A Review: Inbreeding and Outbreeding 
faster even than Malthus supposed, and 
the result of applying new methods to 
field culture is merely to exploit the 
natural fertility of the soil at a higher 
rate. The supposed increase in the 
amount of food is illusory. In the 
United States, naturally the richest 
country on the globe, the per capita pro- 
duction of all the important meat ani- 
mals and some of the great agricultural 
crops is decreasing. 
“At present the situation is this: 
China, having reached the limit of her 
food supply, and having little or no 
foreign trade, has become stationary in 
population. Large portions of Europe 
and the country of Japan have reached 
the limit of sustenance within them- 
selves, but are increasing at a rate of 
from 10 to 15 per 1,000 annually be- 
cause their commerce is such as to per- 
mit importation to supply the deficit. 
Australia and Asia are increasing at a 
rate which neither their agriculture nor 
their commerce can sustain. The 
Americas and Africa are left as the 
great centers of colonization. Each will 
support a large additional number of 
people, but when they have reached 
their limit—and that limit will come 
within a very few centuries, three at 
most—each country, or at least each 
continent, must support its own popula- 
tion. 
“The world faces two types of racial 
combination: one in which the races 
are so far apart as to make hybridiza- 
tion a real breaking down of the in- 
herent characteristics of each; the other, 
where fewer differences present only 
the possibility of a somewhat greater 
variability as a desirable basis for 
selection. Roughly, the former is the 
* color-line problem; the latter is that of 
the White Melting Pot, faced particu- 
larly by Europe, North America and 
Australia.” 
The authors conclude that the first 
kind of crossing is undesirable, even if 
the two races are both superior, because 
it would tend “to break apart those 
compatible physical and mental qualities 
which have established a smoothly oper- 
127 
ating whole in each race by hundreds of 
generations of natural selection.” It is 
still more objectionable in a cross be- 
tween two races one of which (as the 
Negro) is genetically of inferior capac- 
ity to the other (as the white). 
Their “second thesis is somewhat 
paradoxical. It asserts that the founda- 
tion stocks of races which have im- 
pressed civilization most deeply have 
been produced by intermingling peoples 
who through one cause or another be- 
came genetically somewhat unlike.” This 
thesis is supported by some very weak 
evidence, often little more than sup- 
position. Indeed, many of the anthro- 
pological data presented should be 
backed up by proof: what is the evi- 
dence, for example, which indicates that 
the mulatto shows “extraordinary 
physical vigor?” And the authors are 
likely to get a challenge from some son 
of Erin, for they state that the true 
Irish “are in the main descended from 
two savage tribes, the Iberian and the 
Turanian,. both probably Mongolian ad- 
mixtures,” and that their descendents 
“have hardly a single individual merit- 
ing a rank among the great names of 
history, or a contribution to literature, 
art, or science of first magnitude.” 
A MORE CAREFUL SELECTION OF IM- 
MIGRANTS IS NECESSARY 
“To produce greatness,” the authors 
conclude, “a nation must have some 
wretchedness, for such is the law of 
Mendelian recombination: but the na- 
tion that produces wretchedness is not 
necessarily in the way of producing 
greatness. There must be racial mix- 
ture to induce variability, but these 
racial crosses must not be too wide, else 
the chances are too few and the time 
required is too great for the proper re- 
combinations making for inherent 
capacity to occur. Further, there must 
be periods of more or less inbreeding 
following racial mixtures if there is to 
be any high probability of isolating 
desirable extremes. A third essential in 
the production of racial stamina is that 
