BOOKS AND CURRENT LITERATURE 99 



class. Chapter V (18 pages), on "The biological conditions in the soil," 

 is also an excellent discussion of a scries of questions not generally as 

 well appreciated as the present stage of investigation should allow. Here 

 are treated such topics as water supply, air supply, temperature, food 

 supply, soil toxins and partial sterilization of the soil. Regarding the 

 much discussed problem of soil toxins, Russell concludes that "there is 

 no evidence of the presence of soluble toxins in normally aerated soils 

 sufficienth' supplied with plant food (sic) and with calcium carbonate, 

 but toxins may occur on 'sour' soils badlj^ aerated and lacking in cal- 

 cium carbonate, or on other exhausted soils. There is no evidence of 

 plant excretions conferring [lasting] toxic properties on the soil, but the 

 Woburn fruit tree results show that a growing plant may poison its 

 neighbor." The work of the United States Bureau of Soils along this 

 line is accorded fair treatment and the author's attitude is, on the whole, 

 remarkably unprejudiced, considering the propaganda methods of state- 

 ment adopted in some of the Bureau's publications. 



Chapter VI (12 pages) deals with "The soil in relation to plant 

 growth," a brief application of the principles previously brought out 

 to the groA\i;h of agricultural crops. This chapter considers the practi- 

 cal questions primarily from the standpoint of English soils. Chapter 

 VII (17 pages) is upon "Soil analysis and its interpretation," wherein 

 physical and chemical analysis are both treated. 



An appendix (5 pages) on ' 'The methods of soil analysis," and a selected 

 bibliography (323 titles), followed by a brief index complete the volume. 



B. E. L. 



