6th. Reflected irritation, as from dentition, worms, sexual excesses, injuries to certain nerves, notably the sciatic, or to particular parts of the skin. 1st. =Brain lesions.= Those which affect the medulla and the cortical convolutions around the fissure of Rolando would be expected to be implicated because these centres preside over the principal motor actions of the body and limbs. Yet though these parts are found to be affected with various morbid lesions in a certain number of cases of epilepsy, such lesions are exceptional, rather than the rule. In 20 cases of epilepsy in man, 15 showed no lesion whatever of the brain. Blocq and Marinesco, pupils of Charcot, recently made a critical examination of the medulla and Rolandic cortex in nine cases that died during the fit. All showed granular bodies (degenerated myelin or blood pigment) in the perivascular sheaths but they found these in disseminated sclerosis and even in healthy brains as well. The neuroglia cells of the first cortical layer contained black granules. Otherwise four cases had no change, while five showed sclerosis of the cortex. The medulla was sound in all cases excepting one which showed punctiform hæmorrhages. Visible lesions may be present in other parts of the brain; Wenzel long ago claimed constant lesion of the pituitary body. Beside the cerebral cortex, lesions have been found in the bulb, the hypoglossal nucleus, the olivary body, the hippocampi, the thalamus, the corpus striatum, the quadrigemini, the cerebellum, etc. Hughlings-Jackson who made an extended investigation of the subject concludes that any part of the gray matter of the encephalon may become over-excitable and give rise to a convulsive attack. Not only may the lesion be in any part of the brain, but it may be of any kind: meningitis, cerebritis, softening, tubercle, tumor, hydatid, embolism, or dropsy. Marie Bra found an extreme asymmetry of the cerebral lobes in epileptics. Kussmaul and others found stenosis of the vertebral canal and asymmetry of the two lateral halves of the medulla. 2nd. =Cranial lesions.= These consist largely in blows or falls upon the head, with osteitis, periostitis, fractures with depressions, fibrous neoplasia implicating or not the meninges and pressing on the brain, hæmorrhages from minute arteries, etc. The diagnosis of such lesions will often open a way to a successful treatment. Baker found most of the severe cases from head injuries. 3d. =Disorders of the cerebral circulation.= Burrows, Kussmaul and Turner showed that in animals, loss of consciousness and epileptiform convulsions followed on cerebral anæmia caused by profuse bleeding or by compression of the carotids. The same has been observed in surgical cases after ligation of one common carotid. Hermann caused convulsions in a rabbit by ligating both anterior and posterior venæ cavæ.