Reviews. 
1 29 
temperature the denitrifying bacteria are stimulated to great 
activity, so that a large amount of nitrogen is set free into the 
atmosphere, thus leaving only a small quantity of nitrogen compounds 
available for vegetable use in the warmer regions of the ocean. No 
direct observations, however, have been made on this important 
matter, and it is very probable that a number of factors combine to 
bring about the result. 
A list is appended of some of the more important papers 
bearing on the subject discussed. ' 
Baur, E. Ober zwei deuitrifiziereucle Bakterien aus den Ostsee. 
Wissen. Meeresuntersuchungen, Abt. Kiel, VI., 
1902, p. 9. 
Brandt, K. Ober den Stoffwechsel ini Meere, Wissen. Meeresunters. 
Abt. Kiel, IV., 1S99, p. 215, VI. 1902, p. 25. 
Benecke, W., u. Keutner, J. Uber stickstofFbindende Bakterien aus 
Ostsee. Ber. d. Deutsch. Bot. Ges. XXI., 1903, p. 333. 
Gran, H. Studieu iiber Meeresbakterien. Bergens Museums Aarbog, 
1901. 
Reinke, J. Zur Ernahrung der Meeres-Organismen disponibile Ouellen 
an StickstofF. Ber. d. Deutsch Bot. Ges. XXL, 1903, 
P- 37 i- 
V.H.B. 
REVIEWS. 
A Manual and Dictionary of the Flowering Plants and Ferns. By J. C. 
Willis, M.A., Director of the Roj’al Botanic Gardens, Ceylon, etc. Second 
Edition, revised and rearranged in one volume. Cambridge University 
Press (Cambridge Biological Series), 1904. Price 10s. 6d. net. 
W E welcome a new edition of this useful book. The two parts 
(Part I., “Outlines of the Morphology, Natural History, 
Classification, Geographical Distribution and Economic Uses of the 
Flowering Plants and Ferns”; and Part II., a kind of Cyclopaedia 
of classes, cohorts, orders and chief genera) are now included in 
one compact crown octavo volume, which, owing to the judicious 
use of small type and abbreviations, only extends to 670 pages, and 
is not impossible (thanks to the thinness of the paper) for the side- 
pocket. At the same time a large amount of new material has 
been added, and controversial matter omitted. 
The introductory chapter gains greatly by the addition of a 
section on the aims of “ General Field Work ” and of very practical 
notes on outfit, collecting, preserving and recording, which are 
evidently the fruit of the author’s personal experience in the Tropics. 
