My duties as editor of this volume have been in one respect slight, in another more arduous. For, on the one hand, I have thought it best to leave almost unchanged Prof. Mannaberg's very comprehensive and learned treatment of the history, symptoms, and treatment of malaria . The only changes I have made in his article have been to correct the views and arguments based on the miasmatic theory of the origin of malarial infection which the discovery of the part played by certain mosquitos in transmitting infection has rendered untenable. I have inserted a few details recently added to our knowledge, of that still not fully understood exhibition of malarial infection, viz.: malarial hemoglobinuria, or blackwater fever. I would insist here on the necessity of complete analyses of the urine in such cases. To mention only one point: it is important to determine how quinin is excreted, for if, as has been recently stated, quinin is not eliminated in the urine during the actual hemoglobinuric attack, but only subsequently, this would guide a physician in practice as to the all important question which he finds so difficult to answer, Shall I give quinin or not?

Regarding "malarial cachexia" we are in a transition period, for while many of these cases are due to a distinct parasite (Leishmania donovani), yet in many, it appears from the most recent work, it is impossible to find these.

I have further added a short note on the Romanowsky-Ziemann stain, the best of all stains for the malarial parasites, giving a practical and certain method of preparing it-leaving out of account the numerous elaborate modifications which in my experience have no advantage over the simple method given.

On the other hand, my duties have been more arduous in writing an account of the mosquito malaria question in all its manifold bearings. I have endeavored to give a concise but brief account of all the important facts now known to us. The task has been made easier by the fact that since the discovery of the development of the malaria parasites in the mosquito no fundamental change has been made in our original knowledge. In one important respect this has been extended by the discovery of the part played by the native populations of tropical regions in disseminating the disease. The great fact is now fully recognized that the native (children) population is an ever present and extremely dangerous source of infection, and the origin of malaria among Europeans is completely explained.

Finally, the main methods of prophylaxis have been indicated. Already progress has been made in the anti malaria campaign, and i shall not have contributed this portion in vain if i have conveyed to the physician the necessity, having regard to prophylaxis, for a study not only of malaria but also of mosquitos and their habits.

J. W. W. Stephens, M.D. Cantab. D. P. H.

May, 1905.