On Coloured Vision produced by Santonine. 89 



worts. Artemisia cam'pestris is somewhat rare, but is to be met 

 with on dry, sandy heaths in Norfolk and Suffolk, where it 

 flowers in August. It is called field southernwood. 



Artemisia absinthium, or common wormwood, is found more 

 or less abundantly in waste places and around villages, in dry 

 soils • it flowers also in August, and stands about one foot and 

 a half high. Artemisia maritima is a small grey shrub, seen 

 growing on the sand downs near the sea-shore, and met with 

 also near salt springs and salt marshes in the interior. Like all 

 the plants of this genus, it gives out a peculiarly strong aromatic 

 odour when the leaves are violently rubbed in the hands, and 

 has an intensely bitter taste. 



Artemisia vulgaris (mug wort) is the commonest of our 

 species of Artemisia. It grows three or four feet high, and is 

 found along hedges and in waste places. Like the others, it 

 flowers in August. These plants belong to the great family of 

 Compositce, and to a group which is characterised by many 

 bitter plants highly extolled by the old herbalists and alchy- 

 mistic medicine-vendors of times gone by. Their leaves are 

 much divided' (pinnatifid), more or less downy, and the 

 flowers yellow. 



It is not surprising that a substance like semen contra, so 

 extensively used in medicine for many years, should have 

 been carefully examined in a chemical point of view. All the 

 plants we have just named contain the peculiar principle called 

 Santonine ; we shall see presently how it is obtained. Under 

 the name of Barbotine is known on the Continent the mixture 

 of buds, blossoms, seeds, and flower-stalks of various Artemisia, 

 dried and reduced to a coarse powder. It is the same as our 

 semen contra. We possess an elaborate analysis of it by 

 Tromsdorff, and two analyses quite as elaborate by Wacken- 

 roder. There is, however, little interest in reporting here the 

 figures of these analyses, made many years ago, and in which 

 certain figures include more than one substance. It will be 

 sufficient to state, that the medicinal properties of the worm- 

 wood blossom are owing partly to a volatile oil, similar in 

 nature to essence of peppermint, partly to the bitter resins it 

 contains, and to the crystalline principle Santonine. 



Santonine was discovered about the same time by two Grer- 

 man chemists, Kahler and Alms. They extracted it from worm- 

 wood by treating the flowers, buds, and. seeds (semen contra) of 

 the Artemisia with ether, which dissolved the Santonine ; or by 

 treating the flower-heads, first with alcohol, evaporating to get 

 the alcoholic extract, and treating this with ether. On distilling 

 the latter, the Santonine remains behind, mixed with some 

 chlorophylle or green colouring matter, and a little resin or wax. 

 This mixture was dissolved in strong acetic acid, which takes 



