ing. The three deer were in about the middle of a level grassy plain fully half a mile from where I lay. I focused my field glasses on the group, and soon became much interested in the alertness of the doe. Not for an instant did she show the slightest relaxation of attention. Generally, under such circumstances, a deer is seen to sniff the air in every direction, but this time no air was stirring, and the main feature of the watching was the constant movement of the long ears. At a slight noise, occasioned by my change of position, a noise not even noticed by myself, I was surprised to see the doe start, turn about, and point her ears in my direction. After a minute's silence, her attention was attracted elsewhere, and this time I made the lowest possible "ahem!" Again both ears and head were directed toward me. And so in turn for an hour, I tried all manners of slight sounds, low whistles, snapping the fingers, tapping my rifle stock, scraping the grass with my foot; all were followed, with the precision of the response of a strychnized frog, with the attent turning of the ears in my direction. The writer at that time was not familiar with any special apparatus for the purpose, and so can give no exact measure of the sounds employed. I can only say, however, that they were so slight that, if a deer could hear them half a mile away over a grassy plain, it might be an easy matter for a cat to hear a moderately loud "mew" a mile away, over the surface of water on a still night.
It is not rare to find great differences in keenness of sense among different men. These differences become emphasized by use, as we find in the sight of the sailor or savage, or in the touch of the blind. There is every reason why we should expect to find such differences much more pronounced between different species of animals. So marked, in fact, do they appear that the temptation has always been to declare them differences in kind. Before doing this, we ought to make a beginning, at least, to learn the possibilities of the senses as they exist in different animals. So far as the writer has gone in this direction, he is content to conclude that they are using the ordinary senses, highly refined, it may be, by generations of development; and the every-day logic which tells man and animal alike that the shortest path between two points is a straight line.