Tin: STKI 16 



an<i i.-ii.-!i.-i:il jii.-ilii i- happen to arise as slight varia- 

 tioiin fmin the ancestral type, they will (other ti 

 permitting), I* uj-.n 



msmitted hy heredity to subh- <eiierat 



will he added tu th. pa Thi.s then, 



is natural > D <T tin- survival of the "the 



mainly to the process, the other to 



.:t." 



ocessis 'ii- 1.. that hy which the gardener 



ainl the rattle lipM'.l.T hring about their won.lrrl'ul r- 

 -nil-, .lu-t as tin-si- men. hy alway- -tini:" their 



best iinliviiluaU to hi- :i, sln\\ly hut continu 



imprnve tln-ir stek. s Natui -cess of "selec- 



tion," slowly hut omtiimously mak'> tin- \.trious 8]> 

 of plants and animals hrttn- suited to the conditions of 

 their life. What the skill of Luther I'.urhank has ac- 

 complished in the course of a few generations, Nature 

 takes years or even centuries of experimentation to pro- 



.rtitieial seh-ction, man works on 

 characters irregularly and imperfectly for a short time. 

 \vorks on the whole machine iife by con- 



u-eum ulation during whole geological epochs. 

 Silently and insensibly work in IT, natural ; is daily 



and i M-rutini/iiiir the slightest vari 



imr those that are I; -erving and adding up all that 



are good."* 

 Under natura -ions th M endless range of 



\Ve have seen in chapter I. how like tends 

 to beget like, but that although the t.tTsprin-r is similar to 

 the parent there is ne\ 'ion. Then* 



is latitude allowed for individual variation. The indi- 

 vidual differences are due to age, sex, modification, and 



Thomm ft Geddc*. op. of . : , 156. 



