36 THE PHYSICAL BASIS OF INHERITANCE 



and germ-cells has not gone far. For if 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 diffusely present in the cells of the 

 body in these organisms. Or else we must infer, as some have 

 done, that there is no characteristic heritable material. 



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 



Fig. 5. — Asexual reproduction. A sea-worm (Myrianida) which buds 

 off a chain of individuals. (After Milne-Edwards.) 



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

 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 



