JUST OUT An English Translation of Hugo DeVries’ 
THE MUTATION THEORY 
of the ORIGIN of SPECIES in the VEGETABLE KINGDOM 
TRANSLATED BY y 
Proressor J. B. FARMER and A. D. DARBISHERE 
In Two Volumes, each 582 pages, numerous illustra- 
tions, seven colored plates, cloth, $4.00 per volume 
Volume One Now Ready Volume Two In Prepare 
The promulgation of the principle of untt characters is the main theme of this work, ai 
is emphasized in the first sentence of the Introduction. At the time of the Sublicatidl 
of the first part of the German edition (1900) this principle was new and was also in 
evident oe to the current pti in the slow and gradual plateies. of the 
organic worl During the years that have since elapsed, it has gained almost uni- 
versal acceptance, though there are ‘still some authors, especially among zodlogists who 
are opposed to it. 
Volume II deals with the Origin of Varieties. 
THE OPEN COURT PUBLISHING COMPANY 
Ar cainet be Importers of Standard Books on Science, dmpags ah 
the History of Religion, Ancient and Moder 
Send for complete tllustrated ef scree 
378-388 WABASH AVENUE - - CHICAGO, ILLINOIS 
An Indispensable Book for Students of Botan) 
Methods in Plant Histology 
SECOND EDITION—ILLUSTRATED 
By CuHares J. CHAMBERLAIN, Pu.D- 
HIS BOOK contains directions for collecting and egy 8 plant material 
Specs parang g investigation. It is based upon a course in botanical micro- 
chnique, and is the first complete manual to be published on this subject. 
Free- bend sectioning, the paraffin method, the celloidin method, and the glycerine 
method are treated in detail. In later chapters specific directions are given for 
making such preparations as are needed by those who wish to study the plant 
kingdom from the Algae up to the flowering plant. Special attention is paid to 
pate — of karyo okin etic figures, and formulas are given for the reagents 
more attention has been given to collecting material. New w chapters deal with 
the Venetian turpentine method, microchemical tests, free-hand sections, special 
methods, and the use of the microscope. These changes and additions have 
enlarged the volume from 168 to 272 pages. 
272 pp., 8vo, cloth, net, $2.25; postpaid, $2.39. 
_— 
THE UNIVERSITY OF CHICAGO PRESS 
