58 BOTANICAL GAZETTE [JANUARY 
The reviewer believes that Jost’s treatment of transpiration could be 
greatly improved by adopting Livincston’s idea and method of relative 
transpiration. This gives quantitative determination of the inhibitory and 
regulating factors at work in the leaf under various conditions. The very exact 
work of Briccs and SHANtz on wilting coefficient is passed over with mere 
citation, and data obtained from the rather indefinite work of SACHS on non- 
available water 
any. will tielieve that Jost’s meager and derogatory statement of the 
place of colloids in plant physiology is very inadequate and faces away from 
future progress in the subject. The statement on dormancy in seeds could 
have been written twenty years ago as well as now. Jost apparently attempts 
to illuminate the simple by the complex when he likens the temperature curve 
for rate of diastatic action to similar curves for protoplasmic activity. It 
would be very much more to the point to explain that we know very largely 
the chemistry and physics of the first curve. Rise of temperature increases 
the rate of diastatic action with a rather constant coefficient (somewhat less 
than 2 for each 10° rise). It also increases the rate of coagulation of the enzyme, 
salto rapidly at higher temperatures, hence the high optimum. The 
oagulation is a function of the time as well as of the temperature. This 
ak for the optimum being much lower when the duration of the experi- 
ment is great. The failure of Jost to apply the idea of time as a factor in 
coagulation of proteins by heat is evident a number of times in the book, 
especially in his dismissal of LEPESCHKIN’s conclusion that death in general 
from supramaximal temperatures is due to the coagulation of cell proteins. 
While at one point Jost accepts and clearly discusses BLACKMAN’S conclusions 
n “optima and limiting factors,’ he frequently lapses into the older German 
view and phraseology. Jost’s arguments in favor of the claim that rate of 
water absorption by a cell as affected by temperature is a matter of protoplasmic 
regulation are rather weakened by the recent work of BRowN and WORLEY 
on barley grains, in which they found that temperature effects appear with 
about the same coefficient when non-living membranes only or chiefly are 
involved. Many of these criticisms are an outgrowth of Jost’s peculiar 
brand of vitalism. If he is convinced beyond a doubt that a physical or 
chemical explanation holds, he accepts it, but at too many points in his lec- 
tures he fails to outline the attack along these lines 
In spite of its virtues in organization, the book soak be greatly improved 
by better organization of the materials within the chapters and by a far more 
extensive index. At many points the author makes extensive detours from 
the subject under discussion. Graduate students frequently complain that 
they must read certain lectures several times and finally reorganize them 
before they can be held in mind. Paragraph headings such as BARNES 
or NATHANSOHN have used would serve the double purpose of making the 
plan of organization more evident and perhaps of leading to a better plan. 
An author index separate from or as a part of a more extensive general 
