338 THE SELF-FERTILIZATION OF PLANTS. 



of selection, man almost invariably wishes to go to 

 an extreme point" i. e., zvitk some one character only. 

 "On the whole" (p. 266, Vol. ii, Animals and Plants, 

 &c), "we may conclude that whatever part or charac- 

 ter is most valued, — whether the leaves, stems, tubers, 

 bulbs, flowers, fruit, or seed of Plants * * * — that 

 character will, almost invariably , be found to present 

 the greatest amount of difference, in kind, and degree. 

 And, this result may be safely attributed to man having 

 preserved, during a long course of generations, the 

 variations which were useful to him, and neglected the 

 others." 



And again he shows (page 34, Origin of Species), 

 that there are great differences, in the parts which 

 are valued, and no or little differences, in the parts 

 neglected; which is owing to the parts, which are 

 valued, being retained at each stage of their re-develop- 

 ment, while the parts, not valued, occupy a common 

 level of degeneration ! 



" Compare," says he, " the diversity of Flowers, in the 

 different varieties of the same species, in the Flower- 

 garden; the diversity of Leaves, Pods, or Tubers, 

 or whatever part is valued, in comparison with the 

 Flowers, of the same varieties ; and the diversity of 

 the Fruit, of the same species, in the Orchard, in com- 

 parison with the Leaves, and Flowers, of the same set 

 of varieties. See how different, the Leaves of the 

 Cabbage are, and how extremely alike the Flowers; 

 how unlike, the Flowers of the Hearts-ease are, and 

 how alike the Leaves; how much the Fruit of the dif- 

 ferent kinds of Gooseberries, differ in size, color, and 

 hairiness, and yet the Flowers present very slight 

 differences. It is not, that the varieties which differ 

 largely, in some one point, do not differ at all in other 

 points. * * * The laws of Correlation of growth, 



