No. 440.] 



NOTES AND LITERATURE 



563 



A glance at the map with which the paper is illustrated suggests 

 the thought that we have in Professor Webster's article a strong 

 defense of the Wallacean theory of distribution and of the important 

 part played by barriers in determining the spread of animal life ; it is 

 to be regretted that the recent propaganda of the theory of isothermal 

 distribution of organisms, while undoubtedly of great value in indicat- 

 ing the possibility of artificial cultivation, has tended to obscure the 

 importance of geographical features under really natural conditions. 



' H. F. Wickham. 



BOTANY. 



Livingston's Osmotic Pressure and Diffusion in Plants. 1 — The 



author begins with a treatment of the purely physical phenomena con- 

 nected with diffusion and osmosis, rightly holding that it is difficult 

 for the student of physiology to easily obtain the information he needs 

 in compact form. Such a treatment covering, as it does but forty- 

 four pages could not possibly be detailed, nor does the author main- 

 tain that it is. Nevertheless a summary of this kind can be exceed- 

 ingly useful, if in no other way than to stimulate the student to 

 further reading. This resume is clear and sufficiently full to give an 

 adequate conception of the theories concerned. There are six chap- 

 ters in the first part, which treat of the fundamental theories of the 

 nature of matter, of diffusion and diffusion tension, of solutions and 

 ionization, of osmotic phenomena and the measurement thereof. 



In the second part on the physiological aspect of the matter, the 

 author continues his summari/.ition of the work which has been 

 done, but of course in far greater detail than in the previous half, 

 since the field is smaller and since this is the real object of the book. 

 In the first chapter the question of turgidity is taken up. The impor- 

 tance of this subject demands full treatment, and forty-two pages 

 are devoted to it ; the author does not develop anything new, how- 

 ever. In the even more complicated, and certainly more dubious, 



