“The mind,” says Dr. W. F. Evans, “can be made the plastic or formative principle of the body, and that thought can retard, pervert, or stimulate and correct the different functions of the human organism.” The relation of spirit and matter is very intimate, and some very clever thinkers resolve all matter into spirit, in its ultimate analysis. Bishop Berkeley affirms this in his “Principles of Human Knowledge.” In section seven he says “there is not any other substance than spirit.” If we view nature from a materialistic standpoint, we see only one-half of what we think we do, and even that must be very imperfectly judged by our senses. Friedrich Wilhelm Joseph Schelling states the relation of matter and spirit, in very simple and plain words, so that a child can understand what he says: “Nature is spirit visible, and spirit, is invisible nature.” This may be illustrated in physical science from what chemistry teaches of the physical properties of the _diamond_, whose atoms or molecules are so perfectly continuous and closely aggregated that it forms one of the hardest substances known to physicists. These atoms of pure carbon may be made to repel each other, so that the diamond assumes a gaseous state, which is imperceptible to our senses. I am aware that the definition of a gas is not that which metaphysicians would accept as applicable to spirit, and yet it illustrates the idea from a physical standpoint. It is much better to illustrate a question with something with which people are generally familiar. The body and every organ and tissue forming a constituent part of it, is simply the plain ordinary matter in motion, vitalized by what we call life, and this life principle is a mystery, and what is true of the diamond is true of the human body in its entirety. If placed in a crematory, it is reduced to a few ounces of bone ash, and, with the addition of a little acid, this too would soon disappear into invisible gases, so that the doctrine of philosophers, that matter is spirit, is, after all, not so far removed from physical evidence. Physiological science gives abundant proof that the mind has a powerful influence over the body. By mind is meant all that class of mental phenomena called reason, and the emotions and passions. Doctor Evans says “the body is included in the being of the mind,” or, in other words, that matter is included in the being of spirit. The thinking quality of the mind is undoubtedly the mainspring of its action, of which the formation of ideas is the highest kind of mental activity. These originate either within the mind or are brought within its sphere by transformed impressions from without, but through the power of the Will these are more or less modified, and may, indeed, be entirely suspended, so that the mind may become entirely passive and not think of anything. It is the exercise of this Will power which may make the operations of thought conducive to health or disease.