Local or partial delusions of self are much more common. When the disturbance of nutrition which gives form to the delusion is in the skin, the patient imagines that his skin is made of velvet or of horn, or that he is swarming with vermin, or that he is uncleansably dirty. If it be in the body he may think that he is inhabited by a rat, a wolf, a dog, a cat, a weasel, a crab; that he has no inside; that he or she is pregnant (for this delusion is by no means confined to the female sex); that his bowels are completely stopped, and so forth. If the disturbance of nutrition be in the limbs, he thinks that they are made of glass, of brass, of iron, of putty; that they are absent, are too large, too small. If in the head, his brains are boiling, they have been taken out and his head is empty, or another person's brains have been substituted for his own; his head is bursting, there is no back, no top to it, and so forth.

CHAPTER XV.

THE FORMS OF INSANITY (Continued).

Dementia.

SIMPLE dementia is, as we have seen, the natural condition of man in his declining years. It is a stage that has to be passed through on the road to death, if death takes place by the natural expiry of the forces of life, and not by violence or by the quasi-violence of disease. Normally, dementia is a process of simple enfeeblement and decadence. As the bodily powers diminish, the mental horizon contracts. Little by little, there steals upon the organism an inability to concern itself with matters that are far removed from its own immediate welfare. Little by little, its attention becomes more and more concentrated on the things which are passing immediately around it, and which affect it most. directly. The ability to deal with abstractions fails, and there remains at last only the vestige of the mental, as of the bodily strength. In extreme old age-a period which, as before explained, is to be reckoned, not by years, but by the degree to which the power of living has ebbed away— the individual sits doubled up in his chair, his head sunk forward on his breast, his eyes staring straight before him, his jaw dropped, his arms hanging uselessly by his sides, his hands resting inactive, his legs with the knees either resting against each other or fallen apart, his ankles bent sideways, and his feet lax. Speak to him, and he answers only the simplest questions, and not always these. Scarcely ever does he initiate a remark, save perhaps to ask for food or

drink. He can neither dress nor undress himself. He has to be fed like a child. Often he is dirty in his habits, and has to be cared for like an infant. Such is the end of life in every one in whom life goes on to the end.

Now it sometimes happens that, owing to the incidence of some one or more of the stresses already considered, this failure of energy, which is due to occur at the end of life, sets in prematurely. It has been said that old age cannot be estimated altogether by years. If we set a ball rolling, its speed will not begin to slacken appreciably until the impetus that we gave it begins to be exhausted; and the stronger the initial impetus, the further the ball will go, and the longer it will run, before it comes to rest. So with the living organism; all lives receive at conception an impetus which is to carry them forward to the end, but the impetus is not equally powerful in all, and hence in some it is exhausted at sixty or seventy, while in others it suffices to carry the organism over the century. It may happen, however, that owing to the exceptionally rough nature of the ground, the velocity of the ball is materially diminished. at an early stage in its career, and that it comes to rest prematurely; and similarly it may occur to the human organism, that, owing to the incidence of some stress, dementia sets in prematurely; and we may have, in a young man or woman of forty-five, forty, thirty-five, or even at an earlier age, a state of things precisely similar to that in the senile dement. The same enfeeblement of body, the same loss of initiative, the same emptiness of the storehouse of energy, the same decadence, almost to the point of absence, of mind, that naturally occur in old age, may set in in earlier life, if the life have been subject to some severe drain upon its energies. Thus, it will occasionally happen that after very severe exertion, either bodily or mental, undertaken by a person who had no very copious store of energy to fall back upon, he may fall into a condition of dementia virtually identical with the dementia of old age. The chief and most searching source of exhaustion of the nervous system is,

however, an outbreak of mania, and the commonest occasion of premature dementia is an antecedent mania. Every case of mania ends in dementia. Doubtless this fact has another aspect, as we shall presently see. From one point of view the exhaustion of the mania may be looked on as a cause of the consequent dementia; from another point of view, the mania may be regarded as an incident or a bye-product of the process of dementia; and both views would be correct. At present, however, we confine ourselves to the first of these aspects.

It has been said that mania is the commonest antecedent of premature dementia ; it has now to be said that dementia is an invariable consequent of mania. Every case of mania, unless it is cut short in its maniacal stage by physical accident, or by the accident of disease, goes on into dementia. The generality of this statement will no doubt be startling to those who have had experience in the care of lunatics, and will arouse much antagonism. "What!" they will say, "Every case of mania end in dementia! Do not scores and hundreds of cases of mania recover every year? Nonsense." To which I reply, Certainly, numerous recoveries from mania take place every year; but this does not invalidate my position. By dementia as ordinarily understood, is meant a permanent condition, but dementia is not necessarily permanent. Doubtless, the dementia of old age is permanent and progressive; doubtless, also, many cases of mania end in a dementia which is permanent; but this character of permanence is not a necessary attribute of dementia. Every alienist of experience will remember cases of mania which have gone on into dementia, and which, after a longer or shorter period, have emerged again from the dementia and recovered; and, when it is thus put to them, I doubt not that every alienist will admit that every case of mania, which has recovered under his care, has passed through a stage of greater or less mental enfeeblement between the subsidence of the maniacal excitement and the restoration of mental health. Of course it may be said that this intermediary