BOOKS AND CURRENT LITERATURE 309 



destined to play a significant role in the metabolic and protoplasmic 

 theories of the next decade. 



As indication of the general carbohydrate composition of the 

 material used by Spoehr portions of two analyses may be quoted; one 

 of Opuntia phoeacantha, which is a mucilaginous species; the other of 

 Opuntia versicolor, which is less so. 5 



Water 78.70 82. 15 



Total sugars 3.53 1.97 



Total hcxose sugars 1 . 81 1 . 59 



Total pentose sugars (including pentosans) 1.64 0.36 



Pentosans 1.55 0.23 



The monograph contains detailed descriptions of the analytical 

 methods employed for the extraction and clarification of the plant 

 juices and for the separation and determination of the hexose and 

 pentose sugars. The specialist will find these of value. Such more 

 general readers as resemble the reviewer in being a little hazy con- 

 cerning the exact relationships and behaviors of the numerous sugars 

 which are now known will thank Spoehr for his clear and compre- 

 hensive Introduction, a chapter well suited to introduce not only 

 this particular monograph, but sugar metabolism in general. — E. E. 

 Free. 



A New Economic Botany. — Under the title "Applied Economic 

 Botany," 6 a new botanical text is presented in the Farm Life Series, 

 which, according to the preface, is needed because of poorly adapted 

 books on the market. With the statement regarding the adaptability 

 of texts already in use, the reviewer does not entirely agree. Most of 

 the complaints against our present texts in botany, if investigated, 

 would not be scored against the books, but against the teacher. If 

 fewer botanical classes in secondary schools were taught by latin, 

 history and chemistry teachers, there would be fewer complaints against 

 textbooks. With another of the author's statements however, few 

 will disagree. Undoubtedly the secondary schools are trying to cover 

 too much ground instead of limiting their field to fundamentals. This 

 again is the fault of the teacher. It is doubtful if any text will really 

 hold such instructors in check. 



5 Data selected by the reviewer from table 8, page 40 of the monograph, 



6 Cook, Mel. T. Applied Economic Botany. 1919. 



THE PLANT WORLD, VOL. 22, NO. 10 



