215 



a college text-book on plant physiglogy it would be quite in- 

 adequate, but as text on the physiology of plant (crop) production 

 it is a distinct success. The point of view of the entire book 

 may be inferred from the statement on page 495, where, in 

 discussing growth movements, the author says: "A study of the 

 phenomena is more important educationally in liberalizing our 

 views of plant relations than of any direct assistance in special 

 problems of plant production." 



At various points throughout the text one queries as to whether 

 or not the student is expected to have had a college course in 

 elementary botany. If so, much of the pure physiology of the 

 book will be of the nature of a review to him, except in so far 

 as he follows out the admirable suggestions for collateral reading, 

 given at the close of each chapter. If an elementary course is 

 not taken for granted, then one may question the possibility of 

 the reader understanding a discussion of proteoses and peptones, 

 amides, Leguminosae, degradation products, amino and amido 

 acids (p. 261), and "the curve of CO2 excretion" (p. 287). In 

 like manner the quotation on pages 309-310, from Coulter and 

 Chamberlin, seems much too technical. 



In discussing the relation of pruning to growth (p. 236), there 

 is no reference to the very pertinent topic of the self-pruning of 

 many trees; and the large amount of experimental work that 

 has been done, in this country and in Europe, on the effects 

 of the electric current in soil and air, on crop-production, and 

 the very considerable literature that exists on the subject would 

 seem to merit at least a passing reference in a book of this scope. 



On page 69 turgor is attributed to hydrostatic pressure, though 

 on page 67 osmotic pressure is correctly said to vary "with the 

 number of particles in the solute." Growth is held to involve 

 differentiation (pp. 307-308), thus taking no account of a funda- 

 mental distinction quite commonly held elsewhere, and especially 

 necessary to recognize for many lower plants. In the first table 

 on page 431 the meaning of the figures and of the column-head- 

 irigs is not obvious; the character /jl, used in the table at the bot- 

 tom of page 423, is nowhere explained in the book; and in the 

 table on page 405 it is not clear what units of time are referred to. 



