£0 • MINUTES OF 



On the componoU Principle of Vegetables. 



several Jutfces flow out; and not unfrequently spontaneously. By chemical 

 analysis these balsams are found to consist of a peculiar resin, dissolved in volatile 

 or ethereal oil. ' 



V. CoxcERxiVG Gum Resjxs. 



lik% gum resins are a natural' mixture of extract and resin. They seldom 

 How riatujally fro-.n plants, but issue out fron incisions made for that purpose. 

 They are sonieti nes white, as in the tithtfnalwi and ths Jig-tree; sometimes yel- 

 low, as in the cheliddnium: so that we mav consider these substances as true emul- 

 sions, whose constituent principles vary in their proportions. 



The gum resins are partly soluble in water, and partly in alcohol. 



0>fE character of gum resins is, that tbey render water turbid in which 

 they are boiled. 



This class is sufficientl}' numerous ; but I shall only treat of the principal 

 species. 



When the resinous principle is mixed with the gummous, it is called the 

 gummi-resinous principle, of which nature is the gum assa-fcctida which exudes 

 from the ferula assa-foetida; gum galbanum, from the bubon galbanum; also oi- 

 lihanum, moniaeum, scammoiiy, gomboge, euphorbiuni, gutta, myrrh, bdellium, 

 cpnponax, sarcocoUa, and storaj:, which exude from their respective trees. ' - 

 VI. Concerning the Fecula of Vegetables. 



Feculum exists in all white and brittle parts of vegetables, — particularly 

 in tuberculous roots, and in the grains of gramineous plants. It is a pulverulent, 

 dry, white, insipid, combustible matter. It yields by d.istillation, a large proper- 

 tion of pyro-mucous acid; is soluble in boiling water; forms, viith this liquid, a 

 jelly; is convertible by the nitric acid, into oxalic and malic acid ; forms the basis 

 of the nourishment of animals; and becomes, with sufficient readiness, a principle 

 in the living animal body. All the solid parts of vegetables, are, more or less, 

 capable of affording foeculum. But, some yield it in a greater abundance; and it 

 is, therefore, prepared rather from these for the uses of the arts, as the foecula 



