Electrical influences and speed of chemical change

connected with electrical phenomena. In man under basal metabolic condi-tions, some 20 per cent of the oxygen taken up by the body in respiration is consumed in the brain. In reviewing the speed of chemical change in the brain one is thus concerned with an appreciable proportion of the energy metabolism of the body: much of the present account assesses the respiration, carbohydrate metabolism, and energy-rich intermediates of the brain and of parts of the brain; it is especially con-cerned with the manner in which these metabolic characteristics are affected by experimentally applied electrical influences. Other aspects of the speed of chemical change in the brain have been described elsewhere (73). In Vivo. Much quantitative information on how the level of cerebral metabolism varies with the functional state of the brain has come in the last decade from analysis of arterial and cerebral venous blood (51, 52, 73, 95). This has shown that a normal rate of cerebral oxygen consumption in man or the monkey, of some go &gm of brain/hr. (3.3-3.8 ml O&o gm/min.) can be reduced to about 55 pu/gm/hr. in anesthesia and can be increased by convulsive agents. The highest rate recorded wa