26 



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 quan- 

 tities of poisonous insecticides in general use, that would prove fatal or 

 dangerous to man and our domestic animals. It is impossible to be very 

 exact in this matter as Toxicologists differ in their opinions as to the 

 quantities required to prove fatal. This is undoubtedly 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 language 

 as arsenic, is not very much used as an insecticide, but some of its com- 

 pounds 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 fourteen 

 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. 



x\bout one-sixth as much will probably prove fatal to a person three 

 years old. 



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

 years old. 



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

 year old or under. 



Blyth in his " Poisons, their Effects and Detection" states that the 

 following doses of arsenic may be considered as dangerous : two grains 

 for an adult, thirty grains for a hors&, ten grains for a cow, one-half of 

 a grain to one grain for a dog. 



There are numerous cases on record of recovery after enormous 

 doses. In nearly all these cases, however, two conditions are recorded : 

 first, that the poison was taken after a full meal, and secondly, that 

 very early and free vomiting occurred. This, indeed, is doubtless the 

 explanation of many cases which otherwise appear inexplicable. 



