from some previous human
case.

Lastly, what of the left wing of our army of extermination, composed of
those light-horse auxiliaries--the general progress and new developments
of civilization, and the net results upon the individual of the
experiences of his ancestors, which we designate by the term "heredity"?
For many years we were in serious doubt how far we could depend upon the
loyalty of this group of auxiliaries, and many of the faint-hearted
among us were inclined to regard their sympathies as really against us
rather than with us, and prepared to see them desert to the enemy at any
time. It was pointed out, as of great apparent weight, that consumption
was decidedly and emphatically a disease of civilization; that it was
born of the tendency of men to gather themselves into clans and nations
and crowd themselves into villages and those hives of industry called
cities; that the percentage of deaths from tuberculosis in any community
of a nation or any ward of a city was high in direct proportion to the
density of its population; and that the whole tendency of civilization
was to increase this concentration, this congestion of ground space,
this piling of room upon room, of story upon story. How could we
possibly, in reason, expect that the influences which had caused the
disease could help us to cure it?

But the improbable has already happened. Never has there been a more
rapid and extraordinary growth of our great cities as contrasted with
our rural districts, never has there been a greater concentration of
population in restricted areas than during the past thirty-five years.
And yet, the prevalence of tuberculosis in that time, in all civilized
countries of the earth, has shown not only no increase, _but a decrease
of from thirty-five to fifty per cent_. To-day the world power which has
the largest percentage of its inhabitants gathered within the limits of
its great cities, England, has the lowest death-rate in the civilized
world from tuberculosis, although closely pressed within the last few
years by the United States, whose percentage of urban population is
almost equally large, while England's sister island, Ireland, with one
of the highest percentages of rural and the lowest of urban population,
has one of the highest death-rates from tuberculosis, and one which is,
unfortunately, increasing.

The real cure for the evils of civilization would appear to be _more
civilization_, or, better, perhaps, _