When Lannelongue published his accounts of his first cases of craniectomy for microcephalus, the hope was raised that microcephalic idiocy would prove a curable form of mental deficiency, and would come to be classed among the ordinary surgical diseases of children, as being mainly a bony deformity to be remedied by the use of the knife and the saw; and though Lannelongue himself did not follow Virchow's teaching and regard premature ossification of the cranial sutures as the primary cause of microcephalus, but attributed it to its actual cause, namely, arrested development of the brain, still he considered that there was undue compression and consequent dwarfing due to bony pressure, and that craniectomy would relieve this and lead to increase of brain growth.