600 CONSIDERATION OF CARBON COMPOUNDS. 



52. ALKALOIDS. 



General Remarks. The basic substances found in plants are 

 grouped together under the name of alkaloids, this term signifying 

 alkali-like, in allusion to the alkaline or basic properties of these 

 substances. They show their derivation from ammonia to a more or 

 less marked degree, as, for instance, in their power to combine with 

 acids to form well-defined salts, to combine with platinic chloride to 

 form insoluble double compounds, etc. 



The compounds formed by the direct combination of alkaloids with 

 acids are, in the case of oxygen acids, named like other salts of these 

 acids, for instance, sulphates, nitrates, acetates, etc. In the case of 

 halogen acids, however, a different method has been adopted, because 

 it would be incorrect to apply the terms chlorides and bromides to 

 substances formed not by the combination of chlorine or bromine with 

 other substances, nor by the replacement of hydrogen in the respective 

 hydrogen acids of these elements, but by direct combination of these 

 acids with the alkaloids. The terms hydrochloride and hydrobromide 

 have been adopted by the U. S. P. for the compounds obtained by 

 direct union of alkaloids with hydrochloric and hydrobromic acids. 

 Formerly the terms hydrochlorate and hydrobromate were used. 



Alkaloids are found in the leaves, stems, roots, barks, and seeds of 

 various plants ; it often happens that a certain alkaloid is found in 

 the different species of one family, and it is often the case that 



various alkaloids of a similar composition are found in the same plant. 



General properties of alkaloids: 



1 . They combine with acids to form well-defined salts, and are set 

 free from the solutions of these salts by alkalies and alkali carbonates. 



2. In most cases those containing no oxygen are volatile liquids, 

 those containing oxygen are non-volatile solids. 



3. The volatile alkaloids have a peculiar disagreeable odor, remind- 

 ing of ammonia ; the non-volatile alkaloids are odorless. 



4. Most solid alkaloids fuse at a temperature above 100 C. (212 

 F.) without decomposition, but are decomposed when the heat is 

 raised much beyond the fusing-point. 



5o Most alkaloids are insoluble, or nearly so, in water, but soluble 

 in alcohol, chloroform, benzene, acetic ether, and many also in ether. 



6. The hydrochlorides, sulphates, nitrates, acetates (and most other 

 salts) of alkaloids are either soluble in water, or in water which has 

 been slightly acidulated, and also in alcohol ; but they are insoluble, 

 or nearly so, in ether, acetic ether, chloroform (except veratrine and 



