324 _ - Lhe American Naturalist. [April, 
of identification and description, to separate them from the 
general type. Just as soon as botanists come to feel that all 
so-called species of plants are transitory and artificial groups 
maintained for convenience in the study of nature, they will 
not ask whether they are modified outside the garden or in- 
side it, but will consider groups of equal distinctness and per- 
manence to be of equal value in the classification of knowl- 
edge, wholly aside from the mere place of their origin. At 
the present time, the garden fence is the only distinction be- 
tween many accepted species and many discarded ones. 
The cultivation of man differs from the methods of nature 
only in degree, not in kind; and if man secures results sooner 
than nature does it is only another and indubitable proof of 
the evolution of organic forms. It is certainly a wholly un- 
scientific attitude to demand that forms originating by one of 
nature’s methods are species, while similar forms originating 
by another method are beneath notice. 
If species are not original entities in nature, then it is use- 
less to quarrel over the origination of them by experiment. 
All we want to know, as a proof of evolution, is whether 
plants and animals can become profoundly modified under 
different conditions, and if these modifications tend to persist. 
Every man before me knows, as a matter of common observa- 
tion and practice, that this is true of plants. He knows that 
varieties with the most marked features are passing before 
him like a moving panorama. He knows that nearly every 
plant which has been long cultivated, has become so pro- 
foundly and irrevocably modified that people are disputing as 
to what wild species it came from. Consider that we cannot 
certainly identify the original species of the apple, peach, plum, 
cherry, orange, lemon, wine grape, sweet potato, Indian 
corn, melon, bean, pumpkin, wheat, tobacco, chrysanthemum, 
and nearly or quite a hundred other common cultivated 
plants. It is immaterial whether they are called species or 
varieties. They are new forms. Some of them are so distinct 
that they have been regarded as belonging to distinct genera. 
Here is the experiment to prove that evolution is true, worked 
out upon a scale and with a definiteness of detail which the 
