Principles of Heredity 137 



From Mendel's style it may be inferred that if he had 

 meant to state universal dominance in peas he would 

 have done so in unequivocal language. Let me point out 

 further that of the 34 varieties he collected for study, he 

 discarded 12 as not amenable to his purposes*. He tells 

 us he would have nothing to do with characters which 

 were not sharp, but of a " more or less " description. As 

 the 34 varieties are said to have all come true from seed, 

 we may fairly suppose that the reason he discarded twelve 

 was that they were unsuitable for his calculations, having 

 either ill-defined and intermediate characters, or possibly 

 defective and irregular dominance. 



IV. PROFESSOR WELDON'S COLLECTION OF "OTHER 

 EVIDENCE CONCERNING DOMINANCE IN PEAS." 



A. In regard to cotyledon colour: Preliminary. 



I have been at some pains to show how the contradictory 

 results, no doubt sometimes occurring, on which Professor 

 Weldon lays such stress, may be comprehended without 

 any injury to Mendel's main conclusions. This excursion 

 was made to save trouble with future discoverers of 

 exceptions, though the existence of such facts need 

 scarcely disturb many minds. As regards the dominance 

 of yellow cotyledon-colour over green the whole number of 

 genuine unconformable cases is likely to prove very small 

 indeed, though in regard to the dominance of round shape 

 over wrinkled we may be prepared for more discrepancies. 

 Indeed my own crosses alone are sufficient to show that 

 in using some varieties irregularities are to be expected. 



* See p. 43. 



