Discusses the data obtained, pertaining to certain nervous attacks occurring among the primitive races of the Fuegian Archipelago. It was observed that some of the findings corroborated the ideas of sexual repression proposed by Freud. The organization of the people also seemed to substantiate certain psychoanalytic concepts. The Yahgans and Onas in whom sudden outbursts of furor and violence predominated were men ranging from 25-35 yrs of age. An attack usually began suddenly, and a certain form of melancholia, brooding or moodiness, seemed to precede many of the attacks, with a realization that an attack was coming upon them. The mental traits, as shown by an analysis of their taboos, myths and dreams, were very primitive in organization. These people resembled children, without inhibitions or repressions, and hence their attacks of violence and furor were sudden emotional reactions, but without any phenomena of conversion. (PsycINFO Database Record (c) 2006 APA, all rights reserved)