306 INSANITY tic insanity, has of late years received much at- tention, and many remarkable relations have been established between it and other diseases and insanity, especially that form called impul- sive insanity. The tendency to epilepsy is he- reditary, although it may be produced by blows on the head and other injuries to the brain. It has been found to have strong relations to pa- ralysis, to chorea, and also to phthisis, which are indicated by the fact that children of tuber- culous parents may inherit epilepsy, chorea, or paralysis, and vice versa; or insanity in off- spring may follow these diseases in parents. These diseases may also follow each other in the same individual, an attack of mania appear- ing in place of epilepsy, the latter, however, being the primary disease. The investigations of Dr. Echeverria have aided in establishing many important facts in regard to the subject, which had previously received the attention of Delasiauve, Morel, Falret, Baillarger, Trous- seau, and others. They comprised the exam- ination of more than 700 epileptics, embracing a period of over 13 years. The recorded cases number 532, of which 267 were cases of epi- leptic insanity, comprising 141 males and 126 females. Out of these the causes were dis- tinctly ascertained in 123 males and 104 fe- males. Insanity, paralysis, or epilepsy oc- curred among the ancestors of 37 males and 46 females ; among the ancestors of the 37 males there were 11 cases of phthisis, and among those of the 46 females there were 13 cases of phthisis. He found that epileptic insanity may have an intermittent, remittent, and a continu- ous form ; the intermittent being characterized by periodical attacks of variable regularity, the remittent having only partial recovery of in- tellectual soundness between the epileptic par- oxysms and maniacal attacks, and the continu- ous form presenting a permanent and unmodi- fied condition of insanity. Dr. Echeverria does not find that the petit mal and the grand mal of epilepsy exercise so different an influ- ence upon the violence of the succeeding mani- acal attacks as has by some been supposed. The acts of the epileptic insane are always sud- den and instantaneous, and beyond the control of the will ; but it must not be assumed that the mania which causes the acts is itself instan- taneous. He thinks that most of the cases of mania transitoria are those of epilepsy or epi- leptic insanity. Epileptic insanity is of a vio- lent and dangerous character, with strong homi- cidal tendencies, and is remarkable from the fact that the patient during his maniacal ex- citement, which may last for hours, and during which he may be wandering around, is wholly unconscious. (See also Maudsley, " Responsi- bility in Mental Disease," 1874.) The aphasia which occurs in certain cases of insanity is be- lieved by many to have found an explanation in the experiments of Dr. Ferrier of King's college, London, which are regarded as strong evidence of the localization of cerebral func- tions ; but the correctness of this conclusion is denied by Dr. Brown-S6qnard in a paper read before the national academy of science at Washington in April, 1874. Dementia, or loss of mind, may be primary, or it may be secon- dary to other forms of insanity, as mania, gen- eral paralysis, epilepsy, and more rarely melan- cholia, and differs from idiocy and imbecility in not being congenital. It is the inevitable stage into which degeneration of brain tissue, if continued long enough, always passes, and is of course incurable, the only treatment being that directed to the general health, and when possible ministering to the comfort of the suf- ferer. Idiocy and Imbecility. The great dif- ference between these conditions is, that though they are both congenital, the subjects of the former have badly shaped and deficiently de- veloped brains, while those of the latter are usually well shaped, but fail in consequence of congenital pathological conditions similar to those found in dementia. This condition is to a certain though less extent also found in idiots, but many of them are more susceptible of mental cultivation than imbeciles, because the brain of the idiot may be somewhat de- veloped by exercise. (See IDIOCY.) Pathology of Insanity in general. The subject of an at- tack of acute mania may die in a week from the commencement. A post-mortem examina- tion shows the cerebral membranes congested ; the sinuses and the veins of the pia mater may be full of blood, and there may be effusion of serum beneath the arachnoid and the serous membrane. In those who have had previous attacks or who have been partially insane there is often thickening of the bones of the cra- nium, with adhesion and thickening of the dura mater, indications of a chronic inflammatory condition. The brain will present discolored patches of a pink or purple hue, and also soften- ing. The cells, nerve tubes, and connective areolar tissue may also be found more or less changed. Blood cysts are often found in the cavity of the arachnoid, and extravasated blood on the surface of the convolutions and in the cerebral substance. In cases of chronic mania and dementia there are usually more definite changes. The nerve cells are altered in char- acter, and the nerve tubes leading from them are shrunken and sometimes disconnected. The inferior tissues are increased, and abnormal tissues take the place of those that are healthy, interfering with the functions of that which remains. The wasting of the brain is an im- portant pathological condition. There is a loss of substance, the brains of the insane weighing less in proportion to the cavity of the cranium than in other cases. Dr. Lockhart Clarke has pointed out peculiar and numerous cavities in the white substance of the convolutions and of the optic thalami of the brains of chronic ma- niacs and the demented, and also in those who have died of general paralysis. These cavities are generally regarded as widened perivascular spaces, formed by the dilatation of the peri- vascular canals which surround the blood ves-
