Franz, Sensations folloiumg Nerve Division. 



119 



five determinations of the just perceptible determined by one of 

 the Bloeli instruments. 



TABLE I. 

 Touch Thresholds on Hand. Block Instrument. 



*Approximate, since instrument reads only to 60. 



The point A on the left hand was within the area in which 

 pressure (pencil) was not felt. B was within the area in which 

 pressures w^ere felt, but no sensations accompanied stimulation of 

 cotton wool or a caiuers-hair brush. C, J), E, and F, were areas 

 in which the epicritic sensibility was found intact. It will be noticed 

 from the table that the amount of stimulus to produce a sensation 

 at point C was twice the amount of that necessary on the other areas, 

 D, E, and F, and that it was greatly in excess of that required 

 on the normal hand. The points D, E, and F, supposedly normal, 

 showed an increase in the threshold value^ — approximately double 

 the normal. On the fingers similar results were found. On the 

 parts in which pressure of the pencil was immediately perceived, 

 but no sensibility to cotton wool, the limit of stimulation with the 

 Bloch instrument was not felt, and in the areas in which epicritic 

 sensibility was retained there was an abnormally great threshold 

 value. Only in those parts where cotton wool could be felt was it 

 possible to make any determination with the Bloch instrument, 

 and when the results in these experiments were compared with the 

 results of the right hand, the difference between the apparently 

 normal area of this left hand with the known normal area of the right, 

 are as strikingly marked as those in the table just given, and those 

 in the table mentioned below. On apparently normal points of the 

 thumb of the left hand, sixteen exi^eriments with instrument A gave 



