320 CONSIDERATION OF CARBON COMPOUNDS. 



is found in the different species of one family, and it is also 

 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 (without elimination of water) to 

 form well-defined salts, and are set free from the solutions of 

 these salts by alkalies and alkaline carbonates. 



2. Those containing no oxygen (amines) are volatile liquids, 

 those containing oxygen (amides) are non-volatile solids. 



3. The volatile alkaloids have a peculiar, disagreeable odor 

 reminding of ammonia, the non-volatile alkaloids are odorless. 



4. Most solid alkaloids fuse at a temperature above 100 

 without decomposition, but are decomposed when the heat is 

 raised much beyond the fusing-point. 



5. Alkaloids are insoluble, or nearly so, in water, but soluble 

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



6. The chlorides, 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, chloroform, benzene, benzin, 

 and amyl alcohol. 



7. The solid alkaloids, as well as their salts, may be obtained 

 in a crystallized state. 



8. Most alkaloids are white. 



9. Most alkaloids have a very strong, generally bitter taste. 



10. Most alkaloids act very energetically upon the animal 

 system. 



11. Most alkaloids give precipitates with tannic acid, picric 

 acid, phospho-molybdic acid, potassium-mercuric iodide, arid the 

 higher chlorides of platinum, gold, and mercury. 



12. Most alkaloids give beautiful color reactions when treated 

 with oxidizing agents, such as nitric acid, chloric acid, chromic 

 acid, ferric chloride, chlorine water, etc. 



General mode of obtaining alkaloids. The disintegrated vege- 

 table substance (bark, seeds, etc.) is extracted with acidified 

 water, which dissolves the alkaloids. When the alkaloid is 

 volatile, it is obtained from this solution by distillation, after 

 having been liberated by an alkali. 



