100 



first oi these, the " Relation of Plants to Mechanical Forces," is 

 found a very full treatment of experiments which have to do with 

 contact stimuli — more particularly by the curling of tendrils — 

 on which the author himself has already done much work. 



The third chapter, entitled " Influence of Chemicals upon 

 Plants/' treats of this subject in its broadest aspect, including a 

 full list of experiments on the toxic action of various salts. The 

 title of this section may possibly be open to criticism by some, 

 owing to the somewhat limited field which the term " chemicals " 

 covers, in its common, though perhaps not correct, usage. 



In the relation of plants to the influence of water, gravity, temper- 

 ature, electricity and light is found the subject of the next five chap- 

 ters. In the consideration of the influence of light the author treats 

 it from the interesting standpoint of light as a stimulating rather 

 than as a retarding agent in the matter of phototropic effects. 



Chapter nine deals with the " Composition of the Body," or, in 

 other words, with the substances found in plants. Following this 

 the " Exchanges and Movements of Fluids," including osmosis, 

 the transpiration current, etc., are taken up, while " Nutritive 

 Metabolism " is not introduced until the eleventh chapter. 



In connection with this we find the subject of the next chapter 

 is " Respiration, Fermentation, and Digestion." Under the last- 

 named head fall the experiments with enzymes which are very 

 complete and practical. 



The phenomena of growth in itself, aside from the growth at- 

 tending curvatures, is kept until almost the last, perhaps that they 

 may be contrasted and compared with those of reproduction, 

 which is very fittingly the final chapter of the book. An appendix 

 oi chemical and physical tables and a copious index is included. 



Throughout the book we find a clear cut and concise style 

 which to the student will prove a great boon. Particularly are 

 the opening sections of each chapter to be mentioned ; they serve 

 to properly orient the reader on what is to follow. When the 

 immense ground to be covered is considered, the very complete 

 list of experiments can but prove satisfactory and almost always 

 well chosen. Several new contrivances, among which is a pre- 

 cision auxanometer, will recommend themselves to the experi- 

 menter. H. M. Richards. 



