succeeded in establishing a rational and positive relation between the structure of that organ and its functions, even those which are most evidently physical: the discoveries hitherto made known with regard to its anatomy, are confined to some circumstances regarding the form, connections, or texture of its parts which had escaped the observation of preceding anatomists; and whenever any one has supposed that he had proceeded ́farther, he has only introduced, between the well known structure and its common effects, some hypothesis, scarcely capable of satisfying for a moment even the least sceptical minds.

All the actual discoveries which have hitherto been made, may be reduced to new methods of dissecting the brain, new connections and directions perceived between its different masses, and the organic elements composing them, or new peculiarities observed in some of its parts.

We are far, however, from despising these results; they direct us to the only route which may at last conduct us farther; and although we do not yet know the whole length of this route, we are satisfied, that every step made in it brings us nearer to its termination, by some fraction of its length.

We proceed, then, to explain and examine, under these three heads, of method, connection, and peculiarities, the discoveries announced by Drs. Gall and Spurzheim.

Anatomists know that there are three principal methods of demonstrating the brain.

The one most generally practised in the schools, and described in books, is that of Vesalius, which consists in removing successive layers of this organ, and in pointing out what presents at every cut. It is the one the most easily performed for the sake of demonstration, but the most difficult to be followed in the mind. The true relation of those parts, which we see always cut, escapes, not only the pupil, but the teacher also; it is almost as if one were to divide the trunk of the body by successive sections to point out the position and form of the lungs, heart, stomach, &c. This method, however, is still almost the

only one which is employed in the work of Vicq-d'Azvr, the most splendid, and one of the most valuable which has appeared on the subject of the brain.

The second mode, which deranges much less the organ, the structure of which it is intended to explain, is that of Willis, which, as far as we can judge by the obscure description of Galen, very much resembles that employed by the ancients. After removing the pia mater, the poster or lobes of the brain are raised, we penetrate between the tubercula quadragemina and the fornix, and cut its anterior pillar; after detaching the lateral parts of the hemispheres, they are turned forwards: in this manner we have a good view of the under part of the fornix and corpus callosum; we preserve entire, the great and small tubercles of the interior; but the thickness of the hemispheres renders it more difficult to practise this mode in man than in other animals.

The third method was very long ago sketched by Varolius, and afterwards more fully detailed by Vieussens. By this mode the under part of the brain is first examined, and the medulla oblongata is followed across the pons varolii, the thalami optici, and corpora striata; its fibres are seen expanding to form the hemispheres; it is even possible to stretch out the hemispheres by removing their lateral attachment to the crura cerebri; to divide longitudinally the spinal marrow and the cerebellum; and then each half of the former is seen forming a pedicle, which is implanted into the side of the hemisphere, as the stem of a mushroom is fixed into its pileus.

This mode possesses the very great advantage of allowing us to follow more easily the direction of the medullary fibres, the only circumstance which can afford us any idea with regard to the course of the cerebral functions; and it is probable, that it would have been more generally adopted, if Varolius had not represented it in a very coarse figure, and if the work of Vieussens had not always remained, for what reason it is difficult to determine, in a kind of discredit which it did not deserve.

It is nearly this method of Varolius which is followed by Drs. Gall and Spurzheim, and which a part of their memoir is intended to defend; a labour, indeed, very useless, for so complicated an organ as the brain ought to be examined on every side; it must be cut into in every way; and whenever any plan is discovered which points out some new circumstance, it furnishes an important addition to anatomy.

We shall therefore judge of their mode by the results; and, for that purpose, we shall detail and compare them with those which have been obtained by preceding anatomists.

It is well known, that the opinion most generally received with regard to the minute organization of the brain, is, that the cortical substance of the hemispheres, and of the cerebellum, being almost entirely vascular, is a sort of secreting organ: that the medullary substance, almost every where of a fibrous appearance, is a collection of excreting vessels, or at least of conducting filaments; that all the nerves are emanations from this substance, bundles of these vessels; that the medulla oblongata, and spinal marrow, is itself a bundle larger than the others, from which the different pairs of spinal nerves go off in succession: lastly, that the nerves called cerebral, are the first which go off from the great medullary mass of the encephalon; consequently, it is believed that all the influence of the nervous system upon organic life, as well as all the efforts of the will, descend from the brain along the nerves; and that the impressions received from the external senses, re-ascend by the same route; but by a singular contradiction, at the same time that they make the medullary substance, and consequently the nerves, originally extend to the whole of the cortical substance, several physiologists think themselves obliged to search for some circumscribed place from which all the nerves emanate, or, what signifies the same thing, in which all the nerves terminate; in short, for what anatomists call the seat of the soul.

It must be allowed, that this has been for a very long time the opinion most generally received, and that it is still very pre

valent; although the most prudent philosophers have never brought it forward but as an hypothesis very slightly supported by facts.

Several of its partizans, however, have allowed themselves to be led into doubts and contradictions. Haller, for example, says in one place, that he cannot suppose that medullary fibres originate any where else than in the brain ;* in another, that every nerve comes ultimately from the medulla of the brain or cerebellum; while, in a third place,‡ he supposes that the cineritious matter of the spinal marrow may form them in the same manner as that of the brain.

In fact, this distribution of the cineritious matter in different parts of the nervous system, was one strong argument against the exclusive importance ascribed to the encephalon, and to it might be added several others.

It might be remarked at all times, that the action of the nerves upon organic life continues for some time after the brain no longer contributes to it. Well known experiments upon insects and worms proved, that if in man, and the other animals where the brain is very large, this organ is necessary to the functions of animal life, it is not always so in those species where it is of less size, and that in some of these we may even instantaneously produce, by dividing it, two centres of volition and sensation.

It has also been known for a very long period, that the spinal marrow does not diminish in proportion to the nerves which go off from it, as it ought to do if it were only a bundle of these nerves sent from the brain; that, on the contrary, it swells at certain places, from whence the largest nerves go off. Prof. Soemmerring has recently remarked, that the size of the medulla oblongata in animals is not in proportion to that of the brain as it ought to be, if it were a congeries of excretory tubes from the brain, but that, on the contrary, it is often in an inverse proportion; the successive investigations of Monro, Prochaska,

* Phys. iv. p. 385.

† Ibid. p. 393.

+ Ibid. p. 384.

Reil, have given us ideas of the structure of the nerves quite different from those which we would be obliged to form if we were to derive all of them from the medullary substance of the encephalon, and by it from the cortical substance. Several phy siologists, therefore, within these few years, have again begun to consider the nervous system as a net-work, all the portions of which contribute, in a certain degree, and especially according to their size, to the organization and functions of the whole; and not as a tree which, having only one trunk, distributes itself into branches and twigs, after the manner, for example, of the arterial system.

Drs. Gall and Spurzheim, in adopting this opinion, do not adduce new proofs of it, but only repeat those which we have stated, and which had been brought forward many years before.

It appears, that in Germany and other places, various objections have been made to their system which we would not have made, but which they have taken the trouble to answer.

When they, for example, described, that in the fœtus without a head, the nervous system performs its functions of organic life without the assistance of the brain, it was opposed to them, that the acephali are only fœtuses where the brain has been destroyed by the effects of dropsy. This objection, which is true in some acephali, certainly does not apply to all; and it is by no means rare to see some which have been completely developed, although they do not show the smallest mark of having ever had either a head or any of the upper parts of the trunk.

We, therefore, readily agree with Drs. Gall and Spurzheim, with regard to the general idea which they entertain, as well as a great many anatomists, of the nervous system. But while they, with so many others, consider it as a net-work, they have some particular ideas concerning the links and knots of which this net-work is composed; and here the part of their doctrine begins which is peculiar to them.

As far as we have been able to understand, it appears to us,