the variations are transmitted to his offspring in accordance with the laws
which prevail with the lower animals. Again, are the variations the
result, as far as our ignorance permits us to judge, of the same general
causes, and are they governed by the same general laws, as in the case of
other organisms; for instance, by correlation, the inherited effects of use
and disuse, etc.? Is man subject to similar malconformations, the result
of arrested development, of reduplication of parts, etc., and does he
display in any of his anomalies reversion to some former and ancient type
of structure? It might also naturally be enquired whether man, like so
many other animals, has given rise to varieties and sub-races, differing
but slightly from each other, or to 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 in the first and
succeeding generations? And so with many other points.

The 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 one
another, 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 conveniently
deferred for a time: and we will first see how far the bodily structure of
man shews traces, more or less plain, of his descent from some lower form.
In succeeding chapters the mental powers of man, in comparison with those
of the lower animals, will be considered.

THE BODILY STRUCTURE OF MAN.