1915] /• Arthur Harris and Ross Aiken Gortner S7 



fruits were placed, as soon as found, in a Container with moistened 

 bibulous paper and closed by ground glass or a rubber sealed cover. 

 Additional proliferous fruits were added to the Container until a 

 sample sufficiently large for the expression of sap was obtained. 

 The abnormal mass was not removed from the fruits until the 

 sample was prepared for chemical analysis. The very exacting 

 task of dissecting over 100,000 fruits wduld have been an almost 

 impossible undertaking but for the untiring zeal of Miss Margaret 

 Gavin, Miss Lily Gavin, Miss Edna K. Lockwood and Mr. Charles 

 W. Grane, for whose assistance we desire to express our sincere 

 thanks. 



B. ExTRACTiON OF THE SAP. The includcd mass was separated 

 from the ovary wall. After weighing, the samples were packed 

 separately in thick walled test tubes, which were tightly closed with 

 rubber stoppers and, as an extra precaution, capped with oiled paper 

 fastened around the neck of the test tube by a tightly drawn rubber 

 band. The tubes were then plunged in a mixture of finely chopped 

 ice and salt at a temperature of — 17°, or lower (care being taken to 

 keep the mouths of the test tubes above the freezing mixture). 

 The freezing box was placed in a larger ice box to maintain the low- 

 est possible temperature^ and allowed to remain at least 10 hours to 

 insure the complete freezing of the tissues (See Gortner and Har- 

 ris, 1914). This method of freezing the tissues is less expensive 

 than that by liquid air (Dixon and Atkins, 191 3) and, for large 

 samples, is much more convenient and apparently quite as effective. 



The Contents were removed (after being carefully thawed) with 

 great care, to prevent any contamination, f olded in a small Square 

 of heavy muslin cloth (which had been boiled through three changes 

 of distilled water and dried at 110° in the absence of dust), and the 

 Juice expressed by means of a small, heavily tinned, "beef-juice" 

 press. The liquid was centrifuged at high speed to remove sus- 

 pended solids and the physico-chemical constants determined on 

 the clear sap. 



C. Determination of the specific electrical conductiv- 

 ITY. The electrical conductance, k, at 30°, was determined in the 



5 Aften ten hours the temperature of the ice and salt Solutions was still as 

 low as — 8° to — 10°. 



