BOOK REVIEWS. 



299 



''Die Eeizbewegungen der Pflaiizen." By Dr. Ernst G. Prin^gs- 

 heim. Svo., 326 pp., 96 figs. (Springer, Berlin, .1912.) M. 12. 

 Bound M. 13.20. 



For this book the author states it is intended less for the botanical 

 specialist than for the plant-lover who observes the salient features of 

 plant response to stimulation, and seeks to group together and to com- 

 prehend the phenomena before him without necessarily grappling with 

 all the technical detail of the text-books. With this in view the illus- 

 trations are mostly photographs, giving a more life-like picture than 

 drawings. 



Whenever possible Dr. Pringsheim compares plant response with 

 human sensibility, thus emphasizing the common basis of all living 

 things. Despite the difference between plants and man, he says the 

 same physical and chemical forces act on both as stimuli. Gravity 

 keeps both upright. Light acts powerfully on both as a factor in 

 orientation. Taste and smell guide us in choice of food; plant roots 

 and fungoid threads reach out after their nourishment in virtue of 

 chemical excitability; bacteria swim drawn by the same cord. Both 

 react to mechanical stimuli — e.g. stroking or tapping — to rise and fall 

 of temperature, to movements of water, and differences of moisture. 



For plants movement is the least ambiguous reaction, and it is 

 the main subject of this book. But other reactions also are described. 

 Change of form, which plants manifest more conspicuously than man 

 and animals generally. The plant organism, as a whole, is of. much 

 lower individuality. Its different parts accordingly respond by 

 changes of form intO' stem, leaves, &c., in a degree that is not possible 

 in the animal body. The chemical reaction of plants is more obscure. 

 Eecovery from wounds, growth of lost parts, is doubtless partly due to 

 the working of internal stimuli, 'as well as to direct chemical action 

 on metabolism. But this field has as yet been very imperfectly ex- 

 plored for man, and for plants the difficulties are infinitely greater. 

 The book, after preface and introduction, deals with the different 

 I orders of movements — e.g. free movement from place to place, move- 

 I ment of protoplasm, movements connected with growth, turgor, &c. 

 It next treats of the different stimuli (gravity, light, temperature, 

 mechanical and chemical factors), and of the several plant reactions. 

 Lastly the nature of " Excitability " and its development are dis- 

 cussed — with a bibliography and index. 



It should be a very interesting compilation for all who have not 

 access to the original papers. The illustrations are excellent, and the 

 discussion of the more obscure points of chemical action on plant 

 metabolism is lucid and suggestive. 



" Sub-Alpine Plants, or Flowers of the Swiss Woods and 

 , Meadows." By H. Stuart Thompson, F.L.S. 8vo., 325 pp. 

 . (Routledge, London, 1912.) 7s. 6d. net. 



The need for such a book is so well stated in the opening words 

 of the preface that their quotation here is irresistible. 



