BOOKS AND CURRENT LITERATURE 125 



ker, which would put the student in touch with that source of infor- 

 mation too little known to physiologists. The same criticism may 

 be made concerning the treatment of india-rubber, namely, that 

 they are merely ordinary chemical analytical methods, no mention 

 being made even of Whittelsey's important contribution to this aspect 

 of the work, nor to those of Spence and of the reviewer on the be- 

 havior of rubber in the living plant. The physiologist will find in 

 these chapters, little to guide him even to work already done from his 

 point of view. But it would be unjust to judge the whole book from the 

 treatment of these more obscure subjects, since the meagreness of 

 matter concerning them rests in part at least on our lack of knowledge. 



One finds, on the other hand, that the portion of the text devoted 

 to methods for the study of the nutrition and growth of the seed- 

 ling is quite full and extremely useful, and the same may be said of 

 many other subjects, such as respiration, photosynthesis, and nitrogen 

 assimilation, while the gas-analysis methods that play so important 

 a part in the study of these matters, are described in detail. Of 

 especial value are the chapters on sterilization of higher plants, methods 

 of studying the surface tension of protoplasm (including Czapek's 

 important contribution), the enzymes (Bunzel's highly refined methods 

 here being presented), respiration and photosynthesis, in all of which 

 many procedures not before collated in a single book, are brought 

 together. A considerable space is devoted also to forcing, measure- 

 ment of growth, of transpiration (including stomatal movements), 

 bleeding pressure, and osmotic pressures. 



There are throughout the book a number of striking omissions, an 

 excuse for which is not at hand. No mention is made of the water cul- 

 ture methods of Livingston, and of Schreiner and Skinner, the latter 

 especially important. Although Francis Darwin's porometer method 

 is described, Ball's very ingenious "stomatograph" has escaped at- 

 tention. Nothing is said of methods for studying evaporation, and 

 their importance as a standard, as developed by Livingston and em- 

 bodied in his conception of relative transpiration, although analogous 

 methods, such as Wiesner's for measuring light intensities, do appear. 

 Nearly all the devices for the study of transpiration are given except- 

 ing one form of potometer perhaps the most generally useful of the 

 simple types, although the paper describing its earliest use is cited. 

 Dixon's important thermoelectric method of determining the concen- 

 tration of saps, is given. 



One misses, however, indications of appreciation of the work of 



