us to understand the pathology and etiology of malaria. Secondly, they help us in diagnosis. Thirdly, our knowledge of the parasite is invaluable in directing treatment. Lastly, a knowledge of the life-history of the malarial parasite is of extreme value for the prevention of malarial disease, for could we by mechanical or other arrangements prevent the mosquito attacking the human body, we could prevent the malarial parasites from entering the human body; or if we could abolish the mosquito by drainage or other means from a country, then we might be sure that we would abolish the malaria of that country also. Attempts are being made to solve these practical problems. At the present moment such attempts are being actively made in Rome by Professor Celli and elsewhere by others. I have no doubt that in the course of a few years we shall get some very valuable results in this direction and that, thanks to this new-born knowledge about the malarial parasites, better times are rapidly approaching for malarial countries.