1 68 Keegan : The Chemistry of some Common Plants. 



that digitoxin, and perhaps also digitonin, are only decomposed 

 digitalin. 



Woundwort. Stachys sylvatica. Notwithstanding- the 

 rather repulsive odour and quondam medicinal repute of this 

 plant it is not very specially interesting from our point of view. 

 The odour is due to the acetate of some alcohol allied to the 

 terpenes. The leaves contain a considerable amount of carotin, 

 and about 10 per cent, of an iron-greening tannin which does 

 not precipitate gelatine, and is somewhat similar to caffeetannin, 

 but it does not precipitate quinine, and ultimately turns brown 

 when its ammoniacal solution is exposed to the air. Much resin 

 of course may be expected and is found, also much proteid, but 

 very little mucilage, and a moderate deposit of starch. The ash 

 of the dried leaf amounts to 8*5 per cent., and is rather poor in 

 potass and lime, so that on the whole the plant is not so 

 exhausting to the soil as most of those aforesaid. The hue of 

 the flowers is rather dull, and their colouring matter is not 

 fully developed as might have been anticipated, in view of the 

 abundance of volatile oil and resin indicative of an incomplete 

 transformation of the products of deassimilation. 



Heather. Calluna vulgaris. This is the emblem of solitude ; 

 its growth is slow and its life prolonged. It affects siliceous 

 soils and eschews lime. In open elevated moors it is about one 

 foot high, but in open woods on sandy soils it springs up erect 

 some three or four feet. It is by no means a thirsty plant, and 

 only contains about 8 per cent, of water. The chemistry is of 

 rather special interest. The organs are abundantly charged 

 with wax ; there is considerable carotin, some fat, but not much 

 resin. Quercitrin and quercetin are especially prominent, and 

 form the basis of its special dyeing property for wool so popular 

 in former times. The tannin amounts to about 6*5 per cent, 

 and is iron-greening and phlobaphenic. Free phloroglucin occurs 

 in all parts of the plant (distinguished from other Sympetake). 

 Starch and oxalate of calcium are abundant ; but the attempt to 

 obtain from the plant a decoction capable of alcoholic fermenta- 

 tion — 'Scotch whisky' — proved a miserable failure, and it was 

 imagined that no real sugar was present. It does exist, how- 

 ever, both simple and combined in the glucosides arbutin and 

 erieolin ; a bitter principle called vaccinin is also found. The 

 mineral matters (ash) of the Heather have been the subject of 

 considerable investigation ; in the dried plant it varies according 

 to different experiments from 1 '95 to 6*35 per cent., and (pure) 

 contains from 30*9 to 48*1 per cent, of silica. My own analysis 



Naturalist, 



