When mental disease develops subse quent to an operation, the patients often show a strong hereditary tendency to in sanity, the result of insane, intemperate, or neurotic ancestry. This is especially true in relapsing or circular insanity. H. M. Hurd (Amer. Jour. of Obstet.. Mar., '99).
Two cases of dementia in twins aged 33 years. This illustrates the fact that nervous systems and brains which have the same physical construction will act in the same way under given patho logical conditions. Heredity in psychical affections is particularly well shown in many cases of insanty in twins. S. Souchanoff (Klinitchesky Jour., Apr,, 19001.
The simulated paranoia of chronic alcoholism belongs to a different group (Group VI).
III. Psychoses due to simple disturb ance of nutrition in the brain, such as ana?mia and hypermmia. To this group belong the majority of cases of melan cholia (depression) and mania (exalta tion). In many cases the diagnosis "melancholia" and "mania" arc incor rect, a transitory depression or exaltation being regarded as the essential clinical manifestation.
IV. Psychoses due to microscopical structural alterations in the brain. These are primarily probably nutritional or toxic.
In this class are included general pare sis, catatonia, consecutive dementia, senile dementia, and epileptic dementia. In a majority of the brains of those dying insane, maeroseopical examination shows a milky opacity of the arachno. pia, closely associated with underlying morbid processes in a space which can be covered with the two hands placed to gether, the lower ends of the hypothenar eminences covering the spot where the fissures of Rolando meet. The giant pyramids are the first to show markedly altered structure. J. B. Tuke (Edin burgh Med. Jour., Feb. to June, '94).
The doctrine of the neuron and the interrelation of neurons within the cen tral nervous system affords a foundation for possibilities in nerve-activity. The cortical areas are themselves complex structures, yet in each cluster the indi vidual neuron preserves not only its in . tegrity as distinct from other neurons, but also its threefold character as a nutritive and dynamic doubly-connected apparatus. The human brain shows four layers: (1) the molecular layer; (2) the ambiguous layer; (3) long pyram idal layer ; ( 4) mixed pyramidal or polymorphic layer, including Meynert's layer, plus spindle layers. Alteration
and destruction of fine naked collaterals and nerve-terminals shown to exist in the molecular layer and swelling and soften ing of minute protoplasm-granules at tached to special processes in the super ficial layer of the cortex. Lloyd Andrie zen (Brain, P. 6S, p. 549, '95).
Changes as given by Lloyd Andriezen explain the diminished sensitiveness of an alcoholic subject to impressions from without, and also the general loss of memory and lack of association of ideas. Microscopical examination cannot give us all the information we desire when the initial cause is not known. The con viction is steadily growing that actual agents which produce tissue-changes are chernico-toxic, absorbed or ingested, pro duced by altered tissue-metabolism or elaborated by bacteria. Dercum (Jour. Amer. Med. Assoc., July 15, '95).
Possibility of there being no non inedullated nerve-fibers in the cerebral cortex. Naked axis-cylinders ought to be a physiological impossibility in cere brum; their presence could only give rise to irregular overflow of energy, with corresponding confusion. It is probably through protoplasmic processes in lateral buds or gemmules that the axons influ ence protoplasm of dendrons and cells. Their uncovered endings come into close contiguity with gemmules. The gemmules that are specially liable to in jury from toxic or morbid influences are the first portions of the neuron to atrophy and disappear in certain dis eases. H. J. Berkley (Medical News, Nov. 9, '95).
The presence of micro-organisms in the cerebro-spinal fluid and cortex involve their pre-existence in some other part of the organism, and their presence during the course of acute mental disturbances is not relational or causative, but associ ative. H. A. 'Tomlinson (Northwestern Lancet, Sept. 1, '97).
There are no renal functional insani ties. All show positive anatomical le sions. Brains studied in catatonia and involutional melancholia; the neurogliar hyperplasia found in nowise less than in general paralysis. Nissl (Mtinchener med. Welch., Oct. 31, '99).