OILS, RESINS, OLEORESINS, GUM RESINS, AND BALSAMS. 37 



tions of hassorin (tragacanthin 50 per cent.) and a gum 

 soluble in water. It also contains starch, cellulose, 

 water (14 per cent.), mineral constituents (3 per cent.), 

 sugar, and traces of organic acids and coloring-matters. 

 The soluble gum is not identical with arabin, in that it 

 precipitates with lead acetate. 



Adulterations. — Such are not common, as tragacanth 

 is such a typical, product. Other gums, such as Cara- 

 manca and Moussul, have been used. These are said 

 to be derived from wild plum and apricot trees. 



OILS, RESINS, OLEORESINS, GUM RESINS, AND 

 BALSAMS. 



In taking up this series a complicated and as yet im- 

 perfectly understood group of substances is approached. 

 Their chemical structure has been widely investigated, 

 and many facts of vital interest are known, but pharma- 

 cologically these bodies are in need of much more ex- 

 tended investigation. 



In part it must be remembered that most of these 

 compounds are not simple chemical bodies. They are 

 usually mixtures of resins, oils, gums, and aromatic acids 

 making balsams. Therefore the group of oils, resins, 

 gum resins, and balsams makes a natural group of closely 

 allied substances — physically and chemically, if not 

 pharmacologically. 



From the very earliest times the pleasant odors that 

 have been given off by plants have attracted the atten- 

 tion of travelers, and, either because of their odors, 

 agreeable tastes, or medicinal virtues, many of these 

 aromatic plants have entered into the world's commerce 

 up to the present time in their original form, being either 

 previously dried or prepared in some commercially pos- 

 sible manner. With the improvements in technology 

 this class of aromatic compounds, made up for the most 



