140 A Defence of Mendel's 



example, Fillbasket has green cotyledons and seed- coat 

 green except near the hilar surface. Crossed with Serpette 

 nain blanc (yellow cotyledons and yellow 7 coat) this variety 

 gave three pods with 17 seeds in which the seed-coats were 

 almost full yellow (xenia). Three other pods (25 seeds), 

 similarly produced, showed slight xenia, and one pod with 

 eight seeds showed little or none. 



On the other hand Fillbasket fertilised with nain de 

 Bretagne (yellow cotyledons, seed-coats yellow to yellowish 

 green) gave six pods with 39 seeds showing slight xenia, 

 distinct in a few 7 seeds but absent in most. 



Examples of xenia produced by the contrary proceeding, 

 namely fertilising a yellow pea with a green, may indubitably 

 occur and I have seen doubtful cases ; but as by the nature 

 of the case these are negative phenomena, i.e. the seed-coat 

 remaining greenish and not going through its normal 

 maturation changes, they must always be equivocal, and 

 would require special confirmation before other causes were 

 excluded. 



Lastly, the special change (xenia) Mendel saw in "grey" 

 peas, appearance or increase of purple pigment in the thick 

 coats, following crossing, is common but also irregular. 



If a transparent coated form be taken as seed-parent 

 there is no appreciable xenia, so far as I know, and such a 

 phenomenon would certainly be paradoxical*. 



In this connection it is interesting to observe that 

 Giltay, whom Professor Weldon quotes as having obtained 

 purely Mendelian results, got no xenia though searching 

 for it. If the reader goes carefully through Giltay's 

 numerous cases, he will find, almost without doubt, that 

 none of them were such as produce it. Reading Giant, as 



' In some transparent coats there is pigment, but so little as a 

 rule that xenia would be scarcely noticeable. 



