186 A Defence of Mendel's 



attributable to ancestry, and that in fact one character has no 

 natural dominance over another, apart from what has been 

 created by selection of ancestry. This piece of reasoning, 

 one of the most remarkable examples of special pleading to 

 be met with in scientific literature, must be read as a whole. 

 I reproduce it entire, that the reader may appreciate this 

 curious effort. The remarks between round parenthetical 

 marks are Professor Weldon's, those between crotchets are 

 mine. 



" Mendel treats such characters as yellowness of cotyledons 

 and the like as if the condition of the character in two given 

 parents determined its condition in all their subsequent off- 

 spring*. Now it is well known to breeders, and is clearly shown 

 in a number of cases by Galton and Pearson, that the condition 

 of an animal does not as a rule depend upon the condition of any 

 one pair of ancestors alone, but in varying degrees upon the 

 condition of all its ancestors in every past generation, the 

 condition in each of the half-dozen nearest generations having 

 a quite sensible effect. Mendel does not take the effect of 

 differences of ancestry into account, but considers that any 

 yellow-seeded pea, crossed with any green-seeded pea, will behave 

 in a certain definite way, whatever the ancestry of the green and 

 yellow peas may have been. (He does not say this in words, 

 but his attempt to treat his results as generally true of the 

 characters observed is unintelligible unless this hypothesis be 

 assumed.) The experiments afford no evidence which can be 

 held to justify this hypothesis. His observations on cotyledon 

 colour, for example, are based upon 58 cross-fertilised flowers, 

 all of which were borne upon ten plants ; and we are not even 

 told whether these ten plants included individuals from more 

 than two races. 



" The many thousands of individuals raised from these ten 



* Mendel, on the contrary, disregards the " condition of the 

 character " in the parent altogether ; but is solely concerned with the 

 nature of the characters of the nametes. 



