The Theory of Natural Selection. 263 
hereditary transmission of what are called congenital 
characters. And this is all that Darwin’s theory 
necessarily requires. 
The fourth fact is, that although heredity as a whole 
produces a wonderfully exact copy of the parent in 
the child, there is never a precise reduplication. Of 
all the millions of human beings upon the face of the 
earth, no one is so like another that we cannot 
see some difference; the resemblance is everywhere 
specific, nowhere individual. Now this same remark 
applies to all specific types. The only reason why 
we notice individual differences in the case of the 
human type more than we do in the case of any other 
types, is because our attention is here more incessantly 
focussed upon these differences. We are compelled 
to notice them in the case of our own species, however 
small they may appear to a naturalist, because, unless 
we do so, we should not recognise the members of our 
own family, or be able to distinguish between a man 
whom we know is ready to do us an important service, 
and another man whom we know is ready to cut our 
throats. But our common mother Nature is able 
thus to distinguish between all her children. Her 
eyes are much more ready to detect small individual 
peculiarities than are the eyes of any naturalist. No 
slight variations in the cast of feature or disposition 
of parts, no minute difference in the arrangement of 
microscopical cells, can escape her ever vigilant 
attention. And, consequently, when among all the 
innumerable multitudes of individual variations any 
one arises which—no matter in how slight a degree— 
gives to that individual a better chance of success in 
the struggle for life, Nature chooses that individual 
