164 PRUSSIC OR HYDROCYANIC ACID. 
8. PRUSSIC OR HYDROCYANIC ACID. 
613. This acid contains no oxygen, but consists of carbon, 
hydrogen, and nitrogen, in the following proportions : 
Carbon, 2 equivalents at 26 
PUPOGOI LA cvesscsecies l4 6 
Hydrogen, 1 ............... 1 
27 parts. 
614. It exists in the seed of the Peach, Cherry, Almond; — 
and may be obtained by distilling Laurel leaves. ‘The leaves — 
of the Prunus Lauro-cerasus give a considerable quantity 
_ when distilled. 7 
615. Besides these, there are many vegetable acids of less 
interest, such as the Succinic, obtained from Amber; the 
Suberic, from Cork; the Pectic, from the Carrot, &e- 
They are of little importance, and do not exist in any con- 
siderable quaitity in the vegetable kingdom. 
ah : CHA P, 1V._VEGETABLE ALKALIS, &c. 
Bark, which has a tonic effect, there has been found some : 
peculiar principle, in combination with a vegetable acid, — 
____ which principle is the cause of the virtues of the plant. This — 
__ Principle is called an Alkali, because it possesses the pro- 
Sa Morphia in opium, quinine in 
