300 UMBELLIFERJi. 



devoid of vittae. When a meriearp is cut transversely, the seed exhibits 

 a reniform outline, due to a deep furrow in the albumen on the side of 

 the commissure. 



The fruits of hemlock are dull greenish grey, and have but little 

 taste and smell ; but when triturated with a solution of caustic alkali 

 they evolve a strong and offensive odour. 



Microscopic Structure — Hemlock fruits differ from other fruits 

 of the order by the absence of vittse.' In the endocarp, there is a 

 peculiar layer of small nearly cubic cells surrounding the albumen. 

 The cells of the endocarp are loaded with a brown liquid consisting 

 chiefly of conine and essential oil. 



Chemical Composition — -The most important constituent of the 

 fruits of hemlock Conine or Conia, C^H"NH, a limpid colourless oily 

 fluid, 0846 sp. gr, at 12°"5 C. It has a strong alkaline reaction, and boils 

 at 170°C. in an atmosphere devoid of ox3'gen, without decomposition. It 

 was first observed by Giseke at Eisleben, Saxony, in 1827, recognized 

 as an alkaloid by Geiger in 1831, and more amply studied by Wertheim 

 in 1856 and 1862. To obtain it, an alcoholic extract is submitted to dis- 

 tillation with a little slaked lime. The product should be neutralized with 

 oxalic acid, and the oxalate of conine removed by absolute alcohol mixed 

 with a little ether, oxalate of ammonium being insoluble. The oxalate 

 of the alkaloid shaken with caustic Ij'e and ether, affords the conine, on 

 evaporating the solvent and distilling the alkaloid in a current of dry 

 hydrogen. In the plant it is combined with an acid (malic ?), and ac- 

 companied by ammonia, as well as by a second, less poisonous crystalliz- 

 able base, called Conhydrine, C^H^'NO, which may be converted into 

 conine by abstraction of the elements of water. From these alkaloids a 

 liquid non-poisonous hydrocarbon, Conylene, C®H", has been separated 

 by Wertheim. Even in nature one hydrogen atom of conine is fre- 

 quently replaced by methyl, CH^; and commercial conine commonly con- 

 tains, as shown by A. von Planta and Kekule, methyl-conine, C^H^NCHl 

 Lastly there is present in hemlock fruits a third alkaloid having pro- 

 bably the composition C"H"N. 



As to the 3'ield of conine, it varies according to the development of 

 the fruits, but it is at best only about i per cent. According to Schroff 

 (1870), the fruits are most active just before maturity, provided they are 

 gathered from the biennial plant. At a later stage, conine is probably 

 partly transformed into conhydrine, which however is present in but 

 very small proportion, — about 1^ per mille at most. 



In its deleterious action, conine resembles nicotine, but is much less 

 powerful. 



Schiff (1871-1872) has artificially produced an alkaloid partaking of 

 the general properties of conine, and having the same composition ; 

 but it is optically indifferent. Conine, on the other hand, we find turns 

 the plane of polarization to the right. 



The fruits of hemlock contain also a volatile oil which appears devoid 

 of poisonous properties ; it exists in but small quantity and has not yet 

 been fully examined. 



Uses — The fruits of hemlock are the only convenient source of the 

 alkaloid conine. They were introduced into British medicine in 1864, as a 

 1 See Moynkr de Villepoix, Annales des Sciences natureUes, Botanique, v. (1878) 348. 



