sarily and inevitably doomed: we merely destroy it a few hours earlier than it would die if left alone.

But whilst unequivocal bony distortion may render the birth of a living child impossible, a minor degree, or disproportion from other causes, may necessitate craniotomy in one labour and not in another. As Dr. Davis remarks :—

Let us not, on the other hand, take for granted, that because craniotomy has been the only alternative in one labour, it must of necessity be resorted to on a subsequent occasion. On account of the swelling of the maternal tissues and foetal scalp, of rigidities by inordinate ossification of the head, or by reason of its being above the average size, perforation may have been perfectly proper in the first confinement; and in a succeeding delivery, a child of equal or of not much smaller size, may pass living without obstruction. Again, though much more rarely, a patient's first or second labour may be easy, and a following one difficult, requiring the forceps, or even craniotomy, on account of the like swelling in the soft tissues, undue hardness or thickness of the fœtal cranium, or from its head being longer than on previous occasions." (p. 62.)

This is quite true, no doubt, but such cases are rare, and would be still less frequent if we had the care of the patient from the beginning. By proper treatment several of these causes might be prevented or removed, so as to bring the case within range of the forceps.

In conclusion, we find that one of the limits of the forceps operation is marked by certain symptoms, the force or feebleness of uterine action, and time; the other limit by mechanical disproportion. Craniotomy is almost always (except in the case of dead children) a question of mechanical disproportion, comprised between the measurements which will not permit the passage of a living child, and those which prohibit the passage of a mutilated one.

Having said so much, we must refer our readers to Dr. Davis's book for his opinions on the induction of premature labour; on face, breech, footling, and transverse presentations. Although we may not always agree with him, yet we feel high respect for his judgment and intelligence.

REVIEW III.

Accom

1. Anatomie Comparée du Système Nerveux, considéré dans ses Rapports avec l'Intelligence. Par Pr. LEURET et P. GRATIOLET. pagnée d'un Atlas de 32 Planches dessinées d'après nature. Tome Second, comprenant l'Anatomie du Cerveau de l'Homme et des Singes, des recherches nouvelles sur le développement du crâne et du cerveau, et une analyse comparée des fonctions de l'intelligence humaine. Par M. PIERRE GRATIOLET, Aide-Naturaliste-chef des Travaux anatomiques au Museum d'Histoire Naturelle, Membre de la Société Philomathique.-Paris, 1857. 8vo, pp. 692. Comparative Anatomy of the Nervous System, considered in its Relations with Intelligence. By MM. LEURET and GRATIOLET. Second Volume, comprising The Anatomy of the Brain of Man and the

Quadrumana, new Researches on the Development of the Cranium and of the Brain, and a Comparative Analysis of the Functions of the Human Intelligence. By M. PIERRE GRATIOLET.

2. An Essay on Physiological Psychology. By ROBERT DUNN, F.R.C.S., Fellow of the Royal Medical and Chirurgical Society, &c.-London, 1858. 8vo, pp. 94.

3. The Human Mind in its Relations to the Brain and Nervous System. By DANIEL NOBLE, M.D., Visiting Physician to the Clifton Hall Retreat, &c.-London, 1858. Post Svo, pp. 157.

on.

*

AFTER an interval of nearly twenty years, M. Leuret's valuable treatise on the Comparative Anatomy of the Nervous System, the continuation of which by his own hand was prevented by his early and lamented death, has been completed by M. Gratiolet, an anatomist whose position gives him the greatest facility for the prosecution of such researches, and whose ability we believe to be fully adequate to the first portion of his task. The power of observing and analysing psychological phenomena, however, is a very different gift from that which makes a good dissector; and here, as it appears to us, M. Gratiolet by no means equals the savant whose work he has undertaken to carry We shall not attempt a systematic analysis of his work; but shall extract from it such materials as suit our present purpose, which is that of inquiring into the progress of Cerebral Physiology since the date of an essay which appeared in the pages of one of our predecessors just twelve years ago." This essay, we believe we may say without vanity, has had an important influence in the subsequent direction of the thoughts and inquiries of our countrymen in relation to its subject; and it is explicitly referred to as the foundation of the two smaller treatises before us, which proceed from two gentlemen, who, whilst themselves putting forth very different views as to points of detail, closely accord as to all general considerations both with each other and with ourselves. Mr. Dunn's Essay consists of a series of papers which have appeared in the 'Journal of Psychological Medicine, and which are now issued in a collected form, having for their object to expound the general bearing of Physiology upon Psychology, and at the same time to advance certain new propositions which appear to their author to be deducible from the results of inquiries carried further in the same direction. "Written," as he says of them, "at varying intervals amid the distraction of medical practice," they bear some "marks of needless repetition and of a want of unity in the treatment of the subject;" but of such imperfections it would be hypercritical to take account in a series of papers containing so much that is interesting and valuable. Dr. Noble's little book, which is essentially an expansion of the earlier chapters of his treatise on Psychological Medicine, is more compact and less elaborate; but its object is less to develope any new views, than to present, in a form adapted to the general reader, a summary of what is known, or may

* British and Foreign Medical Review, vol. xxii. p. 488.

be reasonably surmised, as to the dependence of different forms of Psychological activity upon the instrumentality of differents parts of the Encephalon. The notice which we took of it in our last number supersedes the necessity of any further allusion to it on the present occasion.

Taking our stand upon the Article just referred to, the great purpose of which was to show in general terms what the Cerebrum does and what it does not do, we shall first direct the attention of our readers to the most important facts which have been substantiated or rendered probable, by subsequent researches into the comparative anatomy of the cerebrum. In this survey we shall limit ourselves to the Mammalian series; for it is here that the Cerebrum first asserts its predominance over the sensorial centres; and it is not a little remarkable that in this single class we should accomplish the entire ascent from a grade of cerebral development that seems but little elevated above that of the Bird, to one in which the proportions are so completely reversed, that the Cerebrum, both in size and complexity, throws every other part except the Cerebellum literally as well as metaphorically into the shade. The difference in this respect between the Fish and the Marsupial, is not nearly as great as that which exists between the Marsupial and Man. For even the external augmentation of the Cerebrum in the lower of these two series, is not by any means to be taken as an indication of its proportional development; since a very slight examination suffices to show that the hemispheric ganglia are still, in the lowest Mammalia, nothing else than incrustations (so to speak) wrapping round the comparatively large sensorial centres; whilst a more careful examination of their internal structure brings to light a corresponding simplicity in the arrangement of its fibres. But as we ascend through the higher Mammals, we find the size of the Cerebrum to increase beyond all proportion to that of the sensory ganglia; its superficial layer of vesicular matter is vastly augmented not merely in thickness, but in extent of surface; and its fibrous structure progressively increases in complexity, so as almost to defy the efforts of the most skilful anatomist to unravel its multiple interlacements. The Cerebrum is, in our apprehension, the most distinctive portion of the Mammalian organization. The arrangement of the genital apparatus (in which we include the mammary glands) peculiar to this class, is subservient to that prolongation of the period of dependence of the offspring upon the parent, which we find throughout animated nature to stand in relation to a higher grade of ultimate development. And as the various modificatious of general structure which its different types present, can be easily shown to be far more intimately related to distinctive peculiarities in their respective habits of life than they are elsewhere, we should anticipate finding in the Mammalian series a diversity of conditions of cerebral organization, corresponding to that diversity in the construction of the sensory and motor apparatus which so remarkably distinguishes its several orders, and yet more closely related to that progressive advance in intelligence which is the essential character of elevation in this class. The researches of comparative anatomists, though far from informing

us completely as to the Cerebral organization of the several types of Mammalian structure, have brought together a mass of material which admits (to say the least) of provisional arrangement; and we shall now inquire what are the general conclusions to which the facts thus classified appear to point.

Four leading modifications of cerebral structure have been recently shown by Prof. Owen* to be distinguishable in the class Mammalia ; and these are concurrent with such modifications in other important systems of organs, as, in the opinion of that distinguished naturalist, to afford the most satisfactory basis for the primary division of the group: :

I. The first and lowest sub-class may be termed from its cerebral character Lyencephala, or loose-brained, the cerebral hemispheres being comparatively loose or disconnected with each other, owing to the want of the great transverse commissure or corpus callosum. The size of these hemispheres is such as to leave exposed the olfactory ganglia, the cerebellum, and more or less of the optic lobes; their surface is generally smooth; and the anfractuosities, when any present themselves, are few and simple. This division includes the two orders (Monotremata and Marsupialia) of "implacental" Mammals, which have been considered by many Zoologists to rank as a distinct sub-class, on account of their very marked points of affinity to the oviparous Vertebrata, but which Prof. Owen now regards as constituting a group equivalent in value to each of the other three, and as having special relations of analogy with the Lissencephala. Although our acquaintance with these animals is comparatively imperfect, yet it can scarcely be questioned that as regards intelligence they hold the lowest rank in the entire Mammalian series; and that their habits of life are almost entirely determined, as in the Oviparous Vertebrata, by the instincts peculiar to each species, which are capable of very little modification either by education or by change of external conditions.

II. The next well-marked stage in the development of the Cerebrum is where the corpus callosum is present, but connects cerebral hemispheres as little advanced in bulk or outward character as in the preceding sub-class; the cerebrum leaving both the olfactory lobes and the cerebellum exposed, and being commonly smooth, or with few and simple convolutions in a very small section composed of the largest members of the group. The Mammals so characterized constitute the sub-class Lissencephala, or smooth-brained; under which are ranked the orders Rodentia, Insectivora, Cheiroptera, and Bruta (this last being the equivalent of the Edentata of Cuvier). In each of these orders, many points of affinity to the oviparous Vertebrata are discernable; and notwithstanding that an undue reliance on dental characters has led almost all systematists to assign a much higher position to the Cheiroptera and Insectivora (the former having been generally ranked next to the Quadrumana, and the latter between the Cheiroptera and the Carnivora), we feel satisfied that in thus degrading them, Professor

*Journal of the Linnean Society, vol. ii. 1857, p. 18.

Owen has assigned to them a far more appropriate place than that which they have previously occupied. The aptitude of the Cheiroptera. Insectivora, and certain Rodentia, to fall, like Reptiles, into a state of true torpidity, associated with a corresponding faculty of the heart to circulate imperfectly-aerated blood, is an important physiological character of degradation; as is also the predominance still manifested in all these orders, as among the Bruta, of the instinctive over the intelligential direction of their actions. It is among the Rodentia and Insectivora that we find the most remarkable examples of the constructive and the migratory instincts, which the Mammalian class presents; and there are so many obvious points of parallelism between these two orders, that nothing but a foregone conclusion as to their dissimilarity could have led scientific naturalists to separate what less instructed observers have recognised as closely allied.

III. The third leading modification of the Mammalian cerebrum is marked by such an increase in its relative size, that it extends over more or less of the cerebellum and of the olfactory lobes. Save in a few exceptional cases of the smaller and inferior forms of the Quadrumana, the superficies is folded into more or less numerous gyri or convolutions; whence the name Gyrencephala, or convolute-brained, assigned by Professor Owen as the designation of the third sub-class, under which he includes the orders Cetacea and Sirenia (the former carnivorous, the latter herbivorous pisciform mammals), the Ungulata or hoofed quadrupeds (which he distributes under the four orders Toxodontia, Proboscidia, Perissodactyla, and Artiodactyla), and the Unguiculata, now limited to the Carnivora and Quadrumana. In this sub-class we look in vain for those marks of affinity to the Ovipara which are exhibited by the preceding; and in it "the Mammalian modification of the Vertebrate type attains its highest physical perfections, as manifested by the bulk of some, by the destructive mastery of others, by the address and agility of a third order. And, through the superior psychological faculties,-adaptive intelligence predominating over blind instinct, which are associated with the higher development of the brain, the Gyrencephala afford those species which have ever formed the most cherished companions and servitors, and the most valuable sources of wealth and power, to Mankind."

IV. In Man, the brain presents an ascensive step in development, higher and more strongly marked than that by which the preceding sub-class was distinguished from the one below it. Not only do the cerebral hemispheres overlap the olfactory lobes and cerebellum, but they extend in advance of the one, and further back than the other. Their posterior development is so marked, that anatomists have assigned to that part the character of a third lobe; it is peculiar to the genus Homo, and equally peculiar is the posterior horn of the lateral ventricle and the hippocampus minor,' which characterize the posterior lobe of each hemisphere. The superficial grey matter of the cerebrum, through the number and depth of the convolutions, attains its maximum of extent in Man. With this highest form of brain are associated peculiar mental powers, the possession of which entitles the.