THE BEGINNINGS OF LIFE. 



595 



^ tendency, ^;^ 



^ ^orm and strr* 

 of internal 



failed to attach an adequate importance to such instances 

 of ^spontaneous' variation as he has recorded. These 

 instances seem to afford very interesting examples 

 of the operation in higher organisms of those in- 

 fluences which suffice to produce such multitudes of 



heterogenetic changes amongst 



lower o 



anisms ; so 



*.. 



► 



that they supply most valuable additional testimony as 

 to the continued influence of *^ organic polarity' in 

 determining the form and structure of higher organ- 



quite ini. 



3ccur 



hange. 



Darwin hassaiJc 



isms 



1 



Mr 



I 



and others to regulate the forms of organisms through- 

 out all their developmental stages ^j and, as we have 

 already endeavoured to show, the wonderful powers 



■nportant inta^ of repair exhibited by Crustacea, fish, amphibia, and 



about specific iri 



F the very intes: 



that treasury of I 



( 



Is and Plants "^ 



e\ 



•idencetopro«' 



i 



ficient import* 

 ^ific variation' 



\ 



ively low esti 



ffl 



•rativ 



» 0^ change in \ 



that^J^■'^^ 



X in ^' 



of ch^"' 



^ Believing that living organisms are ultimately compounded of exceed- 

 ingly complex molecules or ' physiological units/ exhibiting multitudes 

 of minute differences amongst themselves, Mr. Spencer says such ' specific 

 molecules, having the immense complexity above described, and having 

 correspondently complex polarities which cannot be mutually balanced 

 by any simple form of aggregation, have for the form of aggregation in 

 which all their forces are equilibrated, the structure of the adult or- 

 ganism to which they belong, and they are compelled to fall into this 

 structure by the co-operation of the environing forces acting on them 

 and the forces they exercise on one another/ (Appendix to ' Principles 

 of Biology,* vol. ii. p. 4S8.) 



^ Appendix to ' Principles of Biology,' vol. ii. p. 489. Prof. Grant 

 also writes in the same strain when he says: — 'No animal can be 



formed without its passing through the entire long series of 



developmental changes peculiar to each. Whether the product of the 

 nucleus is to be a Monad or a Whale, each successive stage of the process of 

 formation has within itself the sole and exclusive potentiality of the next stage 

 in advance, and none therefore can ever be overstepped or omitted.' 

 ('Recent Zoology/ 1861, p. 89.) 



qq 2 



