22 



then immediately to retire. The building should then be 

 kept closed for forty-eight hours and all windows and doors 

 opened for four hours before it is again occupied by men. 

 " (3.) Stringent precautions to preclude any chance of 

 firing the inflammable vapour must be taken. 



•" For every 2;"> square feet of floor space supply 1 square foot of 

 evaporating surface (flat tins or dishes). 



" Each pan or dish should receive 1 11). of liquid. The dishes'" 

 should be placed on level supports -t feet from the ground. An entire 

 store of grain could thus be freed of insects at one operation extending 

 from Saturday to Monday. 



''(/•) To free grain from insects on a smaller scale: Carbon 

 bisulphide in the proportions here recommended will destroy insects 

 in grain without affecting the germinating powers of the seeds. 



' ; Every person who stores corn, peas or other grain subject to 

 insect attacks should prepare a fumigating box as follows : — 



" Obtain a barrel, puncheon or packing case of suitable size. 

 Line the inside with building paper stuck on with a mixture of varnish 

 and whitening (chalk). Construct a lid which can be fastened down 

 firmly on a bearing coated with felt. For every 50 cubit feet of space 

 in the receptacle employ 1 oz. of bisulphide. For an ordinary flour 

 barrel one teaspoonful (■§• oz.) of bisulphide should suffice, if the 

 receptacle be tight and free from leaks. § 



" Place the bisulphide in a saucer on the surface of the grain, 

 keep tightly closed for thirty-six hours." 



'' (g.) Clothes Moths : Great damage to clothes is done in the 

 tropics by various species of moths. Camphor and naphthaline or 

 pyrethrum insect powder tend to keep the adult insects away, but the 

 former, at any rate, have no effect on the larvae when they have once 

 cemmenced their attack on the clothing." 



" Before putting clothing, woollens, or furs into store it is advis- 

 able to treat them with carbon bisulphide. An ordinary tin trunk 

 can be used if newspapers are spread over the top and the lid kept 

 tightly closed. Pour half a wine glass-full of the liquid on the sur- 

 face of the clothing, spread the papers quickly and shut tight. Should 

 the box be opened at intervals afterwards, naphthaline balls or insect 

 powder serve to keep away a fresh infection. The liquid will not 

 injure the clothing or leave any stain." 



*' (/() Household insect* : Should it be desired to destroy cock- 

 roaches, bed bugs or fleas in a house, it should be treated on the lines 

 laid down for disinfecting a granary." 



" A suitable time for this treatment would be an occasion when 

 the house is to be shut up for three or four days or longer. Individual 

 rooms could be treated, if desirable. Stringent precautions to avoid 

 ignition of the vapours or their inhalation by human beings are of 

 course necessary." 



" (i) insects in Tobacco, Museum specimens and Books : These 

 can be readily destroyed by treatment in a suitable closed vessel with 



