MISCELLANEOUS 227 



There are many forrnulte recommended, according to the 

 particular phint and kind of insect to be dealt with. Thus a 

 mixture for fruit trees is made by boiling 10 lb. of quicklime 

 with 20 lb. of sulphur in about 20 gallons of water for about two 

 hours, then mixing this with 40 gallons of water in which 

 30 lb. of lime and 15 lb. of common salt have been dissolved. 

 This wash must only be used in winter, when the leaves are off. 



For scab in sheep the so called *' lime and sulphur dip " has 

 some strong partisans, especially in Cape Colony. However 

 it may be prepared (and the variations in the proportions of 

 lime, sulphur, and water appear to be very great ; thus, to 

 100 gallons of water quantities of lime varying from 4^ lb. to 

 20 lb., and of sulphur from 15 to 25 lb., are recommended 

 by various correspondents, and the ratio of lime to sulphur 

 varies from 1 : 1 to about 1:5), there can be little doubt that 

 the dip is injurious to wool. All alkalies and alkaline sul- 

 phides have a strong caustic action on such organic substances 

 as hair and wool, as is evidenced by the use of calcium sulphide 

 in strong solution for removing hair, both for toilet purposes 

 and also, on the larger scale, from skins prior to tanning. But, 

 if the injury to the quality of the wool can be excused, there 

 appears to be strong evidence in favour of the efficacy of the 

 dip as a remedy for and preventative of scab. 



It is of importance, however, to understand the principles of 

 its preparation. As already stated, the really active ingredient 

 is the calcium sulphide and polysulphide, though the free 

 sulphur doubtless would be useful, especially as a preventative 

 of re-infection. This free sulphur, however, can only be 

 applied to the wool if the dip is well stirred during the 

 operation of dipping, since it is quite insoluble in water, and 

 this practice is rarely followed. When lime is boiled with 

 sulphur the reaction results in the formation of calcium sulphide 

 and calcium thiosulphate, as indicated by the equation : 



