The Art of Massage
J. H. Kellogg, M.D.
    Massage, in its varied applications, has either direct or indirect relation to every structure and function of the body; but in its ordinary applications, this therapeutic measure directly and immediately affects especially the following: -
    1. The skin, with its connective tissue network, its sebaceous and sweat glands, hair follicles, and the infinite number of minute blood vessels and sensitive terminal nerve filaments -trophic, vasomotor, and sensory.
    2. The connective tissue lying just beneath the skin, with its rich supply of veins and lymph vessels and spaces.
    3. The muscles which chiefly constitute the fleshy portions of the body, and which receive special attention in the various manipulative procedures of massage, both as individual muscles and as functional groups.
    The muscles constitute about one half the weight of the body.  They receive about one fourth of the blood. When their vessels are dilated under the influence of exercise or massage, they may contain one half of the blood. The body heat is chiefly generated in the muscles by the oxidation, or burning up, of the glycogen deposited in them from the blood. When the muscles are active, one fourth of the energy set free is expended in work, three fourths in heat. Voluntary muscular exercise expends the energy of both the nerve centers and the muscles.  Massage stimulates vital activity in the muscles without taxing the nerve centers.  The muscles are constantly active under the influence of the nervous system, even when in a state of apparent rest.  This insensible activity is known as muscle tone.  It is very noticeable in the abdominal muscles, the tone of which enables the muscles to act in opposition to the diaphragm, aiding in expiration.  Massage increases muscular tone by improving their nutrition.
    4. The large blood vessels, both veins and arteries, but principally the veins, the circulation of which may be readily accelerated or impeded according as the manipulations are applied in the direction in which the, blood runs in the veins, or in the opposite direction. The large lymph channels which usually accompany the larger veins are also brought directly under the influence of massage through appropriate manipulations. The heart itself may be reached by certain special-procedures,
and is greatly influenced by nearly all forms of manipulation.
    5. The large nerve trunks, which, with the terminal nerve filaments, are influenced by all forms of manipulation, but especially so by certain procedures which are particularly efficacious in producing stimulating or sedative effects.
    6. All the large viscera of the abdomen, - stomach, colon, small intestines, pancreas, spleen, liver, kidneys, - which may be brought more or less directly under the influence of massage by a skilled operator; while less directly, but still effectively, the lungs and heart may also be influenced by certain procedures.
    7. The bones, joints, and ligaments must also be mentioned as structures which are directly affected by massage.  The student of massage should make a careful study of the muscles, bones, and joints, and, in fact, so far as possible, of the entire anatomy.  To facilitate this study, a number of colored plates have been prepared, which are exact reproductions of the famous copper-plate engravings prepared under the direction of the eminent German anatomist, Bock.