Chap. XXVI. COMPENSATION. 343 



may at the same time lead to the augmentation of one part and 

 the diminution of another. There can be no doubt that an organ 

 may be greatly increased without any corresponding diminution 

 in the adjoining parts. To recur to our former illustration 

 of the Irish elk, it may be asked what part has suffered in con- 

 sequence of the immense development of the horns ? 



It has already been observed that the struggle for existence 

 does not bear hard on our domesticated productions ; conse- 

 quently the principle of economy of growth will seldom affect 

 them, and we ought not to expect to find frequent evidence of 

 compensation. We have, however, some such cases. Moquin- 

 Tandon describes a monstrous bean, 7 in which the stipules were 

 enormously developed, and the leaflets apparently in conse- 

 quence completely aborted ; this case is interesting, as it repre- 

 sents the natural condition of Lathyrus apliaca, with its stipules 

 of great size, and its leaves reduced to mere threads, which act 

 as tendrils. De Candolle 8 has remarked that the varieties of 

 Raphanus sativus which have small roots yield numerous seed, 

 valuable from containing oil, whilst those with large roots are 

 not productive in this latter respect ; and so it is with Brassica 

 asperifolia. The varieties of the potato which produce tubers 

 very early in the season rarely bear flowers ; but Andrew 

 Knight, 9 by checking the growth of the tubers, forced the plants 

 to flower. The varieties of Cucurhita pepo which produce 

 large fruit yield, according to Naudin, few in number ; whilst 

 those producing small fruit yield a vast number. Lastly, 

 I have endeavoured to show in the eighteenth chapter that with 

 many cultivated plants unnatural treatment checks the full 

 and proper action of the reproductive organs, and they are 

 thus rendered more or less sterile; consequently, in the way 

 of compensation, the fruit becomes greatly enlarged, and, in 

 double flowers, the petals are greatly increased in number. 



With animals, it has been found difficult to produce cows 

 which should first yield much milk, and afterwards be capable of 



7 ' Teratologie Veg.,' p. 156. See also s . Memoires du Museum,' &c, torn, 



iny paper ou climbing plants in ' Jour- viii. p. 178 



nal of Linn. Soc. Bot.,' vol. is., 1865, ^Loudon's < Encyclop. of Gardening,' 



P- 1H - p. 829. 



