A third separation, however, seemed to be too much for this faithful animal's temper. He became gloomy, desponding, refused his food, and for a long time his life appeared in great danger. His health at last returned, but he no longer suffered the caresses of any but bis keeper, and towards strangers manifested the original savageness of his species.

It must, in fact, be always an interesting matter of inquiry respecting the descent of an animal so faithful to man, and so exclusively his associate and his friend, as the dog. Accordingly, this question has been entertained ever since Natural History took the rank of a science. But the origin of the dog is lost in antiquity. We find him occupying a place in the earliest pagan worship ; his name has been given to one of the first-mentioned stars of the heavens, and his effigy may be seen in some of the most ancient works of art. Pliny was of opinion that there was no domestic animal without its un. subdued counterpart, and dogs are known to exist absolutely wild in various parts of the old and new world. The Dingo of New Holland, a magnificent animal of this kind, has been shown to be susceptible of mutual attachment in a singular degree, though none of the experiments yet made have proved that he is capable, like the domestic dog, of a similar attachment to man. The parentage of the wild dogs has been assigned to the tame species, strayed from the dominion of their masters. This, however, still remains a question, and there is reason to believe that the wild dog is just as much a native of the wilderness as the lion or tiger. If there be these doubts about an animal left for centuries in a state of nature, how can we expect to unravel the difficulties accumulated by ages of domestication ? Who knows for a certainty the true prototype of the goat, the sheep, or ox ?

To the unscientific reader such questions might appear idle, as having been settled from time immemorial; yet they have never been finally disposed of. The difficulty, as with the dog may be connected with modifications of form and color, resulting from the long continued interference of man with the breed and habits of animals subjected to this sway.

Buffon was very eloquent in behalf of the claim of the sheep-dog to be considered as the true ancestor of all other varieties. Mr. Hunter would award this distinction to the wolf; tup-posing also that the jackal is the same animal a step further advanced towards civilization, or perhaps the dog returned to its wild state. As the affinity between wolf, jackal, fox, and dog, cannot fail to attract the notice of the most superficial observer; so he may ask if they do not all really belong to one species, modified by varieties of climate, food, and education? If answered in the negative, he would want to know what constitutes a species, little thinking that this question, apparently so simple, involves one of the nicest problems in natural history. Difference of form will scarcely avail us here, for the pug, greyhound, and spaniel, are wider apart in this respect, than many dogs and the wild animals just named It has often been said that these varieties in the dog have arisen from artificial habits and breeding through a long succession of years. This seems very like mere conjecture. Can the greyhound be trained to the Pointer's scent or the spaniel to the bulldog's ferocity? But admitting the causes assigned to be adequate to the effects, then the forms would be temporary, and those of a permanent kind only would serve our purpose. Of this nature is the shape of the pupil of the eye, which may be noticed somewhat particularly, not merely to make it plain to those who have never thought on the subject, but with the hope of leading them to reflections on this wondrous inlet to half our knowledge, the more especially as the part in question may be examined by any one in his own person by the help of a looking-glass. In the front of the eye then, just behind the transparent surface, there is a sort of curtain called the iris, about the middle of which is a round hole. This is the pupil, and you will observe that it contracts in a strong light, and dilates in a weaker one, the object of which is to regulate the quantity of light admitted into the eye. Now the figure of the pupil is not the same in all animals. In the horse it is oval; in the wolf, jackal, and dog, it is round, like our own, however contracted ; but in the fox, as in the cat, the pupil contracts vertically into an elongated figure, like the section of a lens, and even to a sort of slit, if the light be very strong.

This is a permanent character, not affected, as far as is at present known, by any artificial or natural circumstances to which the dog has been subjected. Naturalists, therefore, have seized upon this character as the ground for a division of animals of the dog kind, the great genus Cam's of Linnasus, into two groups, the diurnal and nocturnal; not to imply that these habits necessarily belong to all the individuals composing either of these divisions, for that would be untrue, but simply that the figure of the pupils corresponds with that frequently distinguishing day-roaming animals from those that prowl only by night.

We will give a few anecdotes to show how different this animal is in his specific character to the wolf, and that he has a natural tendency to acknowledge man as his friend and protector, an instinct never shown by the wolf.

In Ceylon there are a great number of what are called wild dogs, that is, dogs who have no master, and who haunt villages and jungles, picking up what food they are able to find. If you meet one of these neglected animals, and only look at him with an expression of kindness, from that moment he attaches himself to you, owns you for his master, and will remain faithful to you for the remainder of his life.

" Man," says Burns, " is the God of the dog; ho knows no other; and see how he worships him! With what reverence he crouches at his feet, with what reverence he looks up to him, with what delight he fawns upon him, and with what cheerful alacrity he obeys him ! "