DIPPING SHEEP FOR TICKS AND SCABS 423 



tially of two classes with reference to their source, re- 

 gardless of the ingredients which they contain. These 

 are proprietary and non-proprietary dips. 



The former are made from secret formulas which are 

 known only to those who make them. The basic ingre- 

 dients that compose them may be known in a general 

 way, but the exact methods of compounding and prepar- 

 ing them are known only to the proprietors. Their effi- 

 cacy is attested by testimonials from those who have 

 used them, and by the extent to which they have come 

 into general use. Some of those dips have been in use 

 for many years, and the popularity which has come to 

 them should be regarded as evidence of their efficacy. 



The latter are non-proprietary. The ingredients 

 which compose them are known, also the methods of 

 compounding and preparing them. They have the sanc- 

 tion in many instances of governmental authority, and 

 such sanction has been secured for them on the basis of 

 necessity. Such necessity has arisen from the enactment 

 of laws for the protection of sheep, more especially in 

 transit, from the contaminating influences resulting from 

 the presence of parasites. In various countries such 

 enactments have been found necessary for the mainte- 

 nance and prosperity of the sheep industry. Such legis- 

 lation made dipping compulsory under certain conditions, 

 and made it necessary also to prescribe the ingredients 

 that should be used in preparing dips, the amount of each 

 to be used, the methods of compounding them and also 

 the manner in which they shall be used. 



A somewhat bitter and prolonged controversy has 

 arisen between those who have put proprietary dips on 

 the market and the Bureau of Animal Industry in the 

 United States, with regard to the dips that shall be given 

 the authoritative stamp of public use in compulsory dip- 

 ping, as, for instance, when breeding stocks were about 

 to be conveyed from state to state. The Bureau claimed, 

 and apparently with reason, that before giving its sane- 



