1917] CURRENT LITERATURE 439 
cells, but with their decomposition products and the exchange between the 
cell and its surroundings,” and that from our knowledge of these “we may 
speculate on the composition of the cell and the changes that go on in it during 
functional activity,” represents two lines along which productive work is being 
done and will continue to be done, he is leaving in the background a third line 
which has also proved helpful and promises still more for the future. 
We might wish that the author had given more recognition to the fact 
that many plant processes are conditioned by the permeability or impermeabil- 
ity of non-living plant membranes. These, however, are very minor criticisms 
on a book which commends itself strongly by its many excellent features. 
Among the important topics discussed in the introduction are viscosity as a 
factor in igo ee phenomena, and the relation of semipermeability to 
electric phenome 
His pamaaey ‘ the en: membrane (p. 94) as a separate phase which 
may change with the physiological condition of the cell, and of the protoplasm 
as sometimes consisting of as many as four phases, in all of which partition 
solubility must be considered, as well as the molecular condition of each solute 
in each phase and in the bathing medium, leads him to the conclusion that “all 
of these factors make the subject of cell permeability a very complex one, no 
general rules without exception having been found. All we can do at present 
is to collect data on the permeability of cells to various substances.”’ It is 
to be hoped that this will commend itself so strongly to biologists that we shall 
have a larger output of data and a smaller output of theories. 
The following shortened chapter headings will suggest the general scope of 
the book: electrolytic dissociation; ne Pere, eee n and hydroxy] 
ion concentration; surf es, non-electrolytes, 
and colloids; enzyme action; ceca and its qsnche negative osmosis; 
anesthesia and narcosis; amoeboid motion, cell division and parthenogenesis; 
muscular contraction; blood and other cell media. 
The “chemical summary” in the appendix will be very useful. The 
literature list includes over 1500 papers arranged alphabetically according to 
authors. References in the text to this list facilitate more detailed study 
of any desired topic. Instead of the conventional index to the text, there is 
an index to this literature list —GrorcE B. Rice. 
NOTES FOR STUDENTS 
Taxonomic notes.—BLaAkE? has described a new Rudbeckia (R. Deamit) 
from atlas closely allied to R. speciosa. 
Coxer’ has published a detailed and handsomely illustrated monograph 
of the Amanita group as represented in the eastern part of the United States. 
2 Brake, S. F., A new Rudbeckia from Indiana. Rhodora 19:113-115. 1917. 
3 Coker, W. C., The Amanitas of the eastern United States. Jour. Elisha 
Mitchell Sci. Soc. 33:1-88. pls. 69. 1917. 
