584 



Journal of A gricultural Research 



Vol. XII, No. 9 



acts in a similar manner to compounds with a low boiling point, while by 

 killing the eggs with fully developed embryos it acts as a compound hav- 

 ing a high boiling point. The Pearl oil used in the experiments is a prod- 

 uct from the California oil fields and therefore differs chemically from the 

 other kerosenes used. 



In order to obtain further data on the toxicity of kerosene to eggs, two 

 brands of kerosene were broken up into fractions of different boiling 

 points. The two brands used were Pennsylvania Best sold by the Pure 

 Oil Co. and Perfection oil put out by the Standard Oil Co. of Indiana. 

 The data obtained by this experiment are shown in Table IV. The 

 fraction of Pennsylvania Best boiling between 140° and 187° C. killed 

 only freshly laid eggs. The fraction between 187° and 234° C. killed 

 both the fully developed and freshly laid eggs, while the fraction between 

 234° and 280° C. killed all the eggs. Apparently the lower fraction did 

 not remain long enough upon the fully developed eggs to produce any 

 influence. It was noted in the kerosene experiments that the higher 

 fractions killed at the time of hatching. This may explain the fact that 

 the partially developed eggs treated with the second fraction allowed 

 100 per cent to hatch. These eggs being too far developed were not 

 effected by changes in permeability such as would kill a freshly laid egg, 

 while the compound had sufficient time to evaporate from the surface of 

 the egg before the emergence of the larva. 



Table IV. — Toxicity of different fractions of kerosene on eggs of different ages 



Brand. 



Pennsylvania Best. . 



Age. 



Fully developed ... 

 Partially developed 



Freshly laid 



General 



do 



Percentage hatching after dippinur for 5 seconds ia 

 fractions with boiUng points of — 



140 -187 

 C. 



100 

 100 

 o 

 100 

 100 



187 -234 

 c. 



100 



o 



100 



100 



234 -2 So 

 C. 



O 



o 



o 



100 



Residue 

 above 



280° C. 



Undis- 

 tiUed. 



O 

 O 



100 



50 



Brand. 



Age. 



Percentage hatching after dipping for s 

 seconds in fractions with boiling 

 points of — 



i35°-i83° C. 



i83°-23i'' C. 



23i°-28o'' C. 



Perfection 



Fully developed . . . . 

 Partially developed 

 Freshly laid 



