GROWTH AND NUTRITION 107 



birth are usually below the normal size at maturity. King offers 

 the explanation, "The normal action of growth factors is in- 

 hibited from the very beginning of postnatal life by unknown 

 constitutional causes, not by environmental conditions." It may 

 be, however, that the small size at birth is due to interference 

 with adequate nutrition during the prenatal state, and so is 

 merely a case of early underfeeding. It would not be surprising 

 if underfeeding during the fetal stage should be more injuri- 

 ous than during the postnatal period. 



