290 CONSTITUTIONAL VIGOUR Chai\ VIIL 



scoparius were not touched by a very severe winter ; 

 whereas all the self-fertilised plants were killed half- 

 way down to the ground, so that they were not able to 

 flower during the next summer. Young crossed 

 seedlings of Nicotiana withstood a cold and wet 

 summer much better than the self-fertilised seedlings. 

 I have met with only one exception to the rule of 

 crossed plants being hardier than the self-fertilised : 

 three long rows of Eschscholtzia plants, consisting of 

 crossed seedlings from a fresh stock, of intercrossed 

 seedlings of the same stock, and of self-fertilised ones, 

 were left unprotected during a severe winter, and all 

 perished except two of the self-fertilised. But this 

 case is not so anomalous as it at first appears, for it 

 should be remembered that the self-fertilised plants 

 of Eschscholtzia always grow taller and are heavier 

 than the crossed ; the whole benefit of a cross with this 

 species being confined to increased fertility. 



Independently of any external cause which could 

 be detected, the self-fertilised plants were more liable 

 to premature death than were the crossed ; and this 

 seems to me a curious fact. Whilst the seedlings 

 were very young, if one died its antagonist was pulled 

 up and thrown away, and I believe that many more of 

 the self-fertilised died at this early age than of the 

 crossed ; but I neglected to keep any record. With 

 Beta vulgaris, however, it is certain that a large number 

 of the self-fertilised seeds perished after germinating 

 beneath the ground, whereas the crossed seeds sown at 

 the same time did not thus suffer. When a plant 

 died at a somewhat more advanced age the fact was 

 recorded ; and I find in my notes that out of several 

 hundred plants, only seven of the crossed died, whilst 

 of the self-fertilised at least twenty-nine were thus 

 lost, that is more than four times as many. Mr. Galton, 



