Savage man also has this faculty developed, as all travellers and explorers well know.  They are as keen as a wild animal to sense the nearness of enemies, or, in some cases, the approach of man-eating beasts.  This does not mean that that these savages are more highly developed than is civilized man—­quite the reverse.  This is the explanation:  when man became more civilized, and made himself more secure from his wild-beast enemies, as well as from the sudden attacks of his human enemies, he began to use this sense less and less.  Finally, in the course of many generations, it became almost atrophied from disuse, and ceased reporting to the brain, or other nerve centres.  Or, if you prefer viewing it from another angle, it may be said that the nerve centres, and brain, began to pay less and less attention to the reports of this sense (trusting more to sight and hearing) until the consciousness failed to awaken to the reports.  You know how your consciousness will finally refuse to be awakened by familiar sounds (such as the noise of machinery in the shop, or ordinary noises in the house), although the ears receive the sound-waves.

Well, this is the way in the case of this neglected sense—­for the two reasons just mentioned, the average person is almost unaware of its existence.  Almost unaware I have said—­not totally unaware.  For probably every one of us has had experiences in which we have actually “felt” the presence of some strange person about the premises, or place.  The effect of the report of this sense is particularly noticed in the region of the solar plexus, or the pit of the stomach.  It manifests in a peculiar, unpleasant feeling of “gone-ness” in that region—­it produces a feeling of “something wrong,” which disturbs one in a strange way.  This is generally accompanied by a “bristling up,” or “creepy” feeling along the spine.  The organs registering the presence of a strange or alien creature consist of certain delicate nerves of the surface of the skin, generally connected with the roots of the downy hair of the body—­or resting where the hair roots would naturally be, in the case of a hairless skin.  These seem to report directly to the solar-plexus, which then acts quickly by reflex action on the other parts of the body, causing an instinctive feeling to either fly the scene or else to crouch and hide oneself.  This feeling, as may be seen at once, is an inheritance from our savage ancestors, or perhaps from our lowly-animal ancestral roots.  It is a most unpleasant feeling, and the race escapes much discomfort by reason of its comparative absence.