§ 155. DIGITALEIN, DIGITONIN, ETC. 143 



dissolve it freely. Boiled with dilute acids iu alcoholic solution, 

 it is transformed into toxiresin (soluble in ether) without the 

 simultaneous production of sugajr. With hydrochloric acid it 

 gives a reaction resembling that of digitahn, but is not coloured 

 violet by sulphuric acid and bromine water. Digitahn, digitoxin 

 and toxiresin are all characterized by very energetic physiological 

 action that may be of use in their identification.' 



I take this opportunity of referring to three other constituents 

 of foxglove, which, however, are insoluble in ether. They are 

 the following : 



DigUalem. — This substance agrees in its. physiological action 

 with digitalin and digitoxin, but differs from them in its 

 solubility in water and cold absolute alcohol. It is sparingly 

 soluble in chloroform, and is precipitated from alcoholic solution 

 by the addition of a large quantity of ether. Boiling with dilute 

 acids decomposes it into glucose and digitaliresin. Sulphuric acid 

 and bromine produce the same colouration as with digitalin. 

 Tannic acid and basic acetate of lead precipitate it from aqueous 

 solution (§. 55). 



Digitonin is, as already observed .(§ 79), allied to saponin ; it is 

 amorphous and soluble in water, to which it injparts the property 

 of frothing. Ether precipitates digitonin from alcoholic solution 

 more easily tha,n it does digitalein. Baryta-water, tannic acid, 

 and basic acetate of lead precipitate it from its concentrated 

 aqueous solution. Boiling with hydrochloric acid resolves 

 digitonin into glucose, digitoresin and digitonein, with a gradual 

 development of a gitrnet-red colouration. Cone, sulphuric acid 

 colours it brownish red, which is not changed to reddish violet 

 by bromine. 



Digitin is a resinous substance that can be obtained in warty 

 crystals from alcoholic solution. , It is insoluble id water, ether, 

 benzene and chloroform, and possesses no marked physiological 

 action. 



For coriamyrUn compare Eiban.^ 



For ericolm, which is decomposed by hot dilute sulphuric acid, 

 yielding glucose and ericinol, see Eochleder and Schwartz.* 



' Compare my ' Ermittelung d. Gifte,' 2nd ed. 272 el seq. 



" Bull, de la Soc. chim. de Paris, vi. 87, 186<l: ; vii. 79. 1865 (Amer. Journ. 

 Pharm. xxxvi. 114), 



' Annal. d. Chem. iind Pharm. Ixxxiv. 366, 1852, and Chem. Gentralblatt, 

 61, 1853. Compare also my 'Ermittelung d. Gifte,' 2nd ed., 300 et seq. 



