They are taught to understand, signals; and when pasturing, at the smallest signal from the keeper, they bring back and collect the wandering animals. They attack all strangers with fury; so that they prove a great security against robbers. They know every inhabitant of the kraal or village, and these they suffer to approach the cattle with the greatest safety.*

With respect to sheep, Buffon, I think, rashly maintains, that the race must have been long ago extinct, if man had not taken them under his protection. But sheep are endowed with a strong associating principle, and when threatened with an attack, they form a line of battle, and boldly face the enemy. In a natural state, the rams constitute one half of the flock. They join together and form the front. When thus prepared for repelling an assault, no lion or tiger can resist their united impetuosity and force.+

Upon the whole, it seems to be established as a principle, that, where there is no room for the exercise of pure Instinct, either by man's interposition or otherwise, it will languish, like all the natural senses, or even the higher faculties of the mind.

*Smellie, ii. 324. + Ibid, ii. 284.

SECT. II.

On the Perfection of the Natural Senses as distinguishable from Instinct.

In closely examining the subject, in order to ascer tain to what principle certain actions of the brutes belong, there seems a propriety at least in our present state of knowledge in distinguishing between instinct and the natural senses. And it must be admitted that there is a perfection of these senses which brutes often retain when in closest familiarity with man. We cannot clearly perceive that the operation of instinct depends on an acute smell or a sharp sight, or on any of the natural senses carried to perfection. For how these should wholly direct the beaver or the bee, is beyond our comprehension. It appears therefore that the perfection of the five outward senses is neither to be accounted an evidence of pure instinct on the one hand, nor of extraordinary sagacity and reason on the other. For it is obvious. that a camel may scent water at the distance of half a league in the desert, or a blood-hound may trace his master among hundreds of people in a fair, from the sense of smelling alone; as the vulture's eye may perceive a carcase from heights in the air beyond the power of human vision to reach; yet pure instinct or that mysterious power which operates blindly and uniformly, as in the bee, may have no part in these perceptions. While on the other hand, the instances

of fidelity in the dog, and intelligence in the elephant, are as little to be considered depending on the perfection of the natural senses.

Boyle gives us a remarkable account of acute smell in a dog. "A person of quality, to whom I am near allied, assured me, that to try whether a young bloodhound was well made, he caused one of his servants, who had not killed or touched any of his deer, to walk to a country town, four miles off, and then to a market town three miles distant from that; which done, this nobleman, a competent while after, put the bloodhound upon the scent of the man, and caused him to be followed by a servant or two; the master himself going after to know the event; which was, that the dog, without ever seeing the man he was to pursue, followed him by the scent to the above mentioned places, notwithstanding the multitude of market people who went along in the same way, and of travellers who had occasion to cross it: and when the blood-bound came to the chief market town, he passed through the streets without taking notice of any of the people there, and left not till he had gone to the house where the man he sought for rested himself, and found him in an upper room.'

"A gentleman of my acquaintance, who has often occasion to employ blood-hounds, assures me, that if a man have but passed over a field, the scent will lie so as to be perceptible to a good dog of that sort for several hours after. An old ingenious hunter informs * Boyle's works, Effluvia.

me, he has observed that the scent of a flying and heated deer will sometimes continue on the ground from one day to the next."*

We might collect a great variety of instances of the exquisite perfection of the senses in the lower animals; and we know that man in his state of nature possesses them in an extraordinary degree; the Indian being able by his sight alone to trace footsteps in the woods, on the leaves upon the ground, which could not be discovered by others. Blind men acquire so keen a sense of touch, that the tip of the finger is almost like an eye in discovering the qualities of near objects; and they can distinguish colours merely by a nice discrimination of that peculiar state of the surface of bodies to which each colour belongs. Boyle mentions that he knew a physician, who, in a fever, had his sense of hearing so nice and tender that he very plainly heard soft whispers, made at a considerable distance, which were not in the least perceived by the healthy by-standers; but when the fever left him, he heard as other men. And a medical friend of mine stated that he knew an instance of a gentleman whose sense of smell was so painfully acute, as to occasion him serious inconvenience. He could even distinguish his friends in a room, and different individuals, by the sense of smell alone.

An interesting illustration of the acuteness of sense is given by Dugald Stewart, concerning James Mitchell, a boy, born both blind and deaf, who hav* Boyle's works, Effluvia.

E

ing no other senses by which to keep up a connection with an external world than those of smell, touch, and taste, chiefly depended for information on the first, employing it on all occasions, like a domestic dog, in distinguishing persons and things. By this sense he identified his friends and relations, and conceived a sudden attachment or dislike to strangers according to the nature of the effluvium that escaped from their skin. He appeared to know his friends by smelling them very slightly, and he at once detected strangers. It was difficult, however, to ascertain at what distance he could distinguish people by this sense; but he appeared to be able to do so at a considerable distance from the object. This was particularly striking when a person entered the room, as he seemed to be aware of this before he could derive information from any sense than that of smell. When a stranger approached him, he eagerly began to touch some part of the body, commonly taking hold of his arm, which he held near his nose, and after two or three strong inspirations through the nostrils, he appeared to form a decided opinion concerning him. If it were favourable, he shewed a disposition to become more intimate, examined more minutely his dress, and expressed by his countenance more or less satisfaction. But if it happened to be unfavourable, he suddenly went off to a distance with expressions of carelessness or disgust.*

Collins relates "that the quickness of the New Hol

* Good's Study of Medicine, vol. iii. p. 257.