CASE XXX. T. G. a man, about fifty-five years of age, was admitted into the hospital, January 20, 1798. It was stated, that he had been disordered a year and half, and that his madness arose from repeated intoxication. Having set fire to several hay-stacks, and committed frequent depredations on the neighbouring farmers, it had been found necessary to confine him in the county goal. His behaviour in this situation marked the cunning and malignity of his mind, so that he was always attempting some mischief either by violence or stratagem. When brought to the hospital he conducted himself with propriety and order, and appeared to be in a state of recovery. On the second of May he was attacked with a diarrhoea which daily encreased, notwithstanding the medicines employed for its removal. His mind became violently agitated from the commencement of the diarrhoea, and it was found proper to secure him. On the 8th, dysenteric symptoms appeared, which continued to the 13th, when he died. _Appearances on Dissection._ The head was opened twenty-four hours after death. The pericranium was loosely attached to the scull, and the dura mater adhered but slightly to the internal surface of the cranium; there was a considerable quantity of water between the dura mater and tunica arachnoidea, this latter membrane (especially where the hemispheres meet) was of a milky whiteness, and generally so in the course of the veins of the pia mater. The glandulae Pacchioni were very large and numerous. Between the tunica arachnoidea and pia mater there was much water; and from the lateral ventricles, which were uncommonly enlarged and distended, eight ounces of fluid were collected: the infundibulum was remarkably large: the membrane lining the cavity of the lateral ventricles had its veins very turgid: the consistence of the brain was softer than natural. The fluid obtained from the brain in this case being very pellucid and abundant, it was submitted to some chemical tests in order to ascertain its composition. An attempt of this kind had been made before; (vide Case 23) the present may be considered a small addition to our knowledge of this fluid, though by no means a satisfactory developement of its materials, according to the severity and precision of modern analysis.[11] ANALYSIS OF THE FLUID. _Tincture of Galls_, produced a white precipitate in moderate quantity. _Lime Water_, afforded a considerable quantity of a white precipitate, which was redissolved without effervescence by muriatic acid. _Solution of Sulphat A drop of this solution added to of Copper._ two drams of the brain fluid tinged it with a pretty deep blue. The presence of animal matter is inferred from the deposition produced by infusion of galls. The precipitation by lime-water indicates the phosphoric acid.