15 



The inference that terpeneless oil of lemon, produced by distilling 

 off the more volatile terpenes from the ordinary oil, is more likely to 

 be injurious to seed-corn than either the terpenes or the crude oil, is 

 confirmed in an interesting manner by the results of experiments de- 

 scribed by Dr. Whitten in the paper already referred to, in which he 

 says: "At the present the trend of evidence tends to show that the 

 [corn] grains bear immersion in the lighter oils without injury for 

 much longer periods than in the heavier oils, and that the injurious 

 after-efifects of the latter are more pronounced than those of the 

 former."' 



As a general conclusion from this phase of my discussion, it may 

 be said that my supposition that injury to planted seed-corn near 

 Bloomington was owing to dififerences in the quality of the oils applied 

 to the seed, was unfounded; and the cause of the observed variation in 

 the effects of treatment must be sought elsewhere. 



As a further test of this conclusion we may take two sets of plant- 

 ings, made at the insectary, in which the seed was treated with the 

 same lemon oils, in mixtures of the same strengths, as were used by 

 Mr. W. R. Scott, of Knoxville, and Mr. Frank Clark, of De Long, two 

 Knox county farmers w^ho reported serious injury to their seed. Sam- 

 ples of the oils were obtained from these farmers with statements of 

 the strengths used by them. Both bought their lemon oil in Knox- 

 ville, but from dilTerent druggists. From the following table it will be 

 seen that the insectary plantings of seed treated with these oils yielded 

 results not materially different from those of the untreated check- 

 plantings made at the same time; and the injury reported must hence 

 have been due to some local cause. 



Pot Plantings Treated with Ordinary Lemon Oil and Alcohol as useo 

 BY W. R. Scott and Frank Clark. Experiment of September 22, 1907 



Insectary test 



Scott's sample 

 Clark's sample 

 Checks 



^Bulletin, Illinois State Laboratory of Natural History, Vol. X, Art. V, 

 p. 269. 



