THE CHORUS OF MAN’S STAGE 
vironments over ages of time. Such indeed is the almost 
universally accepted conclusion of scientific men. It is 
called the theory of organic evolution. As to the relative 
importance of the parts played by different agencies in pro- 
moting the evolutionary process there is as yet no general 
agreement; but as regarding the general proposition there 
is nearly unanimous consent. 
If the proposition of organic evolution requires further 
support, it may be found in the experiments of the present 
day. For example, the little plant, St.-John’s-wort, which 
in America and Europe seldom exceeds a foot in height, 
was transplanted to New Zealand about eighty years ago. 
There it has become a tree reaching forty feet in the air. 
Pigeons which came originally from the wild blue rock 
pigeon have been developed, under the care of breeders, 
into the astonishing variety of forms familiar to fanciers. 
Dogs and horses, too, under the selection of breeders, 
range through forms almost as various. In laboratory ex- 
periments of the past half century, hundreds of what may 
be accepted as new species of invertebrates and vertebrates 
have been originated. Man himself is proved to vary. 
Thus the races of Europe, which have furnished over 
twenty million emigrants to America within the past cen- 
tury, betray, according to Hrdlicka, definite changes of the 
shape of the skull and other of the most deep-seated skele- 
tal characters in their descendants of only a few genera- 
tions. 
Still more remarkable is the evidence of change which 
we shall take up in the next chapter, where we follow the 
human development from conception to old age. It is 
thought by some to be derogatory to the dignity of man 
that he should be considered to have ascended from sub- 
ordinate creatures during the progress of ages. Yet it can 
not be denied that every human individual goes through an 
extensive evolution in his own individual development and 
passes through forms equally repulsive to the squeamish 
eye. A fact which is often overlooked in this connection 
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