WIXTEEGEEEX. 329 



sell it pure. Some of the Canadian distillers refuse to describe 

 their methods of rectifying the crude oil, and others describe three 

 ways of clearing it — decolorisation, filtration and redistillation ] 

 the decolorisation is said to consist in putting the oil in a bottle, 

 adding a few crystals of citric acid and agitating occasionally until 

 the oil is colourless or nearly so. 



There are three layers of bark on the wood. The outer thin 

 tissue contains no oil ; the next, or middle layer, is of a greenish 

 colour and likewise contains no oil ; the inner layer, next to the 

 wood, which is much thicker than the others and more spongy, 

 contains the oil. Some distillers use the gaultheria plant 

 exclusively, others mix it indiscriminately with the birch, and by 

 some the birch alone is used. It is according to the relative 

 abundance of the material in the locality. The yield from the 

 gaultheria fresh leaves, in an air-dry condition, has been ascer- 

 tained to be 2 per cent, but it varies according to the time of 

 collection. By the crude method of distillation employed by 

 settlers in the woods, the yield is only 0*5 to 0"8 per cent. The 

 yield of oil from the birch, distilled by the usual primitive 

 methods, varies from 0'2 to 1 per cent. The yield is most 

 abundant during the months of July and August. Of course the 

 percentage of yield varies with the proportion of the bark to the 

 wood in the charge. The former plant is considerably more 

 expensive to gather, costing at the lowest calculation about thirty 

 dollars per ton, the labour being very tedious and the labourer 

 earning, at that rate, scarcely sufficient to live on. 



The oils from the two plants are both being marketed as "'AVinter- 

 green oil," and both are subjected to systematic adulteration with 

 petroleum, <^c. 



The pure oil of wintergreen is mobile, refractive and quite 

 colourless, but it darkens by age if kept in the light in a bottle 

 which is frequently opened. It consists mainly of methyl salicylate. 

 Although it was formerly believed to contain 10 per cent, of light 

 oil or " light ring," which was lost or washed away with the waste 

 water in the careless process of distillation adopted in the woods, 

 it now appears that the originator of the statement (named below) 

 that it contains 10 per cent, of light oil either made a mistake or 

 experimented upon a sample which was adulterated with nearly 

 10 per cent, of turpentine (which is most likely). An elaborate 



