RicHARDs: DETERMINATION OF ACIDITY 245 
colorless and which contain only a small amount of colloidal 
substances which flocculate out in a neutral solution. "The last 
method outlined was used, with considerable success, during the 
summer of 1917 at Carmel, California, when the acidity of a 
number of types of the local plants was determined in addition 
to that of the succulent forms which were being investigated in 
detail. The results were interesting, but too few in number to 
warrant publication at this time. 
