302 Transactions of the American Institute. 



and its effects were short-lived. Sulphur, arsenic, &c., were deci- 

 dedly objectionable in their eflfects upon sheep, operators and 

 wool. 



It is but a few years since, in the effort to extract from coal tar 

 a substitute for that indispensable medicine, quinine, that the beau- 

 tiful anniline colors were discovered; and in seeking to perfect 

 these, first carbolic, and then its active principle, cresylic acids 

 were extracted from coal tar. 



Very soon the powerful disinfectant, anti-septic and insect- 

 destroying powers of carbolic acid were made knoTVTi, and a firm 

 in Manchester, of manufacturing chemists, turned the latter quality 

 to an excellent purpose, and made and brought into almost uni- 

 versal use, " McDougall's Sheep Dip," 



This, a compound of this acid, formed into a soft soap, was every- 

 where named to me as the only effective destroyer of the scab and 

 foot rot insects, and complete preventive to their re-attacking the 

 same animals for some months. 



I carried a moderate supply to Texas, and there fully tested its 

 value in destro^ang insect life, and preventing their attacks upon 

 man, animals and plants. 



I found, however, that all insects possess a vitality and vigor in 

 all parts of this continent, which they do not in the cooler and 

 moister climate of England, and that a solution of the same 

 strength that proved effective there, merely paralyzed for a time 

 many insects here. For example, in washing dogs to destroy fleas, 

 using the solution of sheep dip, the insects dropped out, apparently 

 dead; but on being left a few minutes in the sun, rallied, and began 

 to hop about. Since then, I have seen used a similar soap, con- 

 taining, however, cresylic instead of carbolic acid, which possesses 

 all the qualities desired. It is now employed as the active compo- 

 nent in many most useful compounds. 



To "return to our muttons." A solution of this cresylic sheep 

 dip, of a strength to cost from two to two and a half cents per 

 head of sheep treated of the average size ai]d weight of wool here, 

 is used as a bath or dip. In England and Scotland, I found that 

 lambs were dipped early in the summer, but the bulk of the flock 

 not until later, when the blow fly is expected. This fly deposits 

 her maggots in the wool, during a dark, moist, warm season, which 

 soon penetrate the skin and do great damage, but do not touch 

 sheep which have been dipped in this compound. The sheep ai"e 

 kept in the bath for from one to twc minutes. 



