76 



FLOWERS 



often known ; semen contra (another of its names) is an abbreviation 

 of ' semen contra vermes.' The drug appears at first sight to consist 

 of a number of small, brownish, ridged seeds the true nature of which 

 becomes apparent when they are dissected. 



Description. The flowerheads are of a greenish yellow colour, but 

 turn brown by drying and keeping. They are only about 1'5 mm. 

 long, elongated ovoid in shape, and somewhat angular ; their surface 

 is shining and glabrous, or at most only slightly harry. 



The involucre consists of imbricated ovate or lanceolate bracts, 

 furnished with a distinct keel, on each side of which are shining oil- 

 glands ; the latter, however, are not easily seen even under a powerful 

 lens. After soaking in water the bracts can be removed with dissecting 

 needles, and in the centre from three to six 

 very minute, unexpanded, tubular florets will 

 be found ; they are completely enclosed by the 

 upper bracts of the involucre, and bear minute 

 oil-glands on the lower portion of the corolla. 

 The drug exhales, when crushed, an agree- 

 able, aromatic odour, and possesses a bitter, 

 aromatic, camphoraceous taste. It frequently 

 contains a considerable admixture of fragments 

 of the leaves and very slender flower stalks. 



The student should soak the wormseed in 

 water for twenty-four hours, and then dissect 

 a flowerhead with the aid of the dissecting 

 needles and a lens. He should note 



(a) The imbricated, keeled, glabrous bracts, 



(b) The minute florets enclosed within them, 



(c) The characteristic odour and taste. 



Constituents. Wormseed contains a volatile oil and two crystalline 

 principles, viz. santonin, to which the anthelmintic property of the 

 drug is due and artemisin. The santonin attains its maximum (2*3 

 to 3'6 per cent. Ehlinger, 1885) in July and August. After flowering 

 it rapidly disappears. 



Santonin, C 15 H 18 3 , forms colourless bitter crystals that are very 

 slightly soluble in water but unite with alkalies, forming soluble salts 

 of monobasic santonic acid, C 15 H 20 O 4 . Exposed to light, santonin 

 assumes a yellow colour (photosantonin) . 



Santonin is extracted from the flowerheads by treating them with milk of 

 lime, the santonin being converted into soluble calcium santonate. From the 

 filtrate excess of calcium is removed by a current of carbon dioxide, and the 

 calcium salt is converted into the sodium salt by means of sodium carbonate. 

 The liquid is filtered warm and the santonin separated by the addition of sulphuric 

 acid. It is purified by decolorisation with charcoal and recrystallisation from 

 hot alcohol. 



IG. 45. Flowerhead of 

 Artemisia. A, entire, 

 showing imbricated 

 bracts with external 

 glands : B, cut longi- 

 tudinally, showing 

 florets. Magnified. 

 (Luerssen.) 



