3 6 THE PHYSICAL BASIS OF INHERITANCE 



fact being that the leaf of a plant, or a quarter of a zoophyte, 

 or an eighth of a sea-anemone, may grow into an entire organism 

 with reproductive cells, we must infer that the characteristic 

 heritable material, usually segregated in the reproductive cells, 

 is present in the cells of the body in these organisms. 



The feature common to the ordinary forms of asexual multi- 

 plication is, that the reproduction is independent of eggs or 

 sperms, or of any process comparable to fertilisation. What 

 starts the new life, and lorms in this case the material basis of 





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Fig. 5. — Asexual reproduction. A sea-worm (Syllis ramosa), in which 

 budding has produced a branched temporary colony. (After Mcintosh.) 



inheritance, is a liberated portion of the parent. The heredity- 

 relation is one of obvious material continuity. 



As regards inheritance, the feature characteristic of asexual 

 multiplication is that the resemblance between parent and 

 offspring tends to be complete. As Sedgwick (1899) expresses 

 it : " The offspring do not merely present resemblances to the 

 parent — they are identical with it ; and this fact does not appear 

 to be astonishing when we consider the real nature of the process. 

 Asexual reproduction consists in the separation of a portion of 



