436 EXTERNAL PARASITES OF ANIMALS 



Commercial dips. There are a large number of these proprietary 

 dips on the market, many of which contain as the active agent coal- 

 tar derivatives. Use only those that have the approval of the 

 United States Department of Agriculture, and follow closely the 

 directions given on the container. 



Crude oil emulsion (for spraying stock). 



Soap 1 lb. 



Crude oil 4 gal. 



Water 1 gal. 



Dissolve the soap in hot water, and while still hot add the oil slowly 

 and agitate into an emulsion by pumping the mixture back into itself. 

 For use, dilute with water so as to secure a 20 or 30 per cent 

 emulsion (see p. 430). 



Lice powder. 



Gasoline 3 parts 



Crude carbolic acid (90-95 per cent strength) 1 part 



Mix these together, and then stir in enough plaster of Paris to take 

 up all the moisture. If properly made, a dry pinkish powder will ba 

 the result. If good crude carbolic acid of the proper strength cannot 

 be obtained, cresol may be substituted, but will not give quite as good 

 results. 



Cresol disinfecting soap. Measure out 3 quarts of raw linseed 

 oil in a four or five-gallon stone crock ; then weigh out in a dish 1 

 pound 6 ounces of commercial lye or " Babbit's potash." Dis- 

 solve this lye in as little water as will completely dissolve it. Start 

 with I pint of water, and if this will not dissolve all the lye, add 

 more water slowly. Let this stand for at least three hours until the 

 lye is completely dissolved and the solution is cold ; then add the cold 

 lye solution very slowly to the linseed oil, stirring constantly. Not 

 less than five minutes should be taken for the adding of this solution of 

 lye to the oil. After the lye is added, continue the stirring until the 

 mixture is in the condition and has the texture of a smooth, homoge- 

 neous liquid soap. This ought not to take more than a half hour. 

 Then, while the soap is in this liquid state, and before it has a chance 

 to harden, add with constant stirring, 8| quarts of commercial 

 cresol. The cresol will blend perfectly with the soap solution and 



