UNDER THE APPLE-TREES 
such a vast period of time, that their survival value 
from generation to generation is and must be very 
slight. 
Take the case of the horse, for instance. The 
development of the horse seems to stretch over a 
period of at least three millions of years, or from the 
eohippus of Eocene times, an animal less than two 
feet high, and probably weighing less than one 
hundred pounds, to the horse of later Tertiary 
times, the pliohippus, much like the superb crea- 
ture we know to-day, five feet high, and weighing 
ten or twelve hundred pounds. If this animal in- 
creased in height only one quarter of an inch in 
ten thousand years, he would be six feet high in 
less than two million years. So if we allow him three 
million years to develop in, his increase in height 
must have been even less than one fourth of an 
inch in ten thousand years. Think of it! Our horse 
of to-day might be increasing or diminishing in 
size at that rate and the fact never be noticed dur- 
ing the whole historic period. In weight the same; 
one eighth of a pound in one hundred years, and 
he would weigh fourteen thousand pounds in less 
than two million years, a rate of increase that our 
scales would hardly detect in a century of time. 
The transformations of the other animals have 
probably been equally slow. Science would feel 
safe in saying that a flying fish never becomes a 
bird, but can we conceive how slight the change 
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