§ 167. ^CILLAi'N, SENEGIN, SAPONIN. 173 



in. cone, sulphuric acid, -with immediate production of a fine red 

 colouration. 



For digitalm and diyitalein, see § 155. 



Seilldm, a gluposide obtained from Scilla maritiina, resembles 

 digitaiin 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, with green fluorescence, and the solution is 

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

 precipitate scillain. ^ 



Sapaain and digitonin are likewise 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 respects (frothing of the solution, etc.), 

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

 stances are also allied to saponin : 



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

 was found by Christophsohn^ to differ from that body only iii 

 the rapidity with which the violet colowation was produced by 

 sulphuric acid. It can be estimated by the methods detailed 

 jn § 78. 



Christophsolm also proved that both saponin andsenegin are 

 accompanied in the drugs yielding them by another substance that 

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

 principles themselves. This other substance remains in solution 

 after separation of the^apbnin by baiyta^water, but could not be 

 obtained, in a state of purity. 



Melojnihln, 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 solubility in water, and in the ease 



' Compare Jannerstedt, Archiv f. exp. Pathol, und PharmacoL xi. 22, 1679 

 (Amer. Joum. Pharm. Iii. 91). 



^ Loc, cit. 



3f4itzb. der Dorpater Naturf. Gea. 240, 1879; 94, 1881. Pharm, Joum. 

 and Trans. [3], x. 909, 1013, xii. 681, 



