4. passive and active moments.
Stroking consists in gentle rubbing directed from the periphery upward, commencing the process above the inflamed part and continuing it over the diseased area; the pressure, at first light but finally firmer, will force the exudates into the tissues above, which have been emptied by the preparatory rubbing.
Kneading means rubbing the part circularly with the pulps of the fingers and the thumb or the palm of the hand, and is best combined with pinching up of the skin or muscles singly or together, and gently rolling them between the fingers and palms.
Percussion is effected by tapping the surface over the diseased part with the tips of all the fingers held on a level, or with the ulnar side of the hands, or, after covering the part with a towel, three parallel pieces of stiff rubber tubing, fixed in a handle (a muscle beater), may be employed, gently striking the part transversely to its long axis.
Passive movements should be made at the close of each sitting if a joint is concerned.
Massage is sometimes advisable twice daily, but often once a day or every other day is better; each sitting may last from fifteen minutes to one hour.
EXAMINATION BY RADIOGRAPHY
X-Ray Examination. This method of examination depends on the property of penetration of matter possessed by a radiation from an electrically excited Crookes’ tube. This radiation has been proved to lie outside the spectrum, and has been named X-ray.
It may, for purposes other than those required by the expert, be looked upon as a source of light which has the property of penetrating the tissues to a greater or less extent according to their density, and the shadows cast by it can be recorded on a photographic plate, or may be viewed with the naked eye by means of a screen composed of a thin layer of barium platinocyanide, a substance which becomes highly fluorescent in the presence of this radiation.