20 EXTERMINATING THE TEXAS-FEVER TICK. 
for ticks, but on account of its expense is not likely to come into 
general use, and dipping in a vat is therefore on the whole the best 
and cheapest method of applying remedies when large herds are to be 
treated. 
Farms and pastures may be freed of ticks by treating all cattle 
at regular intervals with an effective tick-destroying agent. If 
the treatment is applied with such success as to destroy all ticks 
Fic. 12.—Pail spraying pump for small herds. 
that reach the cattle from time to time, thus preventing any engorged 
females from dropping on the pasture after the beginning of the 
treatment, the pasture will become free of ticks after the same 
period of time has elapsed as would have been required if all animals 
had been excluded, beginning on the same date; that is, a per- 
fectly successful treatment would be practically the same as the 
complete exclusion of the herd. The dates on which the starving 
378 
