CLASSIFICATION 269 



The constitution of strychnine and brucine has not yet 

 been determined, though possible formulae have been suggested 

 by Perkin and Robinson.* 



V. Isoquinoline Alkaloids. These may be divided into the 

 three following groups : 



(a) Papaverine group, including Papaverine, Narcotine, 



Laudanosine, etc., closely allied to which are 



Hydrastine and Hydrastinine from Hydrastis cana- 



densis. 



(b} Morphine group, including Morphine, Apomorphine, 



Thebaine, and Codeine. 

 (c) Berberine group, including Berberine and Corydalis 



Alkaloids. 



The constitutional formulae for alkaloids of this group are 

 for the most part exceedingly complex, and it will suffice here 

 merely to show the skeleton formulae of a member of each 

 group : 



/\/\ /\/\ 



I ! IN 

 \/\ 

 b 



Papaverine Morphine f Berberine 



In addition to the alkaloids mentioned above, there are 

 a very large number which cannot as yet be classified, since 

 their constitution is still unknown ; these include amongst 

 others ergotinine from ergot, colchicine from Colchicum, taxine 

 from Taxus baccata, aconitine from Aconitum Napellus, del- 

 phinine from Delphinium, etc. 



GENERAL PROPERTIES OF ALKALOIDS. 



The alkaloids are, as a rule, composed of the four elements, 

 carbon, hydrogen, nitrogen, and oxygen, but a few are 

 known, such as coniine, nicotine, and one or two little-known 

 ones, such as hymenodictine and conessine (from bark of 

 Wrightia antidysenterica\ which contain no oxygen. 



* Perkin and Robinson : "J. Chtm. Soc., Lond.," 1910, 97, 305. 

 t This formula is subject to revision. 



