is breed are now under the control
of fancy, and the blood is being led far away from its old
characteristics. The bull-terrier and other varieties, which retain
something of the form and of the solemn demeanor which characterized
their ancestors, but which are too small to assail horned cattle, mark
the vanishing stages of this great stock, which will soon be known
only in memory. The history of this peculiar herd-dog shows us how
marvellously pliant the body and mind of this species has become under
the conditions of civilization. The rude process of unconscious
selection, acting without steadfastness of purpose or rationally
developed skill, serves to sway the qualities of the animal this way
or that to meet the ever-changing requirements of use or fancy. A
similar selection in the case of our horned cattle has within a few
centuries converted the cows into mild-mannered and sedentary
milk-making machines, and has deprived the bulls of the greater part
of their ancient savage humor. Owing to this change in the quality of
their associates in captivity the dogs have also been led into great
variations. The same type of interaction may be traced again and again
in the isolated part of the world enclosed within our fences, as well
as in the free realm of the wildernesses. All the individuals in the
great host of life affect each other as do the soldiers of a
well-organized army in the movements of a battle.

The shepherd-dog, the turnspit, and the bull-dog are the three
remarkable variations of the canine blood which were brought about by
a process of training and selection unconsciously directed to the
institution of breeds suited to special economic ends. The other
varieties of dogs have been shaped more distinctly for purposes of
amusement or for the indulgence of mere fancy. The several varieties
of hounds, harriers, beagles, pointers, setters, terriers, etc., have
been designed to meet a dozen or more variations in the conditions of
the chase. The marvellously complete way in which special
peculiarities have been developed in mind and body makes this field of
domestic culture the most fascinating subject of inquiry to the
naturalist. The ordinary fox-hound has had his inheritances determined
so as to fit him for pursuing a small animal which can rarely be kept
in view during its flight, and which can only be followed by the odor
it leaves in its trail, so these creatures run almost altogether under
guidance of thei