UNDER THE APPLE-TREES 
the tree, but it does not plant it, nor make it grow, 
nor prescribe one form to the pine and another to 
the oak. Do we not have to think of all these 
things as involved in the mystery of the evolution- 
ary impulse itself? What that impulse is, in the 
terms of the rest of our knowledge, or whence it 
comes, or how it adheres to matter, is one of the 
fundamental mysteries. 
Biologists who hold to the mechanistic concep- 
tion of life, or to its explanation in terms of chem- 
istry and physics, lose their reckoning when con- 
fronted by the strange power of regeneration which 
certain low forms of animals possess, and which 
the higher forms do not possess. The body of the 
newt has power to grow a new eye to take the place 
of a lost one, and to reproduce it by a new process, 
radically different from the process that gave it 
the first eye. This, and other like phenomena, to 
my mind can be interpreted only in terms of intelli- 
gence. Such a procedure transcends all we know 
of chemistry and physics. Something in the body 
knows what it wants, and knows how to proceed 
to obtain it. The impulse or organizing tendency 
that certainly had a beginning in geologic time is 
equally mysterious, and equally beyond the reach 
of the chemical and physical forces as we know 
them in the inorganic world. I am compelled to 
think of this impulse as inherent in matter, and as 
involved in the physicochemical forces, but I am 
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