摘要: It has been observed by neurosurgeons that in a certain number of patients undergoing large craniotomies involving exposure the brain for long periods and cortical exploration there develop focal symptoms paralysis, such as hemiplegia aphasia, even when no cerebral substance removed. These appear within few hours or one to two days after operation are generally transitory, although they may persist some cases several weeks. At Dr. Penfield's suggestion, Echlin 1 started series experiments determine what effects on meninges might be produced operative exposure. He described lesions following simple at which, from their nature similarity anatomic distribution those electrical stimulation, appeared him due ischemia. In animals whose brains were exposed more than