BRAIN, Diseases of. These are so many and so diverse that a general article cannot readily be written upon them. In general they may be divided into: (1) Developmental de fects. These are considered under idiocy, im becility (qq.v.), etc. (2) Acute infections in which the brain itself or its surrounding mem branes are attacked by some form of bacterium, such as influenza bacillus, the pneumococcus, that ordinarily is the main cause of pneumonia, the typhoid organism, or certain forms of cocci. These diseases are discussed under the heads, encephalitis, meningitis, cerebral abscess, epi demic cerebrospinal meningitis (qq.v.). (3) Acute and chronic poisoning, including delirium tremens in alcoholism (q.v.), toxic manias, etc. (4) Diseases of the blood vessels of the. brain. The condition generally known as apoplexy arises from disease of the cere bral vessels. This manifests itself in three different forms due to cerebral haemorrhage, cerebral thrombosis or cerebral embolism. These are discussed here. In all, the symptoms are much alike, as similar areas in the brain may be affected by each. In haemorrhage there is a bursting of one of the cerebral blood vessels, with pouring out of blood into ad jacent brain tissue and destruction. A cer tain blocking of the artery also results. In thrombosis, the walls are diseased and a soft mass collects on the inside of the blood vessel in the brain and blocks it up. This shuts off the circulation in a certain area supplied by the artery and there is degeneration in that area with softening perhaps and cyst formation. In embolism some foreign body from some other part of the arterial system is swept into a blood vessel of the brain and blocks it up. In all three forms of apoplexy the attack may be very slight, if the cause is a temporary loss of consciousness, or a paralysis in one limb, or a hemiplegia that is transitory— these may be all that is noted. But the usual attack of apoplexy is much more severe. The patient is rendered unconscious, the face is purple or congested, there may be voiding of urine and feces, the breathing is slow and snoring in character, the pulse is usually slowed to 50, and often soft and full; nausea and vomiting and lowered temperature may also occur. The
pupils may be dilated and the eyes may appear crossed. There is usually noted a difference in the two sides of the face, one side of the body is different from the other, and on lifting the limbs there is a change in their resistance. The patient may remain in this condition and die very soon, or he may have a rising temperature for a week and then die, or he may recover consciousness to find that one entire side of his body is paralyzed, or incapable of being moved by the wish. If the right side is involved the patient usually has defects in his speech (aphasia, q.v.). After a few days, this paralysis may pass away, but it usually persists for life in some form or other. Almost in variably the paralyzed limbs improve greatly; at first the leg and later the arm, and the im provement may be very great so that only a slight trace of what was a disabling affliction remains. The shades and variations in sylm toms and in the outcome are numberless. treatment of an attack of apoplexy requires prompt attention. Heat to the extremities, mustard bath to the feet, absolute quiet, removal of constricting bands about the neck, placing the patient on the non-paralyzed side, in many cases blood-letting; these are the generally recognized things to do. The outlook is always serious. Haemorrhage is apt to occur in those over 50, thrombosis is those affected with syphilis, and may occur at any age, embolism usually accompanies some infectious disease, such as pneumonia, rheumatism, scarlet fever, childbirth fever, etc., and may affect old or young. (See DIPLEGIA ; HEMIPLEGIA ; MON OPLEGIA). (5) Accident or injury to the brain. These may occasion various forms of hem iplegia ; diplegia, particularly in the injuries of childbirth,. epilepsy, etc. (6) Tumors of the brain. (See TUMORS OF THE). (7) Organic disease of the brain functions. This gives rise to various forms of psychoses. Softening of the brain is a term denoting either a dementia (q.v.) of old age, or the progressive dementia known as general paresis (q.v.). The insanities in their various forms and phases are treated in their appropriate rela tions under one inclusive head. (See INSANITY). Consult Jelliffe and White, 'Diseases of the Nervous (1917).