Hunter . — The Aerating System of Vicia Fab a. 633 
primarily or incidentally they take an important part in the respiratory 
activity of that portion of the root which is some distance from the root- 
hair bearing region, and also from the aerial portions of the plant. 
Fig. 6 . Schematized longitudinal section of Vicia Faba illustrating the distribution of the 
aerating system in different regions of the plant. 
A consideration of the evidence which has been brought together leads 
to the conclusion that the aerating system of Vicia Faba is elaborately 
adjusted, in order to ensure an efficient gaseous exchange for each living 
cell, no matter where its position may be in the plant tissues. 
T t % 
