force should be carefully and instinctively kept within the limits of the patient's strength, and this, with all these other manœuvres, should stop short of fatigue. To alternately resist flexion and extension is the pons asinorum of manipulators, and, in a considerable experience of teaching massage, I have found but few who could learn to do it at all. Its importance can not be overestimated as a means of cultivating the strength of weakened muscles, while, at the same time, finding out how much they can be used. Many a patient who has recovered from an old injury is still as much incapacitated as ever, from the fact that his latent energies can only be discovered and made available in this manner. Midway between passive and resistive movements, in the course of certain recoveries, stand assistive movements. They are but little understood and seldom used. They may be illustrated as follows: Let it be supposed that, in the absence of adhesions and irreparable injury of the nerve-centers, the deltoid has but half the strength requisite to elevate the arm. So far as any use is concerned this is the same as if there were no power of contraction left in the muscle. But, if only the other half of the impaired vigor be supplemented by the carefully graduated assistance of the operator, the required movement will take place; and, in some cases, if this be regularly persisted in, together with manipulation and percussion, more vigorous contraction will be gained, and, by-and-by, the patient will exert three fourths of the necessary strength, and later the whole movement will be done without aid; and, as strength increases, resistance can be opposed to the movement. Partial loss of motion can often be accurately estimated by holding the limb suspended in a cloth attached to a spring-balance. When the patient makes effort the limb weighs less. By means of a spring-balance resistive motion can also be estimated. Still another kind of movement may be spoken of—namely, vigorous passive motion—with a view to breaking up adhesions in and about joints, a description of which does not come within the scope of this paper. It is the secret of success and of failure of the people who call themselves "bone-setters," the methods of whom have been well studied and explained by Dr. Wharton P. Hood, of London, in his very interesting book "On Bone-Setting, so called."
A description of massage of the head and the benefits that arise from it must be left to another time.
The relative importance of the foregoing procedures has been partly indicated while describing them. According to the needs of individual cases, one or more of these will predominate or be omitted, and it is well that the advice of a physician be sought on this subject, for there would be no use in giving a patient friction the capillary circulation of whose skin was already sufficiently good; and it would be a waste of time and strength to administer passive and resistive movements to patients who were already fatigued from overwork. To rouse the dormant action of cold skin and flabby muscle, percussion will be