522 
Smith . — The Temperature-coefficient of 
The method of Matthaei was to adopt only those numbers as measures 
of the influence of the temperature-factor which were obtained under condi- 
tions in which the temperature was shown to be limiting and the other 
factors in considerable excess. Working with one fixed light and a series 
of increasing temperatures, she found for that series a curve of the well- 
known inflected form with a rising limb for the lower temperatures, followed 
by a horizontal limb for the higher temperatures. Starting all over again 
with a more intense light, this finding repeated itself with the inflexion point 
at a higher temperature, and similarly with still more intense lights, the 
collection of curves being shown in Fig. I. 
Her interpretation is that the rising limb is a true measure of tempera- 
ture effect, while the horizontal limb is limited by light and merely expresses 
the light intensity, uninfluenced by temperature. Now, since the object of 
Brown and Heise is to show that assimilation is very little affected by 
temperature, they proceed on the general plan of casting doubts upon the 
soundness of the numbers in the rising limb of the curve (and upon these 
only) by appealing to seasonal changes, experimental errors, or other 
unsupported hypotheses. They are then left with merely a set of horizontal 
