1. Head, Henry: Studies in Neurology, pp. 59, 259. London 1920. — Their findings about the sensibility to pain in “protopathic” areas show that the pain-threshold may be raised while at the same time the supraliminal pain is markedly increased. This amounts to saying that the limen is no measure of sensibility in general but only of sensibility to liminal stimuli — a finding which has its parallels in other fields of sensation.
2. A similar method has for example been used byC. Stumpf in determining the loudness of sounds [cf. Sitzgsber. preuß. Akad. Wiss.17 (1918)].
3. It goes without saying that the designation of a pain as “passive” is arbitrary in so far as it depends upon what pain was chosen for observation.
4. If I had been more interested in adaptation of pain, it would have been wiser to use pains with less pronounced pressure-components. — On adaptation s. e. g.Burns andDallenbach: Amer. J. Psychol.45 (1933).
5. A similar mutual independence of pain and its neutral concomitant (especially warmth) has recently been found in experiments on “habituation”, cf.K. Wilde: Zur Phänomenologie des Wärmeschmerzes. Psychol. Forsch.20 (1935).