No. 427.] NOTES AND LITERATURE. 595 
first half of Vol. II has been made ready for publication. This first 
part appeared last summer. The first volume, reviewed in this journal 
(Vol. XXXII, pp. 450, 451, 1898), treated the subjects comprehended 
under metabolism. The first half of the second volume discusses 
growth and the factors that control it, development, variation, and 
inheritance — in short, different kinds of work done by the plant, 
dependent.upon and made possible by the processes discussed in the 
earlier volume. In a book planned as this is, with the first volume 
devoted to the transformation of matter and the second to the trans- 
formation of energy, more or less repetition is necessary, but it is a 
repetition which gives to Pfeffer's treatment of the subjects in plant 
physiology the exhaustiveness which the physiologist needs. This 
is no book to be put into the hands of undergraduates; it is for the 
man who has studied long and is studying hard. However much one 
may wish that Pfeffer's literary style were not so difficult, one cannot 
help recognizing that it is full of meaning. 
The arrangement of matter in Vol. II of the second edition differs 
somewhat from the first edition ; consequently comparison of the two 
editions as to size is difficult. One sees at once, however, that if 
the second half of the volume is to treat the subjects of movements 
and the production of heat, light, and electricity in anything like pro- 
portional fullness, the book will be considerably larger than in the 
first edition. The additions to the first part are many of them the 
results of Pfeffer's own work, either investigation or teaching. This 
will be equally true of the second part of the volume. 
Such a work as this, presenting the status of a science as a whole, 
shows where the great gaps in our knowledge are. For instance the 
plant physiology of to-day consists of the facts discovered in studying 
land and fresh-water plants, and of the interpretations of these facts. 
Indeed, the fresh-water alge have taken only a minor place as sub- 
jects of physiological inquiry, so that we have to-day a physiology 
interpreted by too many in terms applicable to land plants only. T 
laboratory guides carry this to the extreme, but they show how 
one-sided our knowledge is. Pfeffer's book can contain only a few 
references to the marine alge. I am convinced that the careful 
physiological study of marine plants, though such study may reveal 
no new principles, will modify and correct many of the conceptions 
prevailing to-day. The status of the science is satisfactory, but 
there is room for much more research. ote po 
