most valuable to our nation, are attracted from the country to
our towns. If residence in towns seriously interferes with the
maintenance of their stock, we should expect the breed of Englishmen
to steadily deteriorate, so far as that particular influence is
concerned.

I am well aware that the only perfectly trustworthy way of
conducting the inquiry is by statistics derived from numerous
life-histories, but I find it very difficult to procure these data.
I therefore have had recourse to an indirect method, based on a
selection from the returns made at the census of 1871, which appears
calculated to give a fair approximation to the truth. My object is
to find the number of adult male representatives in this generation,
of 1000 adult males in the previous one, of rural and urban
populations respectively. The principle on which I have proceeded is
this:--

I find (A) the number of children of equal numbers of urban and of
rural mothers. The census schedules contain returns of the names and
ages of the members of each "family," by which word we are to
understand those members who are alive and resident in the same
house with their parents. When the mothers are young, the children
are necessarily very young, and nearly always (in at least those
classes who are unable to send their children to boarding schools)
live at home. If, therefore, we limit our inquiries to the census
"families" of young mothers, the results may be accepted as
practically identical with those we should have obtained if we had
direct means of ascertaining the number of their living children.
The limits of age of the mothers which I adopted in my selection were,
24 and 40 years. Had I to begin the work afresh, I should prefer
the period from 20 to 35, but I have reason to feel pretty well
contented with my present data. I correct the results thus far
obtained on the following grounds:--(B) the relative mortality of
the two classes between childhood and maturity; (C) the relative
mortality of the rural and urban mothers during childbearing ages;
(D) their relative celibacy; and (E) the span of a rural and urban
generation. It will be shown that B is important, and C noteworthy,
but that D and E may be disregarded.

In deciding on the districts to be investigated, it was important to
choose well-marked specimens of urban and rural populations. In the
former, a town was wanted where there were various industries, and
where the population was not inc