IQI?] 



HA A S—PRO TOP LA SM 



235 



sible, however, that the acid sap is contained in vacuoles rather 

 than imbibed in the protoplasm proper. 



Summary 



1. The actual acidity and the total acidity of a number of 

 plant tissues were determined. 



t 



2. There is no constant relation between the two, but great 

 variations occur in different plants and in different parts of the 

 same plant. 



3. In one case (cranberry fruits) the surprisingly high actual 

 acidity of o . 004N (as determined by the gas chain) was found in 

 the living cells. 



Laboratory of Plant Physiology 



Harvard University 



