i88 SCIENCE PROGRESS 



resulted in the occurrence of epidemic diseases of various kinds which always 

 tend to accompany the cultivation of individual plants on a large scale. Many 

 of the diseases are of fungal nature, and these are often those most difficult to 

 cope with. Every crop is liable to attack sooner or later, however resistent it 

 may appear to be on its first introduction. When tea was introduced into Ceylon 

 as one of the principal crops, about a quarter of a century ago, it was often said 

 that the main thing to be careful about was to get the right variety, as once in, it 

 was difficult to get out. No disease of any consequence appeared to attack 

 the bushes, and after the awful experience of coffee it seemed as if at last a 

 plant had been secured which was easily going to hold its own against all parasitic 

 invasion. But tea is not immune, any more than is any other crop, and as the 

 years go on the number of plant diseases referable to fungi continually increases 

 with the growth of intensive culture. 



A book on diseases of hot-country plants, their nature, prevention, and 

 curative treatment, will appeal with force to those whose business lies in the 

 tropics, where cultivation is carried on under climatal conditions peculiarly 

 favourable to the spreading of pests of many kinds, while their eradication is 

 attended by corresponding difficulties. 



Dr. Cook is already known as a writer on plant pathology, and his experience 

 in Cuba and elsewhere has enabled him to gain a first-hand and extensive know- 

 ledge of the subject. The broad lines on which his book on The Diseases oj 

 Tropical Plants is laid down are similar to those of other writers who have dealt 

 with the subject in connection with the vegetation of temperate climates. He 

 considers the general nature and symptoms of disease in general, and, in order 

 that his readers may be the better able to follow him, gives a brief outline of the 

 structure of the higher plants. This is followed by a classification of the fungi, 

 and a short account of the chief disease-producing animals. The greater part 

 of the volume is devoted to a description of the particular diseases (and the 

 organisms which cause them) of individual economic plants, whilst in a special 

 chapter the chief fungicides and forms of spraying apparatus are described. 



The book is a useful one ; but perhaps it will appeal more to the scientific 

 expert, or the plant-sanitation officer, than to the planter. The latter will 

 find much that he would scarcely understand or appreciate without a previous 

 botanical training. It does not, however, follow that this is to be regarded as a 

 blemish, for, after all, plant-sanitation work is a highly expert business, and it can 

 hardly be undertaken by an amateur without grave risk. If one desired to urge 

 a point of criticism on general grounds it would be that the author seems to have 

 tried to cater for both classes of readers, the planter and the pathologist. Perhaps 

 this was inevitable. At any rate, Dr. Cook has done his work well, as far as a 

 book of modest dimensions would allow, and the planter will doubtless derive 

 much instruction from it. He will be able to appreciate the urgent importance 

 of extending our knowledge of a subject which touches his own material 

 interests so closely. 



The book is well printed and illustrated, but the misprints are somewhat more 

 numerous than they should be. 



Philosophy of the Practical, Economic and Ethic. Translated from the Italian 

 of Benedetto Croce by DOUGLAS AlNSLlE, B.A. (Oxon), M.R.A.S. [Pp. 

 xxxvii + 585.] (London ; Macmillan & Co., 1913. Price \2s. net.) 



The volume translated by Mr. Ainslie is entitled The Philosophy of the Practical. 

 Those who are not acquainted with the peculiarities of modern metaphysics must, 



