EVOLUTION AND THE PRESENT AGE boop 9) 
natural selection was an immensely important contri- 
bution to the doctrine of evolution, but it should no 
more be confounded with that doctrine than Lyell’s 
geology or the Newtonian astronomy should be con- 
founded with it. 
If Herbert Spencer had not lived in the nineteenth 
century, although the age would have been full of 
illustrations of evolution, contributed by Darwin and 
others, yet in all probability such a thing as the doc- 
trine of evolution would not have been heard of. 
What, then, is the central pith of the doctrine of 
evolution? It is simply this: That the changes that 
are going on throughout the universe, so far as our 
scientific methods enable us to discern and follow 
them, are not chaotic or unrelated, but follow an intel- 
ligible course from one state of things toward another: 
and more particularly, that the course which they fol- 
low is like that which goes on during the development 
of an ovum into a mature animal. This, I say, is the 
central pith of the doctrine of evolution. It started 
in the study of embryology, a department in which 
Darwin had but little first-hand knowledge. Spen- 
cer’s forerunner was the great Esthonian naturalist, 
Carl Ernest von Baer, who published in 1829 a won- 
derful book generalizing the results of observation up 
to that time on the embryology of a great many kinds 
of animals. Curiously enough, von Baer called this 
book a “ History of Evolution,” although neither then, 
nor at any time down to his death, was he an evolu- 
tionist in our sense of the word. So far from it was 
he that in his later years he persistently refused to 
accept Darwin’s theory of natural selection. 
Now in studying the development of an individual 
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