f. Although delirium can by no means be taken as evidence of inflammation in the brain, it is a very constant symptom when the superficial structure and membranes are the seat of acute inflammatory action. The diagnosis, however, rests less on the presence of delirium than on other points to be noticed hereafter: it is generally of a more violent kind than any yet referred to, and more resembles acute mania ; the patient is noisy and un manageable, attempts to get out of bed, tosses the bedclothes about in confusion, and would often injure himself or others if not restrained : it is less characterized by fixed delusion than by wild shouting and screaming ; it is usually impossible to obtain an answer to any question, or to fix the attention on anything that is said.
When such a condition exists, we seek for evidence of inflam mation in quickness of pulse, flushing of face, throbbing of tem poral arteries, intolerance of light or of sound, indications of spasm, convulsions, or paralysis, history of pain, vomiting, and constipa tion. (See Chap. XIII. § 2.) g. The Delirium of Insanity.—Cerebral pathology is yet so entirely at fault in the correct association of certain mental states with special change of nervous structure, that no attempt will be made to classify the various features of mania ; the question of diagnosis need not be further pursued than to point out the dis tinctions between the delirium, which is a symptom of recognized conditions of disease, and that which is more properly, in the present state of our knowledge, considered as merely mental. Neither does it come within the scope of a manual of diagnosis to discuss whether or not alienation or perversion can be predi cated of mind, independently of disease of the organ of mind ; but there seems to be no greater difficulty in acknowledging this possibility than in confessing to the truth which Revelation teaches, of the fallen and imperfect condition of the mind of man, as a moral and responsible creature. And as it is possible, by purely physical processes, to correct perversions of the moral faculties, and by similar means to restore the mental faculties in what is called the moral treatment of the insane, a curious analogy is thus established between them. It is enough for us that the terms mental alienation, insanity, or unsoundness of mind are used to designate conditions different from those which we are acquainted with, as diseases of the brain.
As these terms imply, the prominent character of the state we are now discussing is an aberration of the reasoning faculties, the patient is unable to form a correct judgment on ordinary premises; and this may be limited to some particular subjects, or may apply, more or less, to all. But, besides the inability to reason correctly, there is generally a coexistent perversion of some particular fa culty, moral or intellectual, or of some one of the affections, giving in each case its peculiar stamp to the form of insanity, and perhaps the only real cause why the judgment is erroneous. From this perversion springs the fixed delusion so often present in the insane—a false idea permanently engrafted in the mind, which, in its turn, leads to the production of hallucinations and illusions: these are independent of delirium, which we are now considering as a symptom of acute mania. When this condition is superadded, all the ideas are thrown into confusion, the fixed delusion itself may for a time be lost, or be in abeyance, or may acquire greatly increased force ; some other prominent idea may take possession of the mind ; or there may be perfect incoherence. The delirium of insanity exactly corresponds, in these re,spects, to the delirium of disease, and is only more distinct and more exalted. It comes nearest to that of acute inflammation, with which it is often exactly identical ; and the diagnosis must be based on the mode of incursion and the indications derived from other symptoms.
When the attack has been ushered in by perversion of the affections, alterations in temper or spirits, or by peculiarity of manner in acting or speaking, especially when these can be traced to some cause of anxiety, bad news, or sudden fright, it is pro bably mania. Now and then, if the reports of friends may be trusted, cases of delirium tremens commence in a similar manner ; and we must guard against such a mistake by ascertaining whether there have been dissipation or excess prior to its occurrence. If due regard be had to those symptoms referable to the " general state" of the patient, the skin, the pulse, and the tongue, faulty diagnosis, which cannot always be avoided in diseases of the brain, will not lead to errors in treatment ; rational as opposed to empi rical remedies, can alone give satisfactory results.