208 Experimental Zoology 
tion the particular wild forms found in his vicinity. More often, 
however, the results may be due to the wild forms having been 
crossed with the domesticated forms so that the characters of 
the former have become impressed on the domesticated animals 
and plants. 
There is satisfactory evidence in the case of plants to show that 
wild “varieties” and elementary species have often been crossed 
with domesticated plants in order to produce hybrids having one 
or more of the characters of the wild forms. Not only have wild 
varieties of the surrounding country been used, but wild varieties 
from all parts of the world, especially in modern times. Thus 
many of our domesticated animals and plants are hybrids, and 
the process of selection has been employed to pick out, amongst 
the great diversity of types produced in this way, those forms 
that have a practical value or that appeal to man’s esthetic or 
commercial taste, or to his fancy for novelties. 
It is probable in many of these cases that the wild “varieties” 
that have yielded valuable results are true elementary species 
having fixed characters that have come from germinal variation, 
and not local races whose peculiarities are due solely to the exter- 
nal conditions to which they have been subjected. 
Selection under Domestication of Mutations, Saltations, Sports, 
and Discontinuous Varieties in General 
It is probable that the sudden occurrence of sports or saltations 
has furnished breeders with much of the material for the produc- 
tion of new forms. It has long been known that new types ap- 
pear in domesticated animals and plants. If these are picked 
out — selected — and progeny raised from them, it is possible 
to establish a new race. In the case of hermaphroditic plants, 
self-fertilization of the new individual will give at once a large 
number of individuals like the parent. In unisexual animals 
and plants the new form must be crossed with the original 
stock from which it sprang. In some cases all of the offspring 
may be like the new form, and from some of them a new, fixed 
type may be raised. In other cases, all the offspring may be 
