CHAPTER IV 
HYBRIDISM 
The alleged sterility of hybrids a'stumbling-block to evolutionists— 
Huxley’s views— Wallace on the sterility of hybrids—Darwin 
on the same—Wallace’s theory that the infertility of hybrids 
has been caused by Natural Selection so as to prevent the 
evils of intercrossing—Crosses between distinct species not 
necessarily infertile—Fertile crosses between species of plants 
—Sterile plant hybrids—Fertile mammalian hybrids—Fertile 
bird hybrids—Fertile hybrids among amphibia—Limits of 
hybridisation—Multiple hybrids—Characters of hybrids— 
Hybridism does not appear to have exercised much effect on 
the origin of new species. 
HE alleged sterility of the hybrids pro- 
duced by crossing different species 
has long proved a great stumbling- 
block to evolutionists. Huxley, in 
particular, felt the force of this objection to the 
Darwinian theory. If the hybrids between 
natural species are sterile, while those of all 
the varieties which the breeder has produced 
are perfectly fertile, it is obviously quite use- 
less for evolutionists to point with pride to the 
results obtained by the breeder, and to declare 
that his products differ from one another to a 
greater extent than do many well-recognised 
species. 
Tit 
