48 Ohsei'vations on Parasites and Parasitic Diseases 



Sheep-Dipping. 



The benefits arising from the clipping of sheep are universally 

 admitted by flock-owners, not only for the destruction of parasites, 

 but for the general health and comfort of the animal, as also for 

 its beneficial effect upon the growth of wool. 



Baths for sheep-dipping may be classed under four principal 

 heads, viz. : — Vegetable decoctions — Arsenical solutions — Sul- 

 phuretted mixtures, and those, the antiparasitic properties of 

 which are chiefly due to Alkaline carbolates in combination with 

 tarry matters. Two, or sometimes more, of these compounds are, 

 however, not unfrequently mixed together, both by farmers and 

 manufacturers. 



Vef/etable Decoctions. — These preparations are multitudinous, 

 and also variously combined. The principal agent, however, in 

 most of them is tobacco, with Avhich decoctions of some one or 

 other of the following narcotic vegetables, as being the most active, 

 are mixed in different proportions, viz. : — henbane, monkshood, 

 figwort, hellebore, foxglove, stavesacre, Sec. As a rule, vegetable 

 decoctions are safe applications, if not too much concentrated, 

 and they may consequently be used under circumstances un- 

 favourable to the employment of arsenical solutions. Notwith- 

 standing this, they are not in great request in England ; but in 

 Western Australia reliance is placed almost entirely on a decoc- 

 tion of tobacco mixed with sulphur, both for the destruction of 

 ticks and lice, and also as a cure for scab — a disease which often 

 causes immense losses in that country. The number of sheep to 

 be dipped in Australia in a day, amounting frequently to several 

 hundreds, calls for economy of time and labour, and hence 

 various expedients, quite foreign to us, are necessarily had re- 

 course to for getting over the work. The following extract from 

 an article on sheep-dipping in that country by Mr. J. Annand, 

 who had had considerable experience in the matter, is taken from 

 the 'Veterinarian' for June, 1862 : — 



" A bath is made which contains 1 lb. of tobacco and 1 lb. of sulphur to 

 every 5 gallons of water, and into this the animals are plunged. The mixture 

 is always kept as warm as the animals canbtr^r it, avoiding of course extremes. 

 Coppers are erected to boil the tobacco, after which the decoction is placed in a 

 large dip or receptacle, and the sulphur is then added. These dips are constructed 

 of various sizes, and sunk in the ground. The heat of the mixture is kept up 

 by the addition of hot liquor, and partly by the bodies of the sheep themselves. 

 The dips should not be too large, as there is then a greater difficulty in keeping 

 up the temperature of the fluid. If too small, however, there is a danger of 

 the sheep striking on the bottom, when precipitated into the receptacle from 

 the pen above. A good size is that which will hold ten or a dozen sheep com- 

 fortably at one time. 



" I enclose a sketch of the dip, yards, &c., which will assist your readers in 

 understanding the method of using the bath. 



