In the long catalogue of human qualities which characterize our thoroughly domesticated dogs, we must not fail to take account of their sense of property. In this the creature differs from all other of our domesticated animals. It is a common characteristic of mammals, both in their wild and tame state, that they feel a motive of ownership in the food which they have captured or in the den which they have made their lair; but beyond these narrow personal limits we see no evidence of any sense of ownership in land or effects. We readily observe, however, that our household dogs not only know the chattels of their master and distinguish them from those of other people, but they also learn to recognize the bounds of their house-lot or even of a considerable farm. When a dog, even of a militant quality, enters on territory which he does not feel to belong to him, he is at once a very different creature as compared to his condition when he is on his own land. He treads warily and will accept without dispute an order to take himself off. A perception of this sort indicates an extraordinary amount of sympathy and discernment. It requires us to assume that the creature has a good sense of topography and that he observes closely the various acts, none of them perhaps very indicative, which go to show the limits of his master's claims. Although the mental qualities of our highly domesticated dogs are singularly like those of their masters, the likeness going to the point that the household pet is apt to have acquired something of the general character of the people with whom he dwells, there are many suggestive differences arising from failures of development which are in the highest measure interesting to those who study the species. We note, in the first place, that although for ages in contact with the constructive work which occupies his masters, the dog shows no tendency whatever to essay any undertakings of this nature. He is quite alive to considerations of personal comfort and is particularly fond of a warm bed; yet, except for a few unverified stories, we may say that there is no evidence whatever to show that they ever try to improve their conditions by deliberately providing themselves with warm bedding. In no well-attested case has a dog shown any sense as to the nature of any mechanical contrivance. They will learn which way a door opens, and rarely if ever do they undiscerningly close it when it is slightly ajar and they wish to pass through the opening; but I have never been able to observe or obtain evidence to show that they would without teaching pull down a latch in the way in which a cat readily learns to do. Much as dogs have had to do with guns, they display no kind of interest in the arms except so far as they are tokens of sport to come. They connect the explosion with the capture of game, and will search for it in the direction toward which the barrel was pointed. I