3°8 
THE PLANT WORLD. 
usually forceful and interesting, and the effect of reading it is a mental 
stimulus. The titles of the seven Parts are as follows: Current concep¬ 
tions; The periodic law; Gaseous ions; Natural radio-activity, a new 
property of matter; The resolution of the atom; Inorganic evolution; 
The new knowledge and the old problems. Over 54 cuts illustrate the 
text. C. S. G. 
Minnesota Plant Diseases. By E. M. Freeman. State Publication, St. 
Paul, Minn. 8vo. Pp. xxiii -f- 432. 1905. 
In the August/ 1905, Plant World we published an article by Professor 
C. E. Bessey entitled, “How Much Plant Pathology Ought a Teacher 
of Botany to Know ? ” At that time there was no one publication of 
recent date presenting in non-technical language the essential facts of plant 
diseases. All teachers who feel the need of such knowledge as Professor 
Bessey outlined will find Dr. Freeman’s book a most welcome vol¬ 
ume. The edition is uniform with Minnesota Plant Life, and, like the 
latter, is as interesting and instructive as it is authoritative. Throughout 
the work there is carried out the author’s high ideal not to offer a receipt 
book, but “ to disseminate knowledge of the destructive parasites of the 
useful plants of this state, to assist all concerned in the cultivation of 
plants to a more intelligent and thorough understanding of the habits of 
these parasites, and to point out established methods of combating such 
diseases.” The aim is “ rather educational than immediately practical.” 
The book is a model of what such state publications ought to be. 
C. S. G. 
The Fern Allies of North America North of Mexico. By Willard Nel¬ 
son Clute. 8vo. Pp. xiv 4 * 278. Illustrated. New York: Frederick 
A. Stokes Co. 1905. $2.00 net. 
The best feature of this work is the author’s attempt to make it an out- 
of-doors book, by emphasizing life-histories and giving many suggestions 
for further field observations. For those who have patience to use it, 
the numerous illustrations, though no more satisfactory than those of the 
author’s fern book, may be of considerable help in learning to identify 
the species. The scope of the book ought to furnish a broader idea of 
the groups treated than the manuals of more restricted range, and the 
collection of illustrated accounts of many rather recently described forms 
will be a convenience. But why, to be popular, must a book be unsyste¬ 
matic in arrangement and description, diffuse in style, and unscientific in 
statement? From a considerable experience with nature lovers, the re¬ 
viewer believes that beginners would distinguish species far more easily 
by means of briefer, even semi-technical descriptions, such as appear in 
two or three popular guides to trees and ferns, than by reading through 
five or six pages to learn the characters of, for example, the field horse¬ 
tail. Many will uphold the author’s position that it is preferable to em¬ 
ploy names in common use, but it would be difficult to imagine anything 
more confusing to the “ novice ” for whom the author expresses such 
frequent concern, than his constant and controversial nomenclatural di- 
