§ 167. SCILLAIN, SENEGIK, SAPONIN. 173 



in cone, snlphuvic acid, with immediate production of a fine red 

 colouration. 



For digitalin and äigitalein, see § 15.5. 



SclUdin, a glucoside obtained from Scilla maritima, resembles 

 digitalin in physiological action. It is sparingly soluble in cold 

 water, but freely in alcohol, and when boiled with dilute hydro- 

 chloric acid is decomposed into sugar and a second substance, 

 soluble in ether. Concentrated hydrochloric acid is coloured red 

 when boiled with scillain, and this is followed by the separation 

 of a greenish flocculent deposit. Concentrated sulphuric acid 

 dissolves it brown, Avith green fluorescence, and the solution is 

 coloured bluish-red by bromine. Basic acetate of lead does not 

 precipitate scillain. ^ 



Saponin and dujltonin are likeAvise glucosides ; they have already 

 been described in §§ 77, 78, 79, 155, where mention has been 

 made of their insolubility in absolute alcohol. My object in 

 referring to them again here, is to draw attention to the resem- 

 blance they bear, in many resj^ects (frothing of the solution, etc.), 

 to the preceding glucosides (cyclamin, etc.). The following sub- 

 stances are also allied to saponin : 



Seneghi — which, however, is possibly identical with saponin — 

 was found by Christophsohn- to differ from that body only in 

 the rapidity with which the violet colouration was produced by 

 sulphuric acid. It can lie estimated by the methods detailed 

 in § 7S. 



Christophsohn also proved that both saponin and senegin are 

 accompanied in the drugs yielding them by another substance that 

 has a much more powerful action on the heart than either of those 

 princii^les themselves. This other substance remains in solution 

 after separation of the saponin by baryta-water, but could not be 

 obtained in a state of purity. 



Melanthin, found by Greenish^ in the seeds of Nigella sativa, 

 is not precipitated by ether from alcoholic solution. It resembles 

 saponin in being freely soluble in weak spirit, but may be 

 distinguished by its slight solul)ility in water, and in the ease 



^ Compare Jarmerstedt, Archiv f. exp. Pathol, und Pharmacol, xi. 22, 1S79 

 (Amer. Journ. Pharm, lii. 91). 



- Loc. cif. 



3 Sitzb. der Dorpater Naturf. Ge.s. 240, 1879 ; 94, 1881. Pharm. Journ. 

 and Trans. [3], x. 909, 101-3, xii. 681. 



