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BOOKS AND CURRENT LITERATURE 



ter (32 pages) on "The requirements of plants." Plant physiologists 

 will find this chapter very valuable. It includes a thoroughly modern, 

 though necessarily brief, discussion of the relations obtaining between 

 plant activities and temperature, with consideration of the temperature 

 coefficient. Light receives but a superficial treatment; a much more 

 thorough discussion is, however, impossible at present. Among material 

 conditions of plant activity, oxygen, water and "food" receive attention. 

 The first two are accorded only a very inadequate treatment, as would 

 be expected in a book on soil. The idea again finds expression (pp. 28 and 

 29) that transpiration is considerably influenced through variation in the 

 vapor pressure of the foliar cell sap, though such influence has been shown 

 (by Drabble and Drabble^) to be practically negligible. The term 

 food is used to denote inorganic material requisites, and the weight of 

 the present publication is added to the incubus of muddle which prevails 

 over the physiological aspect of this word. After announcing the title 

 Food, the author parenthetically acknowledges, however, that his usage 

 is logically wrong, stating (p. 30) that "the food of plants, or rather the 

 raw material out of which food is synthesized, consists," etc. But the 

 parenthesis will not be noted by the average reader, who will almost 

 certainly come from the reading of these and subsequent paragraphs 

 with the misconceptions that usually go with the word food. Russell's 

 treatment of the influence of the ordinary minerals on plant groAvth is 

 excellent. 



The third chapter (27 pages) deals with "The constitution of the 

 soil," and includes, besides adequate discussions of the mineral and 

 aqueous portions, a welcome consideration of the organic soil materials 

 from a modern standpoint. The author apparently does not regard the 

 gaseous phase of the soil as logically a part of it, though he gives atten- 

 tion elsewhere to the influence of soil gases upon plants. 



Chapter IV (24 pages), on "The carbon and nitrogen cycles in the 

 soil," is a very clear and readable treatment of the complex nitrogen and 

 carbon changes which are of such fundamental importance to plant 

 activity. Within the imposed spatial limits and in the present stage 

 of investigation of these recondite changes, this chapter could not be 

 notably improved; it appeals to the reviewer as a masterpiece of its 



^ Drabble, E., and Drabble, H., The relation between the osmotic strength of 

 cell sap in plants and their physical environment. Bio-chem. Jour. 2: 117-132. 

 1907. See also Livingston, B. E., The relation of the osmotic pressure of the cell 

 sap in plants to arid habitats. Plant World 14: 153-164. 1911, and references 

 there given. 



