oe THE ORIGIN OF SPECIES Ir 
and matter and force are the two names of the 
one artist who fashions the living as well as th 
lifeless. Hence living bodies should obey th 
same great laws as other matter—nor, throughou 
Nature, is there a law of wider application than 
this, that a body impelled by two forces takes the 
direction of their resultant. But living bodies 
may be regarded as nothing but extremely complex 
bundles of forces held in a mass of matter, as the 
complex forces of a magnet are held in the steel 
by its coercive force; and, since the differences 
of sex are comparatively slight, or, in other words, 
the sum of the forces in each has a very similar 
tendency, their resultant, the offspring, may reason- 
ably be expected to deviate but little from a course 
parallel to either, or to both. 
Represent the reason of the law to ourselves by 
what physical metaphor or analogy we will, how- 
ever, the great matter is to apprehend its existence 
and the importance of the consequences deducible 
from it. For things which are like to the same 
are like to one another; and if, ina great series of 
generations, every offspring is like its parent, it 
follows that all the offspring and all the parents 
must be like one another; and that, given an 
original parental stock, with the opportunity of 
undisturbed multiplication, the law in question 
necessitates the production, in course of time, of 
an indefinitely large group, the whole of the mem- 
bers of which are at once very similar and are blood 
