224 THE DESCENT OF MAN. Part I. 
single act of variation, as is general with monstrosities , 14 
and this race is crossed with another not thus charac- 
terised, the characters in question do not commonly 
appear in a blended condition in the young, but are 
transmitted to them either perfectly developed or not at 
all. As with the crossed races of man cases of this kind 
rarely or never occur, this may be used as an argument 
against the view suggested by some ethnologists, namely 
that certain characters, for instance the blackness of the 
negro, first appeared as a sudden variation or sport. 
Had this occurred, it is probable that mulattoes would 
often have been born, either completely black or com- 
pletely white. 
We have now seen that a naturalist might feel him- 
self fully justified in ranking the races of man as distinct 
species ; for he has found that they are distinguished by 
many differences in structure and constitution, some 
heing of importance. These differences have, also, re- 
mained nearly constant for very long periods of time. 
He will have been in some degree influenced by the 
enormous range of man, which is a great anomaly in 
the class of mammals, if mankind be viewed as a single 
species. He will have been struck with the distribution 
of the several so-called races, in accordance with that 
of other undoubtedly distinct species of mammals. 
Finally he might urge that the mutual fertility of all 
the races has not as yet been fully proved ; and even if 
proved would not be an absolute proof of their specific 
identity. 
On the other side of the question, if our supposed 
naturalist were to enquire whether the forms of man 
kept distinct like ordinary species, when mingled tc- 
14 ‘ The Variation of Animals,’ Ac., vol. ii. p. 92. 
