FOR many weeks the thoughts of scientific colleagues everywhere, as well as those of a large group of the lay public, have frequently turned to the bedside of Sir Ronald Boss where he was lying grievously ill. All who knew Sir Ronald personally cherished the hope that they might again be privileged to meet him, though in their minds they knew that such an event was unlikely. The parting came on Friday last, when he crossed the dark river into the land of silence. To few men have such brilliant and intellectual attributes been given, and none has had greater influence upon the comfort and welfare of the human race. The versatility of his genius was really remarkable. Not only was he the author of several mathematical works of high order, but his volumes of verse showed him to possess rich talents of poetic conception and expression. His scientific work is appropriately surveyed on p. 465 of this issue by Sir Malcolm Watson, director of tropical hygiene and principal of the Department of Malaria Control at the Ross Institute and Hospital for Tropical Diseases, where Sir Ronald Ross died. We are fortunate in being able to publish this appreciation from one who did so much to apply the results of Sir Ronald's investigations to anti-malarial measures in the Federated Malay States, Singapore, and elsewhere, and has been closely associated with him at the Ross Institute for several years.