The Sense of Smell
In the dog we trace the triumph of
olfactory power
. How indistinct must be that scent which is communicated to, and lingers on, the ground by the momentary contact of the foot of the hare, the fox, or the deer; yet the hound, of various breeds, recognises it for hours, and some sportsmen have said for more than a day. He also can not only distinguish the scent of one species of animal from another, but that of different animals of the same species. The fox-hound, well broken-in, will rarely challenge at the scent of the hare, nor will he be imposed upon when the crafty animal that he pursues has taken refuge in the earth, and thrusts out a new victim before the pack.
The sense of smelling is, to a certain degree, acute in all dogs. It is a provision wisely and kindly made, in order to guide them to their proper food, or to fit them for our service. It may possibly be the medium through which much evil is communicated. Certain particles of a deleterious nature may be, and doubtless are, arrested by the mucous membrane of the nose, and there absorbed, and the constitution, to a considerable degree, becomes affected. Hence appears the necessity for attention to ventilation, and especially to prevent the membrane of the nose from being habitually stimulated and debilitated by the effluvia generated in a close and hot kennel.
M.
instituted some curious experiments on the sense of smelling, and he was led to believe that it depended more on the fifth pair of nerves than on the olfactory nerve. He divided the fifth pair, and from that moment no odour, no puncture, produced the slightest apparent impression on the membrane of the nose. In another dog he destroyed the two olfactory nerves, and placed some strong odours beneath the nostrils of the animal. The dog conducted himself as he would have done in his ordinary state. Hence he concluded it probable that the olfactory nerve was not that of smelling.