still more like the feeling which a constant current applied to the skin of the back induces. Now in both these cases the vascular tonus is doubtless largely increased for a longer or shorter time.

The healthy, vigorous man, who is in condition, has a tolerably high arterial tension; his vaso-motor centre is in a state of powerful tonic excitation, and his vaso-motor nerves are not readily inhibited (he cannot be easily made to blush, for instance).

The circumstances which increase our vascular tonus-as long as our organs are healthy-appear to add to our vigour. Why should it be so? If rest is the period of recuperation or restoration, if a diminished blood-supply be a condition of rest, then a high degree of activity of the vaso-motor centre should tend to health; by preventing waste of energy until each organ is needed (and then the vaso-motor nerves are either centrally or locally inhibited or antagonized), by keeping each organ at rest until its activity is needed, there will be a greater store of energy-yielding material at disposal, and the activity of the tissue elements will be all the more perfect in that they are uninjured by the fatigue-producing substances which are the products of activity: in other words, that man will, cæteris paribus, be the most efficient and economical machine whose organs are the seat of the smallest waste as long as they are inactive; naturally, however, the quality and quantity of the work will depend very much on the quality of the organ, on its power of storing-up, and on the perfection of the vascular mechanism, in so far.that this must permit of as large a supply of blood being given at the required moment for the maximum conversion of energy.

There are two points upon which I think it right to add some observations, so as to prevent my being misunderstood.

1. The facts which are day by day being accumulated point to the existence of local vaso-motor mechanisms, which are subordinated to the general vaso-motor centre (if such a centre really exists apart from the former), so that it is not only conceivable, but certain, that an affection of, or a change in, a local vaso-motor mechanism might be induced without a necessary affection of the general vaso-motor mechanism. A general high tonus does not, for example, imply that its possessor should have

a tendency to sleep, for sleep is doubtless due to a positive cerebral anæmia, to the production of which the activity of a centre, specially connected with the cerebral circulation, probably contributes.

2. Whilst such counter-irritation as I have recommended appears to exert a tonic action on the vaso-motor centre, and on the body generally, I am quite aware that several methods of counter-irritation produce an opposite effect. The shock and great depression which, especially in women, sometimes follow the application of blisters, seem to show that severe counterirritation very frequently tends to depress rather than to raise the tone of the vascular system.

Reviews.

1. The Physiology of Mind. By HENRY MAUDSLEY, M.D. Macmillan and Co.

2. The Functions of the Brain. By DAVID FERRIER, M.D., F.R.S., Smith, Elder, and Co.

THE two books named above have by a lucky chance appeared almost simultaneously. The physiology of mind and the functions of the brain are presumably much the same thing; Professor Ferrier would say, mind was a function of the brain, and Professor Maudsley would say, the brain was the organ of mind; but no two works could be more different. They are not, however, for this antagonistic, but rather complementary; the one to the other, as indeed is most happily indicated by the titles.

Dr. Maudsley's is an old friend with a new face, being the first part, considerably amplified, of his work on the Physiology and Pathology of the Mind, making a third edition of this portion. The verdict of the profession and of the scientific public has therefore been given upon it in a favourable sense, and we have only to ratify it. Whatever Dr. Maudsley writes is sure to have fervour and vehemence, and as in his case out of the fulness of the heart the mouth speaketh, it is fortunate that his mind has saturated itself with the old English classics, so that his abounding eloquence flows in pleasing channels. He goes indeed farther back, for many of his verbal inspirations and Homeric turns of expression are quite common, and illustrations occur which recall Ovid. Shakespeare is, so to speak, his mother tongue, and, like many Englishmen, when in earnest, he finds nothing so apt for conveying his meaning in its full intensity and depth as passages from the Old Testament Scriptures. The reader is liable to be carried away in the rush of words, and it is an absolute necessity that he should, if at all amenable to the influence of rhetoric, quell his excitement at the end of each chapter by a careful study of the tabulated contents at the beginning of the work. These tables of contents

are really excellent, and exhibit the close and coherent chain of reasoning which underlies the vehement utterances and almost superabundant illustrations of the text.

The book is divided into eight chapters, some of which overlap each other a good deal; for example, we have Chap. v. on the supreme cerebral centres and ideation, Chap. vi. on emotions or affections of mind, Chap. vii. on volition, Chap. viii. on actuation, Chap. ix. on memory and imagination. Obviously emotions, volition, actuation, memory, imagination are related to the supreme cerebral centres as closely as ideation, and no one has laboured more than Dr. Maudsley to show that ideation, emotion, and volition are indissolubly associated, and are in some sense merely different aspects of the same operation, and we think, on the other hand, that actuation might have received further elucidation, by being considered in connection with the sensory centres through which the so-called motor intuitions are organised.

One of Dr. Maudsley's great aims is to overthrow the metaphysical conception of mind, and to exhibit the brain, not as the instrument, which mind as a metaphysical entity employs, but as the organ whose function is mind. This is the burden of the second chapter, on mind and the nervous system. In the introductory chapter on the method of the study of mind, Dr. Maudsley, as regards the old method of interpretation of selfconsciousness, not only slays the slain over and over again, but drags it thrice round the arena at his chariot-wheel, and yet if the book has a fault, it arises from want of complete emancipation from the terms and modes of thought which took their origin in metaphysics. There are many points on which we differ from Dr. Maudsley, and we think he has by no means taken full advantage of the light thrown on the physiology of the mental operations by aphasia, and by recent investigations such as those of Hitzig and Ferrier; but the book is one which may be recommended on every ground.

In Dr. Ferrier's work we naturally turn first to the account of the experimental researches on the function of different convolutions, with which his name is associated. They are summarised, and the results given clearly and definitely. Incited to the investigation by the observations and speculations of Dr. Hughlings Jackson on the effects of disease in certain convolutions, following Hitzig in point of time, but apparently quite independently, and employing a superior method, he identified the motor area of the cerebral cortex which lies, as is now well known, in monkeys and in man, along each side of the sulcus of Rolando, comprising mainly the two ascending gyri, which bound it, but extending forwards and backwards for a short distance along gyri which join them. The motor centres of the

lower extremity occupy the upper part of this area, those of the face and tongue, the lower or Sylvian end or expansion of the two convolutions, those of the arm and hand being intermediate in situation. The fact that constant and definite movements follow the application of the interrupted Faradic current in given situations is placed entirely beyond dispute; but objections have been raised to the interpretation put upon the results. It has been said that the electricity is conducted vaguely, or along nerve-fibres accompanying the vessels of the pia-mater. This is almost on the face of it absurd, and has been shown to be untrue. Other interpretations are that the centres identified are centres of co-ordination, or are seats of muscular sense, and it has even been gravely suggested that the movements are comparable with those induced by tickling the foot. These are overthrown by Ferrier, and may be set aside, but it may still be argued with some plausibility that the functional activity of the cells is not excited, but that the Faradic currents act upon the fibres leading from them to the lower centres; since if the grey cortex is removed or destroyed, the movements can be reproduced by applying the electrodes to the exposed white substance of the gyrus. We think Dr. Ferrier shows good cause in favour of the participation of the cells themselves, but in any case the conclusion remains that in these convolutions we have the "way out" of volitional motor impulses, and since their cells must be the agents in the transmission of such impulses, they constitute the motor centres of the cortex. An interesting corroborative fact is that when a given cortical centre, identified by stimulation, is removed, a corresponding paralysis is produced. In dogs, however, and lower animals it is fugitive, and power returns. Carville and Duret have shown by destruction of the corresponding centres of the opposite hemisphere, and by section of the corpus callosum, that there is no suppléance, or compensation, by the other half of the brain, and they consider that some other part of the cortex must take on the function of the portion destroyed. Ferrier more justly attributes the recovery of power to the substitution of automatic for volitional movements, to which the mechanism of the nervous system readily lends itself in dogs, and he states that in monkeys and in man the paralysis induced by destruction of a cortical motor centre is permanent. We venture, however, to question this opinion; the experimental evidence adduced in the case of the monkey is not conclusive, and if paralysis were the invariable result of disease in the convolutions constituting the motor area in man, it would scarcely have been left to Hitzig and Ferrier to identify this region by their experiments. Physicians and pathologists would have done it long since. It appears to us that the best illustrative parallel to the recovery from paralysis,