278 THE BREEDING OF ANIMALS 



her growth or has approached maturity in her develop- 

 ment, the changes which take place in her organization 

 and which may be due to her pregnant condition will 

 obviously not affect her growth. On the other hand, if 

 the mother is young and growing rapidly, gestation 

 might act as a check to growth if the physiological pro- 

 cesses of the mother are necessarily and chiefly directed 

 toward the development of the foetus. The physiological 

 processes concerned in the nutrition of the foetus are 

 somewhat complex and the interrelations between the 

 mother and her unborn young not completely deter- 

 mined. The information available on the subject does 

 not specifically answer the question. We know that the 

 absorption of fats from the intestine proceeds at a more 

 rapid rate during pregnancy. Increased amounts of fat 

 in the liver cells also are associated with pregnancy. 



There is a tendency to increase in body weight during 

 gestation. The maternal body increases in weight 

 independently of the increase in size of the foetus and 

 foetal membranes as shown by Gassner 1 and confirmed 

 by others. This increase in weight is common to the 

 mature pregnant mammalian mother and is not confined 

 to the young parent only. It is possible, therefore, that 

 this increase might be due to increased fat in the body 

 and not to any increase in the skeleton. If this were 

 found to be true, it would tend to confirm current opinion 

 as to the retarding influence of gestation on the growth. 



262. The Missouri experiments. At the Missouri 

 Experiment Station 2 careful measurements have been 

 made of a large number of immature pregnant sows and 



1 Marshall, "Physiology of Reproduction," chap. XI. 



2 Mumford, Bulletins 131 and 141, Missouri Experiment 

 Station. 



