Two cases have been described in which irreversible histological changes in the brain may have been caused by preceding heavy electro-convulsive treatment. The changes consisted mainly of a proliferation of the marginal glia and of the glia of the white matter. They were thus similar to the pathological lesions known to occur in idiopathic epilepsy but they were not accompanied by loss of nerve cells in the cornu Ammonis or in the cerebellar cortex.
The changes were mild in spite of an unusually heavy shock treatment. It is emphasized that even such slight changes are by no means common after this form of tretment.