dermis, constituting vesicles; and lastly, there may be suppuration, and the formation of pustules; each of these stages following an ascending grade of irritation; the degree in which the irritation is evinced depending in a greater measure on the temperament of the individual than upon the quantity of the

cause.

"Guided by the Willanean classification alone, we should be led, seeing the alterations above described, in their first stage, to refer the disease to that group which includes erythema; in its second degree of severity, we might follow the example of all the dermatologists of the present day, and regard it as a vesicular disease, while in the highest and less frequent form of aggravation we should place it, as did Willan, among the pustules. It is clear, from the differences of such distinguished men, that any attempt to deduce its true position in cutaneous nosology from the accidental appearances respective of degree of irritation that it may present, must not only fail, but lead to serious errors in diagnosis. I have seen cases of scabies in which there were no vesicles and no pustules, but, nevertheless, the acarus revelled there in undisturbed enjoyment. Where would be the reputation of the medical practitioner who took no steps in such cases to protect the families in which they existed against the transmission of so repulsive a disease?" 288.

In the ninth chapter those diseases are assembled which depend on hypertrophy of the papillæ of the dermis; a pathological condition that, determined to be present in Icthyosis, causes the removal of that disease, from the squamæ of Willan, to a much more natural group, including corns, warts, and horns. The tenth chapter comprehends. under the title of disorders of the vascular tissue of the dermis, Nævus and Purpura. The eleventh chapter includes disorders of the sensibility of the dermis, and the twelfth, disordered colouration of the skin.

Diseases of the sudoriparus glands form the subject of chapter thirteen, and diseases of the sebaceous glands of chapter fourteen. Under the name of Icthyosis Sebacea, the author describes a remarkable form of concretion on the surface of the skin, simulating ichthyosis, and, no doubt, sometimes mistaken for that disease.

"In addition to simple increase in quantity, it occasionally happens that the secretion of the sebaceous glands is also altered in its quality; when this is the case, the secretion spreads upon the surface of the epidermis, and forms a thin layer, which dries and hardens, and breaks in the direction of the linear markings of the skin into small polygonal portions, corresponding in form with the area of the compartments, bounded by these cutaneous lines. The small polygonal divisions are increased in thickness by the accumulation of fresh sebaceous secretion, they become discoloured from exposure to dust and dirt, and they assume a brownish or grayish tint, approaching more or less to dirt colour. In the latter state, the small masses have the appearance of scales, (icthyosis sebacea,) closely adherent to the epidermis, hard and dense in texture, and presenting various degrees of thickness. This affection may occur upon any part of the body, but is most frequent on the face, particularly on the forehead and the nose, upon the abdomen, and upon the flexures of joints; indeed, upon all those regions in which the greatest number of sebaceous glands exist, and which are most protected from the friction of dress. The scales are sometimes cast from time to time, particularly during the summer season, and give place to others formed by successive concretion; at other times they remain adherent for months, and even for years." 292.

This disorder has recently been made the subject of a pamphlet by Dr.

Jacobovics of Pesth, in which that author ascribes to it the name of "tubercules bigarrés," and erroneously considers it a new variety of Molluscum. On Molluscum Contagiosum Mr. Wilson disserts largely, and advances some new cases of this disorder. He positively denies the contagious property ascribed to the disease by Bateman, and examines the evidence of their nature and history given by Tilesius, Bateman, Dr. John Thomson, Dr. Carswell, Alibert, Biett, Cazenave and Schedel, Gilbert, Dr. Jacobovics, Dr. Henderson and Dr. Paterson.

The diseases of the Hairs and their Follicles engage the thirteenth Chapter. Ringworm is considered under the name Favus, assigned to it by Rayer, and the complexity which has hitherto attended this disease is well explained by the author.

"No term has been more abused in medical nomenclature than has the word porrigo, and the confusion which exists in relation to the precise disease intended to be conveyed by the appellation will not cease, until the term is discarded altogether. It is with this view that I have made no use of it in the present treatise, other than as synonym. The species of porrigo of Willan, applied by that author to the disease under consideration, are two-porrigo lupinosa, corresponding with our favus dispersus; and porrigo scutulata, the favus confertus. A very common appellation for favus in the words and works of many of the most eminent English practitioners of the present day. and, indeed, the most correct term, is porrigo favosa. Here I conceive Willan erred; for both that author and Bateman employ the designation as significant of a variety of impetigo-impetigo of the scalp. Porrigo larvalis is impetigo faciei; porrigo furfurans appears to be an eczema, or, probably, pityriasis; and porrigo decalvans an alopecia." 315.

Speaking of the supposed vegetable nature of this disease, Mr. Wilson observes, and very justly:

ture.

"However closely the fungous growth here may resemble a plant, its vegetable nature is very far from being established. The simplest forms of animals are composed, like the mycodermis, of cells, variously connected together; and subsequent research may prove the growth under consideration to be of a similar naTo my mind there is nothing improbable in the supposition of the origin of the growth from morbidly developed epidermic cells of the hair-follicle, or from the corpuscles of the sebaceous substance. In a preceding section of this work, I have shown that the latter are susceptible of considerable alteration, and that in this state they assume an appearance widely different from that of their normal condition. Mr. Busk also entertains doubts with regard to the vegetable nature of the mycodermis, and deduces an opinion favourable to his opinion, from the chemical analysis of the crusts of favus, given by Thenard, who found them composed of

Syphilitic affections of the skin form the subject of chapter sixteen; while the seventeenth and last is occupied by the history and description of the entozoa of the skin, the acarus scabiei and folliculorum; the preparation and therapeutic effects of two new medicines, Anthrakokali and Fuligokali; and a notice of three cases of a very rare disease, the Sudatoria, which occurred in Paris during the summer of 1842.

The Acarus folliculorum was discovered by Dr. Simon of Berlin, and a paper describing his discovery with figures of the animal, appeared in Muller's Archive for June 1842. The description of the animal given by the discoverer is however very imperfect as regards its anatomical structure. Mr. Wilson, in the work before us, makes some additions to the anatomy of the animal, and in a paper recently read before the Royal Society finds reason to alter the name of the creature, to entozoon folliculorum. In this paper he gives an elaborate description of the anatomy of the Entozoon, shows that it differs essentially from the generic characters of Acarus, and discovers its ova and mode of development, the latter being an elaborate and curious process. Of his success in finding the animal after perusing the paper of Dr. Simon, he thus speaks:

"I was not long in obtaining subjects: almost every face that I met supplied me with abundance, and the difficulty seems to be, not to find the creature, but to find any individual, with the exception, according to Dr. Simon, of newly-born children, in whom these animalcules do not exist. It is by no means necessary to commence our search by selecting an acne punctatem, or even a comedo; almost every collection of sebaceous substance which can be squeezed forth from the numberless cutaneous apertures upon the nose, the forehead, the face, and probably from other parts of the body, will furnish subjects. Moreover, Dr. Simon has observed that the parasites are situated near the mouth of the follicle; consequently, that portion of sebaceous substance which is squeezed out with the least force is the part which is most likely to be inhabited by the acarus.

"The acarus folliculorum would seem to give rise to no uncomfortable effects by its presence, unless, perchance, it should multiply to such an extent as to become a source of irritation to the follicle-a supposition which Dr. Simon admits, for it is found in persons whose skin is perfectly healthy and clear, and in whom no signs of cutaneous irritation are present. These animalcules undoubtedly feed on the sebaceous substance in which they lie embedded, and which is the cause of their existence. I have commonly found two in the small mass of this substance expressed by the fingers, often four and five, and in one instance eight closely connected together. Hitherto I have confined my examinations to living persons, having levied for contributions among my more intimate friends, and have not as yet had recourse to a skin studded with acne." 389.

We have now reached the conclusion of the volume, and our perusal has been both agreeable and instructive. The work is well got up, it is illustrated with a wood-engraving title-page of the entozoon folliculorum, and presents an excellent key to its matter in an ample table of contents and alphabetical index. The book is not written for a day, but for an age; the style is good and precise, the language well selected, and the information which it contains genuine and copious. We think it adapted to cast a new light on the pathology and treatment of diseases of the skin, and to form an admirable guide to the medical practitioner, to whom and to the student we warmly recommend it.

PRINCIPLES OF HUMAN PHYSIOLOGY, WITH THEIR CHIEF APPLICATIONS TO PATHOLOGY, HYGIENE, AND FORENSIC MEDICINE. Especially designed for the use of Students. By William B. Carpenter, M.D. Lecturer on Physiology in the Bristol Medical School, &c. London, Churchill, 1842. pp. 680.

THE elementary treatises on Physiology published in this country of late years, have scarcely brought their information up to the level of the science which existed even at the time of their first appearance: and the rapid progress of physiological knowledge has now left them far in the rear. The works of Bostock, Elliotson, Mayo, and others, though containing much valuable matter, scarcely touch upon certain facts recently established, and views recently divulged, which at present give, to the whole science of life, its principal impulse and direction. Dr. Carpenter's book, therefore, has not made its appearance uncalled for, while its peculiar character would have rendered it valuable, even though the sources of elementary information for the English student of physiology had been more abundant than they are. It might be thought that the excellent English versions of the first German physiologists which have either been recently completed, or are now in progress as those of Muller and Wagner-would have supplied the deficiency referred to. But it will be found on examination, that these works, though of a higher scientific cast than the treatise before us, are not as well calculated for the use of the student-the profound and original views, and elaborate detail of the minutest facts with which they abound, rendering them much more profitable to the mature physiologist, than to one only just entering on the same grand but bewildering field of research. Dr. Carpenter's work is, in particular, much better adapted to the medical student than any other of the kind that we have met with, in as much as its plan has a direct reference to medicine, and the bearings of physiology on the various branches of that science and art are set forth in a philosophical and lucid

manner.

Dr. Carpenter introduces his subject by a general view of the connexion of physiology with the other branches of medicine. This introduction cannot be too strongly recommended to the student. It contains a very able and comprehensive yet simple exposition of the relations of the science of life to medicine in general of the dependencies of the different branches of medicine on each other-and of the relative value of the practical conclusions derived from scientific principles, and from direct experience.

CHAPTER I. treats of the place occupied by man in the scale of being, and involves the consideration of the distinction between animals and plants-the general subdivisions of the animal kingdom-the characters of its four primary groups-and the characteristics of man. All these subjects are treated with accuracy and judgment. The following is an ingenious addition to the various attempts at forming a precise line of demarcation between animals and vegetables.

"A distinction might probably be erected between the animal and vegetable kingdoms, upon the mode in which the first development of the germ takes place. The seed of the plant at the time of fertilisation, principally consists of a store of nourishment prepared by the parent for the supply of the germ, which is introduced into the midst of it. The same may be said of the egg of the animal. In both instances, the first development of the germ is into a membranous expansion, which absorbs the alimentary materials with which it is in contact, and prepares them by assimilation for the nourishment of the embryonic structure, the most important parts (in the higher classes of animals, and in phanerogamic plants, the only permanent parts) of which are in its centre. Now, in plants, this membranous expansion (the single or double cotyledon) absorbs by its outer surface, which is applied to the albumen of the seed, and takes it more or less completely into its own substance. In animals, this expansion is developed in such a manner, that it surrounds the albumen, enclosing it in a sac, the inner surface only of which is concerned in absorption. This sac is, then, the temporary stomach of the embryonic structure; it becomes the permanent stomach of the radiata; but in the higher classes only a portion of it is retained in the fabric of the adult, the remainder being cast off, like the cotyledon of plants, as soon as it has performed its function. Thus, then, the first nisus of animal development is towards the formation of a stomach, for the internal reception and digestion of food, whilst the first processes of vegetable evolution tend to the production of a frond-like membrane, which, like the permanent frond of the lower classes of plants, absorbs nourishment by its expanded surface only." 12.

This distinction obtains uniformly till we descend to the lowest degrees of the animal scale; but here we meet with an exception in the early condition of the branching asterioda, which, before the development of the polype-cells, appear to be nourished by absorption throughout their surface, but which, though not yet perfectly developed, are, nevertheless, unquestionably animals. It is not improbable that the attempts to discriminate between the essential nature of animals and plants may lead to results widely different from those with a view to which they have been instituted.

. It is nearly certain that all organised bodies, whether animal or vegetable, originate from a similar germinal spot, and are at first developed by a like process the successive evolution of cells. The more we become

acquainted with the organisation of animals and plants, the more points of similarity do we discover among them; while, with reference to the lowest types of presumed animal existence-the porifera-the further we investigate them, the less ground do we find for certainty as to which kingdom they belong to.

These considerations would rather incline us to infer, that animal and vegetable life are not separated by any exact boundary, and that certain beings, low in the scale of organisation, not only appear to be, but actually are, connecting links between them.

CHAPTER II. embraces a general view of the functions of organised bodies based upon the important physiological truth, that the state of life, in whatever form, is one of perpetual change. The grand distinction between an inorganic and a living body is this: an inorganic body, in order to preserve its existence in the same form, must be exempted from the impression of surrounding bodies;-in other words, it must remain