SCIENTIFIC PROCEEDINGS (in). 



Olneya tesota and of the leaves of the leafy P. cockerellii parasitic 

 on Populus wislizeni, Salix wrightii and Fraxinus attenuate,. 



Sap was extracted after antecedent freezing of the tissues in 

 an ice and salt mixture 1 to facilitate extraction 2 and the constants 

 determined on the centrifuged sap. 



Table i shows the average values of A and of P as determined 

 from a published table. 3 



TABLE I. 

 FREEZING POINT LOWERING A, AND OSMOTIC CONCENTRATION, P. 



For each comparison the osmotic concentration of the tissue 

 fluids of the parasite is higher than that of the host. Thus the 

 results of earlier investigations in Jamaica and Arizona are 

 confirmed. 



TABLE II. 

 SPECIFIC ELECTRICAL CONDUCTIVITY, K X io 8 , AND THE RATIO OF X TO A, K/A X 10*. 



The constants for specific electrical conductivity and for the 

 ratio of electrical conductivity to freezing point lowering appear 



1 Gortner and Harris, PI. World, 1914, xvii, 49-53. 



2 Dixon and Atkins, Sci. Proc. Roy. Dublin Soc., 1913, N. S., xiii, 422-423; 

 Gortner, Lawrence and Harris, Biochem. Bull., 1916, v, 139-142. 

 1 Harris and Gortner, Amer. Jour. Bot., 1914, i, 75-78. 



