332 CONSIDERATION OF CARBON COMPOUNDS. 



464. State the general physical and chemical properties of alkaloids. 



465. Give a general method for the extraction and separation of 

 alkaloids from vegetables. 



466. Mention the chief constituents of opium, and explain the process 

 for determining the percentage of morphine in opium. 



467. Mention the properties of morphine and its salts ; give tests for 

 them. 



468. Mention the principal alkaloids found in cinchona bark, and 

 give a process by which the total quantity of these alkaloids and of 

 quinine may be determined. 



469. State the physical and chemical properties of quinine and cin- 

 chonine. Which of their salt? are officinal, and by what tests may these 

 alkaloids be recognized and distinguished from each other? 



470. Give tests for strychnine, brucine, atropine, and veratrine. 



48. CYANOGEN AND ITS COMPOUNDS. 



Occurrence in nature. Cyanogen itself does not occur in 

 nature, but compounds of it are found in a few plants (amygda- 

 lin), and also in some animal fluids (saliva contains sodium 

 sulphocyanate). Gases issuing from volcanoes (or from iron 

 furnaces) sometimes contain cyanogen compounds. 



Constitution of cyanogen compounds. The univalent residue 

 cyanogen, CzN, or GN, or Cy, was the first compound radical 

 distinctly proved to exist, and isolated by Gay-Lussac, in 1814. 

 The name cyanogen signifies "generating blue," in allusion to 

 the various blue colors (Prussian and Turnbull's blue) contain- 

 ing it. The symbol Cy, frequently used in place of CN, has 

 been adopted merely to simplify the writing of formulas of 

 cyanogen compounds. 



Cyanogen and its compounds show much resemblance to the 

 halogens and their compounds, as indicated by the composition 

 of the following substances: 



C1C1, HCl, KI, HC10, 



Chlorine. Hydrochloric Potassium Hypochlorous 



acid. iodide acid. 



CNCN, HBr, KCN, HCNO, 



Cyanogen. Hydrobromic Potassium Cyanic acid, 



acid. cyanide. 



CNC1, HCN, AgCN, HCNS, 



Cyanogen Hydrocyanic Silver cyanide. Sulphocyanic. 



chloride. acid. acid. 



