702 MELANTHACEtE. 



SEMEN COLCHICI. 



Colchicum Seed ; F. Semence de Colchique ; G. Zeitlosensamen. 



Botanical Origin — Colchicum autumnale L., see page G99. The 

 inflated capsule, which grows up in the spring after the disappearance 

 of the flower in the autumn, is three-celled, dehiscent towards the apex 

 by its ventral sutures, and contains, attached to the inner angle of the 

 carpels, numerous globular seeds, which arrive at maturity in the latter 

 part of the summer. 



History — Colchicum seeds were introduced into medical practice 

 by Dr. W. H. Williams, of Ipswich, about 1820, on the ground of their 

 being more certain in action than the corm.^ They were admitted to 

 the London Pharmacopoeia in 1824. 



Description — The seeds are of globose form, about to of an inch 

 in diameter, somewhat pointed by a strophiole, which when dry is not 

 very evident. They are rather rough and dull ; when recent of a pale 

 brown, but become darker by drying, and at the same time exude a 

 sort of saccharine matter. They are inodorous even when fresh, but 

 have a bitter acrid taste ; they are very hard and difficult to powder. 



Microscopic Structure — The reticulated, brown coat of the seed 

 consists of a few rows of large, thin-walled tangentially-extended cells, 

 considerably smaller towards the interior, the outermost containing 

 starch grains in small number. The thin testa is closely adherent to 

 the horny greyish albumen. The cells of the latter are remarkable for 

 their thick walls, showing wide pores ; they contain granular plasma 

 and oil-drops. The very small leafless embryo may be observed on 

 transverse section close beneath the testa on the side opposite the 

 strophiole. 



Chemical Composition — The active principle of colchicum seed is 

 termed Colcldcin, but the chemists who have made it the subject of 

 investigation are not agreed as to its properties. Thus Oberlin (1856) 

 showed it to contain nitrogen, but without possessing basic properties. 

 By treatment with acids, the amorphous colchicin yields a crystallizable 

 body, Colchicein. HUbler (1864) prepared colchicin in the same way by 

 which the so-called "bitter principles," like dulcamarin (p. 451) are 

 obtainable. He assigned to colchicein acid qualities and, strangely 

 enough, the same formula he gave for colchicin itself, namely C^'^ff^NO". 

 Maisch^ as well as DiehP again obtained discrepant results. Colchicin of 

 definite composition has not yet been isolated. 



It would appear that in an aqueous or alcoholic extract of the seed 

 an extremely small amount of an alkaloid is present, but that a basic 

 substance is immediately formed on addition of mineral acids, or also 

 oxalic acid. This suggestion is to some extent supported by the follow- 

 ing facts : — 



By adding the usual test solution for alkaloids, i.e. iodohydrogyrate 

 of potassium (50 grammes of iodide of potassium, 13"5 of perchloride of 

 mercury in one litre), to an aqueous solution of an alcoholic extract of 



^London Medical Repository, Aug. 1, ^PAarm. /owm. ix. (1867) 249. 



1820. . ^Proc. Americ. Pharm. Assoc. 1867. 363. 



