10 
THE DESCENT OF MAN. 
Part I. 
races differing so much that they must be classed as 
doubtful species ? How are such races distributed over 
the world ; and how, when crossed, do they react on 
each other, both in the first and succeeding genera- 
tions ? And so with many other points. 
Ihe enquirer would next come to the important point, 
whether man tends to increase at so rapid a rate, as to 
lead to occasional severe struggles for existence, and 
consequently to beneficial variations, whether in body 
or mind, being preserved, and injurious ones eliminated. 
Do the races or species of men, whichever term may be 
applied, encroach on and replace each other, so that 
some finally become extinct? We shall see that all 
these questions, as indeed is obvious in respect to most 
of them, must be answered in the affirmative, in the 
same manner as with the lower animals. But the 
several considerations just referred to may be conve- 
niently deferred for a time ; and we will first see how 
far the bodily structure of man shows traces, more or 
less plain, of his descent from some lower form. In the 
two succeeding chapters the mental powers of man, in 
comparison with those of the lower animals, will be con- 
sidered. 
The Bodily Structure of Man.— It is notorious that 
man is constructed on the same general type or model 
with other mammals. All the bones in his skeleton 
can be compared with corresponding bones in a monkey, 
bat, or seal. So it is with his muscles, nerves, blood- 
vessels and internal viscera. The brain, the most im- 
portant of all the organs, follows the same law, as shewn 
by Huxley and other anatomists. Bischoff,’ who is a 
hostile witness, admits that every chief fissure and fold 
‘ (frossbirnwiudungen des Menschen,’ 18CS, s. 9U. 
