EXPERIMENTAL DATA ON ACIDITY DETERMINATION. 



T\BLE 7. Effect of removal from plant of acidity of joints of Opuniia versicolor. Tucson, 



March 1911 and July 1912. 



Acidity of material direct from living plant compared with that from joints which had 

 been detached but exposed under otherwise similar conditions. The wound surfaces where 

 the joints had been separated were not in this case painted with vaseline. In the first series 

 the total acidity of a 50-gram sample and the acidity of the pure juice per cubic centimeter 

 are given; in the second series only the juice acidity is indicated. Acidity is given in terms 

 of cubic centimeters of N /10 KOH. 



SERIES I. MARCH 20-21, 1911. 



SERIES II. JULY 15, 16, 1912. ACIDITY OF JUICE ONLY. 



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