distances, the organ of sight has another measure: the images formed at the fundus of the eye, without varying in intensity, decrease in size as the object recedes; now, in proportion as the image diminishes in size, it makes a less sensible impression on us; and, when this image is of a certain smallness, it is no longer sensible. The different parts of objects should, then, disappear to us according to their size, at different distances. Hence, as soon as we have acquired sufficient knowledge of objects, we judge of their remoteness by the size of such of their parts as no longer make sensible impressions on us.

The other physiological observations to be adduced on the present occasion relate to generation. The first is calculated to perplex us rather than to elucidate the obscurities of this mysterious process; but the facts are curious and well authenticated. The EARL of MORTON, in a letter read to the Royal Society, states that he received, some years since, a male quagga, from the Cape of Good Hope. From this animal and an Arabian blood chesnut-coloured mare (who had not been leaped previously,) a female hybrid was produced, which presented indications, both in her colour and form, of her mixed breed. The mare after this came into the possession of another person, (from which time the quagga was never in her presence,) and was impregnated by an Arabian horse: the offspring was also an hybrid, for, though it had the form and general appearance of the Arabian horse, it presented in several respects the characters of the quagga, as the stripes and marks on the body and in the hair of the mane that are proper to this animal.

Some observations have lately occurred to Mr. RAFINESQUE, which refute two of the axioms that have long been prevalent amongst naturalists respecting hybrid animal productions: that quadrupeds of the same genus only are capable of producing mules; and that prolific mules result only from animals of the same species.

A female cat was left in a cabin situate in the midst of the woods of Kentucky. This cabin was perfectly insulated, being several leagues remote from any other, and there were no other cats within a distance of from fifteen to eighteen miles. On returning to his cabin, after the lapse of several months, the proprietor found his cat suckling a litter of five little monsters, like cats in regard to their body and hair, but having the head, paws, and tail, like those of the common opossum (didelphis Virginianus, of naturalists,) of the United States. These animals lived, and were shown as a curiosity about the adjacent country; but they all died young, and without having any progeny. It is, with reason, conjectured that the cat, thus abandoned and insulated, and which lived on birds, mice, and moles, while in this state, had excited a male opossum to the generative act with her, in the want of a male of the same species, for there are no wild cats even in Kentucky, (those which have been thus termed are really lynxes,) and had been impregnated by it.

Professor of botany and natural history in the University of Lexington, Kentucky, in the United States.

The native hunters of North-America believe that the raccoon (procyon lotor of naturalists,) copulates with the red fox. Mr. Rafinesque says he has seen the entire skin of one of the offsprings of this connexion: it resembled the raccoon more than the fox; it had the head, teeth, paws, &c. of the raccoon; but the neck, height, and colour of the black-tailed red fox. The black stripe on the face, which is so remarkable in the raccoon, was absent; in its place there was one of a somewhat darker colour than the surrounding parts: it was the same with the black rings on the tail. It is probable, then, that this animal, which was perfectly full grown, was the product of the union of a raccoon with a fox, both wild animals, and of different genera, families, and orders. It might, however, be suspected that it may be merely a variety of the raccoon, if the testimony of the natives, who are so intimately acquainted with the manners of the animals of the forests, was not adverse to this opinion. The fact, of hybrid na. ture, is not, however, so well established as it is in the foregoing instance.

With regard to prolific mules, it has been long known that the bison of Americat has prolific connexion with the domesticated bull or cow; and BUFFON, conformably with his notions of hybrid generation, concluded from this fact that they were of identical species, although these animals differ much more from each other than the horse and the ass, or the buffalo and the bull. The bison, which was very common in the whole of North America, and especially in Kentucky, forty years since, has now totally disappeared from the whole of the region. east of the Mississipi, where it was much harrassed: it is still found, in immense troops, in the vast prairies of the plains of the Upper Missouri; though it is constantly retiring westward and towards Mexico, in proportion as it is hunted by fire-arms. It, however, begins to be seen in a domesticated state in Kentucky and several other parts of the western states. It has become almost as tractable as the bull and cow; it likes the company of these animals, and the male readily copulates with the cow, whilst the bull has often much repugnance for the female bison. The mules which result from the connexion, commonly called half-bred buffaloes, partake of the characters of both these animals. They have the form of the cow, but they preserve the colour and the head of the bison, as well as its peculiar hair: they lose the hump, but they still have the inclined back. These copulate indifferently amongst each other, bisons, bulls, or cows; produce new races, and furnish good milk, like the cow. The gesta

There are two species, at least, having this name, east of the Mississipi, (and several west of that river,)-the canis Virginianus, and what Mr. Rafinesque has described in the Western Review under the name of canis leucurus, which differs from the foregoing by having a white tail: both had been confounded under the name of comis vulpes.

↑ Bos bison, LIN.; Bos Americanus, GMELIN. This is the animal which is now exhibited in London under the absurd name of the bonassus. It has a very elose analogy with the bos urus of Gmelin, which is now found only in the marshy forests of Lithuania, the Krapacs and Caucasus, but which formerly existed in Europe, and seems to be the urus of the Greeks.

tion and parturition of a cow covered by a bison, are, however, very troublesome and laborious.

Mr. Rafinesque adds the following instance to the known examples of prolific mules from different species of birds. The Canadian goose (anser Canadensis,) has been completely tamed in the United States, where it now exists in the domesticated state. It immediately had connexion with the domestic goose, from which there has been a prolific offspring, which have produced again new prolific mules by a further mixture of races, and which participate more or less of the nature of the Canadian species as their generation has more or less deviated from it. The Canadian goose has, however, been regarded as a distinct species by all naturalists, even by Buffon, who was led by his systematic views to restrict so much the number of species.*

Prolific union has also taken place between the domesticated duck and, as it is very improperly termed, the Barbary duck, (anas moschata, LIN.) "although," says Mr. Rafinesque, "the latter differs so essentially from the former that it should, perhaps, form a distinct genus, or at least sub-genus.+

Amongst a series of observations lately read to the Society of the Faculty of Medicine of Paris, recorded by the late Dr. DE BOUILLON, of Guadaloupe, is an account which is qualified to remove all doubts, if any yet exist, respecting the possibility of what is commonly called superfotation. A negro-woman produced, at one parturition, two male children, both at the full term of utero-gestation; but one of them was a perfect negro, the other a mulatto. The mother acknow. ledged that she had sexual intercourse in the same evening with both a negro and a white man. Dr. De Bouillon also mentions that, on this circumstance happening, there was pointed out to him a negro-woman who was delivered of three children at the same time, one of which was a mulatto, the other a black, and the third a creole. of the children were still living.

The whole

The extraordinary bulk of the placenta and of the liver, in a fetus born without an oesophagus, and the large quantity of amniotic fluid which accompanied it, of which an account has been published§ by Dr. SUNDERLAND, of Barmen, may, perhaps, be considered to furnish some degree of plausible support to the opinion that the nutrition of the fetus is not effected solely by the navel-string. On the 2d of

CUVIER says, (Règne Animal, tom. i. p. 529,) that the anser Canadensis appears to him to be a true swan. This notion favours still more the objects of Mr. Rafinesque.

It perches on trees in its wild state, which is a circumstance strongly indicative of the propriety of Mr. Rafinesque's opinion, were there even less striking peculiarities in its organization.

A collection of apparent examples of this fact is published in the 41st volume (pp. 404, 512,) of the London Medical and Physical Journal.

Algemeine Medizinisch Annalen, — band, 1821.

It is hardly necessary to mention that fetuses have been born without placenta, and others without navel-string (as in the case related by Mr. Good,) or any vascular connexion with the mother.

6

August, 1820, a woman was delivered of a child, at the full term, which appeared to be in good health. After the delivery, there flowed away a very large quantity of water, and the placenta was found to be two or three times more voluminous than ordinary. A little water sweetened with sugar was given to the child, which it eagerly swal lowed; but the liquid returned instantly by the nose and mouth, and the child seemed in danger of suffocation. All attempts to administer nutriment were fruitless; the same accidents constantly recurred. The child lived eight days, at the end of which period it died from starvation. While it lived it continued to pass feces and urine, but in smaller quantity than is common. On examination of the body, the liver was found to be of extraordinary size; it covered the abdominal viscera as low as the umbilicus; but, in point of colour and form, it presented nothing remarkable, or indicative of disease. The gallbladder was full of bile. On the liver being removed, the stomach and intestines were seen in their usual seats and conformation; but the cardia was wanting, and, at this part, the stomach adhered to the diaphragm by means of some cellular tissue. The right lung was of a rose-colour, and distended; the left, dense, and of a dark colour, showing that the child had breathed only with the former. The heart was well formed. The esophagus was wholly wanting, and the pharynx terminated in a pouch.

The systems of PATHOLOGY of BROUSSAIS, and the new Italian doctrine, as it is termed, continue to possess their partizans, and to give rise to polemical disputations. As the principles of those doctrines have been exposed in foregoing Proëmia, it is only necessary, on the present occasion, to notice the most important of the writings to which they have recently given origin, for it is by them that their history is chiefly characterized. Italy is not in a favourable state for the establishment of new medical doctrines of a systematic kind: the enthusiasm and unrestrained spirit necessary for their promulgation are controverted by political circumstances; and hence we may, in some measure, account for the comparative languor of the sectaries of Rasori, and the rapid decline of the dominion of his principles. These have lately been attacked anew by Dr. SPALLANZANI,* (a nephew of the naturalist of the same name,) but his efforts are not calculated to have much influence, even on a system already falling into ruin.

Two commentaries on the doctrine of Broussais, of very different characters, have been recently produced. One of them, by Mr. BEGIN,+ intended to advocate its principles, and display them in a more perspicuous and orderly manner than has been done by Broussais himself; the other, a jeu d'esprit,t full of the fine satire and delicate

Sulla nuova Dottrina Medica Italiana. Lettere Medico-critiche del Dottore Fisico GIOVAN BATTISTA SPALLANZANI. Reggio.

+ Principes généraux de Physiologie-Pathologique, coordonnés d'apres la Doctrine de M. Broussais. 8vo. pp. 390. Mequignon-Marvis, Paris.

Published, anonymously, in the Revue Médicale; a new monthly Journal of great merit.

ridicule which the French so well know how to employ,-which, while it displays the character and conduct of Broussais and the merit of his writings with great force and sufficient eulogy, describes his vanities, his ingenious obscurities, the nonchalance with which he cuts the gordian knots he happens to encounter, and apologizes for the art with which he has appropriated to himself the opinions of others, in a manner truly Rabelaic.

On taking into consideration the particular points in pathology which are to be noticed in this Essay, it is considered advisable to discuss in the first place such as have extensive relations, and then the rest, in the order of their general importance in regard to the welfare of the animal economy.

What is first to engage our attention is a work which is an amplifi cation of the Dissertation which gained the Jacksonian prize, on Inflammation, when the illustration of this subject was recently proposed by the Court of Assistants of the Royal College of Surgeons. This production comprises many interesting observations; but the author, Mr. JAMES, of Exeter, is too much the disciple of JOHN HUNTER, and he exhibits more of the manner of reasoning of that physiologist than a close investigation into the mode of production of the phenomena he describes: like him, he rests contented with a substitution of terms, instead of endeavouring to explain the operations of which they are only the expression: in a word, his ideas want pre cision, and his pathology depth. Mr. James adduces a new classification of inflammation. His arrangement is founded on the disposition which inflammatory action assumes to spread or diffuse itself, or to be limited by the adhesive process or other means. In this point, too, we recognize John Hunter. As, however, this fortuitous quality of inflammation but seldom constitutes a generic difference in the form which the disease assumes, but depends on several varying conditions of temperament and other things in the patient, and on accidental conditions of the atmosphere and other external circumstances, it appears to be objectionable, and not likely to be adopted by the generality of pathologists. The author's considerations in other respects, especially those relating to semiology and therapeutics, are judicious, and developed with sufficient order and perspicuity. They are characterized by such qualities, rather than by novelty of principles or originality of ideas, and therefore are not adapted for particular discussion in this Essay.t

The brain has of late been to the French pathologists what the abdominal viscera have long been to the English,--the great object of interest and the subject of their especial consideration. Several works of much value have been the results of their labours. That which

Observations on some of the general Principles, and on the particular Nature and Treatment of the different Species of Inflammation. 8vo.

A formal analysis of the work will appear in the London Medical and Physical Journal, for August.

F