﻿19 16] RIGG, TRUMBULL, LINCOLN— TOXIC SOLUTIONS 411 



standard solution used was that resulting from the decay of 500 gm. 

 of the rhizome in 800 cc. of water. Table III shows the results of 

 the test on three different solutions thus prepared. 



TABLE III 



The osmotic pressure of 10 per cent (1 volume of solution 

 to 9 volumes of water), 7^ per cent, and 5 per cent solutions 

 of these standard solutions was calculated from the results 

 shown in table III. These computed values are shown in 

 table IV. 



TABLE IV 



These particular dilutions are suggested because these (and in 

 some cases greater) dilutions proved toxic to plants grown in them 

 by Rigg (9). 



Surface tension 



Tests of the surface tension of bog waters were made by the 

 Jolly method. The results are shown in table V. 



