OF ALKALOIDS, ETC. 215 



does not crystallise so well (Fig. 22). 



Caffeine crystallises from chloroform in a network of needles. 

 The crystals are thicker in the middle than at the ends. For 

 the most part they are brilliandy white, but some of the 

 larger show colour on account of their greater thickness. 

 When the selenite is used each crystal assumes an independent 

 tint (Fig. 23). 



Chrysophaxic i\ciD is most characteristic when fused in a thin 

 film, and allowed to solidify, when it forms moss-like aggregates 

 of laminar crystals which depolarise, retaining their yellow 

 colour (Fig. 24). It crystallises in six-sided monoclinic prisms 

 from benzine. 



CiNXAMic Acid crystallises from ether in perfectly formed 

 monoclinic prisms of varying hues. If the solution be too 

 concentrated the crystals set in a mass, showing no colour, 

 but arranging themselves in concentric waves (Fig. 25). 



Colchicine crystallises witli extreme difficulty from water. The 

 varnish-like residue left on evaporation, if kept in a dry place, 

 will ultimately sliow the crystals at margin (Fig. 26). 



CoNEiNE Hydrobromate crystalliscs from chloroform in white 

 needles (Fig. 27). 



CuBEBiNE. — The best solvent for cubebine is chloroform, but the 

 crystals do not depolarise well, and are best viewed as trans- 

 parent objects (Fig. 28). 



Cytisine is soluble in water and dilute alcohol, but not in ether, 

 chloroform, benzol, or bisulphide of carbon. It crystallises 

 well from water, and, when the selenite is used, each crystal is 

 of an independent tint. Where the crystals cross each other 

 at right angles complementary tints are assumed (Fig. 29). 



Cytisine Nitrate crystallises from water in branched prisms of 

 very variegated hues. It is a very pretty object (Fig. 30). 



DiGiTALiNE. — I have been unable to obtain this alkaloid in a 

 crystalline form. 



Elaterixe deposited from chloroform is precisely similar in form 

 to Thebaine (cpv). The crystals are somewhat smaller, and 

 require a power of 210 diameters. With the selenite, each 



