36 THE ORIGIN OF SPECIES I! 
to point out any obvious reason for the appearance 
of the variety. Doubtless there were determining 
causes for these as for all other phenomena; but 
they do not appear, and we can be tolerably certain 
that what are ordinarily understood as changes in 
physical conditions, as in climate, in food, or the 
like, did not take place and had nothing to do with 
the matter. It was no case of what is commonly 
called adaptation to circumstances; but, to use a 
conveniently erroneous phrase, the variations arose 
spontaneously. The fruitless search after final 
causes leads their pursuers a long way; but even 
those hardy teleologists, who are ready to break 
through all the laws of physics in chase of their 
favourite will-o’-the-wisp, may be puzzled to dis- 
cover what purpose could be attained by the stunted 
legs of Seth Wright’s ram or the hexadactyle 
members of Gratio Kelleia, 
Varieties then arise we know not why ; and it is 
more than probable that the majority of varieties 
have arisen in this “spontaneous ” manner, though 
we are, of course, far from denying ‘ that they may 
be traced, in some cases, to distinct external in- 
fluences ; which are assuredly competent to alter 
the character of the tegumentary covering, to 
change colour, to increase or diminish the size of 
muscles, to modify constitution, and, among plants, 
to give rise to the metamorphosis of stamens into 
petals, and so forth. But however they may have 
arisen, what especially interests us at present is, to 
