402 RACES. —HYBRIDS.—CROSS-BREEDS. 
others, which are called permanent varieties or races, because 
their peculiarities can be transmitted by seed. Familiar ex- 
amples of such races are afforded by our Cereal grains, as Wheat, 
Oats, and Barley ; and also by our culinary vegetables, as Peas, 
Lettuces, Radishes, Cabbages, Cauliflowers, and Broccoli. How 
such races of plants have originated, it is impossible fo say with 
any certainty. In the first case they probably arose in an ac- 
cidental manner, for it is found that plants under cultivation 
are liable to produce certain variations or abnormal deviations 
from their specific type, or to sport, as itis termed. By further 
cultivation under the care of the gardener, such variations are 
after a time rendered permanent, and can be propagated by seed, 
These so-called permanent varieties, however, if left to them- 
selves, or if sown in poor soil, will soon lose their peculiarities, 
and either perish, or return to their original specific type ; it will 
be seen, therefore, that races present well-marked characters 
by which they are distinguished from true species. Hence, 
although our cereal grains and culinary vegetables have become 
permanent varieties by ages of cultivation and by the skill of 
the cultivator, they can only be made to continue in that state 
by a resort to the same means, for if left to themselves they 
would, as just observed, either perish or revert to their origi- 
nal specific type; and hence we see also, how important is the 
assistance of the agriculturist and gardener in perpetuating and 
improving such variations. 
Another cause which leads to constant variations from the 
specific type is hybridisation. The varieties thus formed, which 
are called hybrids and cross-breeds, are, however, rarely trans- 
mitted by seed—although, in some instances, such is the case 
for a few generations—but they gradually revert to one or the 
other parent stock. (See Hybridisation.) 
We have now seen that species, under certain circumstances, 
are liable to variations, but that all such varieties have a ten- 
dency to revert to their original specific type. Hence, in a 
practical point of view, species must be considered as permanent 
productions of Nature, which are capable of varying within 
certain limits, but in no cases capable of being altered so as to 
assume the characters of another species. There is not the 
slightest foundation for the theory, which has been advocated 
by some naturalists, of a transmutation of species, All such 
statements, therefore, that have been made, of the conversion 
of Oats into Rye, or of any species whatever into another, are 
entirely without foundation, and have arisen from imperfect 
observation. * 
* The above views as to the origin and nature of species and varieties 
must be understood, as we have stated above, in a practical point of view, 
although until the last few years they were, in every sense, almost uni- 
versally entertained by naturalists ; but they are opposed to those now far 
more generally adopted, and which were first developed in Darwin’s great 
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