18 FARMERS BULLETIN 798. 



measured quantity of dip, and pour in, with thorough mixing, the 

 desired quantity of the water, preferably warm, which sliould be 

 added in approximately the proportion to be used in dipping. Tf 

 after standing for one hour an oily layer or mass (jf globules appears 

 either at the top or at the bottom of the liquid, the dip should not 

 be used with that kind of water. 



Sheep dips are most effective when used with soft Avater. If it is 

 necessary to use alkaline water for diluting such dips, the water may 

 be " broken " by using sal soda in the proportion of from 1 to 4 

 pounds for each 100 gallons of water, depending upon the " hard- 

 ness " of the water. Where the water intended for dipping purposes 

 is very impure the owner should have it analyzed and obtain the 

 advice of a competent chemist on methods of correcting the water to 

 render it suitable for diluting the dip he proposes to use. 



KINDS OF DIPS. 



In choosing a dip for sheep ticks the conditions under which it is 

 to be used should be considered. A dip that might be best under one 

 set of conditions is not necessarily so under all conditions. The 

 nature- of the dip and its effect on the animals when used with the 

 water available at the dipping plant should be considered. If the 

 dipping plant is not supplied with soft water the dip that works 

 best in the water available should be selected. Dips deteriorate by 

 use; that is, after a number of sheep have passed through the vat the 

 active principle of the dip falls below the standard required for 

 effective work. For example, during investigations in the Bureau 

 of Animal Industry 35 lambs in 4 groups were dipped in a vat con- 

 taining 60 gallons of diluted cresol U- S. P., 1 part to 100 parts of 

 water. Samples were taken before and after dipping eaqh group. 

 These samples were analyzed, with the following results: 



Per cent 

 cresylic acid. 



No. 1, taken before any lambs were dipped : 0. 45 



No. 2, taken after 9 lambs were dipped 0.34 



No. 3, taken after 18 lambs were dipped 0. 2G 



No. 4, taken after 27 lambs were dipped 0. 18 



No. 5, taken after 35 lambs were dipped ^ 0.12 



The difficulty has been overcome for some of the dips, and the 

 Bureau of Animal Industry now supplies its inspectors with portable 

 testing outfits for testing the dip at the vat. The only dips for which 

 portable testing outfits are available at present are the arsenic, the 

 nicotin, and the lime-sulphur. 



Certain groups of ready-prepared dips are efficacious and have 

 been used by flock owners with a fair degree of success. Among these 

 may be mentioned the coal-tar-creo.'-ote. the cresol, and the nicotin 

 dips. The only homemade dip wliicli has proved efficacious is the 



