No. 591] TRANSMISSION OF DEGENERACY 155 



striking difference in quality and vitality among the 

 members of small and large litters might be given. It 

 may be supposed that the growth capacity of the eggs 

 maturing in the ovaries of normal and subnormal indi- 

 viduals depends somewhat upon the number of eggs ma- 

 turing at any one time, or ovulation period. A normal 

 animal may be capable of developing two entirely good 

 eggs at an ovulation, or possibly three, whereas a weak- 

 ened, less vigorous individual has ovaries incapable of 

 producing more than one well-nourished or well-devel- 

 oped egg at any one time. Of course, it is understood 

 that the small size of a mammalian egg would make it 

 seem as though it required very little stored food from 

 the ovary, yet that little must be of an extremely fine 

 quality, since so much of the energy of early development 

 is derived from the materials stored within the egg. 



One point which might be interpreted to favor such an 

 explanation is the fact that the small, weak young con- 

 tained in the large litters do not recover and make their 

 shortage good after birth, as might be expected if their 

 inferior condition was simply due to a lack of nourish- 

 ment available in the overcrowded uterine environment in 

 which their late stages of development were passed. 

 Lack of intra-ovarian nutrition would certainly produce 

 a more lasting effect, since it occurs at an earlier stage 

 than lack of uterine nutrition, though of course we do not 

 pretend to deny that poor uterine nutrition would also 

 leave its persisting mark. 



When only one young was produced in a litter the aver- 

 age growth rate of such individuals during the first 

 month after birth was 85.09 grams. Such specimens 

 were not only largest at birth, but they grew fastest after 

 birth. Animals born in litters of two increased 68.46 

 grams during the first month after birth, while those born 

 three in a litter gained only an average of 63.6 grams 

 during the same period. In other words, the last group 

 only gained 75 per cent, of the amount gained by similar 

 specimens which were fortunate enough to be developed 

 alone in the ovary and in the uterus. 



