BRAIN

is enclosed by the skull, between which and the brain are three membranes and a layer of fluid, so that the brain lies in a water bed, which protects it from concu ion. The weight of the brain is about 49 ounces in the male and rather le in the female, this disparity being due to the weight of the average female being le than that of the ie male, The relation of brain weight to body weight is in fish 1 to 5,000, birds 1 to 220, lower mammals | to 180, in apes | to 120, in man 1 to 50. The brain weight of distinguished men is on the whole higher than that of others, whilst that of Europe ans is above that of savages; but thero are many exceptions, quality being of more value than quantity. The brain of the lunatic can often not be distinguished from that of the normal man, nor can that of a criminal be recognised as such. Of the ultimate connection between brain and mind we are ignorant, but much knowledge has been gained during the last thirty years of the exact parts of the brain that are concerned in particular proce es. Certain parts are now known to be concerned in the movement of the various parts of the body, and it is noteworthy that the right side of the body is controlled by the left side of the brain; other parts are concerned in vision, hearing and the other senses; it is thought, but it is not yet known for certain, that the frontal phen is concerned with mental proce es alonc. The bold claims of phrenology, which labels almost every spot in the skall with the name of a virtue or a vice, have no foundation in real science. The diseases to which the brain is liable are numerous. Inflammation of its membranes is meningitis. This is commonly a ociated with water on the brain, because the brain is hollow and contains fluid, which normally is constantly overflowing through three minute pores into the space between the brain and its membranes, and when inflammation occurs the pores become blocked and fluid, which is being constantly formed within the brain, is locked up there. Brain-fever ts a vague term in popular use to denote any condition accompanied by delirium, especially meningitis, Rupture of a blood-ve el within the brain causes apoplery; clotting in a blood-veasel cerebral thrombosis. Softening of the Brain denotes the normal mental decay of advanced life, which may occur prematurely in certain cases. Absce es and tumours also occur, in the treatment of which surgery has made great strides of late. {For Concu ion refer to Blows. Meningitis, Apoplery, and Cerebral Thrombosis are treated under their respective headings.] [s. 338]