504 DISEASES OF CATTLE. 



eradication. This method offers the advantage that the pasture may 

 be used continuously. 



Many efforts have been made to discover a pra^^tical method for 

 dipping cattle to destroy ticks without injury to the cattle, and the 

 bureau has experimented for years with this object in view. Numer- 

 ous kinds of dips have been used and many failures have been 

 recorded, but the most successful results have been obtained by the 

 use of an arsenic solution, the formula for which is as follows : 



In preparing each 500 gallons of the standard arsenical solution there should 

 be used 10 pounds of finely powdered white arsenic containing not less than 99 

 per cent of arsenic trioxid, 25 pounds of sal soda, and 1 gallon of pine tar. The 

 arsenic and sal soda should be boiled together in not less than 25 gallons of 

 water for 15 minutes, or longer if necessary to effect complete solution of the 

 arsenic. Before the pine tar is added the temperature of the solution should be 

 reduced to 140° F. This may be done by the addition of cold water. The pine 

 tar should then be added in a small stream while the solution is thoroughly 

 stirred, after which the solution should be immediately diluted with clear water 

 EuflBcient to make .500 gallons of dip. 



A dip prepared on the basis of the foregoing formula will contain 

 the proportion of arsenic required at the present time (1911) by the 

 regulations of the Bureau of Animal Industry relative to the treat- 

 ment of cattle which are to enter interstate commerce from tick- 

 infested areas. 



When repeated treatments at intervals of two or three weeks are 

 given and continued over considerable periods of time, as is com- 

 monly done in eradicating ticks by the dipping method, and when 

 immediate removal of the cattle to tick-free areas is not contemplated, 

 the amount of arsenic maybe reduced below that demanded for official 

 dippings. A dipping solution prepared in the proportion of 8 pounds 

 of arsenic to 500 gallons of dip has been found very satisfactory for 

 eradication work and is less likely to have injurious effects on cattle 

 than the stronger solution. Some users of the dip believe that the 

 addition of soap to this weaker solution is an improvement. If 

 soap is used it should be cut up and either dissolved in hot water in 

 a separate container or dissolved in the hot ai-^enic and soda solution. 

 For 500 gallons of dip about 25 pounds of soap may be added. It 

 may also be foimd of advantage in the 8-pound arsenical solution to 

 increase the quantity of pine tar to 2 or 3 gallons. 



Precautions in use of arsenic. — On account of the fact that arsenic 

 is a dangerous poison, great care must be observed in making and 

 using the arsenical dip. From the time the arsenic is procured from 

 the druggist until the last particle of unused residue is properly dis- 

 posed of, scrupulous care should be taken in handling this poison. 

 Guessing at weights or measures or carelessness in any particular is 

 liable to result in great damage, and not only may valuable live stock 

 be destroyed, but human beings may lose their lives as well. 



