: 
I 
THE DARWINIAN HYPOTHESIS 
[1859] 
THE hypothesis of which the present work of 
Mr. Darwin is but the preliminary outline, may 
be stated in his own language as follows :— 
“ Species originated by means of natural selection, 
or thr rough the preservation of the favoured races 
in the struggle for life.” To render this thesis 
intelligible, it.is necessary to interpret its terms. 
In the first place, what isa species? The question 
is a simple one, but the right answer to it is hard 
to find, even if we appeal to those who should 
know most about it. It is all those animals or \ 
plants which have descended from a single pair of | 
parents; it is the smallest distinctly definable | 
group of living organisms; it is an eternal and | 
immutable entity ; it is a mere abstraction of the 
human intellect having no existence in nature. — 
Such are a few of the significations attached to | 
VOL. II B 
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