[Reprinted from SCIENCE, N. S., Vol. LIL, 

 1351, Pages 494-495, November 19, 1920] 



ON THE RELATIONSHIP BETWEEN FREEZING 



POINT LOWERING, A, AND SPECIFIC 



ELECTRICAL CONDUCTIVITY, K, OF 



PLANT TISSUE FLUIDS 



THE problem of the contribution of noii- 

 electrolytes, of undissociated molecules of 

 electrolytes, and of dissociated ions of electro 

 lytes to the depression of the freezing point, 

 A, in terms of which osmotic concentration is 

 usually measured, is one of considerable bio 

 logical importance. We desire to know, for 

 example, whether an observed difference in 

 the osmotic concentration of the tissue fluids 

 of a species growing in two different habitats 

 is due primarily to differences in the quanti 

 ties of electrolytes absorbed from the medium 

 or to differences in the quantities of organic 

 substances elaborated. The same question 

 naturally arises when one is comparing the 

 osmotic concentration of the tissue fluids of 

 different species in the same habitat. 



In the mixed solutions with which the biol 

 ogist has to deal the problem presents serious 

 difficulties. In certain cases some progress 

 may be made by determining the correlation 

 between the freezing point depression, A, and 

 the specific electrical conductivity, K. 



As a specific illustration we may take the 

 relationship between osmotic concentration 

 and electrical conductivity in a series of 

 plant species growing in the non-halophytic 

 habitats of the north shore of Long Island. 1 



In a series of 19 species of trees, 36 species 

 of shrubs, and 162 species of herbs both A and 



1 Protocols of data and full details are given in 

 a paper in press in the Journal of Physical Chem 

 istry. 



