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POPULAR SCIENCE REVIEW. 
natural-history studies, and its perusal will open up a treasury of fresh 
interest for those who have the opportunity of practically following out the 
course of observations detailed in it. 
The volume, moreover, contains dissertations upon various questions 
which arise naturally from the consideration of the phenomena to which 
we have briefly and very imperfectly called attention, questions which must 
possess great interest for the scientific botanist, such as the actual homo- 
logical explanation of the structure of the flowers in the group of Orchids, 
the gradations in the mode of development of their various organs, the 
effects of the recognition of these gradations upon the phylogeny of the 
group, and the mechanism by which the peculiar phenomena of their 
fecundation are brought about. To enter upon any detailed exposition of 
the results of Mr. Darwin’s investigations in these various directions would 
occupy much more space than we have at our disposal, and we must there- 
fore refer the botanical reader to the book itself, which is certainly one of 
the most fascinating volumes that it has ever been our lot to study. 
This second edition has received very considerable additions, not only 
arising out of the author’s own observations, but also derived from the very 
numerous memoirs which have been published on the subject since Mr. 
Darwin first called attention to the curious facts revealed by the investiga- 
tion of the orchids, some fifteen years ago. The illustrations, which are 
nearly the same as those printed in the first edition, have received some 
few additions ; they are very carefully selected and executed, and serve to 
render all the details most readily intelligible. 
THOME’S TEXT-BOOK OF BOTANY.* 
P ROFESSOR THOME’S “ Text-book of Botany,” which, as the Editor, 
Mr. Bennett, tells us, is the recognized book in use in the technical 
schools of Germany, will no doubt meet with great and well-deserved suc- 
cess in its English dress. Its descriptions of structure are exceedingly clear 
and intelligible, and the arrangement of the subject will be found to con- 
duce greatly to a ready understanding of the internal and external anatomy 
of plants, in which the student will find further assistance in the very 
numerous and excellent illustrations. In this and the physiological section, 
Mr. Bennett has closely followed the German original, appending new ad- 
ditional information in the form of footnotes. But in the succeeding 
chapter, which treats of the morphology of plants, and the classification 
founded upon it, the Editor has departed from this rule, and while retain- 
ing his author’s treatment of the Cryptogamia, he has introduced a classifi- 
cation of the flowering plants in accordance with the system most generally 
accepted in this country. The sections on Palaeophytology, and on the 
geographical distribution of plants, although brief, are good ; and the latter 
is illustrated by a coloured map. 
* “ Text-book of Structural and Physiological Botany.” By Otto W. 
Thome. Translated and Edited by A. W. Bennett, M.A., &c. Small 8vo. 
London : Longmans. 1877. 
