760 THE AMERICAN NATURALIST. [Vor. XXXIV. 
Newbigin. The introductory portion, which is included in the first 
two chapters, deals with the well-known distinctions between pig- 
mental and structural colors and a further classification within these 
two groups. It also contains a brief account of light-producing 
organisms. Then follows a series of chapters devoted to the consid- 
eration of the color phenomena in plants and in the various groups 
of the animal kingdom, special attention being paid to butterflies 
and to birds. As a result of this survey, the author states “that it 
is as yet impossible to give a definite physiological explanation of 
the origin of pigment; that it is practically impossible to classify 
pigments in a logical manner; that most of the problems connected 
with the subject are entirely unsolved." After this general denial 
of results, except from a simply descriptive standpoint, the author 
devotes a closing chapter to the theoretic aspects of the subject. 
This gives in an impartial way the explanations of the origin of 
different types of coloration as advocated by such Darwinists as 
Poulton, by such Lamarckians as Cunningham, and by those who, 
like Wallace, occupy iftermediate grounds ; Simroth's fanciful con- 
ceptions occupy what seems to us an undue amount of space. The 
Darwinian views are criticised from the standpoint of Piepers's able 
paper, and the views of the non-Darwinians are dismissed because 
they imply the inheritance of acquired characters. 
The volume shows little originality, but the very fact that the 
author has no special views of her own to advocate allows her to 
give the views of others in a more impartial way. The book is 
concluded with a good list of references, an index of authors, and 
an index of subjects. It is exceptional in having escaped the hands 
of the chromo-lithographer or, in fact, those of any illustrator. P. 
The Plankton of the Elbe, near Dresden, has been studied by 
Dr. B. Schorler? in collections made at eleven intervals, from April to 
November, 1898, in the main stream and in three contiguous bays. 
The current in the Elbe ranges from 40 to 190 cm. per second, and 
the plankton was less abundant in the main channel than it was in 
the quieter water of the adjacent bays, thus illustrating Schróder's 
law that the volume of plankton in a stream is inversely proportional 
to the rate of the current. In all, 143 species were found, of which 
! Newbigin, M. I. Color in Nature, a. Study in Biology. London, J. Murray, 
1898. xii + 344 pp. 
2 Schorler, B. Das Plankton der Elbe bei Dresden, Zeitschr. f. Gewässer- 
kunde, Bd. iii (1900), pp. 1-27. 
