So likewise, in discriminating the delirium of acute inflamma tion from that of acute mania, besides that light which is thrown on the case by the ascertained absence of peculiarity or perversion of ideas prior to its appearance, still more information may be gained by a strict examination of all the symptoms yet to be detailed, which point to inflammation of the brain.as their c,ause.
As we shall not have another opportunity for discussing the subject of insanity, a few remarks on its more general features may not be inappropriate in this place. Its forms are very varied : the patient may be morose, taciturn, or reserved ; or he may be loquacious, noisy, or unma%ageable ; any one or more of the faculties and affections may be the especial seat of the disease ; his delusions may be fixed and invariable. or may comprehend a constantly changing series of fancies ; and these, again, are usually accompanied by the presence of hallucinations and illusions—mental impressions which seem to the patient to be produced by objects affecting his senses, when in truth they originate in the mind itself. These imaginings of the insane are very different from what may be more properly termed alterations in sensibility : in the latter the force of true impressions on the nerves is exaggerated or diminished in intensity, or their character is confused and indistinct ; in the former, the mental conception is referred to the organs of sense, where impressions are felt exactly analogous to those which would be received if the corresponding object had a real existence ; in the one the sensations are vague and ill-defined, in the other they seem distinct and clear.
In the strict application of terms, the word hallucination implies that no object is present to stimulate the organ to which the idea formed in the mind is referred ; while in illusions, existing objects, which in the first instance pro duce the stimulus, ate clothed by the mind in characters more or less foreign to their true nature, and these are so inextricably blended with the sensation originally produced, as to give rise td the belief that the resulting idea is wholly derived from an external impression.
Morbid fancies are not limited to insanity ; but when the judgment is per verted or lost, they are not corrected by the force of true impressions opposed to them, and hence their permanence and domination in insanity and delirium.
In mental affections the patient is usually out of health, but there are no general symptoms invariably present : the tongue is often foul, the bowels confined, and during the paroxysm of acute mania the pulse may be somewhat accelerated, but we seek in vain for evidence of inflammation, for convulsion, or paralysis, except when imbecility succeeds epilepsy, or paralysis accom panies fatuity ; the symptoms referable to the nervous system neither betray increased sensibility, nor loss of power, but consist of deceptions of the nerves of sense, delusions regarding external objects, and false impressions of the condition of the whole body, or of some particular organ. The main distinc
tion between the false impressions of the insane, and those of the hypochon driac or dyspeptic, is that the belief in their reality in the one case implies an absurdity which the patient's knowledge of the laws of nature would be suffi cient to detect and expose, were he of sound mind ; in the other the conception is not irrational according to his amount of information on the subject. The most prominent exception to this general rule of diagnosis is found in the condition of puerperal mania, which seems to hold a place somewhat inter mediate between mental alienation and the delirium of disease, being allied to the former in the perversion of the affections and the reason, and the absence of distinct signs of disease, while it is assimilated to the latter in its coinci dence with the peculiar state of health belonging to pregnancy and parturition. Its diagnosis cannot be based upon any peculiarity in the manifestation of the mental phenomena, but simply on the ilia of its occurring during the puerperal state, and occasionally after prolonged lactation, when perhaps it is rather to be regarded as mania occurring in a condition of anaemia, than mania asso ciated with pregnancy. In its commencement there is almost always delirium; after its subsidence the patient remains in a condition of temporary unsound ness of mind : undoubtedly faulty nutrition is one of the antecedent circum stances, but there is something more—hereditary tendency, insanity in other members of the family, or individual predisposition, as indicated by repeated attacks in successive pregnancies ; at all events it is alike different from the blood•poisoning of fevers, inflammations, &c., and from delirium depending on change of structure in the brain.