To some extent we have anticipated the consideration of the influence of emotion on spasmodic action of the muscles, in describing the effects produced by powerful emotional states, as terror, which often causes excessive or spasmodic contraction, sometimes amounting to tetanic rigidity. The sobbing of grief, the laughter of joy, afford daily examples of spasmodic muscular contraction from emotional stimulus. The spasm which chokes the voice and converts the fibres of the platysma myoides into rigid cords in terror, the convulsion and tremors of the facial muscles in despair, the clenched hands, the convulsive opening of the mouth and spasm of the diaphragm and muscles of the chest in fear, the spasm of the jaws in rage, the spasmodic rigidity of the muscles in a maniacal paroxysm, are they not written in the graphic pages of Bell ? With the exception of mania, these spasmodic contractions are consistent with health. We shall include under the present section all convulsive attacks, whether epileptic or not, whether infantile, puerperal, or hysterical, trembling palsy, chorea, spasms of the larynx and pharynx, nervous hydrophobia, and tetanus. Physiologically, when of emotional origin, they may all be referred to disturbance, more or less serious, of the functions of the sensori-motor apparatus, including the medulla oblongata.
Protective autoimmunity functions by intracranial immunosurveillance to support the mind: The missing link between health and disease