tion dispassionately, as the author makes a wholesale accusation against his English confrères of having used him unfairly. Dr. Russell Reynolds favours us with Tables for the Diagnosis of Diseases of the Brain,'" constructed for the use of students and others who may find some difficulty in applying their general knowledge of cerebral diseases to the diagnosis of particular cases." The pathology of the alimentary canal is represented by Dr. Habershon's important work on the subject, some parts of which have already appeared in the 'Guy's Hospital Reports.' The third volume of the third series of these Reports is now before us, and contains numerous valuable contributions by the distinguished members of Guy's medical staff. The eighth volume of the Reports of the Pathological Society,' is, as usual, replete with interest, and we hope soon to accomplish a desire, some time entertained, of laying before our readers a summary of the progress of pathological science as represented by this very useful and thriving Society. From America we have received the third edition of Dr. Gross's 'Pathological Anatomy,' with which we may notice a work of Professor Valentin's, on the best mode of instituting autopsies, entitled, 'Die kunstgerechte Entfernung der Eingeweide des menschlichen Körpers.' A fifth edition of Dr. Golding Bird's 'Urinary Deposits,' under the auspices of Dr. Edmund L. Birkett, has been published; with which we couple the second number of Dr. Beale's work on the Microscope, illustrating urinary deposits. An interesting volume 'On the Therapeutic Action of Oxygen,' by Dr. Birch, holds out more hope of this agent proving as useful in the therapeutic treatment of disease as its presence is essential to health. Mr. Gardiner Hill, whose name is identified with the introduction of the non-restraint system in the treatment of the insane, supplies us with A Concise History of the Entire Abolition of Mechanical Restraint'—an event the vast benefits of which receive constant confirmation in the annual reports of the best conducted asylums for lunatics in this and other countries.

Mr. Hunt, to whom belongs the credit of having proved the value of, and thus introduced into general use, the exhibition of arsenic in the treatment of some forms of chronic skin disease, supplies us with a second edition, which has been almost re-written, of his 'Guide to the Treatment of Diseases of the Skin.' To Dr. Marshall Hall's legacy, 'The Treatment of Apnoea by Prone and Postural Respiration,' we shall devote special and respectful attention in our next.

Under the head of the History of Medicine we have to mention a translation, with explanatory notes, by Dr. Charles Collier, of the account given by Thucydides of the plague of Athens, in which we find a novel view advocated by the author-that the disease was scarlatina maligna.

The subject of epidemics, by a natural transition, brings us to public Hygiene: the Sanitary Reports for Clerkenwell and Islington, respectively by Drs. Griffith and Ballard; the Report on Chemical Investigations,' by Dr. Hoffmann and Mr. Will, bearing on the Metropolitan Drainage question, and Mr. Acton's work On Prostitution,' deserve special mention.

Surgical literature is enriched by Dr. Adams' beautifully-illustrated work On Chronic Rheumatic Arthritis,' by a reprint of the valuable papers of Mr. Teale, 'On Plastic Operations on the Face and Neck ;' and of Mr. Butcher's Reports in Operative Surgery.'

In Obstetric Science we have received the translation from the German, by Dr. Matthews Duncan, of a chapter of Dr. Braun's new text-book of midwifery, entitled, 'The Uræmic Convulsions of Preg nancy, Parturition, and Childbed;' and a reprint from the American medical monthly, of 'A Case of Fibrous Tumour of the Uterus, accompanied with excessive Hæmorrhage, successfully treated by Excision,' by Dr. Barker, of New York.

Anatomy is represented by a second edition of Mr. Luther Holden's valuable work 'On Osteology,' which is of special use to the student, and probably of as much to the practitioner who wishes to refresh his fading knowledge of the skeleton and its relation to the soft parts. We shall have occasion to revert more fully to two works which have reached us from America, and may be noticed here preliminarily─Dr. Joseph Jones' Investigations relative to certain American Vertebratæ,' and Dr. Wynne's Report on the Vital Statistics of the United States.'

Mr. Williams' Handbook of Chemical Manipulation,' Mr. Galloway's Manual of Qualitative Analysis,' with Dr. Bence Jones's translation of Mulder's Chemistry of Wine,' represent different phases of Chemical Science, and will command our attention at a future period.

We are glad to announce that Dr. Mayne's 'Expository Lexicon of the Terms, Ancient and Modern, in Medical and General Science,' has advanced another step. The sixth number has just appeared, and carries us from Neurectopicus to Periphacitis. Mr. Irvine has published what appears to be a very correct account, comprising all the documentary and other evidence, of the recent trial of Miss Madeleine Smith for the alleged poisoning of L'Angelier.

Numerous reprints-some of which we may be able to advert to in our quarterly and half-yearly Reports-various pamphlets and papers -are also before us, the titles of which will be found among the list of Books Received for Review.

We would merely, in conclusion, announce that M. Brown-Séquard has undertaken to edit a physiological journal in Paris, under the title, 'Journal de Physiologie de l'Homme et des Animaux.' As yet only the prospectus of this periodical is before us, but it is scarcely necessary on our part to urge upon our readers that a journal of this kind can scarcely appear under more favourable auspices, or such as would be more likely to ensure it a good welcome by the medical profession of Great Britain.

PART THIRD.

Original Communications.

ART. I.

On the Development of the Eye in the Chick.* By PETER YOUNG, M.D., M.R.C.S. Edin., Demonstrator of Anatomy in the University of Glasgow.

Of all the organs of the senses, the eye is the first to present indications of itself. In the chick, observers differ as to the exact period of its appearance. Thus, Huschket states he observed the primitive rudiment of the eye before the termination of the first day; whilst Bart and others say that it first shows itself at the thirty-third hour; but from a considerable number of embryos which I examined, the period of the commencement of the evolution of the eye would seem to vary, for in some cases it had appeared at the thirtieth hour, while in others not until the thirty-sixth. I am not aware that any exact period has been fixed for the first appearance of the eye in the invertebrate animals, but there can be no doubt that it commences to be developed at a period correspondingly early to that in the vertebrate animals; for although Rathkeş states that in Daphnia pulex and other entomostraca the eyes first distinctly appear about the middle of embryonic life as two distinctly separated black points, still it is evident from this that the eye in these animals must have been partly developed prior to this period, since-as we shall afterwards see-the choroid does not make its appearance till some time after the formation of the lens. According to Huschke, the eyes represent at first a simple dilatation or fossa at the anterior extremity of the embryo, bounded on either side by the inner border of the dorsal laminæ. This fossa is soon converted into a vesicle or shut sac by the growth inwards from the two borders or the dorsal lamina of a fine membrane, which closes it. This optic cavity communicates at first with the cerebral vesicle by one opening, but soon the anterior and posterior borders of the optic dilatation approach each other, whilst at the same time the anterior cerebral cell pushes itself forwards To the following essay a gold medal was awarded by the University of Edinburgh in

1857.

1835.

† Ammon's Zeitschrift für die Ophthalmologie. Band iii. p. 342. 1833. Valentin's Handbuch der Entwickelungsgeschichte des Menschens, p. 186. Abhandlungen zur Bildungs- und Entwickelungsgeschichte des Menschen und der Thiere. Leipzig, 1833.

Ammon's Zeitschrift fur die Ophthalmologie. Band iii. p. 342. 1833.

between the posterior parts of the optic cavity. By this means each half of the previously simple optic rudiment obtains a more lateral position, and the former single communication is converted into two, which during the further development of the eye become smaller and smaller.

On the other hand, Reichert asserts that the eyes arise from differentiated collections of cells, without having any connexion with the medullary tube, and says that the eye in Batrachian animals represents an elevation of a rounded form on either side of the anterior extremity of the embryo, which are very close to each other, and, when viewed from the side, constitute the anterior boundary of the embryo.

All observers, Huschke and Reichert excepted, are, however, now agreed that the eye at first presents itself as a protrusion on either side of the anterior cerebral vesicle; and from the observations of Bär, Rathke, Remak, Vogt, &c., this would seem to hold good for all classes of vertebrate animals. It is difficult to understand why there should have been any discrepancy of opinion with regard to this

point; for in the chick at least it requires no more than ordinary care to perceive the true state of matters. I have examined a considerable number of chick embryoes at all periods up to the formation of this lens, and I have no doubt whatever that the primitive optic vesicle is a protrusion of the anterior cerebral cell. It would be tedious and superfluous were I to describe every embryo which I examined at this period, since no changes are observable in the optic vesicle, except that it increases in size and alters its position somewhat. Accordingly, I shall only describe one embryo, as I observed it at the forty-eighth hour of incubation, with a magnifying power of sixty diameters.

A protrusion (Figs. 1. and 2) is observable on either side of the anterior-cerebral vesicle, the axis of which is at right angles to that of the embryo. These protrusions have distinct, well-defined walls, equal in thickness to those of the cerebral cell, and their apices are apparently in contact with the horny lamina of the embryo. Although the walls of the optic protrusion are quite distinct and readily seen to be continuous with those of the anterior cerebral vesicle, yet they are not so clearly defined as those of the latter, owing to the deposition of a quantity of molecular matter in them. Their cavities are distinctly seen communicating with that of the anterior cerebral cell, and are somewhat, but very slightly, constricted at their junction with that of the cerebral vesicle. No thickening or other change in the horny lamina is observable opposite the outer extremities of the optic protrusions, although the latter, as already observed, appear to be in contact with it. Four cerebral vesicles are also observable. The anterior is broader and shorter than the second, and exhibits a narrow wellmarked notch at its anterior extremity. The second is narrower and longer than the first, and separated from it by a well-defined construction. The third is narrower and shorter than any of the preceding; while the fourth is somewhat longer than the second, but is narrower than any of the other three. The walls of the latter present a wavy or zig-zag appearance, there being four notches separated by three intervening ridges on its internal surface, the reverse obtaining on the external aspect. There is no distinct line of demarcation between the cavity of the fourth cerebral cell and the canal of the future spinal cord, but they appear to pass gradually into each other, so that the cerebral cells may be regarded, as indeed they really are, dilatations of the medullary tube.

About this period, the relative position of the optic vesicles and anterior cerebral cell changes. This change in position is occasioned by the development of the hemispheres, which arise from the anterior and inferior wall of the anterior cerebral vesicle by the deposition of matter upon the latter. By this means not only are the optic vesicles inclined somewhat backwards, but, owing to the hemispheres and the floor of the posterior part of the anterior cerebral cell (third ventricle) arching downwards, the latter push the anterior borders of the optic vesicles from each other, whilst the posterior borders come in contact with each other on the floor of the third ventricle, so that the optic vesicles, which were at first lateral protrusions of the anterior cerebral cell,