Biological Laws and Social Progress, 5D 
fluctuates only slightly from time to time, as conditions are favorable or un- 
favorable for additions. Such a condition of equilibrium may be temporary 
or it may continue indefinitely. In the former case, under favorable con- 
ditions, it may be followed by a new increase, while unfavorable conditions 
may lead to actual decrease and final extermination. 
In the case of man, the increase of population must be limited finally by 
the supply of food and other necessities. In China and India, at the pres- 
ent time, population varies directly with the food supply. <A similar condi- 
tion, which existed in Japan for more than 150 years, was brought to an end 
by contact with Western civilization and the adoption of Western methods 
and inventions. As a result, population in Japan increased 60 per cent. 
from 1871 to 1915, and the increase still continues. A somewhat similar 
change occurred in Europe after the Industrial Revolution. About 300 
years ago the population of Europe had become stationary because of a 
high death-rate due to war, famine and plagues. When the discoveries of 
science made possible the control of devastating diseases and provided for 
a more constant food supply. population increased rapidly. At the present 
time, because of a declining birth-rate, population is again approaching 
equilibrium,—a condition already reached in France. In England, between 
1871 and 1911, the rate of increase declined from 1.38 per cent. per annum 
to 1 per cent. per annum, and the same tendency is evident in the United 
States and elsewhere. According to East, the high cost of living, due to 
decrease of the food supply, is the chief cause of this decline, but it is not 
the only cause. 
Under conditions now existing in international affairs, when military 
strength is one of the chief concerns of nations, the present tendency of the 
birth rate is naturally considered undesirable. If the population of France 
had increased as rapidly as that of Germany after 1871, the Kaiser would 
probably have hesitated to begin the world war in 1914. But the laws 
which control population are not easily changed to satisfy national ambi- 
tions or fears. It is well, therefore, to recognize the fact, that unless 
science comes to the rescue with improved methods of food production, the 
birth-rate of civilized nations must continue to decline until population be- 
comes stationary. 
The deplorable feature of the situation, from a biological standpoint. is 
the fact that the decline of the birth-rate is selective: it is greatest in those 
classes of society, which by reason of heredity and education, should be ex- 
pected to contribute offspring of greatest value. Such conditions have not 
been confined to modern times. In the two centuries from 500 B. C. to 300 
B. C., Greece produced a group of men whose achievements, judged by 
modern standards, indicate native ability of a high order. But the bril- 
liant Athenian race declined, and many smaller groups,—families of states- 
men, artists and scholars of later centuries, have completely disappeared. 
Few families of this class, according to Broman, survive a period of 250 
years. 
In these modern times, society takes the talented child and educates 
him largely at public expense, in order that he may contribute something 
of immediate value to the state, but the conservation of this talent for the 
use of future generations is a matter in which society has taken little 
interest. Man is wasteful of coal and of other resources of the earth, but 
