28 BOOKS AND CURRENT LITERATURE 



in 1910 and kept bare of vegetation in 1911. Determinations of the 

 nitrate content of these plats were made during the early part of the grow- 

 ing season of 1911. The plat which had grown maize was the only one 

 which had a higher nitrate content than unplanted soil, potato soil was 

 next highest and oats soil contained the least nitrates. Timothy and 

 blue grass gave much less nitrogen in the crop and drainage water com- 

 bined than was in the drainage water from unplanted soil. 



The association during gro\\'th of two different kinds of plants, in soil 

 and in quartz to which nitrates had been added, was found to result in a 

 larger gro'W'th of one or both Idnds than when either plant was grown in 

 pure culture. — Frederick A. Wolf. 



Chemistry of Plant Products. — -Plant physiologists are very for- 

 tunate in possessing a number of excellent text-books on the principles 

 of their subject. However, the developments in the chemical as- 

 pects of the subject have been so rapid and extensive that an incorpor- 

 ation of plant chemistry in these texts has been greatly neglected or 

 considered as beyond the scope of these works. Likewise, the texts 

 of organic, general physiological, and pharmaceutical chemistry have 

 omitted the greater portion of this work. A compilation and discus- 

 sion of the contributions to the chemistry of plant products is there- 

 fore exceedingly welcome. This work^ devotes a section each to: (1) 

 fats, oils, waxes, and phosphatides, (2) carbohydrates, (3) glucosides, 

 (4) tannins, (5) pigments, (6) nitrogen bases, (7) colloids, (8) proteins, 

 (9) enzymes; giving in each case the occurrence, the industrial signifi- 

 cance, if anj% methods of obtaining, characteristic properties and re- 

 actions, microchemical reactions, quantitative methods of estimation, 

 and finally their physiological significance. We miss here any treat- 

 ment of the resins, terpenes, essential oils, and organic acids. Some 

 knowledge of organic chemistry is absolutely essential for the book to 

 be of any value to a student, and in a few cases it is necessary to know 

 the original work in order to gain clarity on the subject discussed, e. g. 

 the discussion of the amphoteric nature of certain proteins (p 302). 

 The application of the principles of physical chemistry is greatly neg- 

 lected, especially is this the case in the chapters on colloids and en- 

 zymes. The tannins are very well treated, and the chapter on chloro- 

 phyll gives a very good resume of the recent work, especially that of 



1 Haas, Paul, and Hill, T. G., An Introduction to the Chemistry of Plant Prod- 

 ucts. 8vo. Pp. 401. London, Longmans, Green and Company, 1913. 



