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THE AMERICAN XATURALIS1. [Vol. XXXVII. 



ered in the second chapter, there is hardly space enough allowed for 

 a very complete discussion of the question. The optimistic point of 

 view is taken that when the nature of the plasmic membranes is 

 known, "it is not improbable that the solution of the problem of 

 water transport will follow as the simplest corollary." In the next 

 chapter the absorption and transmission of solutes is treated of, the 

 important matter of quantitative selection is somewhat lightly referred 

 to, and one is lead to the belief that it is either taken as a matter of 

 course, or that the author does not consider it of the same importance 

 that many physiologists do. Simple diffusion is said to be the great- 

 est factor in the distribution of solutes in the plant body. As to the 

 influence of the osmotic pressure of the surrounding medium upon 

 organisms, which is the subject of the final chapter, the author gives 

 a summary of his own work in that line and of that of other investi- 

 gators. Investigations have shown that growth is accelerated in weak 

 solutions of various substances and retarded in concentrated ones. 

 Cell division may also be influenced by the osmotic pressure of the 

 surrounding medium, and reproduction being a peculiar form of cell 

 division is apparently dependent, in some cases, upon the pressure. 

 Whether the effect is due merely to the extraction of water, or to a 

 strictly chemical influence the author does not decide. 



While there is not a great deal that is new in the volume it is an 

 excellent brief review of the various questions as they stand to-day. 

 As a reading book for more advanced students in physiological 

 botany the book will have considerable value, and it is one which 

 may well be placed upon the shelves of the laboratory reference 

 library. As a final source of information it cannot of course be sat- 

 isfying, but the copious references to the literature make it valuable 

 in this respect also. There is a distinct place for a book of this 

 character. 



H. M. R. 



Pierce's Plant Physiology. 1 — In his preface the author expresses 

 his desire to fill the gap in text books which exists between the mon- 

 umental work of Pfeffer on the one hand, and the clever but short 

 account of plant physiology which is found in Stasburger's text-book. 

 The intention to furnish a good reading book of this character is cer- 

 tainly a laudable one, and in so far as the author has succeeded, he 

 is to be congratulated. It is further stated that only "safe views" 



• Pierce, G. J. A Text-Book of Plant Physiology. New York, Henry Holt ft 

 o. 1903. 8vo., vi-291 pp., 22 figs. 



