1918] CURRENT LITERATURE 569 
These conclusions are quite out of accord with those of the principal 
investigators in this field. ANITZ,’ in his monograph on temperature and 
life processes, gives the following table, calculated from the experiments of 
ATTHAEI on the cherry laurel leaf, probably the most nearly error-free piece 
of work done upon carbon assimilation as effected by temperature. 
Temperature Assimilation CO: Qr0 
Gilbey Ger ee aceee 0.2 
Oe ie Re BPS OAL ie ees 2857 
ie nile ASS CRSA osha ge AB ee oe nee ee 
BOGE rca ria Wise Ba ers Ceres ia 2.12 
ee eae ow pe Te, a tae ps 1.76 
Sor ei, Saleen eke Ba alana wr Paes 1.81 
BO Aa Su cs 2-0 (ess ies 0.23 
KANITz points out that the Van’t Hoff law applies between o and 37°C. 
He also emphasizes the fact that the coefficient is excessive near the minimum 
temperature for the process and too small near the maximum, as is true for vital 
processes generally. The coefficients give no indication that photosynthesis 
is a purely photochemical process. Bayttss® classifies it as a complex 
photochemical reaction with increased energy; it results from the com- 
bination of purely chemical reactions with photochemical effects. The purely 
chemical phases seem to be the rate-determining portion, hence the high 
temperature coefficients. BOovir® gives a similar interpretation of the high 
temperature coefficients of the process. 
e authors misquote Kanitz’s formula for calculating Qr. DENNY’s 
review, upon which they depended, misquotes it, due to a typographical error, 
but they have altered it still further. 
_ NYBERGH attempted to show that photoperception in plants is purely 
photochemical. His main proof was the small temperature coefficient. DE 
Vries has since shown that the coefficient is relatively large and that the pro- 
cess obeys the Van’t Hoff Iaw from 10 to 30°C. 
It is possible that too much emphasis has been placed upon the size of the 
temperature coefficient as evidence for the chemical or physical nature of 
processes in the organism.” In the organism, the process often consists of a 
great number of individual chemical reactions and its rate is the resultant of the 
rates of all of them. On the other hand, we cannot have too many data on the 
effect of temperature (or any other factor) on the rate of vital processes or 
know too much about temperature coefficients which express this effect -WM. 
CROCKER. 
7 Kanitz, Aristmpes, Temperatur und Lebensvorgange. Berlin. 1915. 
8 Bayiss, W. M., Principles of general physiology (pp. 553-556). London. 1915. 
9 Science N.S. 37:373-375- 1913- 
10 Lerrcu, I., Some experiments on the influence of temperature on the rate of 
growth in Pisum sativum. Ann. Botany 30:25-46. 1916. 
