Cattle-Fever Ticks. ' 27 



All the utensils must be free from greasy or oily matter which 

 would coat the arsenic and hinder its solution. The operati >n of 

 boiling requires constant attention to avoid loss by foaming. Hard 

 water may be used, but in that case considerable undissolved mate- 

 rial which, however, does not contain any arsenic, may be left after 

 boiling. 



For a stock solution to be kept on hand and used when needed add 

 no tar, but after the solution has become cold make it up to 25 

 gallons, stir well, let settle, and draw off into containers which can 

 be well closed. In this case the tar stock previously described is also 

 required. 



DILUTING THE DIP TO FORM A BATH. 



First run water into the vat about three- fourths up to the dipping 

 line, at which its capacity must be laiown. If tar stock is to be used 

 the necessary amount will be one-third of a gallon for every 100 gal- 

 lons of vat capacity. Measure it out, mix it with 2 or 3 times its 

 volume of water and pour it along the surface of the water in the vat, 

 stirring a little. 



Every 100 gallons of standard-strength ^ bath calls for II pounds 

 white arsenic, which quantity is contained in four-fifths of a gallon 

 of S-B stock or in 5 gallons of boiled stock. From these figures the 

 quantity of arsenic or stock needed to charge the vat may be cal- 

 culated. Or one may base the calculation on the following facts: 



One pound of white arsenic will make 62^ gallons of bath. 



One gallon of S-B stock will make 125 gallons of bath. 



One gallon of boiled arsenic stock will make 20 gallons of bath. 



All solutions of arsenic are considerably heavier than water and 

 if carelessly put into the vat they may plunge to the bottom and 

 be difficult to mix. Therefore always pour the arsenic stock or a 

 proprietary dip in a thin stream evenly along the vat except at 

 the shallow exit end. Another precaution to be taken in handling 

 l^roprietary dips is never to mix them first with small quantities 

 of water, which may "break" them. Pour them directly into the 

 water in the vat. 



Finally add water up to the dipping line and stir well. An ex- 

 cellent way to stir is by a pail tied to a rope. Sink it at the en- 

 trance end of the vat and haul it along the bottom to the exit. Then 



' The standard strength here refen-ed to is that employed throughout the area in which 

 cooperative tick eradication is conducted. It is based on the supposition that the cattle 

 will be dipped every two weeks throughout the season and meanwhile will remain under 

 quarantine. If, however, they are to leave the quarantined area special precautions 

 must be taken that they carry no tick infection, and consequently they are subjected to a 

 stronger dip, namely, from 0.22 to 0.24 pev cent arsenious osid. The dipping must be 

 done under supervision of an employee of the Bureau of Animal Industry and in accord- 

 ance with regulations published in B. A. I. Order 263. 



