170 



cedes the justice of the criticism but offers a rather lame excuse 

 for continuing the usage. Nitrogen assimilation of Jost could 

 easily be the synthesis of nitrogenous compounds ; photosyn- 

 thesis is already restricted to carbohydrate construction in which 

 light energy is needed and by no means covers other syntheses 

 of carbohydrates in which light is not a factor. As Jost says, 

 there is no good reason for treating nitrogen differently from 

 carbon, but there is no more necessity for that than for perpetu- 

 ating improper terminology " with full cognizance of the diffi- 

 culties involved in so doing." 



To each lecture, as indicated by brackets, there have been 

 added by Jost himself paragraph comments on later work and 

 references to recent literature, so that the English edition is more 

 up to date than the original and those accustomed to always 

 using the German should remember this as well as the fact that 

 Jost himself has made some alterations and corrections. 



The typographical work conforms to the standard of the 

 Clarendon Press though the lines are a little too close together. 



While the reviewer feels that some of the matters here dis- 

 cussed are important he is equally earnest in saying that the 

 translator deserves abundant credit for the valuable service he 

 has rendered in extending the field of usefulness of such an im- 

 portant work. 



Raymond H. Pond. 



Hilgard's Soils* 



Dr. Hilgard is undoubtedly the leading authority on soils in 

 America, having studied them critically for over fifty years, under 

 almost every climatic condition that is found in the United States, 

 and at all stages of economic development from primeval forests 

 and deserts to truck-farms and gardens. The volume before us 

 contains the essence of all his previous publications on the sub- 

 ject, and covers the ground very thoroughly, revealing his exten- 



* Hilgard, E. W. Soils : their formation, properties, composition, and relations to 

 climate and plant growth in the humid and arid regions, xxvii + 593 pp. 89 figs. 

 New York, Macmillan Co. 1906. (On the back of the title-page is a statement 

 that the book was published in July ; but the publishers apparentiy did not begin to 

 advertise it in their own periodical. Science, until September 28, and it was first an- 

 nounced in the New York Times Saturday Review of Books about the same time.) 



