The Dipping of Sheep in so-called Carbolic Dips. 587 



Now, creosote oil is practically insoluble in water; it is therefore 

 necessary to treat it so that when mixed with water it will give a 

 ])ermanent uniform fluid from Avhich the oils will not separate. There 

 are two directions in which this can be accomplished, i.e. (1) by treat- 

 ing the oils so that they will dissolve in water, and (2) by treating 

 the oils so that they will form, when mixed witli water, a permanent 

 uniform emulsion. In the making of these dips a combination of 

 these two methods is used. The phenols are changed into soluble 

 substances by meiuis of caustic soda, which soluble sidtstances (cresy- 

 Intes among others) remain soluble on dilution of the dip with water: 

 while the remaining oily compounds are dissolved in a rosin* soap. 



In making the dip the manufacturer takes the creosote oil and 

 dissolves therein the requisite quantity of rosin, after which he adds 

 a calculated amount of caustic soda solution. The mixture is then 

 l^oiled to saponify tr.e abietic acid, that is to produce rosin soap. If 

 the operations have been properly conducted a clear, brownish, tarry- 

 smelling liquid results which, on dilution with water, should form a 

 whitish uniform emulsion from which no oily globules will separate 

 on standing. 



Having outlined the nature of the substances! v»ith which this 

 article is concerned, the circumstances surrounding two or three 

 dippings which were attended with fatal results may now be recounted. 



('OAL-TAK ])ip " A." 



Early in 1917 the writer was asked to investigate a sample of dip. 

 here called " A," for poisons. The owner of some valuable sheep had 

 dipped them in a mixture of one part of '' A " to 150 parts of water. 

 The tank used had a capacity of about 300 gallons. 



The dipping was carried out early one morning ; the same evening 

 the sheep appeared to be all right, but by the following morning two 

 had died. Eventually 11 died out of a total of 68; all the casualties 

 occurred amongst the first 33. i.e. : Of first lot of 12 dipped, 6 

 died ; of second lot of 21 dipped, 5 died ; of third lot of 35 dipped 

 none died. 



Veterinary Surgeon Simson saw the sheep and described their 

 symptoms as follows : — 



Ante-mortem symptoms — 



Respiration accelerated, short and painful; there was a slight 

 mucous nasal discharge ; there was some swelling in the laryngeal 

 region; there was, before death, slight tympanitis. 



Post-mortem symptoms — 



Pneumonia in all; nephritis in three; bile-stained mucus in the 

 duodenum and mucosa appeared to be in a catarrhal state ; the bladder 

 Avas contracted and contained about a tablespoonful of white mucus ; 



* Rosin consists chiefly of aliictic acivl wliicli, on boiling with caustic soda, gives sodium 

 abietate, a substance which possesses remarkable powers in emulsifying oily materials. 



t There is another type of carbolic dip whose origin is coal-tar, i.e. the cresylic acid dip. 

 This dip is made from somewhat impure coal-tar derived creosols, caustic? potash, and linseed 

 oil. Since the cresyJates formed are soluble in water and since the materials used in the 

 manufacture contain only very small quantities of hydrocarbons, this dip on dilution with 

 soft water remains clear. Lysol is a member of this class of dip. 



