Page:Transactions of the Royal Society of Tropical Medicine and Hygiene, volume 1.djvu/28

4 the new edition of Allbutt's System of Medicine edited by Rolleston.

Of the 1000 pages in Allbutt's book, the first 200 are exclusively devoted to protozoa, mosquitoes, blood-sucking flies, and ticks. In Davidson's work there is hardly a sentence on these subjects. Practically, this is a new and a big and rapidly growing branch of tropical medicine.

In Davidson's work the first chapter in the section on General Diseases relates to malaria. It is a very complete, carefully-written article, embracing all the most important knowledge and views of the time; yet in that article there is not a single word on the mosquito as a carrier of malaria. In those days, although Laveran's great discovery had already been before the world for twelve years, we had got no further than the conviction that the air was the common medium of infection, and there was still a lingering belief in the hippocratic idea that the drinking of marshy water produced enlargement of the spleen. Now a large part of the tropical section of Allbutt's system is occupied with the part played by the mosquito in the malarial drama. Everyone knows that the mosquito is the sole vector of malaria, and an enormous literature has grown up around a discovery which has changed radically our views, not only as regards the etiology and prophylaxis of malaria, but has given a powerful stimulus to the study of the protozoa in gal, and also the role of insects in the transmission of disease germs.

Taking the chapters in Davidson's book in their order, we come next to Tropical Typhoid Fever. Since this chapter was written, Wright's bold and apparently successful prophylaxis has been introduced, and is being extensively practised. This, although not relating to a specially tropical disease, may in time be shown to be a great advance in