414 SALICIN. 



Decompositions. By boiling with dilute hydrochloric 

 or sulphuric acid, it is resolved into sugar and solanidin, 

 with assimilation of three molecules of water. On cool- 

 ing, the solanidin is deposited in the form of a sulphate 

 or hydrochlorate, from the solutions of which in alcohol, 

 solanidin is precipitated by means of ammonia. 



Solanidin, C 25 H 41 ITO(?). Fine needles, of silky 

 lustre ; but slightly soluble in water, in alcohol more 

 easily soluble. It fuses above 200, and sublimes by 

 rapid heating almost without decomposition. A 

 stronger base than solanin; gives with acids easily 

 crystallizing salts ; difficultly soluble in water. 



Solanidin hydrochlorate, C 25 EraO.HCl, forms 

 rhombic columns ; can be sublimed undecomposed. 



Solanin, in contact with concentrated cold acids, 

 yields sugar, but no solanidin, but two other, still 

 but slightly known, bases, which are also formed from 

 solanidin when it is heated with concentrated acids. 



3. Salitin. 



C 13 H 18 7 . 



Occurrence. In the bark and leaves of most willows 

 (Salix species) and of some poplar species. 



Preparation. The bark is cut up and boiled with 

 water, the liquid concentrated and boiled with litharge 

 until decolorized, by which means gums, tannic acid, 

 etc., are thrown down. The dissolved lead combined 

 with salicin is at first precipitated with sulphuric acid, 

 afterwards completely with sulphuretted hydrogen or 

 barium sulphide ; the solution of salicin, filtered from 

 the precipitate, is evaporated to the point of crystalli- 

 zation. 



Properties. Small, colorless, lustrous prisms or 

 laminae, of a bitter taste ; fusible at 198 ; easily solu- 

 ble in hot water, difficultly soluble in cold water, solu- 

 ble in alcohol. In contact with emulsin or saliva, it as- 

 similates one molecule of water, and is resolved into 



