266 THE REIGN OF LAW. 



of every organism, so that any change in one 

 part of it is but the index of changes which 

 run visibly or invisibly throughout the whole. 

 The growths between which we detect a corre- 

 lation, are not really separate things connected 

 only by the few correspondences which we may 

 be able to detect, but are part and parcel of one 

 operation, the result of one Force, exerting its 

 energies through channels which we cannot see, 

 and according to laws of which we can form but 

 a distant and faint conception. The truth is, 

 that Correlation in this sense is involved in the 

 very word " Growth." Each part of every struc- 

 ture which is the result of growth must be cor- 

 related to every other part. This is essential 

 to the very idea of growth, and to the very idea 

 of an organism due to growth. When, there- 

 fore, Mr Darwin says that one of the laws on 

 which variation of form depends is Correlation of 

 Growth, he simply says that variations of Growth 

 depend on growth — for all growths must be cor- 

 related. 



But Correlation in this sense helps but a little 

 way indeed in conceiving the origin of a new 



