430 EXTERNAL PARASITES OF ANIMALS 



weather, should not be driven any great distance immediately after- 

 wards, and should be provided with shade and an abundance of water. 

 Unless these precautions are observed serious injur}^ and losses may 

 result. 



Emulsions of crude petroleum. — In the majority of cases the best 

 agent to use is an emulsion of crude petroleum, preferably Beaumont 

 crude petroleum. The use of the emulsion makes the treatment less 

 expensive than when the oil alone is used. The emulsion is not so 

 injurious to the cattle and is almost if not quite as effective as the oil 

 alone. The formula for preparing an emulsion of crude petroleum is 

 as follows : — 



Hard soap 1 lb. 



Soft or freestone water 1 gal. 



Beaumont crude petroleum 4 gal. 



Making five gallons of 80 per cent stock emulsion. 



When a greater quantity of stock emulsion is desired, each of the 

 quantities in the above formula should be multiplied by such a number 

 as to furnish the required amount. For example, if it should be con- 

 venient to mix 10 gallons at one time, the quantities would have to 

 be multiplied by 2 and if 15 gallons were desired, they would have 

 to be multiplied by 3, and so on. 



In preparing the emulsion the soap should be shaved up and placed in 

 a kettle or caldron containing the required amount of water. The 

 water should be brought to a boil and stirred until the soap is entirely 

 dissolved. Enough water should be added to make up for the loss by 

 evaporation during this process. The soap solution and the required 

 amount of oil are then placed in a barrel or some other convenient re- 

 ceptacle, and mixed. The mixing maybe effected by the use of a spray 

 pump, pumping the mixture through and through the pump until the 

 emulsion is formed. A convenient and time-saving method is to do 

 the mixing in a barrel by first pouring in one part of hot soap solution 

 and then four parts of crude petroleum, and repeating this until the 

 barrel is filled. The oil should be poured in with as much force as pos- 

 sible, and the mixture stirred constantly with a long paddle until the oil 

 is completely emulsified. The mixing is facilitated also by dipping 

 up the mixture and pouring it back with a pail. If made properly, this 

 stock emulsion is permanent, and will keep indefinitely. 



