Leaving out of view the Will, which is a simple homogeneous mental state forming the link between feeling and action, and not admitting of subdivisions, our states of consciousness fall into the two great classes of COGNITIONS and FEELINGS.

COGNITIONS, which are those modes of mind in which we are occupied with the relations that subsist among our feelings, are divisible into three great sub-classes.

Presentative cognitions; or those in which consciousness is occupied in localizing a sensation impressed on the organism-occupied, that is, with the relation between this presented mental state and those other presented mental states which make up our consciousness of the part affected: as when we cut ourselves.

Presentative representative cognitions; or those in which consciousness is occupied with the relation between a sensation or group of sensations and the representations of those various other sensations that accompany it in experience. This is what we commonly call perception-an act in which, along with certain impressions presented to consciousness, there arise in consciousness the ideas of certain other impressions that are ordinarily connected with it: as when from its visible form and colour we mentally endow an orange with all its other attributes.

Representative cognitions; or those in which consciousness is occupied with the relations among ideas or represented sensations: as in all acts of reflection.

FEELINGS, which are those modes of mind in which we are occupied, not with the relations subsisting between our sentient states, but with the sentient states themselves, are divisible into three parallel subclasses.

Presentative feelings, ordinarily called sensations, are those mental states in which, instead of regarding a corporeal impression as of this or that kind, or as located here or there, we contemplate it as pleasure or pain: as when eating.

Presentative representative feelings, embracing a great part of what we commonly call emotions, are those in which a sensation or group of sensations arouses a vast aggregation of represented sensations, partly of individual experience, but chiefly deeper than individual experience, and, consequently, indefinite. The emotion of terror may serve as an example. Along with certain impressions made on the eyes or ears or both, are recalled into consciousness a crowd of the pains to which such impressions have before been the antecedents; and when the relation between such impressions and such pains has been habitual in the race, the definite ideas of such pains which individual experience has given are accompanied by the indefinite pains that result from inherited experience-vague feelings which we may call organic representations. In the infant, crying at a strange sight or sound while yet in the nurse's arms, we see these organic representations called into existence in the shape of dim pains to which individual experience has yet given no specific outlines.

Representative feelings, comprehending not only the ideas of the

feelings above classed when they are called up apart from external objects, but more especially comprehending that higher class of feelings which we ordinarily distinguish as sentiments. In these-as, for example, in the sentiment of justice-sensations have no share: there is no presentative element. This feeling is compounded out of mental states that are themselves wholly, or almost wholly, representative; it involves representations of those lower emotions which are produced by the possession of property, by freedom of action, &c.; and thus is in great part even re-representative.

This classification, here but roughly indicated and capable of much further expansion, will be found in harmony with the results of detailed analysis aided by development. Whether we trace mental progression through the grades of the animal kingdom, through the grades of mankind, or through the stages of individual growth, it is obvious that the advance, alike in cognitions and feelings, is, and must be, from the presentative to the more and more remotely representative. It is undeniable that intelligence ascends from those simple perceptions in which consciousness is occupied in localizing and classifying sensations, to perceptions more and more compound, to simple reasoning, to reasoning more and more complex and abstract-more and more remote from sensation. And in the evolution of feelings there is a parallel series of steps. Simple sensations; sensations combined together; sensations combined with represented sensations; represented sensations organized into groups in which their separate characters are very much merged; representations of these representative groups, in which the original components have become still more vague. In both cases, the progress has necessarily been from the simple and concrete to the complex and abstract; and as with the cognitions, so with the feelings, this must be the basis of classification.

The space which we have here occupied with criticisms on Mr. Bain's work, we might have filled with exposition and eulogy, had we thought this the more important. Though we have freely pointed out what we conceive to be its defects, let it not be inferred that we question its great merits. We repeat that, as a natural history of the mind, we believe it to be the best yet produced. It is a most valuable collection of carefully elaborated materials. Perhaps we cannot better express our sense of its worth than by saying that, to those who hereafter give to this branch of Psychology a thoroughly scientific organization, Mr. Bain's book will be indispensable.

REVIEW VI.

Professor Schroeder van der Kolk on the Minute Structure and Functions of the Spinal Cord and Medulla Oblongata, and on the Proximate Cause and Rational Treatment of Epilepsy. Translated from the original (with emendations and copious additions from manuscript notes of the author), by WILLIAM DANIEL MOORE, A.B., M.B., T.C.D., Honorary Member of the Swedish Society of Physicians, and of the Norwegian Medical Society. (New Sydenham Society.) London, 1859. pp. 291.

ON a former occasion* we gave a summary of the researches of the distinguished Dutch Professor into the structure and functions of the spinal cord, and to the conclusions to which he had been led up to the year 1854. A portion only of the present volume is occupied by the work to which we then drew attention; above three-fourths of it are devoted to two new essays-the one containing an inquiry into the structure and functions of the medulla oblongata; the other having for its object the elucidation of the seat and nature of epilepsy. It will be unnecessary for us to go over the ground trodden in our former article, but before introducing Professor Schroeder van der Kolk's recent researches to our readers, we may remind them that among the views formerly enunciated was the following:-The medulla oblongata appears to be the central point where reflex influences cross to either side, and upon the irritation of which general spasms, as convulsions and epilepsy, seem to depend. This passage may be regarded as the text of the second and third discourse, which, like the first, have been very ably and agreeably rendered into English by Dr. William Moore, to whose talent for languages the literature of this country has already so often been indebted for the interpretation of foreign works.

It appears that Schroeder van der Kolk was chiefly stimulated by Stilling's great works on the Medulla Oblongata (Erlangen, 1843) and the Pons Varolii (Jena, 1846) to enter upon a minute investigation of the former, in the first instance, with almost exclusive reference to pathology.

"However," the author informs us, "the course of the investigation led me from one part to another; the solution of one question gave the key to another; what the structure of man did not reveal, I found demonstrated distinctly and clearly, and beyond my expectations, in animals; and thus under my hands the essay gradually enlarged, and in it I think I have arrived at some, as I hope, not unimportant results, and have as far as possible solved most of the anatomical and physiological questions upon which I have, in the third part, wholly rested my pathological views."

We now proceed as briefly as we can, consistently with clearness, to lay before our readers the quintessence of the author's teaching.

He first dwells upon the points of difference which distinguish the structure of the medulla oblongata from the spinal cord. The central canal of the latter inclines backwards in the medulla oblongata, so as • British and Foreign Medico-Chirurgical Review, vol. xix. p. 85.

to open into the fourth ventricle. The anterior grey horns accompany the canal, and thus come to form the floor of the fourth ventricle, from which the hypoglossus arises; at the same time the posterior cornua are spread out laterally, also contributing to form the floor of the fourth ventricle. There is, therefore, a complete displacement of the posterior columns, and we likewise meet with new parts, as is evident even on a superficial comparison of the size of the cord and of the medulla oblongata. The latter is considerably larger than the former, and this increased thickness is due to the superaddition of parts not present in the cord. These are the corpora restiformia, the posterior pyramids which descend from the cerebellum, the root of the trigeminus and the corpora olivaria. The medulla oblongata is also much increased in size by the nuclei and ganglionic groups, whence Schroeder van der Kolk shows the nerves of sensation to arise. Moreover, it contains transverse arched fibres, which unite the two sides of the medulla oblongata, and certain longitudinal fibres descending from above and terminating in the medulla oblongata. Hence, according to our author, "we may regard the medulla oblongata as the nodus vitæ, or as a central point, where many different bundles of fibres end or take their origin in various ganglionic groups, which hence diffuse their influence over so many different parts of the body."

The question of the decussation and origin of the various nerves of the medulla oblongata receives much attention. The author has satisfied himself with regard to the hypoglossus that it does not decussate, but that it is wholly lost in the hypoglossal nucleus; the same is the case with the other sensitive nerves, and the impression produced on them is conveyed to the opposite side by marginal fibres, so that in fact an indirect decussation is effected; and the result is the same in this respect as if the nerves themselves interchanged their fibres. Of all the nerves of the medulla oblongata, none has so intimate a connexion with its fellow as the facial, which might almost have been assumed à priori from the nearly uniformly bilateral functions of this nerve. It decussates in part directly; a part of its fibres arise from its nucleus. The auditory nerve is naturally the next nerve that is passed under review. Its nucleus or ganglionic cells are very large, only requiring a magnifying power of 8 or 10 diameters to render them plainly visible. Some of the fibres arising from them pass into the cerebellum with a number of fibres derived from the cerebellum and corpus restiforme; fibres also pass from the nucleus of the auditory to that of the facial nerve-a connexion which satisfactorily explains the undoubted reflex influence which is transmitted from the auditory to the facial nerves. This reflex is particularly marked in animals, in whom, with voluntary movement of the ear, there is also manifestly combined an instinctive movement which can only be explained by reference to such a relation as that just spoken of.

"In man, as is well known, there is scarcely any movement of the ears, but the reflex action of terror on the facial nerve," whether induced by an alarming sound, or by other means, "whereby even the frontal and occipital muscles can be rendered extremely tense, and the hairs, as we say, stand on end, has long

since, as well as the retention of the voice from rapid inspiration, been graphically described by Virgil, in the well-known line

'Steteruntque comæ, vox faucibus hæsit.""

The abducent does not, like the other nerves of the medulla oblongata, decussate indirectly through the fibres which arise from their nuclei, but its fibres, instead of passing towards the raphe to meet its fellow, curve outwards away from the raphe; the nucleus in which the nerve terminates being removed further from the latter, and no fibres being seen to pass from the nucleus to the raphe. Should this point receive confirmation, Schroeder van der Kolk considers it to offer a satisfactory explanation of the antagonism between the muscles of the eye, because if the right abducent nerve is connected with the fibres from the brain, which stimulate the left nucleus of the oculo-motor nerve after decussation the, same stimulus would simultaneously bring into action the left internal and right abducent muscle, and vice versâ.

The trigeminus establishes connexions with nuclei of all the nerves of the medulla oblongata, a fact which is quite in harmony with the great range of reflex action by which this nerve is distinguished. The various acts of swallowing, breathing, coughing, are so many instances of the reflected action produced through the trigeminus in the glossopharyngeal, vagus, accessory, and hypoglossal nerves. The author successively traces the mode of connexion established between the fifth nerve and the nerves just mentioned, in the medulla oblongata, and states that the trigeminus is also closely connected with the accessory ganglia and corpora olivaria. The author also points out that, as a general rule, in every place where fibres are given off performing any special function, such as reflex action, fresh groups of ganglionic cells invariably appear, giving origin to these fibres.

From the uniformity of this occurrence in the origin of the trigeminus, Schroeder van der Kolk infers that, as a general rule, wherever a particular action is to be excited through nervous filaments, special ganglionic cells are required, producing the peculiar nervous action. "In like manner," he adds though without proffering any special evidence in behalf of this assertion—“in like manner the orders of our will do not pass directly into the motor nerves, but into ganglionic cells, whence the peripheric action arises for the movement of the muscles."

In a chapter entitled "On the Accessory Ganglia, in the Medulla Oblongata," the structure and functions of the olivary bodies are examined and illustrated, and several pathological facts are brought forward in support of the author's views, which lead mainly to this conclusion :-That the olivary bodies are auxiliary ganglia, which by their mutual connexion produce a bilateral action, and by their connexion with the hypoglossi develope the combinations required for articulation. The greater size of these bodies in man than in animals is explicable on this view; while fatty degeneration, induration, and other morbid conditions have been traced in them in patients whose maladies had been characterized by more or less impairment of speech.