THE fact that a handbook of the diseases of crops has been written would not seem to other than botanists and agriculturists to be anything specially noteworthy. But in the British Empire, where plant economics is certainly better understood and its lessons more eagerly and thoroughly applied than in any other community, it is both true and surprising that no guide to the study of plant diseases and their prevention—at least none worthy of the name—has until now appeared. Nothing more admirable than the papers on vegetable pathology contributed by the Rev. Mr. Berkeley to the pages of the Gardeners' Chronicle, and the many writings of this and other authors scattered throughout our serial scientific literature, can, within their range and for their time, be shown elsewhere. But of recent years remarkable advances have been made, especially in Germany, in the study of the aetiology of plant diseases, and an excellent and comprehensive handbook was prepared a few years ago by Prof. Frank. Without doubt this author has gone as far as the state of science permitted him, but nevertheless a serious attempt to deal with vegetable pathology has yet to be made, and the attempt must be preceded by a great amount of laborious research. The activity shown in the investigation of parasitic diseases leaves little to be desired, but the many other ailments that the plant is subject to are but little regarded. That injuries are done by defective nutrition, by frost, and such like causes, is doubtless well recognised, but beyond this recognition there has not been very much inquiry into the matter. It is as if we were to be content with classifying the diseases of man into those due to the prevalence of east winds and the like. Diseases of Field and Garden Crops. By Worthington G. Smith. (London: Macmillan and Co., 1884.)