1910.] PUliUC DOCUMENT — No. 31. 173 



tlu' idea is still sound and the word still holds. Moreover, the 

 facts are of great practical importance to the actual breeder. 



The question is, Does one individual transmit its characters 

 more perfectly and surely than another ? In order to answer 

 this question, it was found necessary to adopt a new method of 

 calculating coefficients of heredity, explained in the article re- 

 ferred to.^ The study of the material which we then had in 

 hand seemed to give a positive answer to the main question. 

 Apparently, certain individuals did show decided superiority 

 over others in their ability to transmit their characters to their 

 offspring. This conclusion seems to be confirmed with all the 

 other material which we have been able' to study, and it would 

 be very interesting to see the same method — or some improve- 

 ment of it — applied to other plants and animals. For the 

 l)resent, the most interesting feature of our experiment lies in 

 a comparison of the prej)otency of parent and offspring, — in 

 an attempt to answer the question whether prepotency is in- 

 herited or not. 



In the following tables we will present first the figures show^ 

 ing the inheritance of vine length, then those dealing with pods 

 per vine, and finally those dealing with total peas per vine. In 

 each case we present first the coefficients of heredity (computed 

 as shown in the footnote), followed by figures denoting the rank 

 of the several strains in each comjiarison. The designations 

 fi, {-2 and f;; will be understood at once by students of threm- 

 matology. They refer to the three generations of peas com- 

 pared : fs re]n'escnts the crop of 1909, f2 represents their parents 

 (crop of 1908), while fi represents the grandparents, with which 

 this experiment began. 



• Ibid., p. 172. The formula is C = -^. 



crD 



C =: coefficient of heredity, 

 tr ^standard deviation. 



D = difference between the numerical value of the parent character and the 

 mean of the same character in the progeny. 



This we have been calling " Waugh's formula," for the sake of a distinctive name. 



