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TWO EXPERIMENTS IN HOUSE FUMIGATION 



By H. MAXWELL-LEFROY. 



Imperial College of Science and Technology. 



House fumigation with hydrocyanic acid gas or carbon bisulphide is 

 no new thing and some years ago Mr C. W. Mason and I fumigated the 

 greater part of the new laboratories of the Pusa Agricultural College, a 

 building over 400 feet long. But in the cases I have had experience of the 

 difficulties were slight and in the present cases were considerably greater. 



In the first case the house was situated in one of the suburbs and was 

 infested with the house mite {Glycypliagus domesticus, etc.). The use of 

 paraffin, formalin and sulphur dioxide in single rooms had driven the 

 mites over the whole house and the lady of the house was in despair, 

 having struggled without success for some years. It seemed likely that 

 only very drastic treatment in every part of the house simultaneously 

 would succeed and it was necessary that this should not simply mean the 

 rooms but the floors, staircases, outhouses and even the coalshed. 



It is known that hydrocyanic acid gas has a very small power of 

 penetration in grain and it was fairly certain that it would not penetrate 

 the floors if simply generated in the room : so carbon bisulphide was used 

 for floors and at the same time hydrocyanic acid gas was generated. 



The house was an ordinary three story detached one with twelve 

 rooms, no cellars or basement. The houses on each side were less than 

 twenty yards away. The volume of the house was approximately 

 31 feet cube or 30,000 c. feet. The individual rooms were not measured 

 but we tried to fill the whole house evenly and the amounts were allotted 

 roughly according to the size of the room ; all doors were left open inside 

 the house. 



The quantities employed were *40 lbs. cyanide 98 per cent., 40 lbs. 

 sulphuric, and 54 lbs. carbon bisulphide. Including larder, bathi'oom, 

 etc., 21 lots of cyanide and 23 lots of bisulphide were used as follows : 



Cyanide : 1 lot of 6 lbs. in the hall ; 



3 lots of 3 lbs. in the larger rooms; 

 11 lots of 2 lbs. in the smaller rooms; 

 6 lots of i lb. in the larder, etc. 



