PARASITICIDES 39 



For human head lice, creoline (2%) may be applied by means 

 of a fine tooth comb. 



f. Kerosene is an extremely useful insecticide, but must be 

 diluted to prevent injury to animals, and is therefore preferable 

 as a spray for coops and stalls infected with mites or lice. Kero- 

 sene may be used pure for the latter purpose, or as an emulsion 

 not weaker than i to 10. The emulsion is prepared by dissolving 

 y lb. of soap in one gallon of hot water and adding one gallon 

 of kerosene. This forms a stock solution, and illustrates the 

 proportion for all practical purposes. 



Examine a sample of kerosene emulsion, both in stock and 

 diluted one to ten. 



g. Arsenic may be used as the active ingredient for sheep dips 

 and cattle dips. It is extremely poisonous, and the heads of 

 animals dipped must be kept out of the solution and the cattle 

 prevented from licking themselves or each other. Persons 

 employed in dipping operations must proceed with caution. 

 Dipping vats and stock solutions must be kept tightly closed to 

 prevent animals from drinking the poison. Dripping animals 

 must not be permitted where there is green herbage. 



Examine a sample of arsenic crystals. 



h. Pyrethrum powder, or buhac, is a fine yellow dust made 

 from the flower of Chrysanthemum cinerariafolium. This 

 powder is useful against lice and fleas. It is applied by means of 

 an insufflator or duster, and must be freely used. 



Examine a sample of pyrethrum powder or buhac. 



i. Naphthalene flakes are very useful as a repellent. The flakes 

 are dusted on the animals, and brushed into the hair freely. 

 Lice and fleas are strongly repelled. 



Examine a sample of naphthalene flakes. 



j. Tobacco dust or snuff, added in equal parts or one to three 

 of road dust is extremely useful as a dust bath for poultry. 

 Some sulphur may well be added. 



Examine a sample of tobacco dust. 



k. Sulphur may be used in cones, with wicks, for fumigating 



