ACID AND ALKALINE SECRETIONS. 73 



of tills secretion are in the C'uidiona cffi^ 

 c'malis or Peruvian l)ark, Lambert Cincho?ia, 

 t. 1, and every species, more or less, of 

 Gentian. 



Acid secretions are well known to be very 

 general in plants. Formerl) one uniform vege- 

 table or acetous acid was supposed common 

 to all plants ; but the refinements of modern 

 chemistry have detected in some a peculiar 

 kind, as the OxaUc acid, obtained from Oxalis 

 or Wood Sorrel, and several others. The 

 astringent principle should seem to be a sort of 

 acid, of which there are many different forms 

 or kinds, and among them the tanning prin- 

 ciple of tl/e Oak, Willow, &c. 



On the other hand, two kinds of Alkali 

 are furnished by vegetables, of which the 

 most general is the Vegetable Alkali, pro- 

 perly so called, known by the name of Salt 

 of Tartar, or Salt of Wormwood, or more cor- 

 rectly by the Arabic term Kali. The Fossil 

 Alkah, or Soda^ is most remarkable in cer- 

 tain succulent plants that grow near the sea, 

 belonging to the genera Chenopodium, Sal- 

 sola, iScc. When these plants are cultivated 

 in a common soil, they secrete Soda tis copi- 



