Note 17 — Chapter II · THE SMILE AND THE LAUGH.

See an article on “Organic Processes and Consciousness,” by J. R. Angell and H. B. Thompson, in the Psychological Review, vol. vi., p. 55. According to these researches, a hearty laugh, causing sudden and violent changes in the breathing curve, is accompanied by the sharpest and most marked vaso-dilation, as tested by capillary pulse drawing; though in one case the opposite effect of constriction was produced.