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. I have said that occultists have developed, or rather re-developed this sense. They do this in order to have a harmonious well-developed seven-fold sense system. It increases their general "awareness." Certain other knowledge of the occultist neutralizes the unpleasant features of the manifestation of this sense, and he finds it often a very valuable adjunct to his senses of seeing and hearing, particularly in the cases in which he is approached by persons having antagonistic or hostile feelings toward him, as in such cases this faculty is particularly active. In connection with the telepathic sense (to be described a little further on) this sense operates to give a person that sense of warning when approached by another person whose feelings are not friendly to him, no matter how friendly the outward appearance of that person may be. These two extra senses co-operate to give a person that instinctive feeling of warning, which all of us know in our own experience.