. An examination of Weismannism [microform]. Heredity; Evolution; Hérédité; Evolution. Weisinaniis theory of Heredity (1891). 57 the sense ofncver havini^ had any of its hereditary endowments in any \va)' affected by_£ body- tissues in which it^resides, the followin^j important consequences, it will be remembered, arise. The process of organic evolution must have been exclusively due to a natural selection of favourable variations occurring within the limits of this substance itself; and therefore the so-called Larnarckian factors can never have played any part at au m the evolutio
. An examination of Weismannism [microform]. Heredity; Evolution; Hérédité; Evolution. Weisinaniis theory of Heredity (1891). 57 the sense ofncver havini^ had any of its hereditary endowments in any \va)' affected by_£ body- tissues in which it^resides, the followin^j important consequences, it will be remembered, arise. The process of organic evolution must have been exclusively due to a natural selection of favourable variations occurring within the limits of this substance itself; and therefore the so-called Larnarckian factors can never have played any part at au m the evolution of any but the unicelhilar organisms. On the other hand, if this substance has not been thiis perpetually con- tinuous, but more ox less formed anew at each ontogeny by the general body-tissues in which it resides, natural selection has probably been in some corresponding degree assisted in its work of organic evolution by the Larnarckian factors, with the result that the experi- ences of parents count for something in the congenital endowments of their offspring. So much for the first of the two differences between germ-plasm and gemmules, or the difference which arises from the perpetual continuity of germ-plasm. Touching the second difference, or that which arises from the absolute stability of germ-plasm, it will be remembered how from this character there arises another important chain of consequences. Namely, individual variations of the congenital kind can only be~"3ue"to admixtures of different masses of germ- pTasm in every act of .sexual fertilization; natural .scTectTon is therefore dependent, for the possibility of its working, upon the sexual methods of propa- gation ; hence, natural selectidu is without any juris- diction among the unicellular organisms, where the Larnarckian factors hold exclusive swa\' : and hence,. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - colorat
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