110 



page 125 of the Supplement) Hofmeister's clear statement made 

 in 1868, to the effect that mutation, rather than continuous 

 variation, supplies the material for selection in species making. 

 "N.ew forms," said Hofmeister, "do not come into existence by 

 the summation in successive generations of small differences from 

 the customary form, all tending in the same direction; they 

 appear suddenly, and are widely different from the parent." 



If America were as Teutonic in the matter of the publication 

 of scientific books, as it is in the organization of education, 

 and of scientific research, we would not have to rest content with 

 supplements, but would early enjoy an American translation of 

 the second German editions of works important enough to run 

 into a second edition. C. Stuart Gager. 



Schaffner'a Field Manual cl Trees* 



As a field manual to slip in one's pocket, the present volume 

 will unquestionably fill a long felt want, as it condenses the 

 information contained in more complete works. The book is 

 scarcely more than one quarter inch thick, and only 6^ X 43^ 

 inches long and wide. Brief descriptions are given for the genera 

 and species, but not for the families. Keys are provided 

 throughout and the latter feature has been very thoroughly 

 covered. " Key to the genera of trees in the summer condition," 

 "Key to the genera of trees in winter condition," "General key 

 to the families and genera," and "Key to the fruits" will give 

 some idea of the scope and usefulness of this side of the book. 

 In the appendix is a "General classification of the wood of trees 

 included in the manual" and a glossary of terms. The classifica- 

 tion of woods is based on their structure, porusness, and other 

 structural characters. 



Of course the main body of the work is taken up with the 

 description of the individual species. All the usual features are 

 covered, tersely and concisely, and for practical field work, these 

 descriptions will be found quite adequate. There are notes on 



* Schaffner, J. H. Field Manual of Trees, including southern Canada and the 

 northern United States to the southern boundary of Virginia, Kentucky, and 

 Missouri, westward to the limits of the prairie. Pp. 1-154. R. G. Adams Co., 

 Columbus, Ohio. Price, limp cloth, $1.25; limp leather, $1.75. 1914. 



