[Unequal breast-nourishment as pretended cause of differences of features at twin-brothers (author's transl)].

A theological polemical treatise of 1709, as a source for the general history and this history of civilization and especially of ethics, is exploited to declare some scientifical matters of fact. The conception, developed by the author by reason of the different behaviour of twins as adults, the nourishment assimilated in earliest youth would decide the future of man, is analyzed and compared with the modern state of knowledge of the twin-research. On the confrontation of the notions "nature" and "nurture", which can be traced back to Shakespeare, in Galton, the originator of the twin-research, is referred to.