CURREN T- LITERATURE 
BOOK REVIEWS 
Plant physiology 
The third German edition of Jost’s Lectures on plant physiology* ts 
certain changes from the first edition in general organization and point of 
view. Instead of the headings “‘Stoffwechsel,” ‘‘ Formwechsel,” and ae 
wechsel,” for the general divisions of the subject, the new edition has “ Stoff- 
wechsel,” “Formwechsel,”’ and “Ortwechsel.” The heading “Energiewechsel”’ 
is used for chap. xix, the last chapter under ‘“Stoffwechsel.” This brings the 
energy transformations into close connection with the source of the energy, 
which is quite desirable in contrast with the attempt to connect it with any 
particular manifestation of energy, as movement. Lecture 17 of the new 
edition has the’ heading “Oxidation of hydrogen sulfid, hydrogen, methane, 
and ammonia by bacteria. Carbon assimilation without light and chloro- 
phyll.” It corresponds to lecture 18 of the first edition with the heading 
“Sulfo and nitro bacteria.’’ Several other changes appear in lecture headings, 
indicative of change in viewpoint or content. The introductory lecture to 
“‘Formwechsel”’ has been cut down to five introductory paragraphs in the 
chapter on “Growth of the cell.” The 43 lectures of the first edition thus 
become 42 in the present edition, but the pages have increased from 695 
to 760. 
As one reads this excellent treatise, he is impressed by the number of sub- 
jects of which the author has an excellent critical grasp; plant — 
plant anatomy, evolution and heredity, physiological chemistry, etc. 
zer of the subject, with Sacus, remembering, however, that the task of organiz- 
ing the subject is now far more difficult, owing to the enormous amount of 
experimentation and range of knowledge to be included. In most parts of the 
treatise there are excellent summaries of the subjects, entirely up to date. 
This is illustrated by the statement on the synthesis of amino acids, lecithin, 
proteins, etc., which embodies the late work of Trier and others; by the 
eatly improved statement on catalysis and enzyme action; and by the lec- 
tures on hybridization and heredity, on variation, and on species-formation. 
* Jost, Lupwie, epiaieacat iiber Pflanzenphysiologie. xvi+760. figs. 104. 
Jena: Gustav Fischer 
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