168 A Defence of Mendel's 



If the "round" seeds really occurred as a distinct class, on 

 the heterozygotes as described, it is just possible that the 

 fact may be of great use hereafter. 



"We are still far from understanding maternal seed- 

 form and perhaps size as a dominant character. So far, 

 as Miss Saunders has pointed out to me, it appears to be 

 correlated with a thick and coloured seed-coat. 



We have now seen the nature of Professor Weldon's 

 collection of contradictory evidence concerning dominance 

 in peas. He tells us: "Enough has been said to show the 

 grave discrepancy between the evidence afforded by Mendel's 

 experiments and that obtained by observers equally trust- 

 worthy." 



He proceeds to a discussion of the Telephone and 

 Telegraph group and recites facts, which I do not doubt 

 for a moment, showing that in this group of peas which 

 have unquestionably been more or less "blend" or "mosaic" 

 forms from their beginning the "laws of dominance and 

 segregation ' : do not hold. Professor Weldon's collection 

 of the facts relating to Telephone, &c. has distinct value, 

 and it is the chief addition he makes to our knowledge 

 of these phenomena. The merit however of this addition 

 is diminished by the erroneous conclusion drawn from it, as 

 will be shown hereafter. Meanwhile the reader who has 

 studied what has been written above on the general questions 

 of stability, "purity," and "universal" dominance, will easily 

 be able to estimate the significance of these phenomena and 

 their applicability to Mendel's hypotheses. 



