DEVELOPMENT 263 



nutritive condition and weight of the mothers had an 

 important influence on the development of the foetus. 

 This fact is shown in the table on page 262. 



Summarizing the results of four years' work, the author 

 says, 1 " We must conclude from the exhibit here made, 

 comprising the results of 61 births, that the weight of 

 the mother has a direct influence upon the birth weight 

 of the offspring and that in general the lambs having a 

 heavier weight at birth are produced from the larger 

 ewes." 



251. Effect of protein and ash in ration on foetal 

 development. The development of the foetus may be 

 materially influenced by the ration given to the mother 

 during pregnancy. Evvard 1 has shown that if pregnant 

 sows are fed a ration poor in protein, the pigs are smaller 

 at birth. Not only were the offspring smaller at birth, 

 but they were weaker and the death rate greater. The 

 first investigation was made with young sows in 1910- 

 1911. These were fed the rations indicated in the table 

 on page 264 for a considerable period. The results are 

 summarized in the table. 



2 " The basal ration was corn alone. Corn we know is 

 quite deficient in protein (the zein which comprises prac- 

 tically 58 per cent of said protein is peculiarly lacking in 

 two quite important amino acids, namely, tryptophane 

 and lysine) and calcium. It is somewhat surprising to 

 know that calcium comprises practically two-thirds as 

 much of the body substance as does nitrogen, the basal 

 element of protein." 



" Note that the supplemented rations not only pro- 

 duced larger but stronger pigs at birth. A studied survey 



1 Mumford, loc. cit., p. 176. 



2 Evvard, Iowa Academy of Science, Report 1913, p. 326. 



