ur of the common descent
of man and all other vertebrates. The conclusion of this section is
characteristic: "IT IS ONLY OUR NATURAL PREJUDICE, AND THAT ARROGANCE
WHICH MADE OUR FOREFATHERS DECLARE THAT THEY WERE DESCENDED FROM
DEMI-GODS, WHICH LEADS US TO DEMUR TO THIS CONCLUSION. BUT THE TIME WILL
BEFORE LONG COME, WHEN IT WILL BE THOUGHT WONDERFUL THAT NATURALISTS,
WHO WERE WELL ACQUAINTED WITH THE COMPARATIVE STRUCTURE AND DEVELOPMENT
OF MAN, AND OTHER MAMMALS, SHOULD HAVE BELIEVED THAT EACH WAS THE WORK
OF A SEPARATE ACT OF CREATION." (Ibid. page 36.)

In the second chapter there is a more detailed discussion, again based
upon an extraordinary wealth of facts, of the problem as to the manner
in which, and the causes through which, man evolved from a lower form.
Precisely the same causes are here suggested for the origin of man, as
for the origin of species in general. Variability, which is a necessary
assumption in regard to all transformations, occurs in man to a high
degree. Moreover, the rapid multiplication of the human race creates
conditions which necessitate an energetic struggle for existence, and
thus afford scope for the intervention of natural selection. Of the
exercise of ARTIFICIAL selection in the human race, there is nothing
to be said, unless we cite such cases as the grenadiers of Frederick
William I, or the population of ancient Sparta. In the passages already
referred to and in those which follow, the transmission of acquired
characters, upon which Darwin does not dwell, is taken for granted.
In man, direct effects of changed conditions can be demonstrated (for
instance in regard to bodily size), and there are also proofs of the
influence exerted on his physical constitution by increased use or
disuse. Reference is here made to the fact, established by Forbes,
that the Quechua-Indians of the high plateaus of Peru show a striking
development of lungs and thorax, as a result of living constantly at
high altitudes.

Such special forms of variation as arrests of development
(microcephalism) and reversion to lower forms are next discussed. Darwin
himself felt ("Descent of Man", page 54.) that these subjects are so
nearly related to the cases mentioned in the first chapter, that many
of them might as well have been dealt with there. It seems to me that it
would have been better so, for the citation of additional instances
of reversion at this place rather disturbs the logical sequence of his
ideas as