PREPOTENCY 



573 



is fertile territory for careful and exhaustive statistical studies, 

 which alone will yield reliable results on which principles of 

 selection and breeding may be based. 



SECTION III INFLUENCE OF AGE ON PREPOTENCY 



Is one parent prepotent over the other merely by reason of 

 age ? The question is exceedingly important, but the writer is 

 not aware of reliable data bearing upon the subject. The matter 

 could be determined by sufficient investigation into the offspring 

 from parents with some considerable discrepancy as to age, and 

 by comparing the coefficients of heredity between the offspring 

 of young and those of old parents, not only with each other but 

 with the normal of the race. Helpful as it would be to know the 

 facts upon this point, they have not yet been discovered and it is 

 idle to speculate. We have no choice but to wait until the research 

 is made in what will one day constitute a prolific field for study. 



SECTION IV INFLUENCE OF CONSTITUTIONAL VIGOR 

 UPON PREPOTENCY 



This is an important question, upon which we lack reliable 

 information. Common sense seems to indicate that the more 

 weakly parent would not be equally influential in impressing his 

 or her characteristics, but we cannot yet say to what extent the 

 character of the reproductive cells is dependent on vigor. Here 

 again speculation can easily run riot ; but from the fact that, 

 for other reasons, we should reject the non-vigorous parent, the 

 question loses most of its point except in human affairs, which 

 do not concern us here. 



That one stalk in a hill of corn often resists the effects of 

 frost when neighboring stalks are killed is a fact that has long 

 been noted, but whether such plants are prepotent in transmit- 

 ting resistance to frost is not known. It is a significant fact, 

 however, that Dr. Hopkins, of the University of Illinois, when 

 conducting experiments with soils containing an excess of mag- 

 nesium, noticed one year a single wheat plant that flourished 

 well where all others succumbed. Saving seed from this plant, 



