Variation and Feredity 275 
He then makes the following significant statement: “All 
the characters above enumerated which are transmitted in 
a perfect state to some of the offspring and not to others — 
such as distinct colors, nakedness of skin, smoothness of 
leaves, absence of horns or tail, additional toes, pelorism, 
dwarfed structure, etc., have all been known to appear sud- 
denly in individual animals or plants. From this fact, and 
from the several slight, aggregated differences which dis- 
tinguish domestic races and species from each other, not 
being liable to this peculiar form of transmission, we may 
conclude that it is in some way connected with the sudden 
appearance of the characters in question.” 
Darwin has, incidentally, raised here a question of the most 
far-reaching import. If it should prove true, as he believes, 
that inheritance of this kind of discontinuous variation is also 
discontinuous, and that we do not get the same result when 
distinct species are intercrossed, or even when well-marked 
domestic races are interbred, then he has, indeed, placed a 
great obstacle in the path of those who have tried to show 
that new species have arisen through discontinuous variation 
of this sort. 
If wild species, when crossed, give almost invariably inter- 
mediate forms, then it may appear that we are going against 
the only evidence that we can hope to obtain if we claim 
that discontinuous variation, of the kind that sports are made 
of, has supplied the material for evolution. If, furthermore, 
when distinct races of domesticated animals are crossed, we 
do not get discontinuous inheritance, it might, perhaps, with 
justness be claimed that this instance is paralleled by what 
takes place when wild species are crossed. And if domesti- 
cated forms have been largely the result of the selection of 
fluctuating variations, as Darwin believes, then a strong case 
is apparently made out in favor of Darwin’s view that con- 
tinuous variation has given the material for the process of 
_ evolution in nature. Whether selection or some other factor 
