But, although alone among animal instincts-in its strange and useless purpose--for it is as absolutely useless to the species or race as to the dying individual--it is not the only useless instinct we know of: there are many others, both simple and complex; and of such instincts we believe, with good reason, that they once played an important part in the life of the species, and were only rendered useless by changes in the condition of life, or in the organism, or in both. In other words, when the special conditions that gave them value no longer existed, the correlated and perfect instinct was not, in these cases, eradicated, but remained, in abeyance and still capable of being called into activity by a new and false stimulus simulating the old and true. Viewed in this way, the huanaco's instinct might be regarded as something remaining to the animal from a remote past, not altogether unaffected by time perhaps; and like some ceremonial usage among men that has long ceased to have any significance, or like a fragment of ancient history, or a tradition, which in the course of time has received some new and false interpretation. The false interpretation, to continue the metaphor, is, in this case, that the _purpose_ of the animal in going to a certain spot, to which it has probably never previously resorted, is to die there. A false interpretation, because, in the first place, it is incredible that an instinct of no advantage to the species, in its struggle for existence and predominance should arise and become permanent; and, in the second place, it is equally incredible that it could ever have been to the advantage of the species or race to, have a dying place. We must, then, suppose that there is in the sensations preceding death, when death comes slowly, some resemblance to the sensations experienced by the animal at a period when its curious instinct first took form and crystallized; these would be painful sensations that threatened life; and freedom from them, and safety to the animal, would only exist in a certain well-remembered spot. Further, we might assume that it was at first only the memory of a few individuals that caused the animals to seek the place of safety; that a habit was thus formed; that in time this traditional habit became instinctive, so that the animals, old and young, made their way unerringly to the place of refuge whenever the old danger returned. And such an instinct, slowly matured and made perfect to enable this animal to escape extinction during periods of great danger to mammalian life, lasting hundreds or even thousands of years, and destructive of numberless other species less hardy and adaptive than the generalized huanaco, might well continue to exist, to be occasionally called into life by a false stimulus, for many centuries after it had ceased to be of any advantage.