64 INHERITANCE. C[IAp< m 



these same characters now vary under 



fail 



be inherited, owing to their lesser antiquity. But we must 



mg 



g 



cannot be permanently modified by our improved breeds ; and 

 as these latter are of modern origin, it has been thought that 

 the greater antiquity of the wilder breeds has been the cause 

 of their resistance to improvement by crossing; but it is 

 more probably due to their structure and constitution being 

 better adapted to the surrounding conditions. When plants 

 are first subjected to culture, it has been found that, during 

 several generations, they transmit their characters truly, that is, 

 do not vary, and this has been attributed to ancient characters 

 being strongly inherited; but it may with equal or greater 

 probability be consequent on changed conditions of life requiring 

 a long time for their accumulative action. Notwithstanding these 

 considerations, it would perhaps be rash to deny that characters 

 become more strongly fixed the longer they are transmitted; 

 but I believe that the proposition resolves itself into this, 

 that all characters of all kinds, whether new or old, tend 

 to be inherited, and that those which have already withstood 

 all counteracting influences and been truly transmitted, will, as 

 a general rule, continue to withstand them, and consequently 

 be faithfully inherited. 



1 See Youatt on Cattle, pp. 92, 69, 78, 88, 163 : and Youatt on Sheep, p. 325. 

 Also Dr. Lucas, ' L'Here'd. Nat.,' torn. ii. p. 310. 







believe structures, which have already varied, would be 

 liable to go on varying, rather than structures which dur 

 an immense lapse of time have remained unaltered ; and this 

 variation is probably the result of certain relations between the 

 conditions of life and the organisation, quite independently of 

 the greater or less antiquity of each particular character. 



Fixedness of character, or the strength of inheritance, has 

 often been judged of by the preponderance of certain characters 

 in the crossed offspring between distinct races ; but prepotency 

 of transmission here comes into play, and this, as we shall 

 diately see, is a very different consideration from the st 

 or weakness of inheritance. It has often been observed 1 that 

 breeds of animals inhabiting wild and mountainous countries 













