‘ 
332 DIVERGENT EVOLUTION THROUGH SEGREGATION. 
are numerous half-breeds born of these marriages. But the second 
generation is almost barren; and such children as are born—whether 
it be from two half-bred parents, or from one half-breed parent and a 
member of either pure race, are generally weakly. In the third or 
fourth generation the family dies out. It may be added that the half- 
breeds have a marked tendency to baldness, and that their bodies are 
much less hairy than those of the genuine Ainos. This fact has doubt- 
less helped to cause the divergence of opinion with regard to Aino 
hairiness. For the comparatively smooth half-breeds usually speak 
Aino, dress Aino fashion, and are accounted to be Ainos, so that travel- 
lers are likely to be misled, unless constantly on their guard. There 
seem to be half-breeds in all the villages whither Japanese peddlers and 
fishermen have penetrated. There have therefore probably at some 
time or other, been half-breeds in every section of Japan where the two 
races have come in contact.” 
If these two races were equal in civilization and in natural adapta- 
tion to the environment, or if one race was specially adapted to moun- 
tain life and the other to life by the seashore, it seems probable that 
they might permanently occupy adjoining countries without losing any 
of their distinctive characteristics. Broca, after careful collation of all 
the information that could be gathered from the publications of trav- 
ellers and historians, reaches the conclusion ‘that alliances between the 
Anglo-Saxon race and the Australians and Tasmanians are but little 
prolific; and that the mulattoes sprung from such intercourse are too 
rare to have enabled us to obtain exact particulars as to their viability 
and fecundity.”* I have no means of knowing whether later investi- 
gations in Australia and other parts of the world have thrown fuller 
light on the mutual fertility or sterility of the more divergent human 
races, but I am inclined to think that the interest in the subject has de- 
clined since Darwin has shown that such data can never afford proof 
that the different races of man are not descended from common an- 
cestry. There are however signs that a renewed interest in the sub- 
ject is being awakened through the realization that it has a direct bear- 
ing on the theory of the origin of species. 
IMPREGNATIONAL SEGREGATION A CAUSE OF DIVERGENCE IN BOTH ITS EARLIER AND 
LATER STAGES 
As we have already seen, the negative factorst segregate vigor and 
segregate fecundity would tend to produce extinction if not asso- 
ciated with positive forms of segregation. But in the case of or- 
ganisms whose fertilizing elements are disributed by wind and 
water, the qualities that produce these negative forms of segrega- 
tion are usually accompanied by those that produce pre-potential 
“See “Phenomena of Hybridity in the Genus Homo.” By Paul Broca. English 
translation, published for the Anthropological Society of London by Longman, 
Green, Longman, and Roberts (1864), pp. 45-60. 
tFor a definition of negative segregation see page 309 of this paper. 
