4l2 BOTANICAL GAZETTE [ DECEMBER 
gor which must remain low even when their growth stops before 
death. But in other cases they fall behind their better fed 
rivals while their reserve food is still far from used up, as though 
the distilled water were in itself an active agent in restricting 
growth, and the turgor of these plants not uncommonly becomes 
as high as that of those normally grown (Phaseolus vulgaris). 
Such seedlings will sometimes become accustomed to the water, 
and after once ceasing to elongate will put forth a luxuriant new 
growth. As a sample of a number of similar cases a seedling of 
Zea may serve, whose roots were 13™ long February 10; Feb- 
ruary 19 they were still 13°"; but a week later they began to 
grow, and by March 10 measured 30. The roots of the first 
growth were remarkably thick and coarse, and but little branched ; 
the later ones almost capillary and mesh-forming. 
Except for a few plants, and a very few salts, the growth of 
plants in water cultures has never been studied, and will well 
repay a comprehensive, painstaking, comparative investigation. 
Is the influence of K upon the turgor a direct one? That 
is, does the K itself enter into the cell sap, in whatever combi- 
nation, in such quantity as to be a considerable part of the mat- 
ter in solution there, and is Na unable to replace the K in this 
physical function? Or is it by its activity in the protoplasm 
that K regulates the accumulation of other substances in the 
sap, in which respect Na, relatively inert and unessential to the 
plant, could not be expected to be equally effective ? At first 
sight, especially as K is held to play a prominent part in both 
the production and the translocation of the carbohydrates, one 
is inclined to regard the indirect course as the true one. To 
settle the question, seedlings of Phaseolus multiflorus were put into 
water cultures in two ten-liter jars, one containing the normal 
mixture of Ca(NO,),, KCl, K, HPO,, and MgSO,, already given 
under Pisum, the other different only in the substitution of Na 
for K. The jars were kept nearly full by addition of distilled water 
until June 3, during which interval the K fed plants transpired 
about three liters more water than did the others. The “crop” 
was then harvested, the roots quickly dried with filter pape 
ee 
