after the separation, swam in the fluid. The animaleula of the second stratum did the same, likewise those of the successive strata, until the globe was entirely decomposed.'

- What a field for contemplation and inquiry is here opened to the philosopher! It seems that these minute inhabitants of our world have not merely life imparted to them, but passions and affections; for the author tells us, (p. 61.) that some of them carry on fierce wars among themselves. How severe a satire on human ambition is this remark!

On making experiments with infusions exposed to the air, and others more or less secluded from it, the author came to the following conclusion

The number of animalcula developed, is proportioned to the communication with the external a. The air either conveys the germs to the infusions, or assists the expansion of those already there.

The Second Tract contains observations and experiments on. the vermiculi seminales hominum, animalium aliorumque; with an examination of the theory of organic molecules. It has been the singular fortune of Leuwenhoeck, that his observations have been discredited chiefly on account of the extravagant conclusions which he drew from them. His facts are now re-estab lished by the present author's experiments; and the fallacy of Buffon's observations is laid, open.The miscellaneous nature of our Review precludes the discussion of this subject, though so curious in itself, and so ably treated by M. Spallanzani,

In the succeeding tract, consisting of experiments and observations on, animals and vegetables confined in stagnant air, we are greatly surprized to find the author treating on the causes of death produced by impure air, without any reference to the present theory of respiration. He speaks of atmospheric air as a homogeneous fluid; and he only inquires whether its elasneity be impaired by the respiration of animals confined in it. He has drawn a vague inference from his experiments, that the animals are destroyed by a poisonous matter exhaled from thein lungs. We are astonished by the unacquaintance with modern chemistry which this essay discloses.

The tract on some singular animals, which may be killed, and afterward revived, is highly curious and interesting. The Professor is here at home again. This essay turns chiefly on the properties of the wheel-animal, and the sloth.-The wheel-animals may be killed and revived repeatedly, by keeping them dry, and without sand, and afterward moistening them with water. This process of death and resurrection was

775

carried

carried on successfully eleven times, with the same insect. It is a singular circumstance that their revival cannot be effected without the presence of sand. We shall transcribe the enter taining commencement of the second chapter of this essay:

The sand of tiles, the mud of ditches, and of marshes, which pass in the vulgar eye for the vilest of matter, are to the philosophic observer a source of wonder, from the singular beings they contain. To ditches and marshes we owe the armed, club, funnel, bulb, and knotted polypus. It is there we find the fresh water worm, the boat worm, and the springing millepede. Those animals have confounded the human mind, and have created a new philosophy. When the sand of tiles does not serve for an abode to wheel-animals, it will. not for that reason be less famous or remarkable. An animal, which revives after death, and which, within certain limits, revives as often as we please, is a phænomenon, as incredible as it seems improbable and paradoxical. It confounds the most received ideas of animality: it produces new ideas, and becomes an object no less interesting to the researches of the naturalist, than to the speculations of the metaphysician. But the celebrity of this sand will encrease, when we learn, that it contains other animals, which, like the wheelanimal, possess the property of resurrection; so that we may almost say, all the animals living in sand are destined to be immortal. I have discovered in sand two new species of animals, which I proceed. to describe. I lament that their rareness has prevented me from extending my observations as far as I could have wished, or rather as far as the importance of the subject would have required.'

The new animals, of which particular descriptions are given, are the sloth, and a minute species of eel; which possess the faculty of reviving after apparent death, like the wheel-animal.

The analogy between animals and vegetables is preserved, M. Spallanzani remarks, in this curious property for many plants spring again after they have perished.' He instances two, the nostoc and the tremella.-He thinks that these facts cannot be explained by supposing that the power of revival depends on simplicity of structure, because other plants and animals, equally simple in their conformation with these, do not possess such a power. He suggests the following explanation:

In animals which have no heart, it is almost probable, that the principle of their life resides in the irritability of their muscles which being the case, if the state of animals is such, that the irritable nature of the heart and muscles is destroyed, so as to leave no hope of it being repaired, it is clear that the animal not only dies, but must always remain dead: but if the irritability is such, that, either by nature or art, it may be re-excited, it is certain that the animal should pass from death to life. It will not matter that 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 lost, as is evinced by facts, and they die: when other animals have once lost this irritability, they never recover it; but wheel-animals, sloths, eels of tiles, &c. resume at once their original life.'

With every possible respect for the character of this eminent naturalist, we must take the liberty of saying that this is no explanation of the phænomena in question: it is merely an enunciation of the facts, in abstract terms; and the reader who analyses it will perceive that he is only informed that, if irritability can be re-excited, under certain circumstances, it may be re-excited. There needs no ghost come from the grave to tell us this, Horatio!

*

In the preceding tract, on the origin of the plantula of mould, the author had taken occasion to discuss, and to confute, the doctrine of spontaneous generation. The microscope shews that the globules, or minute heads of ramose mould, are really mushrooms. The black dust of mould was proved by experiments to be its seed i

But, does the mould, which springs without being sown, and by the care of nature alone, upon an infinity of substances dispersed here and there, also derive its origin from the dust we may suppose disseminated through the air, and upon terrestrial substances? If natural and artificial mould are of the same species, and if the artificial is produced by the dust of the natural mould, I cannot see why the last should not derive its origiu from the same principle, especially since it is demonstrated, that no other part of the mould, as the roots and stalks, aid the reproduction. The hypothesis, sup posing that this dust is invisibly scattered through all, and gives existence to a great quantity of natural mould, is one of the most reasonable hypotheses in philosophy. If each head of ripe mould can furnish a million of seeds, as we have seen, and if each spot of mould contains a prodigious number of heads, it is clear, that in some years, the dust should be extremely multiplied; particularly, from its levity and fineness, it may be universally spread.'

The last piece in this volume is a memoir, by the late excellent M. Bonnet, on the re-production of the head of the land-snail, containing some additional details concerning his observations on that curious subject.

The language of the translation of these tracts is often ungrammatical and inelegant, and we have noticed some foreign idioms, and several uncouth turns of expression which fall under the denomination of Scotticisms. On the whole, however, the task is performed in a creditable manner.

Since the appearance of this volume, the public prints have announced the death of its celebrated author. We apprehend

Irritability! Nothing in physiology wants explanation more than this most mystical and most convenient term.

that

that he had too little of the Sloth in his composition, to allow us to hope that he will revive from the sleep from which no man awakes in this world.

ART. VIII. A Treatise on Febrile Diseases; including Intermitting, Remitting, and Continued Fevers, Eruptive Fevers, Inflammations, Hæmorrhages, and the Profluvia; in which an attempt is made to present at one view, whatever, in the present state of Medicine, it is requisite for the Physician to know respecting the Symptoms, Causes, and Cure of those Diseases. By Alexander Philips Wilson, M. D, F. R. S. Edinb. Physician to the County Hospital at Winchester, &c. Vol. I. 8vo. pp. 682. 9s. Boards. Cadell jun, and Davies. 1799.

TH

HIS work may be considered as a publication of Dr.. Wilson's lectures on the subjects indicated in the copious title-page, and it is offered to students as an ample text book, the study of which may supersede the necessity of resorting to the more voluminous systematic writers. It necessarily partakes of the defects of compositions thus originating, and thus directed. The diffuse mode of instruction, adapted to the lecture-room, is irksome to the reader; and the great difficulty of combining, in one book of moderate size, a clear representation of the infinite number of facts and opinions scattered through original writers, which has been so often felt, is again, demonstrable from the work before us. If, indeed, Dr., Wilson should complete his plan, (which will require, he imagines, four other volumes, of equal size with the present,), we do not conceive that much labour will be saved to the student by perusing them; and we apprehend that Dr. Cullen's first lines, with all their imperfections, will still continue to be preferred as an elementary book.

The introduction is occupied by criticisms on the arrangement of diseases, in Dr. Cullen's Nosology; which will not be univerally interesting. Systems of Nosology are now generally regarded more as guides in reading, for the purpose of particular reference, than as authorities in opinion; and Dr. Cullen's arrangement will be chiefly consulted as a reasoned index, by practitioners who are acquainted with books and diseases. If the classification of diseases, without changing the nomenclature, were of any importance, we should certainly object to the author's distribution of some species, particularly that of Erysipelas: but discussions of this kind are totally unprofitable.

Although Dr. Cullen's System is apparently attacked by Dr. Wilson, yet the present Treatise is in reality a diffuse commentary on the "First Lines;" a great part of it, therefore, will be regarded as a repetition of the Professor's work. We acknowlege,

however,

however, that Dr. Wilson has exerted great industry in filling. up Dr. Cullen's outlines; and we think that his selection of facts has, in general, been judicious; yet the student may sometimes wish that the collection had been less copious. In point of arrangement, Dr. Wilson has not been happy; he has treated. of intermittent, before continued fevers; and he has been under the necessity of referring almost every point of importance from the former, to what he means to say on the latter. This inconvenience he seems to have felt so much, that we are surprized that this part of the work was suffered to remain in its present form. There cannot be a stronger proof of improper order, than the impossibility of treating what belongs to a subject under the head assigned to it.

The observations on the cure of intermittents are solid and judicious; the only remark which occurs to us as important, on Dr. Wilson's opinion, respects the use of hepar sulphuris, as an antidote to an over-dose of arsenic. We have had occasion to try this remedy, which has been recommended purely from chemical affinity; and we have found that very severe purging was produced by it. Dr. Wilson does not seem to have employed the preparations of arsenic to any considerable extent; otherwise, he would probably have spoken with more confidence of their efficacy and safety, under prudent manage-, ment:but his caution; in this respect, is less remarkable, as we find him occupying some pages with a defence of the innocence of Peruvian bark in intermittents': a question which, we believe, no apothecary's boy, in this country, would now require to be elucidated. Discussions of this nature may at this time be properly neglected: since, if the patient be cured, it is no longer inquired whether the cure has been effected according to rule. It may perhaps be of some use to give the younger student an idea of the objections and difficulties which he must expect to encounter from the nurses and old ladies, on his entrance into practice: but the collection of these Veteres Avia, which would form a curious subject for an intelligent. observer, ought to be reserved for the esoteric lecture.

The description of the symptoms of continued fever is accurate, and less spun-out than the section on intermittents. Respecting one symptom, we must differ from Dr. Wilson; he supposes the black fluid, or rather that substance resembling coffee-grounds, which is discharged by stool and vomiting in the fevers of warm climates, and sometimes in those of our own, to be occasioned by a vitiated state of the bile. We have no hesitation in ascribing it to a slow oozing of blood, from the minute vessels in the villous coat of the stomach and intestines. The tar-like stools are so completely similar to

those