enness, and to the deliriums attending distempers. That from mental causes is of the same kind with temporary alienations of the mind during violent passions, and with the prejudices and opinionativeness, which much application to one set of ideas only occasions.
We may thus distinguish the causes for the more easy conception and analysis of the subject; but, in fact, they are both united for the most part. The bodily cause lays hold of that passion or affection, which is most disproportionate; and the mental cause, when that is primary, generally waits till some bodily distemper gives it full scope to exert itself. Agreeably to this, the prevention and cure of all kinds of madness require an attention both to the body and mind; which coincides in a particular manner with the general doctrine of these papers.
It is observed, that mad persons often speak rationally and consistently upon the subjects that occur, provided that single one which most affects them, be kept out of view. And the reason of this may be, that whether they first became mad, because a particular, original, mental uneasiness falls in with an accidental bodily disorder; or because an original, bodily disorder falls in with an accidental mental one; it must follow, that a particular set of ideas shall be extremely magnified, and, consequently, an unnatural association of sameness or repugnancy between them generated, all other ideas and associations remaining nearly the same. Thus, suppose a person, whose nervous system is disordered, to turn his thoughts accidentally to some barely possible good or evil. If the nervous disorder falls in with this, it increases the vibrations belonging to its ideas so much, as to give it a reality, a connexion with self. For we distinguish the recollection and anticipation of things relating to ourselves, from those of things relating to other persons, chiefly by the difference of strength in the vibrations, and in their coalescences with each other. When one false position of this kind is admitted, it begets more of course; the same bodily and mental causes also continuing; but then this process stops after a certain number of false positions are adopted from their mutual inconsistency (unless the whole nervous system be deranged); and it is often confined to a certain kind, as the irascible, the terrifying, &c.
The memory is often much impaired in madness, which is both a sign of the greatness of the bodily disorder, and a hindrance to mental rectification; and therefore a bad prognostic. If an opposite state of body and mind can be introduced early, before the unnatural associations are too much cemented, the madness is cured; if otherwise, it will remain, though both the bodily and mental cause should be at last removed.
Inquiries after the philosopher’s stone, the longitude, &c. to which men are prompted by strong, ambitious, or covetous desires, are often both cause and effect, in respect of madness.
