394 Agricultural Experiment Station, Ithaca, N. Y. 



air in the greenhouse. Under these conditions the plant readily 

 gives off water and if the loss is greater than the roots can supply 

 the tissues first wilt, then collapse and die. The ability of the 

 roots to supply the moisture is affected by the temperature of the 

 soil, the movement of water in the latter, and the presence or 

 absence of salts in solution. In this soil the temperature rises rapidly 

 as soon as the air in the greenhouse becon.es warm, and the roots in 

 consequence immediately begin the work of supplying the leaves 

 with water. The movement of the water in the soil is also rapid, 

 so that the plant is able to utilize it rapidl3\" 



