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GRAVITATIONAL SENSITIVENESS OF THE ROOT-TIP. 273 
that the root could not regain the vertical position A. If this 
were so we should have a series of permanent irreversible curves 
Fig. 9. 
See text for explanation. 
Fig. 10. 
A bean-root, after curving geotropically, has been fixed in a vertical tube. 
occurring 
g, which would lead to just such a continued movement 
past_the vertical of the cotyledons as has been described. 
