Pinard, who must always be honored as one of the founders of eugenics, has, together with his pupils, done much to prepare the way for the acceptance of this simple but important principle by making clear the grounds on which it is based. From prolonged observations on the pregnant women of all classes Pinard has shown conclusively that women who rest during pregnancy have finer children than women who do not rest. Apart from the more general evils of work during pregnancy, Pinard found that during the later months it had a tendency to press the uterus down into the pelvis, and so cause the premature birth of undeveloped children, while labor was rendered more difficult and dangerous (see, e.g., Pinard, _Gazette des Hôpitaux_, Nov. 28, 1895, Id., _Annales de Gynécologie_, Aug., 1898). Letourneux has studied the question whether repose during pregnancy is necessary for women whose professional work is only slightly fatiguing. He investigated 732 successive confinements at the Clinique Baudelocque in Paris. He found that 137 women engaged in fatiguing occupations (servants, cooks, etc.) and not resting during pregnancy, produced children with an average weight of 3,081 grammes; 115 women engaged in only slightly fatiguing occupations (dressmakers, milliners, etc.) and also not resting during pregnancy, had children with an average weight of 3,130 grammes, a slight but significant difference, in view of the fact that the women of the first group were large and robust, while those of the second group were of slight and elegant build. Again, comparing groups of women who rested during pregnancy, it was found that the women accustomed to fatiguing work had children with an average weight of 3,319 grammes, while those accustomed to less fatiguing work had children with an average weight of 3,318 grammes. The difference between repose and non-repose is thus considerable, while it also enables robust women exercising a fatiguing occupation to catch up, though not to surpass, the frailer women exercising a less fatiguing occupation. We see, too, that even in the comparatively unfatiguing occupations of milliners, etc., rest during pregnancy still remains important, and cannot safely be dispensed with. "Society," Letourneux concludes, "must guarantee rest to women not well off during a part of pregnancy. It will be repaid the cost of doing so by the increased vigor of the children thus produced" (Letourneux, _De l'Influence de la Profession de la Mère sur le Poids de l'Enfant_, Thèse de Paris, 1897).