228 TWENTY-FIRST REPORT. 



required) in all soils, and it probably had no effect on the plants, which in this 

 species tolerate a wide range of reaction. 



Two collections of plants were made to see if any variation existed in the 

 concentration of resin. These are designated in Tables 1 and 2 as Series I 

 and II, and correspond to the dates, October 4th and November 3i-d. The 

 data show that October 4th was the time of higher concentration, and agree 

 with data of Miller.' 



•^Unpulilislu'il (lata kindly fiirnishpcl by F. A. Miller, Manager of Eli Lilly Co., 

 Biological Laboratories, Greenfield, Ind.^ 



