posed to mirth and laughter, with a mixture of small inconsistencies and absurdities; that these last should increase from the vivid trains which force themselves upon the brain, in opposition to the present reality; that they should lose the command and stability of the voluntary motions from the prevalence of confused vibrations in the brain, so that those appropriated to voluntary motion cannot descend regularly as usual; but that they should stagger, and see double: that quarrels and contentions should arise after some time; and all end at last in a temporary apoplexy. And it is very observable, that the free use of fermented liquors disposes to passionateness, to distempers of the head, to melancholy, and to downright madness; all which things have also great connexions with each other.
The sickness and head-ache which drunkenness occasions the succeeding morning, seem to arise, the first from the immediate impressions made on the nerves of the stomach; the second from the peculiar sympathy which the parts of the head, external as well as internal, have with the brain, the part principally affected in drunkenness, by deriving their nerves immediately from it.
I come next to consider the deliriums which sometimes attend distempers, especially acute ones. In these a disagreeable state is introduced into the nervous system by the bodily disorder, which checks the rise of pleasant associations, and gives force and quickness to disgustful ones; and which consequently would of itself alone, if sufficient in degree, vitiate and distort all the reasonings of the sick person. But besides this, it seems, that, in the deliriums attending distempers, a vivid train of visible images forces itself upon the patient’s eye, and that either from a disorder in the nerves and blood-vessels of the eye itself, or from one in the brain, or one in the alimentary duct, or which is most probable, from a concurrence of all these. It seems also that the wild discourse of delirious persons is accommodated to this train in some imperfect manner; and that it becomes so wild, partly from the incoherence of the parts of this train, partly from its not expressing even this incoherent train adequately, but deviating into such phrases as the vibrations excited by the distemper in the parts of the brain corresponding to the auditory nerves, or in parts still more internal, and consequently the seats of ideas purely intellectual, produce by their associated influence over the organs of speech.
That delirious persons have such trains forced upon the eye from internal causes, appears probable from hence, that when they first begin to be delirious, and talk wildly, it is generally at such times only as they are in the dark, so as to have all visible objects excluded; for, upon bringing a candle to them, and presenting common objects, they recover themselves, and talk
