TARTARIC ACID. 161. 
1. ACETIC ACID. 
606. This substance, the pure matter of vinegar, does not 
often occur free in vegetables, but is generally in combina- 
tion with potassa or lime. In the sap of some trees it is pre- 
sent in very minute portions. It is formed during acetous 
fermentation, and by the destructive distillation of wood. 
Formed in the latter way, it is called Pyroligneous Acid. 
Acetic acid is transparent and colourless, has a fragrant 
odour, and a strong sharp taste. It consists, according to 
some chemists, of 
Carbon, 4 equivalents 24 
o eayyen, S.A sa 24 
Hydrogen, © 8 sis ccsccccis. 3 
51 parts. 
Dr. Prout, in his analysis of this acid, found that it contains 
three atoms of hydrogen, the oxygen and hydrogen being ex- 
actly in the proportion to form water. According to other 
views, there is an excess of one atom of oxygen. 
2. TARTARIC ACID. 
607. This acid exists in vegetables, mostly in union with 
potassa, forming a supertartrate. It may be procured from 
the pulp of the Tamarind (Tamarindus indica,) from the 
juice of the grape (Vitis vinifera), and of the Mulberry 
(Morus nigra). It is also said to exist in considerable quan- 
tity in Sorrel (Rumex acetosa), and in Dandelion _ 
todon Taraxacum). It consists of 
