126 The Journal 
are apparent. In fact, there may be an 
actual improvement. But the truth is, 
we did not set out to answer that ques- 
tion. It had already received a correct 
answer. What we wndertook to inquire 
was whether inbreeding 1s imjurious 
merely by reason of the consanguinity. 
We answer, “No!” The only injury 
proceeding from inbreeding comes from 
the inheritance received. The constitu- 
tion of the individuals resulting from a 
process of inbreeding depends upon the 
chance allotment of characters pre-ex- 
isting in the stock before inbreeding 
was commenced. If undesirable char- 
acters are shown after inbreeding, it is 
only because they already existed in the 
stock and were able to persist for gen- 
erations under the protection of more 
favorable characters which dominated 
them and kept them from sight. The 
powerful hand of natural selection was 
thus stayed until inbreeding tore aside 
the mask and the unfavorable charac- 
ters were shown up in all their weak- 
ness, to stand or fall on their own 
merits. 
AS A MEANS OF IM- 
PROVEMENT 
INBREEDING 
“Tf evil is brought to light, inbreeding 
is no more to be blamed than the detec- 
tive who unearths a crime. Instead of 
being condemned it should be com- 
mended. After continued inbreeding 
a crossbred stock has been purified and 
rid of abnormalities, monstrosities, and 
serious weaknesses of all kinds. Only 
those characters can remain which 
either are favorable or at least are not 
definitely harmful to the organism. 
Those characters which have survived 
this ‘day of judgment’ can now be esti- 
mated according to their true worth. 
As we shall see later, vigor can be 
restored immediately by crossing, Not 
only is the full vigor of the original 
stock restored, but it may even be in- 
creased, due to the elimination of many 
unfavorable characters. If this in- 
creased vigor can be utilized in the first 
generation, or if it can be fixed so that 
it is not lost in succeeding generations, 
then inbreeding is not only not inju- 
of Heredity 
rious, but is highly beneficial. As an 
actual means of plant and animal im- 
provement, therefore, it should be given 
its rightful valuation.” 
Heterosis or hybrid vigor has already 
been alluded to, What is its explana- 
tion? Evidently, since it is the reverse 
of inbreeding, it merely means a stimu- 
lation due to the presence and comple- 
mentary action of dominant factors. 
After a brief discussion of sterility, 
and of the role of inbreeding and out- 
breeding in evolution and in breed- 
improvement, the authors pass on to 
man—a subject with which they show 
less familiarity, although their general 
conclusions are for the most part 
sounder than their illustrations. 
After describing some of the strains 
of degenerates which have practiced 
inbreeding, and also mentioning the 
Athenians of the Golden Age, whose 
superiority they believe to have been 
largely due to inbreeding, they con- 
clude: 
“Owing to the existence of serious 
recessive traits there is objection to in- 
discriminate, irrational, intensive in- 
breeding in man; yet inbreeding is the 
surest means of establishing families 
which as a whole are of high value to 
the community. On the other hand, 
owing to the complex nature of the 
mental traits of the highest type, the 
brightest examples of inherent mental 
ability have come and will come from 
chance mating in the general popula- 
tion, the common people so called, be- 
cause of the variability there existent.” 
The latter proposition is not supported 
by adequate evidence, and it is doubt- 
ful whether the authors could support 
it if they tried. 
POPULATION AND FOOD SUPPLY FORC- 
ING RACIAL COMBINATIONS 
Turning to  cross-breeding, the 
authors discuss “the intermingling of 
races and national stamina.” They look 
forward to a continual increase in the 
process of racial amalgamation. 
“The truth is,” they declare, “that the 
world is approaching a population limit 
