The Duke of Argyll remarks that the fashioning of an implement for a special purpose is absolutely peculiar to man; and he considers this forms an immeasurable gulf between him and the brutes. "This is no doubt," says Darwin, "a very important distinction; but there appears to me much truth in Sir J. Lubbock's suggestion,[56] that when primeval man first used flint-stones for any purpose, he would have accidentally splintered them, and would then have used the sharp fragments. From this step it would be a small one to break the flints on purpose, and not a very wide step to fashion them rudely. The later advance, however, may have taken long ages, if we may judge by the immense interval of time which elapsed before the men of the neolithic period took to grinding and polishing their stone tools. In breaking the flints, as Sir J. Lubbock likewise remarks, sparks would have been emitted, and in grinding them heat would have been evolved; thus the two usual methods of 'obtaining fire may have originated.' The nature of fire would have been known in many volcanic regions where lava occasionally flows through forests." It becomes a difficult task to determine how far animals exhibit any traces of such high faculties as _abstraction_, _general conception_, _self-consciousness_, _mental individuality_. There can be no doubt, if the mental faculties of an animal can be improved, that the higher complex faculties such as abstraction and self-consciousness have developed from a combination of the simpler ones; this seems to be well illustrated in the young child, as such faculties are developed by imperceptible degrees. These high faculties are very sparingly possessed by the savage; as Buchner[57] has remarked, how little can the hard-worked wife of a degraded Australian savage, who uses very few abstract words and cannot count above four, exert her self-consciousness or reflect on the nature of her own existence. If there exist a class of people so inferior in their mental faculties as these, it is not difficult for us to understand how the educated animal who possesses memory, attention, association, and even some imagination and reason, can become capable of abstraction, &c., in an inferior degree even to the savage. It certainly cannot be doubted that an animal possesses mental individuality--as when a master returns to a dog which he has not seen for years, and the dog recognizes him at once.