REVIEWS. 
407 
edition of his well-known “ Botanical Text-book.” The foundation of this 
elaborate work is to be found in a small book published under the title of 
“ Elements of Botany ” more than forty years ago, which was followed in 
1842, the year in which the author entered upon his professorial duties in 
Harvard University, by the first edition of the “Botanical Text-book.” In 
this, as in the present issue, the author founds all his work on a morpho- 
logical basis, a mode of treatment which was novel when first adopted by 
him, but which most recent writers on the principles of botany have 
adopted. 
By the development of the subject, and perhaps of the ideas of the author, 
the plan of this sixth edition has been much enlarged. Instead of a single 
volume it is to consist of four, the first of which only is now before us, 
devoted exclusively to structural botany and the principles of systematic 
botany, with reference, however, solely to phasnogamous plants. The treat- 
ment of the subject is the same as in former editions, proceeding from the 
organography of the seedling plant to trace the structure, form, and arrange- 
ment of all the parts to be developed from it, but in the details we fin d 
much that is new, as might indeed be expected from the advances that have 
been made in botany, as well as in other departments of Natural History, in 
the last twenty years. Thus, to take a single example, we find an entirely 
new section introduced, dealing with the various adaptations of flowers for 
intercrossing and close-fertilization, in accordance with the views so convinc- 
ingly put forward by Mr. Darwin in various works, and supported by an 
immense body of observations recorded by other naturalists, now constituting, 
as our author says, “ a copious special literature.” 
In the chapter devoted to Taxonomy, or the Principles of Botanical 
Classification, the author expounds his views upon the origin of species. 
He accepts the doctrine of evolution in the following sense : Variation, “ if 
sometimes called out by the external conditions, is by way of internal 
response to them. . . . Each plant,” he holds (with Nageli), “ has an inter- 
nal tendency or predisposition to vary in some directions rather than others ; 
from which, under natural selection, the actual differentiations and adap- 
tations have proceeded. Under this assumption, and taken as a working 
hypothesis, the doctrine of the derivation of species serves well for the co- 
ordination of all the facts in botany, and affords a probable and reasonable 
answer to a long series of questions which without it are totally unanswer- 
able. It is supported by vegetable palaeontology, which assures us that the 
plants of the later geological periods are the ancestors of the actual flora of 
the world. In accordance with it we may explain, in a good degree, the 
present distribution of species and other groups over the world.” 
The tenth and last chapter in the book deals with Phytography, or the 
nomenclature and method of describing plants, and includes also a few 
remarks on the formation and management of the . herbarium, and a list of 
the usual abbreviations of the names of botanical writers. A copious glos- 
sarial index concludes the volume, which is beautifully printed and copiously 
and well illustrated. As the author says in his preface, “ It should thoroughly 
equip a botanist for the scientific prosecution of systematic botany, and fur- 
nish needful preparation to those who proceed to the study of Vegetable 
Physiology and Anatomy, and to the wide and varied department of Crypto- 
gamic Botany.” These two branches of the science constitute the subjects 
