CURRENT LITERATURE 
BOOK REVIEWS 
Temperature and life processes 
Kanitz! has written a monograph containing a critical discussion of the 
effect of temperature on life processes. He has brought together the literature 
from the fields of physical chemistry, physiology, pharmacology, bacteriology, 
botany, and zoology. The reader will find 363 citations of literature. Con- 
sideration is given first to the effect of temperature upon the rate of chemical 
processes. It is found that in general the latter follow the Van’t Hoff law, 
that is, the rate at ordinary temperatures is approximately doubled or trebled 
for each increase of 10° C. in temperature. The coefficient for 10° C. rise in 
temperature (Q,.) is then 2 to 3. The formulae of BERTHELOT, ARRHENIUS, 
Von Essen, and Van’t Horr are derived and the relationships discussed. 
From these data equations are deduced by which the value of Q:. may be 
calculated from experimental results at any two temperatures. For this 
purpose either one of the two following equations may be u 
A. —+-10 (log k2—log k:) 
Yo Lh 
: <—s 
or Qn= (3) le—te» 
ky 
in which k.=rate observed at temperature f2., and k,=rate observed at tem- 
perature ¢,. While most chemical processes are in agreement with the Van’t 
Hoff law, abnormal values of Q;. are found in certain types of reactions. High 
values of Q1 are common in monomolecular reactions, for example, in the 
inversion of cane sugar, Qr=5 to 6. Low values of Q,. are formed in hetero- 
geneous system where two processes take part, one process slowing down 
the total rate, for example, when a process is conditioned by diffusion rate, 
Qrw=1.5 to 1.2. In photochemical processes Q1., with few exceptions, is not 
higher than 1.4, usually only 1. 2 or even 1.0. 
Many processes in living organisms sho w a temperature coefficient approxi- 
mately that of the Van’t Hoff law, within certain temperature limits. Among 
the plant processes for which this has been found to be the case the following 
may be mentioned: CO, assimilation: (MatTHaE!) between o° and 37° C.; 
respiration of seedlings (KUIJPER) asa o° and 35° C.; geotropic presenta- 
tion time (RuTGERS) between 5° and 25° C.; Ghatotiops presentation time 
Kanitz, Aristipes, Temperatur und Lebensvorgiinge. 8vo. pp. ix+175. 
figs. 11. Berlin: Gebriider Borntraeger. 1915. 
156 
