444 GENETICS IN RELATION TO AGRICULTURE 
During historical times constant improvement has been made in the 
material thus provided by the early herds and flocks, a century sometimes 
sufficing for the establishment of a new breed of very superior excellence. 
Seemingly these have been remarkable achievements, but we must never 
forget when we consider them that they have been associated almost 
invariably, particularly those which have been most striking, with 
changes in the conditions of life of man himself and the purposes for 
which he has employed his animals. The Arab, nomadic inhabitant 
of the desert, needed for his purpose a horse of speed and stamina, a single 
favorite steed sufficing for each individual. Constant association be- 
tween master and mount developed in the Arab that high pride in the 
excellence of his steed, a most commendable characteristic of the desert 
dwellers of Arabia. We find, therefore, that the horses of these peoples 
are superior in intelligence, stamina, and beauty of form to those of almost 
any other land; we find them with pedigrees carefully kept and tracing 
back to the seventeenth century before the Christian era. According 
to reports of Upton, who lived among the Anezah Bedouins, famed even 
among the Arabs for the superior excellence of their horses, no animal 
was recognized as pure bred which did not trace back to the five mares Al 
Khamseh of Sheik Salaman; and the descendants of these five mares 
are divided and sub-divided into an intricate system of families and sub- 
families. But the modern French farmer with a settled mode of life 
needed horses for different purposes, primarily for drawing implements 
of tillage. Accordingly he took horses of the old draft type, large, 
rawboned, and heavy of weight, but not high in quality or energetic 
in disposition and crossed them with Arabians, Barbs, and Danish horses; 
and it was not long before all the neighboring regions of France and Ger- 
many were demanding horses from La Perche. No long period of im- 
provement was necessary for the establishment of the Percheron breed; 
the excellent qualities which it possessed were contained within the old 
breeds which existed at that time; the improvement was merely a re- 
arrangement and blending of existing qualities in a form to meet the par- 
ticular demand of modernrural conditions. Sucha breed would have been 
of doubtful value to the barbaric races which swarmed over Europe 
over a thousand years ago, but for the life that those races lead today, it 
and other breeds possessing similar utilitarian advantages are performing 
a tremendous agricultural service. It would be possible to recount 
similar cases of breed improvement in all kinds of domestic animals. 
Fundamentally practically all these instances agree in this respect that 
when breeds have been established within a relatively short period of 
time, potentialities have been made use of which already existed in the 
foundation stock. Translated into the more precise terms of genetics 
this statement would imply that the hereditary material of modern 
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