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birth rate is in nowise confined to the 
United States. On the contrary the 
movement in most European countries 
has been in the same direction. In 
twenty-four European countries, all, 
except Ireland, Portugal and Bulgaria, 
’ for which the records are at hand, the 
birth rate 1901-10 was lower than in 
the preceding decade and in nearly all 
of them it was lower than in any earlier 
decade. 
In considering the causes of this great 
change, let me refer first to the position 
of Herbert Spencer. He has argued 
that the various organs of the body 
compete with each other for nourishment 
and growth, that the surplus not re- 
quired by the individual is all that can 
be devoted to the continuance of the 
race, that no other system makes de- 
mands upon the body as heavy as those 
of the nervous system, that civilization 
and education are steadily increasing 
this drain and decreasing the surplus. 
He finds, therefore, a natural and 
inevitable connection of a physiological 
kind between an advancing civilization 
and a decreasing birth rate. Some 
students of American statistics have 
sought to find support for this position 
in our fragmentary and elusive material. 
I cannot go farther with the question 
this morning than to express my 
judgment that these efforts have not 
been successful and that there is no 
conclusive evidence, statistical or other- 
wise, in support of Spencer’s contention. 
While admitting the heavy and increas- 
ing demands upon the nervous system 
made by modern conditions, I would 
point out that the decreased death rate 
and the decrease of sickness by which 
it is probably attended mean an 
increase of human vitality and so of the 
surplus to be drawn upon. Whether 
the increased expenditure on the nervous 
system equals or exceeds this increased 
surplus no one has even tried to prove. 
Until that is done I believe the Spencer- 
ian theory must be deemed only a 
theory. 
THE ‘‘RACIAL POISONS”’ 
Nor can we admit, as others have 
argued, that the decreased birth rate in 
civilized countries is due either to the 
The Journal of Heredity 
growing abuse of alcohol or to the spread 
of venereal disease. Such arguments 
have come mainly from special students 
of these social evils and such students 
often lose the sense of proportion and 
find a relief from every social ill in the 
one reform on which their eyes are 
riveted. 
Walker explained the decrease in the 
American birth rate by the menace to 
the American standard of life from the 
influx of swarms of immigrants accus- 
tomed to cheap food and clothing and 
bad housing and to the effect otf this 
menace upon the birth rate primarily 
of the native stock and ultimately of 
the entire population. This explana- 
tion is improbable, because the decrease 
as we have seen began as early as 1810, 
when immigration was an un.mportant 
influence, and has been matched in 
Australia, where it must be due to other 
causes than that assigned by Walker, 
since Australia has had no great influx 
of immigrants. 
Turning from these inadequate expla- 
nations, the true reason for the fall in 
the birth rate is that in modern times, 
mainly within the last half century, 
births and the birth rate have come 
under the control of human will and 
choice in a sense and to a degree never 
before true. Our leading American 
authority, Dr. John Shaw Billings, put 
it as follows: ‘‘The most important 
factor in the change is the deliberate 
and voluntary avoidance or prevention 
of child-bearing on the part of a steadily 
increasing number of married people 
who prefer to have but few children.” 
Before this change began the birth of a 
child was, to be sure, the result of normal 
physiological processes, but in the vast 
majority of cases the birth itself did not 
indicate a deliberate preference for that 
result on the part of both or either of 
the parents. There is not a single one 
among the experts who denies that this 
is the great underlying cause of the 
modern decline in the birth rate of all 
civilized countries. 
FEWER BIRTHS NECESSARY 
In considering this change may I 
first suggest that some such change 
was an almost necessary consequence 
