944 GENERAL METABOLISM [pt. iii 



moderate underfeeding. As for man, Prochovnik in 1889, on clinical 

 grounds, affirmed that the infants of women on restricted diet were 

 smaller and lighter than those of women on liberal diet. During the 

 European War of 19 14-19 18, which unfortunately provided the 

 German workers with many opportunities of studying this problem, 

 Prochovnik's views were not substantiated. Peller, it is true, found 

 a slight difference in weight, but Momm; Sorgel; Ruge and many 

 others could not obtain any evidence for it. Two considerations, 

 advanced by Zuntz, explain why these results differ from those of the 

 animal researches — (i) in spite of the war diets, the deficiency was 

 not enormously great, and (2) the birth-weight in man is a much 

 less percentage of the maternal weight than in other mammals 

 (see p. 475). 



Dibbelt put pregnant dogs on a calcium-poor diet, and found that 

 the calcium content of the embryos at term was normal. Zuntz's 

 work on rats included an experiment of this kind, which gave equally 

 negative results. But on the other hand Fetzer found that iron-rich 

 diets increased the iron-content of the foetuses, while iron-poor ones, 

 if below a certain level, led to abortion and loss of the litter. The 

 effects of vitamine deficiency and excess on the embryos have also 

 been studied, but for an account of the results obtained reference 

 must be made to Section 16-5. 



The strain on the maternal organism of providing material for 

 foetal growth is strictly outside the scope of this book, but a word or 

 two on the subject may be said here. Gowen investigated the extent 

 to which the milk yield of cows is reduced by gestation, and after 

 a close analysis of extensive statistics concluded that a cow in the 

 9 months of pregnancy produces 342 to 628 lb. of milk less than a 

 non-pregnant one. There is thus a 5 per cent, diversion of milk 

 products to the foetus, a diversion, moreover, which would seem to 

 bear equally on all the constituents of the milk, for the butterfat 

 percentage, for example, is not influenced at all. Very similar results 

 were obtained by Brody, Ragsdale & Turner, who found a diversion 

 to the foetus of 450 lb. of milk, i.e. rather more in dry weight 

 than the foetus at birth which is equivalent to 275 lb. of milk. In 

 mice, according to Kirkham, the increased gestation time of 

 nursing animals seems to be due rather to abnormalities of implanta- 

 tion than to any drain on the maternal body. 



For the considerable literature on the effect of alcohol and other 



