LECTURE II.

GENTLEMEN,-In my last lecture I gave a general survey of the physiology of our mental functions, showing how indissolubly they are bound up with the bodily functions, and how barren must of necessity be a study of mind apart from body. I pointed out that the higher mental operations were functions of the supreme nerve-centres; but that, though of a higher and more complex nature than the functions of the lower nervecentres, they obeyed the same physiological laws of evolution, and could be best approached through a knowledge of them. I now propose to show that the phenomena of the derangement of mind bear out fully this view of its nature; that we have not to deal with disease of a metaphysical entity, which the method of inductive inquiry cannot reach, nor the resources of the medical art touch, but with disease of the nervous system, disclosing itself by physical and mental symptoms. I say advisedly physical and mental, because in most, if not all, cases of insanity, at one period or other of their course, there are, in addition to the prominent

mental features, symptoms of disordered nutrition and secretion, of disordered sensibility, or of disordered motility. Neither in health nor in disease is the mind. imprisoned in one corner of the body; and when a person is lunatic, he is, as Dr. Bucknill has remarked, lunatic to his fingers' ends.

Mental disorders are neither more nor less than nervous diseases in which mental symptoms predominate, and their entire separation from other nervous diseases has been a sad hindrance to progress. When a blow on the head has paralysed sensibility and movement, in consequence of the disease in the brain which it has initiated, the patient is sent to the hospital; but when a blow on the head has caused mental derangement, in consequence of the disease of brain which it has initiated, the patient is sent to an asylum. In like manner, one man who has unluckily swallowed the eggs of a tænia, and has got a cysticercus in the brain, may go to the hospital; another who has been similarly unlucky goes to an asylum. Syphilitic disease of the brain or its arteries lands one person in an asylum with mental symptoms predominant, another in an hospital with sensory and motor disorder predominant. The same cause produces different symptoms, according to the part of the brain which it particularly affects. No doubt it is right that mental derangements should have, as they often require, the special appliances of an asylum, but it is certainly not right that the separation which is necessary for treatment should reach to their pathology and to the method of its study. So long as this is the case, we shall

labour in vain to get exact scientific ideas concerning their causation, their pathology, and their treatment.

Clearing, then, the question as completely as possible from the haze which metaphysics has cast around it, let us ask-How comes idiocy, or insanity? What is the scientific meaning of them? We may take it to be beyond question that they are not accidents; that they come to pass, as every other event in nature does, by natural law. They are mysterious visitations only because we understand not the laws of their production, appear casualties only because we are ignorant of their causality. When a blow on the head or an inflammation of the membranes of the brain has produced derangement of mind, we need not look farther for a cause: the actual harm done to structure is sufficient to account for disorder of function in the best-constituted and best-developed brain. But it is only in a small proportion of cases of insanity that we can discover such a direct physical occasion of disease. In a great many cases-in more than half, certainly, and perhaps in five out of six-there is something in the nervous organization of the person, some native peculiarity, which, however we name it, predisposes him to an outbreak of insanity. When two persons undergo a similar moral shock, or a similar prolonged anxiety, and one of them goes mad in consequence, while the other goes to sleep and goes to work and recovers his equanimity, it is plain that all the co-operating conditions have not been the same, that the entire cause has been different. What, then, has been the difference? In the former case there has been

present a most important element, which was happily wanting in the latter—there has been a certain hereditary neurosis, an unknown and variable quantity in the equation.

Perhaps of all the erroneous notions concerning mind which metaphysics has engendered or abetted, there is none more false than that which tacitly assumes or explicitly declares that men are born with equal original mental capacity, opportunities and education determining the differences of subsequent development. The opinion is as cruel as it is false. What man can by taking thought add one cubit either to his mental or to his bodily stature? Multitudes of human beings come into the world weighted with a destiny against which they have neither the will nor the power to contend; they are the step-children of nature, and groan under the worst of all tyrannies-the tyranny of a bad organization. Men differ, indeed, in the fundamental characters of their minds, as they do in the features of their countenances, or in the habits of their bodies; and between those who are born with the potentiality of a full and complete mental development, under favourable circumstances, and those who are born with an innate incapacity of mental development, under any circumstances, there exists every gradation. What teaching could ever raise the congenital idiot to the common level of human intelligence? What teaching could ever keep the inspired mind of the man of genius at that level?

The congenital idiot is deprived of his human birthright; for he is born with such a defect of brain that he

cannot display any, or can only display very feeble and imperfect mental functions. From no fault of his own is he thus afflicted, seeing that he must be held innocent of all offence but the offence of his share of original sin; but it is nowise so clear that it is not from some fault of his parents. It is all too true that, in many cases, there has observably been a neglect or disregard of the laws which govern the progress of human development through the ages. Idiocy is, indeed, a manufactured article ; and although we are not always able to tell how it is manufactured, still its important causes are known and are within control. Many cases are distinctly traceable to parental intemperance and excess. Out of 300 idiots in Massachusetts, Dr. Howe found as many as 145 to be the offspring of intemperate parents; and there are numerous scattered observations which prove that chronic alcoholism in the parent may directly occasion idiocy in the child. I think, too, that there is no reasonable question of the ill effects of marriages of consanguinity: that their tendency is to produce degeneracy of the race, and idiocy as the extremest form of such degeneracy. I do not say that all the children of such marriages may not sometimes be healthy, and some of them quite healthy at other times; but the general and ultimate result of breeding in and in is to produce barrenness and sterility, children of a low degree of viability and of imperfect mental and physical development, deaf-mutism, and actual imbecility or idiocy. Again, insanity in the parent may issue in idiocy in the offspring, which is, so to speak, the natural term of mental degeneracy when it goes on