522 THE PHYSIOLOGY OF REPRODUCTION 



conclusion finds confirmation in the observation that variations in 

 diet are apparently capable of producing changes in the fcetiis.^ It 

 was noted by Lochhead and Cramer^ that abortion, occurred in 

 three out of six pregnant rabbits fed on a diet rich in carboliydrates 

 during the whole period of gestation. A similar observation is 

 recorded by Cramer and Marshall.^ Wallace ^ states that cows fed 

 on molasses prove to be uncertain breeders, and Heape * that Lincoln 

 sheep fed solely on turnips ai'e specially liable to abortion. 



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 demonstrates the limita- 

 tions in the extent to which the tissues of . the -mother can be utilised 

 for the construction of the embryo. The nourishment of the maternal 

 tissues seems to take precedence over the nutrition of the foetus. 

 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." This generalisation is too sweeping. Observa- 

 tions on rats ^ have shown that the weight of the offspring remained 

 the same on different diets, although on one diet the mother increased 

 in weight durmg pregnancy while on the other it lost^in weight. 

 Purther, 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 f cetus 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, 

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

 diminished by restricting the diet of the mother (hxunan female) ; but 

 many exceptions to this rule are found, which in«fact comes into 

 operation only when the restriction of food has been severe enough 

 to jeopardise the health 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 



1 Thi«mich was, however, unable to discover any diiFerence in the constitu- 

 tion of the foetal fat, after feeding the mother on widely different fats ' 

 (see p. 543). 



^ See Cramer and Marshall, " A Note on Abortion as a result of a Diet rich 

 in Carbohydrates," Jour, of Econ. Biol., vol. iii., 1908. 



^ Wallace, Farm Live Stock, 1907. 



* Heape ascribes the frequency of abortion to the fouling of the turnip-roots 

 by mud and excrement, a condition of things which results from overcrowding. 

 See Jour. Roy. Agric. Sac, 1899. 



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

 Offspring," Lancet, 1903. 



" Cramer (W.), Unpublished observations. 



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

 Fcetus of the Pregnant Rabbit,"^ Pcoc. Roy. Soc. London, B., vol. Ixxx., 1908. 



* Prochownick, Therap. Mnnatshefte, 1901, quoted by Paton (Joe. cit.). 



