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The area insensitive to cotton wool extended slightly further towards the ulnar aspect of the back of the hand than that of the cutaneous analgesia. Between the two lay a narrow zone, where a painful cutaneous stimulus produced a more unpleasant sensation than over the normal skin.

The most striking fact, however, was the maintenance of deep sensibility over the whole of the affected parts on the back of the hand. Pressure with the finger, with a pencil, or any blunt object was immediately appreciated. All those stimuli commonly used by the clinician to test the presence of " touch " were appreciated and well localized. Mr. Dean, who was not familiar with our previous observations, said he should have thought that sensation of touch was intact, had he not known the nerves had been divided.

Fig. 1: To show the extent of the loss of sensation produced by the operation. The ancesthesia to cotton wool and to von Frey's hairs is bounded by the black line. The analgesia to prick and other cutaneous painful stimuli lay within the red crosses. The darkness of the affected area is due to its deep red colour compared with the rest of the hand.

On May 4, nine days after the operation, the hand was exposed to a long series of experiments. The most striking features of this examination were :—

(a) That very moderate pressure on the abnormal area of the skin was appreciated and could be well localized, whilst touches with cotton