362 



Experiments in Dipping Sheep. [sept., 



XII. — Spirits of tar : 2 11). of soft soap dissolved in a gallon of hot water, and 



well mixed with I gallon of spirits of tar, and added to 78 gallons of 

 water. 



XIII. — Tar acids with paraffin : Tar acid, 29 per cent. ; tar oils (paraffin)^ 



36 per cent.; lanoline, 8 per cent.; anhydrous soft soap, 17^ per 

 cent. ; water, 9^ per cent. One gallon of this mixture added to 

 100 gallons water. 



XIV. — Tobacco and sulphur : Made by steeping 35 lb. of finely-ground tobacco 



in water for four clays, with occasional stirring. The extract was then 

 strained off, and added to 10 lb. of flowers of sulpur, and the bulk 

 made up to joo gallons. 

 XV. — Tobacco, sulphur, and tar acid. 

 XVI. — Tobacco mixed with soft soap and sulphur. 

 XVII. — Carbolic acid, sulphur, and powdered hellebore. 



Except Nos. V. and VI., all the dips employed were effective 

 in killing keds, but were less successful in their action on the 

 puparia. In the second series of experiments No. VI. cured 

 scab, but again failed to destroy keds. Generally speaking, the 

 tar acid and crude tar products killed the keds almost im- 

 mediately. The tobacco dips were nearly as active, while the 

 sulphur and arsenic preparations required a little longer time. 



As the puparia appear to hatch out about twenty-one days 

 after being deposited by the female, a second dipping at the end 

 of three weeks would doubtless have a marked effect in getting 

 rid of keds. By that time the puparia left in the fleece after the 

 first dipping would have hatched out, and as there is no evidence 

 to show that keds produce puparia within three weeks after 

 they are hatched, it would only be necessary for the second 

 dipping to destroy the keds which had appeared since the 

 previous dipping. 



It is evident that where some of the poisonous dips are used, 

 a second dipping after an interval of twelve days is injurious to 

 the health of the sheep, so that where a second dipping is desired 

 for the destruction of keds, the proper time would appear to be 

 about three weeks after the first immersion. 



The second series of experiments dealt more particularly with 

 sheep-scab, but Dips II., V., IX., XL, XII., and XV. were 

 omitted from this series, but No. XVII., given above, was used, 

 for the first time. The sheep in this case were dipped twice. 

 In the third series of experiments the sheep were only dipped 

 once, and only four dips — Nos. IV., X., XIII., and XVI.— were 

 used. 



