The various factors concerned in the fall of electrical resistance of the skin, which occurs as a result of psychic and other stimuli, are reviewed.
It is shown that any procedure calculated to cause vaso‐constriction causes the fall both in man and animals. Evidence is adduced that the psychic response is influenced by the circulation in the part of the skin led off.
The amount of the fall in resistance is discussed in relation to its possible situation. It is shown to be the stratum corneum which becomes altered in resistance.
Evidence is adduced that under circumstances in which the psychogalvanic response is observed, vaso‐constriction also always occurs. The view that the reflex is produced as a result of activity of the sweat glands is discussed and shown not to be in agreement with the facts.
The nervous mechanism and biological significance of the skin constrictor reflex is also discussed.