The pressure outside changes continually, and these things spread and grow like all contagions. Nature at times seems wrathful and destructive, and there are, no doubt, deep-seated conditions and changes in the magnetism of the earth and air, not yet comprehended by modern science.
In stamping out contagious and epidemic disease, simple cleanliness has been like a revelation from the gods, and modern surgery has only stopped short of the miraculous.
Society is but the aggregation of individuals, and on the one principle of Self-Control every individual is related to the negative or the positive side of psychical and physical epidemics.
There is scarcely an avenue along these lines that has not been more or less explored by modern science.
That knowledge is still incomplete; that mistakes have been made; that matters have been contemptuously set aside, belittled, or declared to be not worth investigation, was to have been expected. But the progress has been immense, and the light shines on many obscure and difficult problems, where before was the utter darkness of superstition and fear, dirt, degradation, and death.
These phenomena manifest on the physical plane, disturb the social state, and the relations of individuals to each other. They concern the environment of man in a world of matter, sense, and time.
But the Individual Intelligence, which is Man, lives also in another world, related to, but within, around, and beyond the physical.
Man senses or feels it as anterior to birth and extending beyond death. He calls it the subjective or Spiritual World.
The realm of his consciousness is related to it, as the body is related to the physical plane and the things of sense and time. His consciousness seems aware of both planes or both worlds, though ignorant of the real nature and meaning of both, and capable of interpreting neither correctly.
Man feels his way through the life on the outer plane guided by his experience of weight, measure, distance, resistance, and the like.