Descent of Man [ 1871]

* Mr. Bates remarks (The Naturalist on the Amazons, 1863, vol. ii p.
159), with respect to the Indians of the same South American tribe,
"no two of them were at all similar in the shape of the head; one
man had an oval visage with fine features, and another was quite
Mongolian in breadth and prominence of cheek, spread of nostrils,
and obliquity of eyes."
*(2) Blumenbach, Treatises on Anthropology., Eng. translat., 1865,
p. 205.
*(3) Mitford's History of Greece, vol. i., p. 282. It appears from a
passage in Xenophon's Memorabilia, B. ii. 4 (to which my attention has
been called by the Rev. J. N. Hoare), that it was a well recognised
principle with the Greeks, that men ought to select their wives with a
view to the health and vigour of their children. The Grecian poet,
Theognis, who lived 550 B. C., clearly saw how important selection, if
carefully applied, would be for the improvement of mankind. He saw,
likewise, that wealth often checks the proper action of sexual
selection. He thus writes:

With kine and horses, Kurnus! we proceed
By reasonable rules, and choose a breed
For profit and increase at any price:
Of a sound stock, without defect or vice.
But, in the daily matches that we make,
The price is everything: for money's sake,
Men marry: women are in marriage given
The churl or ruffian, that in wealth has thriven,
May match his offspring with the proudest race:
Thus everything is mix'd, noble and base!
If then in outward manner, form, and mind,
You find us a degraded, motley kind,
Wonder no more, my friend! the cause is plain,
And to lament the consequence is vain.

(The Works of J. Hookham Frere, vol. ii., 1872, p. 334.)

If we consider all the races of man as forming a single species, his
range is enormous; but some separate races, as the Americans and
Polynesians, have very wide ranges. It is a well-known law that
widely-ranging species are much more variable than species with
restricted ranges; and the variability of man may with more truth be
compared with that of widely-ranging species, than with that of
domesticated animals.
Not only does variability appear to be induced in man and the
lower animals by the same general causes, but in both the same parts
of the body are effected in a closely analogous manner. This has
been proved in such full detail by Godron and Quatrefages, that I need
here only refer to their works.* Monstrosities, which graduate into
slight variations, are likewise so similar in man and the lower
animals, that the same classification and the same terms can be used
for both, as has been shewn by Isidore Geoffroy St-Hilaire.*(2) In
my work on the variation of domestic animals, I have attempted to
arrange in a rude fashion the laws of variation under the following
heads:- The direct and definite action of changed conditions, as
exhibited by all or nearly all the individuals of the same species,
varying in the same manner under the same circumstances. The effects
of the long-continued use or disuse of parts. The cohesion of
homologous parts. The variability of multiple parts. Compensation of
growth; but of this law I have found no good instance in the case of
man. The effects of the mechanical pressure of one part on another; as
of the pelvis on the cranium of the infant in the womb. Arrests of
development, leading to the diminution or suppression of parts. The
reappearance of long-lost characters through reversion. And lastly,
correlated variation. All these so-called laws apply equally to man
and the lower animals; and most of them even to plants. It would be
superfluous here to discuss all of them;*(3) but several are so
important, that they must be treated at considerable length.

* Godron, De l'Espece, 1859, tom. ii., livre 3. Quatrefages, Unite
de l'Espece Humaine, 1861. Also Lectures on Anthropology, given in the
Revue des Cours Scientifiques, 1866-1868.
*(2) Hist. Gen. et Part. des Anomalies de l'Organisation, tom. i.,
1832.
*(3) I have fully discussed these laws in my Variation of Animals
and Plants under Domestication, vol. ii., chaps. xxii. and xxiii. M.
J. P. Durand has lately (1868) published a valuable essay, De
l'Influence des Milieux, &c. He lays much stress, in the case of
plants, on the nature of the soil.