le to secure this greater comfort."

[136] Ploss, _Das Weib_, Vol. I, chap. XX.

[137] It must not, however, be assumed that the rural immigrants are in
the mass better suited to urban life than the urban natives. It is
probable that, notwithstanding their energy and robustness, the
immigrants are less suited to urban conditions than the natives.
Consequently a process of selection takes place among the immigrants,
and the survivors become, as it were, immunized to the poisons of urban
life. But this immunization is by no means necessarily associated with
any high degree of nervous vigour or general physical development.

[138] Havelock Ellis, _A Study of British Genius_, pp. 22, 43.

[139] "National Health: a Soldier's Study," _Contemporary Review_,
January, 1903. The Reports of the Inspector-General of Recruiting are
said to show that the recruits are every year smaller, lighter, and
narrower-chested.

[140] This has been well illustrated during the past forty years in the
flourishing county of Glamorgan in Wales, as is shown by Dr. R.S.
Stewart ("The Relationship of Wages, Lunacy, and Crime in South Wales,"
_Journal of Mental Science_, January, 1904). The staple industry here is
coal, 17 per cent of the population being directly employed in
coal-mining, and wages are determined by the sliding scale as it is
called, according to which the selling price of coal regulates the
wages. This leads to many fluctuations and sudden accesses of
prosperity. It is found that whenever wages rise there is a concomitant
increase of insanity and at the same time a diminished output of coal
due to slacking of work when earnings are greater; there is also an
increase of drunkenness and of crime. Stewart concludes that it is
doubtful whether increased material prosperity is conducive to
improvement in physical and mental status. It must, however, be pointed
out that it is a sudden and unstable prosperity, not necessarily a
gradual and stable prosperity, which is hereby shown to be pernicious.

[141] The relationship is sometimes expressed by saying that the more
highly differentiated the organism the fewer the offspring. According to
Plate we ought to say that, the greater the capacity for parental care
the fewer the offspring. This, however, comes to the same thing, since
it is the higher organisms which possess the increased capacity for
parental care. Putting it in the most generalized zoological way,
diminished offspring is th