IX) has Professor Browning been able to state categorically that they possess a curative action.In conclusion I would emphasise what must already be apparent from what I have stated, that success in chemotherapy cannot be achieved without the co-operation of workers in several departments-chemid, biological, etc. This study has been made possible by co-operation with Prof. Browning and his colleagues at the Department of Bacteriology at Glasgow University and with the veterinary Research O f f i c e r s of our African colonies. It is in such amperation greatly extended that the future of chemotherapy lies; with the resources of biochemists and physical chemists added we may hope perhaps to see into the underyling processes of which in spite of the great advances of recent years I feel we understand so little.Bromley, Kent