266 
Pearsall.—Shi dies in Growth. 
(i5°C. + i°), and the estimations were only begun after the appearance of 
secondary roots. The results obtained were similar to those of Series III 
(see Table II and Fig. 3), but in this case the stem had only completed about 
Fig. 3. Growth of stem and root in peas (Series IV) at 15° C. after appearance of secondary roots. 
Rate curves of Series IV and VI are given above. In VI the nutrient solution was aerated at A. 
half its growth by the time the roots stopped growing. The rate curves 
seem to show a limiting of the rate of root growth when the stem growth 
rate becomes high. As the stem rate gradually increases, that for the root 
proportionately decreases, and this is quite definitely in harmony, with the 
view that the food supply is diverted to the stem apex—ultimately causing 
a stoppage of root growth. 
