496 THE PHYSIOLOGY OF REPRODUCTION 



According to Noel Paton,^ the size of the offspring of the 

 guinea-pig depends very directly upon the diet and nutrition of 

 the mother during pregnancy. " To the physiologist it demon- 

 strates the Umitations in the extent to which the tissues of the 

 mother can be utihsed for the construction of the embryo. 

 The nourishment of the maternal tissues seems to take pre- 

 cedence over the. nutrition of the fcEtus. The mother appears 

 to pass on the surplus nourishment to the foetus. The better 

 the nourishment of the maternal tissues, the greater the growth 

 of the foetus." On the other hand, it has been proved in the 

 pregnant rabbit that, when the glycogen of the body is reduced 

 to traces by repeated injections of phloridzin, the placenta and 

 foetus still retain considerable amounts.^ In this instance the 

 needs of the foetus have taken precedence over the storage of 

 a carbohydrate reserve for the mother. Like Paton, Prochow- 

 nick ^ states that the size of the offspring may be markedly 

 diminished by restricting the diet of the mother (human female) ; 

 but many exceptions to this rule are found, unless the restriction 

 of food has been severe enough to jeopardise the life of the 

 mother. 



This opens up another question : Does the expenditure for 

 the embryo entail loss to the mother ? "If the mother must 

 transfer a part of her own bodily substance to the germ, the loss 

 is of little importance if she can cover this loss from her food. 

 The setting of the question runs thus : Is the maternal body 

 deprived of protein, fat, and other substances during and in 

 consequence of the formation of a new being, and is its store of 

 these materials, after the resulting birth, or at the close of the 

 puerperium, less than before the advent of pregnancy, or is this 

 not the case ? An unprejudiced cUnical proof from human 

 subjects points to the possible occurrence of both conditions. 

 Many mothers during pregnancy increase so shghtly in weight 

 that their own tissues must have suffered loss during this time, 

 others become heavier to the extent of ten kilograms or more. 



' Noel Paton, " The Influence of Diet in Pregnancy on the Weight of the 

 Offspring," Lancet, 1903. 



^ Lochhead and Cramer, "The Glycogenic Changes in the Placenta and 

 the Foetus of the Pregnant Rabbit," Proc. Boy. Soc, London, B., vol. Ixxx., 

 1908. 



^ Frochownick, Therap. Monatshefte, 1901, quoted by Paton (loc. cit.). 



