THE BEGINNINGS OF LIFE. 93 



Thus c reproduction ' amongst such simple organisms 

 is, after all, nothing but discontinuous growth. This 

 simple interpretation of the distinctive peculiarity of 

 living things was long ago pointed out by Prof. Huxley ; 

 and the fact that growth is frequently discontinuous in 

 living matter flows directly, as we have hinted, from 

 the circumstance of the extreme molecular mobility of 

 its constituent units. All the higher modes of repro- 

 duction which are to be witnessed in living things are 

 only specializations of the process of c gemmation.' 



By reason of the molecular mobility of c living' matter, 

 and the continuous rearrangements brought about therein 

 under the influence of ordinary physical .conditions, it 

 gradually becomes more and more complex in internal 

 structure, and also undergoes variations in its external 

 form 1 . But to whatsoever grades of development organ- 

 isms may have attained, the reproductive faculty (due to 

 the power of discontinuous growth) still remains as one 

 of the chief characteristics of living things. And it 

 always happens, that suitable portions thrown off from 

 the parent organism have the power of developing into 

 organisms of a similar kind however complex and 



and these seem the best fitted for the purpose. Multicentral develop- 

 ment, then, is divisible into continuous and discontinuous.' (' Principles 

 of Biology,' vol. i. p. 135.) 



1 Abundant evidence on this subject will be found in Appendix D. 

 Many of the changes there recorded far surpass the metamorphoses 

 brought about in such crystals as those of mercuric iodide under the 

 influence of new conditions though they are otherwise comparable with 

 these metamorphoses. 



