Exchange and Movements of Gases and Liquids. 51 



dish. Constant movements of this character are in progress 

 in the plant. Note the amount of water drawn into the central 



Fig. 28. Transverse section of a root through the zone of root-hairs. After Frank. 



cavity of the potato, and the change in level of the liquid in 

 the dish (Fig. 27). 



46. Structure of an absorbing root. Examine the 

 roots of a seedling grown in a germinator, with a magnification 

 of about sixty. Numerous root-hairs, consisting of tubular 



