1. The hand is the tool; the arm is only the shaft. High-quality sensory function for the tool is more than ever the key to good results in reconstructive surgery of the upper extremity.

2. The sensibility of the hand is a far more complex function than is usually believed.

3. Tests with pinprick and cotton-wool applicators are too often quite unsatisfactory and even misleading in the hand. Reconstructive work should be based on the two-point-discrimination test, the picking-up test, and the ninhydrin finger-printing test. Although these tests are very crude and have their limitations, they are for the moment the best available. They must be improved or replaced by better methods.

4. Nerve suture and nerve-grafting will often give useful results; but only rarely do these procedures restore close to normal function. In the light of tests now available these results can hardly be accepted as satisfactory. The technique for nerve suture can no doubt be improved.

5. Normal sensibility can sometimes be brought to important areas of the fingers where sensory function is impaired by a number of different surgical procedures.

6. Despite all progress, our knowledge in this fascinating field is far from perfect. Surgery of the hand, as well as the evaluation of sensation in the hand, is still a challenge to human endeavor and to young men, as it was when Sterling Bunnell almost half a century ago published his first work and opened the door to this type of surgery.