8 



appeared no more disturbed than when clear water was thrown upon 

 them from the atomizer. 



After this the worms under observation were not disturbed, but 

 continued feeding quite as if nothing had happened, and passed their 

 transformations in quite as healthy a condition as those which were 

 not treated. 



From these experiments we must conclude that alum as an insecti- 

 cide for the currant worm is a perfect failure. It is possible that 

 some one who tried showering currant worms with alum water, did 

 it just before they were done feeding, and when they went down 

 into the ground, he supposed his application had destroyed them, 

 and at once reported his supposed success in the papers. 



POISONOUS DOSES OF INSECTICIDES. 



We have frequently been requested to give information as to the 

 quantities of poisonous insecticides in general use, that would prove 

 fatal or dangerous to man and our domestic animals. It is impos- 

 sible to be very exact in this matter as Toxicologists differ in their 

 opinions as to the quantities required to prove fatal. This is un- 

 doubtedly due to the fact that some persons are not as susceptible to 

 the action of certain poisons as others, and amounts that would prove 

 fatal in some cases might not prove seriously injurious in others. 



ARSENIC. 



Arsenious acid or white oxide of arsenic, known in common lan- 

 guage as arsenic, is not very much used as an insecticide, but some 

 of its compounds are the most useful insecticides now known. The 

 following table of approximately fatal doses may prove useful, and 

 serve as a basis for calculations on its compounds. 



From one to two grains will probably prove fatal to an adult 

 person. 



About one-half as much will probably prove fatal to a person four- 

 teen years old. 



About one-third as much will probably prove fatal to a person 

 seven years old. 



About one-fifth as much will probably prove fatal to a person four 

 years old. 



About one-sixth as much will probably prove fatal to a person 

 three years old. 



