch for watering land covered fifty times with the beautiful verdure of the tremella, and seen it as often disappear, when there was no water. Colourless hairs or wool only were visible at the sides and the bottom, which the microscope shewed me consisted of the tremella, dry and dead. "What can be the reason why these animals and plants are thus privileged, in comparison to many others which, perishing once, perish for ever?-Shall we perhaps ascribe it to the simplicity of their structure? But this opinion or conjecture does not seem well founded. There are many animals that never revive, whose structure is as simple, or even more so, than that of the resur gent animals. Are not many infusion animalcula, which are com posed of a simple aggregate of vesicles, undoubtedly less complex than wheel animals, which are provided with vessels, wheels, intestines, and ovaries? Yet they do not recover life when once it is lost. Simplicity of structure would even seem an obstacle to their resurrection; for the simple membrane of several species bursts on evaporation of the water: the animal is dispersed, and reduced to an unconnected and disordered heap of fragments. The arm-polypus is no less simple than the animalcula of infusions, being composed but of a granulated gelatinous skin. If simplicity of structure influenced the resurrection of animals, the arm-polypus would certainly be one; and it seems so much the better adapted for resurrection, as it continues alive notwithstanding every method has been taken to destroy animation. It is demonstrated that these polypi sustain no injury by being turned several times outside in, like a glove, or by being cut asunder. If the head is cut off, a sort of hydra with many heads arises, each of which receives food by a different mouth. If these new heads are cut off, new hydras spring up, and each head creates a polypus fit for the formation of more hydras: in short, every particle, even the smallest fragment of a polypus, unfolds, and becomes a new polypus. If an animal so mangled and lacerated does not die, will it not be very credible that, only be ing allowed to remain dry, it may still retain the faculty of resurrection? But facts prove the reverse. The arm-polypus always dies when the water evaporates; and this happens equally whether it is immediately exposed to the air, or lies concealed among its native sub-aquatic herbs. When the water is almost exhausted, the arms are retracted into the animal; it contracts within itself, and dies. It never recovers, though water is copiously supplied. I speak of the arm-polypus, for it is the only species I have been able to find, and is the smallest of Trembley's arm-polypi. "Next to polypi and infusion animalcula, according to my description, the organization of the 1803. sloth seems to be the most simple. We may say the same of the anguillæ of tiles and blighted corn, two species of serpentuli, which may properly be classed with so great a number of the inhabitants of fluids from their organization. Under the tremella in water are often found minute eels, very like those of tiles in size, shape, and simplicity of organization. I have frequently had the curiosity to let them dry, by the water evaporating: all endeavoured to conceal themselves where the filaments of the tremella were thickest ; and when evaporation was complete, they perished, remaining partly entwined among the filaments, and partly heaped above one another. If immediately wet, they revive; but never, if a few minutes elapse. "The eels of vinegar give the strongest evidence of vigour : though they continue motionless when the fluid fails, and are apparently dead, they recover life and action, if wet, after a quarter of an hour. Sometimes I have succeeded in reviving them after half an hour. I do not call this resurrection: if it was such, I cannot see why it should not succeed anew when wet with vinegar, in even a longer time: we may rather say, they do not die so soon as the eels of the tremella, and many other insects left dry: life, though suspended, is preserved, and appears on humectation. "I can discover no greater simplicity in the tremella and nostoc than in many plants that do not revive. Let us throw a hasty glance on the truffle. What vegetable is more simple ? roots, tendrils, or fibres, internal or external; a substance equally compact and uniform throughout, 0 No only only interrupted by veins similar to those winding on some species of marble. It has no analogous organization with other plants, either terrestrial or aquatic; yet truffles, after once drying in the air, do not revive, if put in water. "These mited facts prove the fallacy of those opinions which attribute the resurrection of animals to the simplicity of their organization. But to what other principle can we recur? for we are here constrained to proceed on conjecture, rather than evidence and the view of truth. I shall suggest an hypothesis without engaging to support it. Haller's experiments demonstrate that the vital principle of animals with a heart originally resides in the irritability of this muscle. His experiments are too well known to need repetition. In animals which have no heart, it is more than probable that the principle of life resides in the irritability of their muscles. This being admitted, if the state of the animals is such that the irritable nature of the heart and muscles is destroyed, so as to leave no hope of reparation, it is clear that the animal not only dies, but must always remain dead if the irritability is such that it may be re-excited, either naturally or by art, it is indubi table that the animal will pass from death to life. It will not signify though it remains dead a long time, even for an age. The reader comprehends my idea. When wheel animals, sloths, and the eels of tiles are deprived of water, their irritability is evidently lost, and they die. Other animals, having once lost this irritability, never recover it; but it is awakened in wheel animals, sloths, and eels, and they return to their origin life by humectation. "From the same principle, may we explain why, in certain cases, these animals lose the resurgent property when exposed to powerful heat or penetrating odours, or when some liquids and electricity act upon them. Such agents injure the muscular structure, as ap pears by the rupture of the body and destruction of the irritable power residing in it. This perhaps is the reason why frequent humectations prejudice resuscitant ani mals; for I have really seen it; and in particular observed, that the members of the eels of blighted corn were injured and lacerated by repeated humectation. "We must conclude, from the whole, that as irritability resides in the glutinous part of the mus cle, this part of resurgent animals has qualities very different from the irritable parts of other ani mals, though we are profoundly ignorant of what constitutes the difference, because we foundly ignorant of what the glu ten consists. are pro "I wish to be sincere. A conclusion against the hypothesis may be deduced from my experiments. Irritability is recognised by its appearance, that is, on touching the muscular fibre with any stimulant, it contracts, and becomes rigid. I have often stimulated the mus cular substance of the eels of blighted corn and tiles, with an extremely fine iron point, and attentively observed the consequence. The muscular fibre always seemed to contract a little, when touched, but I must acknowledge the same thing happened to the anguille of vinegar, and to other analogous animalcula, which do not enjoy the |