WINTERGREEN 



509 



The plants are collected, chopped into small pieces, mixed with water 

 and allowed to stand for about 12 hours, when distillation is effected 

 by means of a copper still. The oil is generally further purified by 

 rectification. Owing to the demand for this oil and the high prices 

 obtained for it, it is frequently substituted by oil of birch- and adul- 

 terated with methyl salicylate. The leaves were used at one time in 

 medicine, but they have been nearly entirely supplanted by the oil. 

 Description. Leaves oblong or obovate, from 2.5 to 5 cm. in 

 length, and from 1.3 to 3 cm. in breadth; summit acute, mucronate 

 tipped; margin slightly revolute and serrate with bristle tipped teeth; 

 coriaceous; upper surface dark green and shining, the midrib slightly 

 raised, or depressed, under surface pale green, with 3 to 4 pairs of 



FIG. 216. Gaultheria procumbens: A, entire plant showing horizontally creep- 

 ing stolons and solitary axillary flowers. B, flower showing hypocrateri- 

 form corolla. C, stamen". D, young fruit. E, section of fruit showing the 

 baccate or berry-like calyx which encloses the true fruit or capsule. F, 

 leaf showing venation. G, cross-section of leaf showing epidermis (e), three 

 layers of palisade cells (p), and chlorenchyma (c). H, cross-section of margin 

 of leaf showing in addition a large group of sterome cells. After Holm. 



veins of the first order which diverge at an angle from 10 to 50 from 

 the midrib and unite with each other near the margin; odor distinct, 

 aromatic ; taste aromatic and astringent. 



INNER STRUCTURE. See Fig. 216. 



Constituents. From 0.5. to 1 per cent of a volatile oil, con- 

 sisting chiefly of methyl salicylate. The oil also contains 1 per 

 cent of the following constituents: tricontane; an aldehyde or 



