In youth, divided into its pubescent and adolescent periods, and, in relation to our subject, taking only the forms of mental disease that may come into question or relevance, besides idiocy's minor degrees, the chief to mention are simple dementia, hallucinatory, and confusional cases; melancholic, maniacal, and “transitory” attacks; periodical and circular psychoses; katatonia, hebephrenia, the paranoias; hereditary forms marked chiefly by impulse or moral perversion; cases on “mental besetment” (obsessive) basis. Many other forms of insanity, of course, exist in youth.