riiAP. V. COMPENSATION OF GKOWTII. 149 



tiincc — the seeds bcinj^ sometimes orlliospermons in tlic exte- 

 rior llowers and ca-lospennoiis in the central ilowors — that the 

 elder iJe Caiidollo founded his main divisions in the order on 

 such char;- -ters. Hence, as before remarked, wc see that modi- 

 fications of structure, viewed by systematists as of hi^h value, 

 may be AvlK)lly due to the laws of variation and correlation, 

 without beiuf^, as far as we can judf^e, of the slightest service 

 t(^ the species. 



We may often falsely attribute fo correlated variation 

 structures which arc common to whole groups of species, and 

 which in truth arc simply due to inheritance : for an ancient 

 progenitor may have acquired through natural selection some 

 one modification in structure, and, after thousands of genera- 

 tions, some other and independent modilication ; and these 

 two modiiications, liaving been transmitted to a whole group 

 of descendants witli diverse habits, would naturally l^e tlumght 

 _to be correlated in some necessary manner. Some correlations 

 are apparently due to the manner in wliich natural selection 

 acts. For instance, Al]ih. de Candollc has remarked that 

 winged seeds are never found in fruits wliich do not open : I 

 should ex})lainthis rule by the impossiljility of seeds gradually 

 becoming winged through natural selection, unless the ca])- 

 sules first opened themselves ; for in this case alone could the 

 seeds, which were a little better adapted to be Avafted by the 

 wind, gain an advantage over those less well fitted for wide 

 dispersal. 



Compensation and Economy of Groxcth. 



llie elder GeoiTroy and Goethe propounded, at about the 

 same period, their law of compensation or balanccment of 

 growth ; or, as Goethe expressed it, " in order to spend on one 

 side, Nature is forced to economize on the other side." I think 

 this holds true to a certain extent with our domestic produc- 

 tions: if nourishment flows to one part or organ in excess, it 

 rarely flows, at least in excess, to another part; thus it is dif- 

 ficult to get a cow to give nuicli milk and to fatten readily. 

 The same varieties of tlic cabbage do not yield abundant and 

 luitritious foliage and a copious supply of oil-bearing seeds. 

 When the seeils in our fruits become atrophied, tlie fruit itself 

 gains largely in size and quality. In our poultry, a large tuft 

 of feathers on the head is generally accompanied by a dimin- 

 ished comb, and a large beard by diminished wattles. With 



