1 It is interesting to note that, in osteopathy, a "subluxation" is defined as "an immobilization of a joint in a position of normal motion, usually at the extremity of a given movement." (See Osteopathic Mechanics, by E. F. Ashmore, D.O.). Thus no movement beyond anatomical limits is held to have taken place when this term is applied.

Amongst the osteopaths there are at least three schools of thought. One claims that the nerves convey vitality to the tissues, and that any pressure upon them so lowers the vitality of the tissues supplied that disease or pain follows as a matter of due course. These people claim that they can cure practically anything by their manipulation; and, amongst other things, I have heard it stated positively that acute appendicitis, pneumonia, and a severe cold in the head will all yield rapidly to manipulation. The argument is that the nerve pressure has so lowered the vitality of the appendix, the lung or the mucous membrane of the nose that infection has been rendered possible, while relief of the pressure so restores vitality that spontaneous recovery takes place. This school is an unquestionable danger to the public. The testimony of countless medical men regarding the disasters, which frequently come under their notice following treatment, is so overwhelming as to be decisive as to the reality of the danger. There can, I think, be little doubt that success in these things comes in spite of, and not because of, treatment. Failure I should not attribute to the treatment, though many do so. This view seems to me to pay too great honour to it: it admits a potentiality for evil in these things. This I doubt, and prefer to regard the manipulation as innocuous - impotent alike for good or evil - and to attribute failure rather to lack of appropriate medical care and attention. Thus, it seems to me, manipulative treatment in these cases is probably inoperative, save in so far as it acts as an impediment to appropriate medical or surgical treatment. The same may be said of many other complaints that these people claim to cure, and this is a heavy accusation. There is worse still, however. Not only do they impede or prevent recovery by substituting a useless treatment for valuable therapeutic measures, but active injury is not infrequently done, particularly in cases of tuberculosis, cancer, scoliosis, in such general diseases as renal or cardiac affections, and also in acute rheumatism, gout and osteo-arthritis, to quote only a few examples.

The second school holds that the nerve pressures cause pain by direct action, and, by reflex, can cause almost any trouble not due to recognised infective processes. This is a far less dangerous doctrine; and, were gross displacement of the joints possible, would be quite tenable. It is, however, almost inconceivable that, short of the most severe injury or disease, sufficient displacement can take place to cause pressure on the main nerve trunks, and so produce definite symptoms.

The third school, probably quite rightly, ignores the possibility of all gross displacement except as the result of grave injury, but claims that a very minute amount of displacement affects the sympathetic system, and this gives rise to such complaints as headache, neuralgia and neuritis, if in the cervical region; to chronic irritating cough in the dorsal, and to a variety of ills in the lower part of the back, including "lumbago," "sciatica," and constipation, to quote only three. They still, however, maintain the theory of definite subluxation, and that cure depends upon "reduction."

In the midst of so much doubt and speculation it may well seem ill-advised to advance any other theory, yet two facts seem to stand out with startling distinctness. First, anatomical study of the bones and ligaments of the spine shows clearly that nothing short of considerable force could possibly cause marked displacement; and that, should the requisite force be exerted, it would act so powerfully that the occurrence of minor injury would be almost inconceivable. Actual experiments have further tended to confirm this view.

The second fact which, to me, seems to have been established beyond cavil or refute by definite evidence placed before me, is that countless patients have received relief from symptoms as the result of wearing a low belt-support, or as the result of manipulation, when all other methods of treatment had failed them. Is there any possible way of rendering these two facts compatible? I think there may be.

Dr. Joel E. Goldthwait, in Boston, was kind enough to show me many specimens, and one in particular arrested my attention. The lower articular facets on the articular processes of the last lumbar vertebra did not correspond on the two sides. One was sharply convex and the other almost flat. Now, if we examine the lower articular facets in the lumbar region, we find that they are sharply convex from side to side, while those on the upper surfaces of the articular processes of the vertebra below, with which they articulate, are equally concave. Moreover, the joint line between them is more or less vertical. This means that, were rotation possible, the centre of movement would be more or less at some point either in, or in line with, the spinous process. Rotation is therefore normally impossible. In the thoracic region the shape of the facets would place the centre of movement almost in the centre of the body of the vertebra, and a limited rotation is there conceivable. As we ascend to the cervical region rotation becomes more and more possible, till finally we meet the pivot joint between atlas and axis.

If we suppose for a moment that the curved surfaces of the articular processes are in perfect conformity, movement in the direction intended by nature is the only movement possible, and (so far as the bones are concerned) must be perfectly free and smooth. If, on the other hand, there is the least variation in contour on the two sides, the movement on one side cannot fail to be eccentric when compared with that on the other. Is it not possible, then, that a minute anatomical defect might, by allowing eccentric movement, cause a locking or "jamming" of the joints on the two sides? This would tend to produce an arthritis, and would at once give rise to reflex spasm, particularly in the deeper muscles of the back. There could not fail then to be reflex irritation of the nerves that supply the joints; and possibly also of the nerves which supply the muscles which are thus kept in spasm; and of the nerve trunks which pass out in the vicinity of these muscles.