Copy memoranda regrading the cause of Sleeping Sickness, signed by J Rose Bradford, David Bruce, E Ray Lankester, M Foster, J Lister, Ronald Ross, J Burdon-Sanderson, C S Sherrington, and Dr F W Mott, [Fellows of the Royal Society] The signatories state that in their opinion there is conclusive evidence showing that Sleeping Sickness is caused by the presence in the blood cerebro-spinal fluid, of a parasite allied to that which occurs in the Tsetse Fly disease of animals, and that the parasite is transmitted from man to man by a species of fly. Briefly states their reasons for arriving at these conclusions. Includes an alteration to the memorandum given by Mott. [April 1905]