652 MANAGEMENT OF SHEEP EXTERNAL PARASITES 



on sheep; but, if used strong enough to destroy the eggs of 

 the scab-mites by coagulating the albumen in their substance, 

 it is liable to irritate the skins of the sheep, and give such a 

 shock to their nervous systems that the function of digestion 

 is suspended, and the animals become hoven, as in tympanitis, 

 and a speedy death can only be prevented by immediate 

 washing in clean water. But when used in moderate quan- 

 tities viz., I gallon to 50 or 75 gallons of water the 

 mixture is so safe that it has been designated by the trade 

 " non-poisonous " dip. Only cresylic acid of 95 per cent, to 97 

 per cent, purity is tolerably free from the risk of staining the 

 fleeces of white-woolled sheep, as the lower grades contain 

 pitch-oil, and are so irregular in strength that uniformity of 

 results are difficult to obtain. But from the best manu- 

 facturers of " carbolic " sheep-dip this ingredient of a mixed 

 dip can be purchased in 4O-gallon casks at the reasonable 

 price of 2s. 6d. per gallon, of such a strength that I gallon of 

 the material is sufficient for 75 gallons of water. The 

 ordinary farmer could not save much by preparing the 

 carbolic acid at home. In conjunction with arsenic its effects 

 are most satisfactory. It is not good practice to use a strong 

 carbolic dip, or, in fact, any dip twice within fourteen days, 

 as lambs especially are liable to swell in the limbs as if 

 foundered ; but a carbolic dip may precede or follow an 

 arsenic or other dip within eighteen or twenty-one days 

 with safety and with excellent results. 



Pitch-oil we do not recommend for general use, owing to 

 the objections which wool manufacturers have to its injurious 

 effects on the colour and dyeing properties of the wool. See 

 footnote, p. 652. It is a product of very irregular composi- 

 tion, got by fractional distillation of tar from blast-furnaces 

 or gas-works. It is also known in the oil trade as lusuline, 

 torch-oil, and black naphtha, and the valuable property 

 which it possesses is mainly derived from cresol. The 

 lower grades of pitch-oil should not be used for dipping 

 Cresol is generally considered to be superior to carbolic acid as an anti- 

 septic and vermin-killer, and Allen speaks of it as on the whole less 

 irritating to the skin, especially after the separation of an acrid phenoloid 

 body of high boiling point. 



For details, see Coal-Tar and Ammonia, by Professor Lunge, pub- 

 lished by Gurney & Jackson, London ; and a paper by Alfred W. Allen 

 in The Journal of the Society of Chemical Industry, vol. ix., 1890. 



