An operation was conducted to cut the radial nerve in Head's arm and then to observe the effects of this on movement and sensation in the hand. Observations were taken over a long time period from the date of the operation on 25 April 1903, and extending beyond the period covered in this day book. Descriptions of the physical apperance of Head's hand are made, and photographs of the hand included. The operation was carried out by Rivers, with Head making his own observations. See also the typed experiment log (in 5 volumes with index) which is listed in this collection as WHRivers/2/4.