272 
R. H. TRUE AND H. H. BARTLETT 
solutions which show a strong extraction of ions from the plant, a 
slight improvement being seen in those solutions in which a more 
active absorption took place. The 
solutions of KNO3 seemed further- 
more to induce or accompany a gen- 
eral debility in the seedlings. This 
was shown by the large number of 
plants that for reasons not obvious 
deteriorated in the cultures. Indi- 
viduals developing increased leak- 
age due, perhaps, in part to injury 
not marked enough to lead to de- 
tection and removal were probably 
largely responsible for the irregu- 
larity of the results. The 2$6MX 
io~^ solution compared with the 
neighboring solutions showed an 
aberrantly high loss of ions from 
the roots and probably represented 
the partial failure of one or more 
individuals in the culture. 
/ a a 'it s s 7 
Potassium Sulphate. Experi- 
ment 8 
Twelve solutions of K2SO4 were 
made varying in concentration from 
20 to 240M X I0"^ the concentra- 
tion interval being 20M X lO"^. 
The experiment ran fifteen days. 
The results are plotted in figure 8. 
Potassium sulphate shows a 
physiological action very similar to 
that of potassium nitrate. In the 
more dilute solutions, 20 to 120M 
^ a , . . , X I0-^ the plants lost ions to 
Fig. 8. Curves showing the changes . 
in concentration of the K,S04 solutions the medium m a measure approxi- 
used in experiment 8. mately like that seen m the cor- 
responding nitrate series. In both 
salts an absorption phase appeared in the more concentrated solutions. 
