Till 



changes < >tit th- -l\\ in-ilin- f other parts from 



which >o niiirli activity wa> no linger required, 

 result was "that the whol the* animal 



became more an. I ni.ir.- adapt.-d i,, bfOWSing on in-:. 



f"li: same principle was appl 



many other .structural peculiarities. To dearly und-r 



i this prob: s neces> *.-ort to tin- ti 



<>f inheritance. 



in speaking of inheritance we said that the pan-nt was 

 instee of the & -mi plasm than the pnxlii<'-r 



of tht' chihl. In hiirh.-r plant- an.l animals tin* fill. 



is not prrformr.l l.y tlie body as a whol.-. 

 hut is i^iv'ii ovrr to >prcial groups of o-lls, tin- 

 cells, con-titutinir tin- nvari.-s and testes. l f from 

 these crll> that nr\v in.lix i.luaU ari--. In view of this 

 the problem we have just been consi.l. -ring- is not so 

 >impl-. -.ainpl.% how can the enlargement of a 



muscle due to exercise, so affect the <j, Is, which 



He at some dist <>m th<> muscle in <}iic>tion, as to 



cause the new individual, which shall arise from these 

 germ cells, to have the corresponding muscle in its own 

 body enlarged? Under ordinary condition, it is only 

 thr </<im <//> in the body which haxv any descendants 

 in the following m-neratiun. 7 -' In the body there are 

 muse , bone cells, n-r\v .,!!. Weismann used 



the term .-KI to indud.' all the celU of the body which 

 /* cells. Now the whole body of the offspring 

 comes from the union of two ,/ It; an .-in: from one 



it and a spermatozoon from the other. 7 ' No somatic 

 cell Ljivi- i-ise to any part of the offspring. While the 



i/ed egg is developing into an adult organism it 

 divides into a number of portions called blastomeres, 



T* Metomlf. o r r, t fc Ibid., p. 71. 



