REVIEWS 321 



the ground for planting out to the output of the various manufactured 

 articles and the by-products. A short history is given of the introduction 

 of cocoa, followed by a description of the plant and a short account of the 

 methods of cultivation, which are comparatively simple. It is interesting 

 to note that in Grenada, for example, close planting and a careful attention 

 to the condition of the land enable the cultivator to do without the shade- 

 plants considered, in most other places, to be essential. Wind-screens, in 

 the form of hills and belts of trees, are of course still necessary, and on com- 

 paratively flat land, such as the island of Barbados, it is not possible to 

 grow cocoa successfully. The desirability or otherwise of suckers, or 

 " chupons," as they are called locally, is also discussed. The cauliflory, 

 or formation of flowers on the old bark, and the presence of red pigment in 

 the young leaves, noted by the author in the case of this plant, are com- 

 paratively common phenomena amongst tropical plants. In Trinidad, 

 experiments have now been some years in progress with the view of finding 

 out whether grafting and budding will enable the planter to get quicker 

 returns than is customary, and also to obtain a surer growth of the delicate 

 CrioUo variety by grafting it on the hardy Forastero. The first-named 

 variety gives a better grade cocoa than the commoner Forastero, and is 

 fermented more easily and quickly. So far the experiments have been very 

 successful, and are of importance also in another connection. The plants 

 often vary greatly in their " cropping powers," and this character shows 

 early in the life of the plant and is fixed. It is possible that grafting 

 shoots from prolific plants on to comparatively bad stock would improve 

 the character of the plantation. 



The various diseases to which the plant is subject are not treated of, as 

 to have done so adequately would have unduly increased the size of the 

 book. The actual manufacture of the bean into cocoa powder, chocolate, 

 milk chocolate, and creams, is considered more fully than any other part 

 of the subject, and the author, who is Research Chemist to Messrs. Cadbury 

 Bros., is in a position here to give an authoritative account of what proves 

 a very interesting story. The remaining portion of the book is taken up 

 with the economic problems connected with cocoa and with its dietetic value ; 

 a full bibliography is appended. The book is addressed to the general 

 reader, is simply written, very well and fully illustrated, and can be re- 

 commended to all who wish to obtain a general idea of the problems that 

 the cocoa manufacturer has to face. 



E. M. C. 



A Course o£ Practical Chemistry for Agricultural Students, Vol. I. By 



L. F. Newman, M.A., F.I.C., Fellow of St. Catherine's College, Cam- 

 bridge, and H. A. D. Neville, M.A., B.Sc, F.I.C., Professor of Agri- 

 cultural Chemistry, University College, Reading. [Pp. 235.] (Cam- 

 bridge : at the University Press, 1920. Price 105. 6d. net.) 



The scope of the laboratory manual of which the volume under review forms 

 the first part was described in the pages of this journal when Vol. II, 

 Part I, which appeared some months ago, was noticed. Vol. I includes 

 laboratory exercises which are introductory to the study of chemistry, these 

 exercises being concerned with air, hydrogen, water, carbon dioxide, ammonia, 

 hydrochloric acid and chlorine, acids, bases, and salts. These introductory 

 exercises are followed by sections in which the student is made acquainted 

 with the principles of volumetric analysis. The remainder of the book 

 deals chiefly with the qualitative and quantitative analysis of soils, manures, 

 and plants, and with the physical properties and mechanical analysis of soil. 

 The book concludes with some exercises in elementary physics. Throughout 



