144 A Defence of Mendel's 



It is the curious case of Seton*. Told in the words of 

 the critic it is as follows : 



" Mr Alexander Seton crossed the flowers of Dwarf Imperial, 

 'a well-known green variety of the Pea,' with the pollen of 

 'a white free-growing variety.' Four hybrid seeds were ob- 

 tained, ' which did not differ in appearance from the others 

 of the female parent.' These seeds therefore did not obey the 

 law of dominance, or if the statement be preferred, greenness 

 became dominant in this case. The seeds were sown, and 

 produced plants bearing l green ' and ' white ' seeds side by 

 side in the same pod. An excellent coloured figure of one of 

 these pods is given (loc. cit. Plate 9, Fig. 1), and is the only 

 figure I have found which illustrates segregation of colours in 

 hybrid Peas of the second generation." 



Now if Professor Weldon had applied to this case the 

 same independence of judgment he evinced in dismissing 

 Darwin's interpretation of Gartner's observations, he might 

 have reached a valuable result. Knowing how difficult it 

 is to give all the points in a brief citation, I turned up the 

 original passage, where I find it stated that the mixed 

 seeds of the second generation "were all completely either 

 of one colour or the other, none of them having an inter- 

 mediate tint, as Mr Seton had expected." The utility of 

 this observation of the absence of intermediates, is that it 

 goes some way to dispose of the suggestion of xenia as a 

 cause contributing to the result. 



Moreover, feeling perfectly clear, from the fact of the 

 absence of intermediates, that the case must be one of 

 simple dominance in spite of first appearances, I suggest 

 the following account with every confidence that it is 

 the true one. There have been several "Imperials," 



* Appendix to paper of Goss, Trans. Hort. Soc. v. 1822, pub. 

 1824 (not 1848, as given by Professor Weldon), p. 236. 



