OF ALKALOIDS, ETC. 217 



Santonine when crystallised from chloroform bears a faint resem- 

 blance to strychnine. It forms large feathery rosettes which 

 differ from those of strychnine in possessing a crystal for a 

 nucleus. Like strychnine the films show no colour without 

 the selenite (Fig. 42). 



Salicine crystaUises from alcohol in long needles, rosettes, and 

 feathery tufts, and forms a striking object with the selenite. 

 The rosettes are coloured complementary in a cruciform 

 direction, and the nucleus is also complementary in the opposite 

 direction (Fig. 43). 



Salicylic Acid crystallises from ether in rosettes somewhat re- 

 sembling those of salicine, but the nucleus is a point, and not 

 a circle, as in the latter. It forms an exceedingly pretty object 

 with a low magnifying power (Fig. 44). 



Solanine is sparingly soluble in water, and crystallises therefrom. 

 It is soluble in alcohol, but does not then crystallise. Viewed 

 with the selenite, each crystal assumes an independent tint 



(Fig- 45)- 

 Scoparine. — The only method of obtaining crystals is to dissolve 

 in AmHo and precipitate with HCl, when the crystals are 

 seen immersed in a jelly, or by dissolving in hot alcoholic 

 ammonia and allowing to cool very slowly (Fig. 46). 



Styracine crystallises from slow evaporation of etherial or alcoholic 

 solution in arborescent forms. 



Theobromine is by no means a show object for the polariser; 

 the crystals are very bushy, and not sharply defined like those 

 of theine (Fig. 47). 



Theine crystalHses from etherial alcohol in long needles, an 

 aggregation of imperfectly formed stars (Fig. 48). 



Calcic Tartrate. — If calcic citrate, which is not crystalline, be 

 contaminated with the tartrate, it may be easily detected by 

 aid of the microscope (Fig. 49). 



PoTASSic Hydric Tartrate. — ^^The plate shows the crystals 

 as precipitated from potassic chloride by sodic di-hydric 

 tartrate (Fig. 50). 



