Man was so created, so provided with means for repair, growth, etc., that the body tends to maintain its own functional balance--perfect harmony among all its parts--unless interfered with by some outside agency. There are certain natural laws such as the law of gravitation and the law of momentum and inertia which operate without regard for man or man’s welfare. If man, wittingly or unwittingly, allows himself to come into violent conflict with one of these laws by falling to the ground or in meeting sudden and unexpected opposing force or mass while in motion, that which may be termed a concussion is produced by the meeting of the outside force and the internal bodily resistance. Many such concussions may occur without serious damage. Some produce wounds or injuries which it is possible for the body to heal without causing serious disturbance of function. Other concussions are so violent as to produce displacement of structure which tends to remain permanently. Under Spino-Organic Connection will be found an explanation of the manner in which force applied to various parts of the body tends to affect the spine. Now the displacement of a bone cannot be corrected by the body without outside aid. No method is provided for such correction. Produced by outside force affecting the body, it can only be reduced by outside force. It is this failure of Nature to make man adaptable to _every untoward circumstance_ which renders him susceptible to disease. Subluxation As has been previously stated by no means all concussions of forces produce subluxation. (All subluxations, however, are produced by concussion of forces.) It may be added that not all subluxations impinge nerves and that when they do not so encroach upon nerve tissue they produce no noticeable effect after the first temporary soreness has disappeared. Every subluxation, however, evidences a _tendency_ to disease. Once moved from its normal position and the poise and symmetry of the body disturbed, there are influences which tend more readily to affect the same vertebra. The subluxated vertebra is more easily disturbed by jars, strains, etc., than the normal one because such jars are less regularly distributed to all its parts. A reflex muscular tension due to other and more pronounced subluxations and their disease effects may in turn increase the slight deviations throughout the spine, rendering them in their turn capable of producing disease. When the spine or any part of it has lost its perfect regularity disease is made _possible_, if not a fact at once. The average number of subluxations in each individual is about nine and one-third. Of this number probably not more than one-third (though no accurate figures are available) are actually productive of conditions nameable as disease at any given time. Discrimination between those which do, and those which do not, produce discoverable symptoms in a given case is a matter which requires a nice technical skill and perfect judgment.