288 



BOOKS AND CURRENT LITERATURE 



of solubility relations of the soil minerals and the soil solution, a re- 

 markably understandable chapter on absorption and adsorption in the 

 soil, and a chapter discussing the relations of the plant to the concen- 

 tration of the important nutrient salts in the soil solution. The tenth 

 chapter returns to the dynamic concept of soil phenomena and outlines 

 in detail the dj^namics of the soil solution and the reasons for believing 

 that the concentration of this solution in the useful elements is com- 

 monly maintained at a sufficient value, regardless of the removal of 

 these elements by plants. The three follo^^^ng, and final, chapters dis- 

 cuss respectively the organic compounds (including "toxic principles") 

 lately discovered to be present and important in the soil solution, the 

 theory and practice of the use of fertilizers from the dynamic and 

 physico-chemical vieAV'point of the volume, and the phenomena of exces- 

 sive salt accumulation or soil "alkali," also from the same point of 

 view. Not the least merit of the book is an abundant citation of liter- 

 ature — a merit all too rare in the American papers in this field. If 

 perhaps American publications and especially those of the Bureau of 

 Soils appear a little too prominently in the footnotes that is a natural 

 fault and one which Dr. Cameron recognizes and justifies in his preface. 

 The really important Russian literature appears to be entirely unnoted, 

 but this is readil}' excused on the ground of its inaccessibility to American 

 readers. 



The book is scarce^ one for beginners in soil science or for those 

 without training in chemistry. It must be invaluable to the serious 

 student of soils or to the specialist in chemistry who desires acquaint- 

 ance with the applications — past and prospective — of his science. No 

 one pretending to acquaintance with soil chemistry can afford to ignore 

 this book. It is not necessary to agree with Dr. Cameron but it is 

 necessarj' to know Avhy and wherein one does not — ^E. E. Free. 



Danish Plankton. — Ostenfeld's comprehensive publication' on the 

 plankton of the Danish shore waters embodies work carried out during 

 the years 1898-1901, and will be of special interest to students of marine 

 algae and to marine ecologists. After giving an account of the pre- 

 vious work done upon floating vegetation the author attacks his prob- 

 lem from three distinct centers: (1) The ecological factors in operation, 

 (2) the biology of the larger groups, (3) the distribution of individual 

 species. In order to determine the exact nature of the distribution of 



' Hansen-Ostenfeld, C, De Danske Farvandes Plankton. Kgl. Danske Selsk. 

 Skrifter, 7 Raekke, Nat. Math. Afd. 9, 2, pp. 117-478, Copenhagen, 1913. 



