316 
PHYSIOLOGY: H. S. REED 
Proc. N. A. S. 
fig. 3 
Graph of values for walnut trees. Points represent values of log (t — 96) 
when t < h; crosses represent same when t > fa. 
The value of K here is only . 002 less than that first used and the exponent 
of (t — 96) is practically unity. The root-mean-square deviation of val- 
ues obtained from this equation was 2.65 cm., which differs so slightly 
from the first that there is no real advantage in favor of one equation 
over the other. 
The use of the method described does, however, give a more accurate 
means of computing the growth in cases where the initial growth of the 
organisms falls measurably below that given by the equation as pre- 
viously used. 
* Paper No. 85, University of California, Graduate School of Tropical Agriculture 
and Citrus Experiment Station, Riverside, California. 
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Fuhling's Landw. ZeiL, 68 (130-133). 
Mitscherlich, E. A. (1919), "Zum Gesetze des Pflanzenwachstums/' Fiihling' s Lan dw. 
ZeiL, 68 (419-426). 
Reed, H. S. (1920), "The Nature of the Growth Rate," Gen. Physiol, 2 (545-561). 
Rippel, A. (1919), "Die Wachstumkurve der Pflanzen und ihre mathematische 
Behandlung durch Robertson und Mitscherlich," Fuhling's Landw. Zeit., 68 (201-214). 
Robertson, T. B. (1908)," Further Remarks on the Normal Rate of Growth of an In- 
dividual and Its Biochemical Significance," Arch. Entwicklugsmechn. Organ., 24 (108). 
