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 Mere sur le Poids de l'Enfant_, These de Paris, 1897).
Dr.Dweira-Bernson (_Revue Pratique d'Obstetrique et de Pediatrie_, 1903, p.

370), compared four groups of pregnant women (servants with light work, servants with heavy work, farm girls, dressmakers) who rested for three months before confinement with four groups similarly composed who took no rest before confinement.

In every group he found that the difference in the average weight of the child was markedly in favor of the women who rested, and it was notable that the greatest difference was found in the case of the farm girls who were probably the most robust and also the hardest worked.
The usual time of gestation ranges between 274 and 280 days (or 280 to 290 days from the last menstrual period), and occasionally a few days longer, though there is dispute as to the length of the extreme limit, which some authorities would extend to 300 days, or even to 320 days (Pinard, in Richet's _Dictionnaire de Physiologie_, vol.vii, pp.

150-162; Taylor, _Medical Jurisprudence_, fifth edition, pp.

44, 98 et seq.; L.M.