Idiocy. Mental weakness occurring in the infant or child, prior to the development of the reasoning faculties, must be distinguished from dementia, which is the condition of mental weakness occurring in the adult. Idiots are not infrequently the offspring of a marriage between near relations; in some instances the disease is hereditary in the sense that other members of the family are affected with one or other form of insanity. It may be directly traceable to injury, and is often associated with epilepsy. The child affected is dull and stupid, he speaks imperfectly or not at all, merely uttering meaningless sounds. His memory is very feeble, and he is incapable of feeding or clothing himself and the like. Much can be done by appropriate training and education in some instances, hopeless as the condition might at first sight appear.