Method in the investigation of sensibility after the section of a cutaneous nerve. (Preliminary communication.)

Abstract

The difficulty of obtaining from clinical subjects, untrained in introspection, reliable accounts of the changes in cutaneous sensibility occurring during the regeneration of a cutaneous nerve has been partially obviated by Head 1 and by Trotter and Davies 2 through the use of the experimental method with themselves as subjects. These observers, however, did not take the precaution to make sure of their own ability to give the most accurate descriptions of cutaneous complexes, nor did they work with areas small enough to permit the application of the most exact experimental methods available. For this reason the writer has sought to conduct an experiment with such changes in procedure as should make for a more detailed and thorough description of the sensations involved. The writer acted as subject, and the conditions of the experiment were established by a section of the anterior branch of the internal cutaneous nerve. The following points may be noted:

I. A special attempt was made, during the year preceding the operation, to train the subject in the observation of cutaneous sensation and in the analysis of the sensational complexes mediated by the normal skin. Care was taken to distinguish between the qualities of cutaneous contact, cutaneous pressure, and deep pressure, all of which can be distinguished by practice; between warmth, heat, and burning heat (the last two are complex); and to some extent between the different modes of cutaneous pain. Besides this special training, the subject has had the advantage of general introspective practice, obtained during several years of psychological investigation.

2. The final introspective practice series were so arranged as to supply objective norms for that area of the skin which was afterwards affected.