THE BEGINNINGS OF II FE. 91 



play of forces like that which moulds the materials 

 contained in a piece of Begonia-leaf into the shape of 

 a young Begonia. In the one case as in the other, the 

 vitalized molecules composing the tissues show their 

 proclivity towards a particular arrangement; and whether 

 such proclivity is exhibited in reproducing the entire 

 form, or in completing it when rendered imperfect, 

 matters not.' 



But the reader may ask, What is the meaning or 

 explanation of this power of reproducing their like 

 which is possessed by all living things? 



In order to answer the question we must look rather 

 to what occurs amongst the lowest organisms than to 

 the phenomena presented by higher plants and animals. 

 The fundamental nature of the process of reproduction 

 is revealed most clearly by a consideration of the pro- 

 cesses of ^fission' and 'gemmation/ What we know 

 about these processes, clearly shows that all parts of a 

 lower organism when separated from the parent have 

 the power of developing into living things of a similar 

 kind. This, as we have already pointed out, is pre- 

 cisely analogous to the process whereby a fragment 

 broken from a pre-existing crystal and thrown into a 

 suitable solution gradually grows into a perfect crystal, 

 similar to that from which it had been derived. But 

 organisms are dynamical aggregates amongst the mole- 

 cules of which new motions and new arrangements 

 are continually being assumed, in the course of which 

 there frequently arises a ^spontaneous' division of 



