THE LAW OF PROGRESS 
accomplished these results without in- 
breeding. It is probably true that Nature, 
in the long line of descent from the ark 
to the present time, has at times inbred 
her species, but the natural law against 
such practice is so strong that such occur- 
rences must have been very rare indeed— 
so rare that no perceptible bad results 
have followed. 
I do not wish to be understood as say- 
ing here that Nature has established an 
unchangeable standard of perfection, to- 
wards which she is breeding, for she is 
constantly changing her varieties and 
species to fit them to the constantly chang- 
ing conditions that surround them. These 
changes are so slow, however, that any 
change that would take place during the 
span of a human life is imperceptible to 
us. JI think that Nature’s standard of 
perfection is one that fits her living crea- 
tures to the environment that surrounds 
them. So we see that man, in order to 
become a successful breeder, must make 
his standards of perfection such that 
when the animals he desires to breed 
have been bred up to that standard they 
will fit as harmoniously as possible into 
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