Dr. Henry Monro, again, in a treatise published in 1851, put forward a theory of the pathology of insanity, the essence of which was that the cerebral masses having lost their static equilibrium exhibit in their functions two different degrees of deficient nervous action (coincidently), viz. irritable excess of action and partial paralysis. He maintained that these two states do not fall alike upon all the seats of mental operations, but that there is "a partial suspension of action" of "higher faculties, such as reason and will," while there is an irritable excess of action of the seats of the more elementary faculties, such as conception, etc., and hence delusions and the excessive rapidity of successive ideas. Dr. Monro compares this condition to a case of paralysis, combined with convulsions; and discusses the question whether the temporary and partial paralysis occurring as he supposes in insanity, "results directly and entirely from excessive depression of the nervous centres of those higher faculties, or partly in an indirect manner from nervous energy being abstracted to other parts which are in more violent exercise at the time."[306]
This, it will be seen, is a still clearer statement of the doctrine that insanity is caused by the depression or paralysis of the higher nervous centres and excessive action of others.
As is well known, Dr. Hughlings Jackson, whose views regarding active states of nerve structures as liberations of energy or discharges, are familiar to us all, has adopted and extended Laycock's doctrine, which he designates as "one of inestimable value," and has urged the importance of Monro's doctrine of negative and positive states in cases of insanity, using the term "insanity" in an exceedingly wide sense. He has pointed out that Anstie and Thompson Dickson have also stated the doctrine that so-called "exaltation of faculties" in many morbid states is owing to "insubordination from loss of control," and that the same was said in effect by Symonds, of Bristol. Adopting the hypothesis of evolution as enunciated by Herbert Spencer, Dr. Hughlings Jackson thinks that cases of insanity, and indeed all other nervous diseases, may be considered as examples of Dissolution, this being, I need not say, the term Spencer uses for the process which is the reverse of Evolution. Insanity, then, according to this view, is dissolution beginning at the highest cerebral centres, which centres, according to Jackson, represent or re-represent the whole organism. There are distinguishable, he believes, cases of uniform dissolution, the process affecting the highest centres nearly uniformly, and cases of partial dissolution in which only some parts of these centres are affected. The dissolution, again, whether uniform or partial, varies in "depth;" the deeper it is, the more general are the manifestations remaining possible. The degree of "depth" of dissolution is, however, but one factor in this comparative study of insanity. Another is the rapidity with which it is effected. To this, Dr. Jackson attaches extreme importance, believing that degrees of it account for degrees of activity of those nervous arrangements next lower than those hors de combat in the dissolution. Another factor is the kind of person to whom dissolution "comes." And the last factor is the influence of circumstances on the patient undergoing mental dissolution. All factors should, of course, be considered in each case, or, as Dr. Jackson characteristically puts it, "insanity is a function of four variables." I refer to these opinions to show the direction in which some modern speculation on the nature of insanity tends, that thus tracing the course of thought in recent years we may see how, step by step, certain views have been reached, some of them generally adopted, others regarded as still requiring proof before they can be accepted.
The negative and positive view of the nature of insanity receives support, I think, from the phenomena of Hypnotism which, about forty years ago, attracted, under the name of Mesmerism, so much attention in England in consequence of the proceedings of Dr. Elliotson in the hospital and college where we meet to-day. This was in 1838, and Braid's attention was arrested by what he witnessed in 1841. It is no reason because we have re-christened mesmerism that we should ignore the merit of those who, as to matters of fact, were in the right, however mistaken their interpretation may have been.
Elliotson recorded some striking examples of induced hallucinations and delusions, and in an article in the Journal in 1866, I endeavoured to show how suggestive similar instances which I then reported are in relation to certain forms of insanity, and also in relation to sudden recovery from mental disease; the conclusion being forced upon us that there may be cases in which no change takes place in the brain which the ablest microscopist is likely to detect, but a dynamic change—one more or less temporary in the relative functional power of different cerebral centres, involving loss or excess of inhibition.
Nor can I, in connection with the reference to cerebral localization, allow to pass unrecorded the researches of Fritsch, Hitzig, and Ferrier, on account of the intimate, although only partial relation in which they stand to mental pathology—a relation promising to become more intelligible and therefore more important as the true meaning of the psycho-motor centres becomes better understood; for that we are only on the threshold of this inquiry must be evident, when men like Goltz, Munk, and other investigators call in question the conclusions which have been arrived at.
But be the final verdict what it may, when I look back to the time when "Solly on the Brain" was our standard work, and then turn to Ferrier's treatise on its functions, to the remarkable works of Luys, and to Dr. Bastian's valuable contribution to the International Series, I cannot but feel how unquestionable has been the advance made in the physiology of the brain, strangely bent as Nature is on keeping her secrets whenever the wonderful nexus which binds together, yet confounds not, mind and brain, is the subject of investigation.
The past forty years have witnessed a great change in the recognition of mental disease as an integral part of disorders of the nervous system, and medical psychology is less and less regarded as a fragment detached from the general domain of medicine. Contributions from all lands have conspired to produce this effect, the somatic school of psychologists in Germany having exerted, probably, the most influence. And we are proud to number in France among our roll of associates a physician who, not only by his pathological researches into diseases of the brain and cord, but by his clinical study of affections closely allied to mental derangement, has by the brilliant light he has thrown upon the whole range of diseases of the nervous system, advanced the recognition of which I have just spoken. I need not say that I refer to our distinguished honorary member, Professor Charcot.