Page:Popular Science Monthly Volume 42.djvu/195

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of them when drawing a covert. If a faint drag is detected suggestive of the presence of a fox, but scarcely sufficient to be sworn to vocally, the tail of the finder is at once set in motion, and the warmer the scent the quicker does it wag. Others seeing the signal instantly join the first, and there is an assemblage of waving tails before ever the least whimper is heard. Should the drag prove a doubtful one, the hounds separate again and the waving ceases; but if it grows stronger when followed up, the wagging becomes more and more emphatic, until one after another the hounds begin to whine and give tongue, and stream off in Indian file along the line of scent. When the pack is at full cry upon a strong scent the tails cease to wave, but are carried aloft in full view.

The whole question of tail-wagging is a very interesting one. All dogs wag their tails when pleased, and the movement is generally understood by their human associates as an intimation that they are happy. But when we attempt to discover the reason why pleasure should be expressed in this way, the explanation appears at first a very difficult one. All physical attributes of living beings are, upon the evolutionary hypothesis, traceable to some actual need, past or present. The old and delightfully conclusive dictum that things are as they are because they were made so at the beginning no longer can be put forward seriously outside the pulpit or the nursery. No doubt, in many cases, as, for instance, the origin of human laughter, the mystery seems unfathomable. But this only results from our defective knowledge of data upon which to build the bridge of deductive argument. The reason is there all the time could we but reach it; and almost daily we are able to account for mysterious and apparently anomalous phenomena which utterly baffled our predecessors.

Probably the manner in which domestic dogs express pleasure is owing to some interlocking of the machinery of cognate ideas. In order to understand this better it may be helpful to consider some analogous instances with regard to habits of our own species.

One of the most philosophical of living physicians, Dr. Lauder Brunton, has clearly and amusingly shown that the instinctive delight and eagerness with which a medical man traces an obscure disease step by step to its primary cause and then enters into combat with it, is referable to the hunter's joy in pursuit, which doubtless characterized our savage ancestors when they patiently tracked their prey to its lair and slew it for glory or for sustenance.[1]

Mr. Grant Allen, I believe, first suggested that our apprecia-

  1. The Method of Zadig in Medicine, p. 5. Macmillan & Co. 1892.