2 
INTRODUCTION. 
and this especially holds good with the younger and 
rising naturalists. The greater number accept the 
agency of natural selection; though some urge, whether 
with justice the future must decide, that I have greatly 
overrated its importance. Of the older and honoured 
chiefs in natural science, many unfortunately are still 
opposed to evolution in every form. 
In consequence of the views now adopted by most 
naturalists, and which will ultimately, as in every other 
case, be followed by other men, I have been led to put 
together my notes, so as to see how far the general 
conclusions arrived at in my former works were appli- 
cable to man. This seemed all the more desirable 
as I had never deliberately applied these views to a 
species taken singly. When we confine our attention 
to any one form, we are deprived of the weighty argu- 
ments derived from the nature of the affinities which 
connect together whole groups of organisms — their geo- 
graphical distribution in past and present times, and 
their geological succession. The homological structure, 
embryological development, and rudimentary organs of 
a species, whether it be man or any other animal, to 
which our attention may be directed, remain to be con- 
sidered; but these great classes of facts afford, as it 
appears to me, ample and conclusive evidence in favour 
of the principle of gradual evolution. The strong sup- 
port derived from the other arguments should, however, 
always be kept before the mind. 
The sole object of this work is to consider, firstly, 
whether man, like every other species, is descended 
from some pre-existing form ; secondly, the manner of 
