Vibratory sensitivity as affected by local anesthesia.

Vibratory sensitivity as a function of skin temperature.

“…Here was not only the possibility of determining some of the facts concerning the chemical nature of skin sensitivity, but there was also afforded the possibility of ascertaining the effect of temperature changes on pressure sensitivity and thus determining whether the relation between the two, vibratory and pressure sensitivities, was upheld. This conclusion concerning the identical mediation of the two was drawn in a previous paper by the writer (16), and has, indeed, been urged since the pioneer work of von Frey (5).…”

“…However, if there were this stretching effect with warming the skin one would expect that the vibratory disturbances in the skin would travel much farther, since it was found by the present writer (16) that transmission distances were greatly enhanced in skin stretched with adhesive tape. Yet it will be remembered that such was not the case when the skin was warmed.…”

“…The apparatus used in this study was exactly the same as that previously described by the writer (16). In brief, it consisted of a small sewing needle 0.28 mm in diameter with a fairly sharp point, attached to the armature of an electromagnetic speaker unit.…”

“…The most striking phenomenon of this experiment was that the sensation of vibration was localized not at the needle but in the warmed area. This could be explained on the foregoing hypothesis as follows: The vibratory disturbances travel through the skin for some distance away from the stimulus needle; this has been shown to be the case and the writer, in an earlier paper (16), has described a method of ascertaining it. Although these vibrations are at a level below that necessary normally to stimulate the receptor for vibration, with warming the skin the threshold for this sensation is lowered.…”

The glomus body as a receptor of cutaneous pressure and vibration.

“…An examination of the experimental findings on general vibratory sensibility leads the writer to believe that there may exist different kinds of mechanisms for mediating vibratory perceptions. The recent investigations of Geldard (11), Gilmer (IS), Pieron (24), and Weitz (30) have concurred with the early views of Von Frey (9) and others that cutaneous vibratory sensibility is but another temporal expression of pressure. The work of Echlin and Fessard (8) on the response of "stretch receptors" in frogs, cats, and rabbits, however, would seem to leave open the possibility of kinaesthetic mediation of vibration in man.…”