136 INDUSTRIAL REVOLUTION AND WAGES

American Association for Advancement of Science,
December 29, 1917. He stated:

It is obvious that the basis of every family is two
individuals. The question then resolves itself as
follows: How many children must be born to every
family in order that two individuals may be raised
to maturity? The number of children born must be
more than two for a number of reasons. The first
is the fact of mortality. The death rate is exceptionally
 high in the period of childhood, amounting
in the first year of life to about 10 per cent. of the
babies born. If we begin with 100,000 at birth and
trace them through from year to year, we find that
about 75,000 are alive at the average age of marriage.
 This is according to the mortality rate that
prevails over a large portion of the United States.
The rest have died. This fact alone would make it
necessary that every marriage result in an average
of two and one-half children in order that two persons
 may attain the average age of marriage and
replace their parents in the population. But this
assumes, first, that all persons marry, and, second,
that every marriage is productive. As a matter of
fact, all persons do not marry. In our own country
from 12 to 15 per cent. do not marry until after the
reproductive period, if at all. A considerable proportion
 of marriages, over 7 per cent. are sterile,
When we make the necessary corrections in our figures,
 the average number of children per family
which must be born is increased to close to four in
order that the stock may maintain itself without
increase or decrease.

The United States Bureau of Labor Statistics, the
Chicago Council of Social Agencies, and other responsible
 authorities also gave official approval to this
statement of Doctor Dublin.