Chap. XXI. CARRIED TO AN EXTREME. 241 



In a few instances selection, guided by utility for a single 

 purpose, has led to convergence of character. All the improved 

 and different races of the pig, as Nathusius has well shown, 56 

 closely approach each other in character, in their shortened legs 

 and muzzles, their almost hairless, large, rounded bodies, and 

 small tusks. We see some degree of convergence in the similar 

 outline of the body in well-bred cattle belonging to distinct 

 races. 57 I know of no other such cases. 



Continued divergence of. character depends on, and is indeed 

 a clear proof, as previously remarked, of the same parts con- 

 tinuing to vary in the same direction. The tendency to mere 

 general variability or plasticity of organisation can certainly be 

 inherited, even from one parent, as has been shown by Gartner 

 and Kolreuter, in the production of varying hybrids from two 

 species, of which one alone was variable. It is in itself probable 

 that, when an organ has varied in any manner, it will again 

 vary in the same manner, if the conditions which first caused 

 the being to vary remain, as far as can be judged, the same. 

 This is either tacitly or expressly admitted by all horticulturists : 

 if a gardener observes one or two additional petals in a flower, 

 he feels confident that in a few generations he will be able 

 to raise a double flower, crowded with petals. Some of the 

 seedlings from the weeping Moccas oak were so prostrate that 

 they only crawled along the ground. A seedling from the fasti- 

 gate or upright Irish yew is described as differing greatly from 

 the parent-form " by the exaggeration of the fastigate habit of 

 its branches." 58 Mr. Sheriff, who has been more successful 

 than any other man in raising new kinds of wheat, remarks, " A 

 good variety may safely be regarded as the forerunner of a 

 better one." 59 A great rose-grower, Mr. Eivers, has made the 

 same remark with respect to roses. Sageret, 60 who had- large 

 experience, in speaking of the future progress of fruit-trees, 

 observes that the most important principle is " that the more 

 plants have departed from their original type, the more they 

 tend to depart from it." There is apparently much truth in this 



56 'Die Racen des Schweines,' 1860, 58 y erlotj ^ Des Varietes, 1865 » P- 9*- 

 s - 48> 59 Mr. Patrick Sheriff, in « Gard. 



5 7 See some good remarks on this Chronicle,' 1858, p. 771. 



head by M. de Quatrefages, 'Unite de "o .p omologie ' physiolog.,' 1830, p. 



l'Espece Humaine,' 1861, p. 119. iQg_ 



YOL. II. 



R 



