19 

 CHAPTER III. 



CAUSES OF VARIATION. 



" IT is not impossible/' says a writer of the last century, 

 " that such laws of Nature, and such a series of causes 

 and effects, may have been originally designed, that not 

 only general provisions may have been made for the 

 several species of beings, but that even particular cases 

 (at least many of them) may have been provided for 

 without innovations in the course of Nature*." And 

 let us not suppose that this is a mere wanton specula- 

 tion, unsupported by evidence (if not actually circum- 

 stantial, at least) strongly presumptive ; since the farther 

 we penetrate into the ramifications of the organic world, 

 the less are we inclined to ignore the operation of those 

 various modifying influences which our understanding 

 tells us do everywhere exist. 



To investigate the causes of things, and to endeavour 

 to trace out by slow, inductive processes those second- 

 ary agents, by the assistance of which a large propor- 

 tion of the phsenomena around us are gradually matured, 

 is no insignificant task; yet how much animadversion 

 from without have the students in such fields of research 

 frequently to endure ! A fact many times repeated, and 

 which comes within our daily experience, is too often 

 * Religion of Nature Delineated, p. 103. 



