THK PRINCIPLES OF BREEDING. 
79 
This is a very important view of the science of breeding; for, 
if the principle here stated is true—if it is rigorously just—it 
must be admitted that every breed, brought to a certain state of 
excellence by this uninterrupted succession of improvement, may 
sustain itself in this state of excellence without having recourse 
to the pure breed from which it derived its first principle of im¬ 
provement. All that is necessary is, to employ, for the purpose 
of reproduction, animals of both sexes uniting in the highest 
degree the essential moral and physical qualities of the im¬ 
proved race. There are, however, great difficulties attending the 
conservation of this race; and without incessant care deteriora¬ 
tion from the point attained will soon be evident. 
In despite of the worth of the breed which may have been 
established—although it may approach as nearly as possible to 
the pure race, both as to form and endurance—still it carries 
in its blood a maternal indestructible germ of debasement; 
always ready to develope itself, by little and little, under cer¬ 
tain local influences—always under the power of divers agents 
impairing or modifying the general economy, until, at length, a 
certain alteration of form, an impairment of the moral qualities, 
an efl'acement of the paternal type, takes place, and a reproduc¬ 
tion of the stock of the mother, with all its characters of inferi¬ 
ority. He therefore will act wisely who, from time to time, re¬ 
generates his own improved stock, by crossing it with pure blood 
that has no heterogeneous ignoble stain. 
If we couple together a half-bred horse with a mare of the same 
standard, the character of the progeny would, according to the 
calculation just now made, readily appear iz 0.50. 
The progeny would be of precisely the same grade as the parents. 
Experience, however, tells us that this is not the case; the pro¬ 
duce of the two half-breds undergoes a certain degradation, and 
its value would be over-rated at 0.50, or This may appear to 
be an anomaly; it is only apparently so, and implies no contra¬ 
diction to the principle laid down : on the contrary, this dege¬ 
neration strengthens the rule, and clearly shews that the pure 
blood is the essential ameliorator. It proves that part of its 
influence is annulled—that [)art of its regenerative power is lost 
by the sole fact of its mingling with blood less pure, less rich, 
and by means of which its agency is modified, its power 
diminished. It has to combat both the local influences, which 
are more or less opposed to the success of the cross, and the ten¬ 
dency to the reproduction of the maternal type arising from its 
being indigenous to the country. 
If we apply the same reasoning to superior crosses—to gene¬ 
rations the most distant from the original inferior native stock— 
