The next species of alienations of the mind is melancholy. Vapours, hypochondriacal, and hysterical disorders, are comprehended under this class. The causes of it are self-indulgence in eating and drinking, and particularly in fermented liquors, want of due bodily labour, injuries done to the brain by fevers, concussions, &c., too much application of the mind, especially to the same objects and ideas, violent and long-continued passions, profuse evacuations, and an hereditary disposition; which last we may suppose to consist chiefly in an undue make of the brain.
In women the uneasy states of the uterus are propagated to the brain, both immediately and mediately, i.e. by first affecting the stomach, and thence the brain. In men the original disorder often begins, and continues for a long time, chiefly in the organs of digestion.
The causa proxima of melancholy is an irritability of the medullary substance of the brain, disposing it upon slight occasions to such vibrations as enter the limits of pain; and particularly to such kinds and degrees, as belong to the uneasy passions of fear, sorrow, anger, jealousy, &c. And as these vibrations, when the passions are not in great excess, do not much transgress the limits of pleasure, it will often happen that hypochondriac and hysteric persons shall be apt to be transported with joy from trifling causes, and be, at times, disposed to mirth and laughter. They are also very fickle and changeable, as having their desires, hopes, and fears, increased far beyond their natural magnitude, when they happen to fall in with such a state of brain as favours them.
It often happens to these persons to have very absurd desires, hopes, and fears; and yet, at the same time, to know them to be absurd; and, in consequence thereof, to resist them. While they do this, we may reckon the distemper within the bounds of melancholy; but when they endeavour to gratify very absurd desires, or are permanently persuaded of the reality of very groundless hopes and fears, and especially if they lose the connecting consciousness in any great degree, and violate the rules of decency and virtue (the associations of this kind being overpowered, as it were, in the same manner as they are sometimes in dreams), we may reckon the distemper to have passed into madness, strictly so called; of which I now come to speak in a general brief way.
The causes of madness are of two kinds, bodily and mental. That which arises from bodily causes is nearly related to drunk-
