192. NATURE AND LIFE. 
of hydrogen, carbon, and oxygen, neither acid nor alkaline, 
which may be regarded as the result of the union of a 
- hydrocarburet with the elements of water. Common alco- 
hol, or spirits of wine, is the type of the most impor- 
tant series of alcohols, that of the mono-atomic alcohols. 
Chemists represent it by the formula C*H°O, to indicate 
that a molecule of it arises from the union of two atoms of 
carbon with six atoms of hydrogen and one of oxygen. 
Independently of the alcohols, which are of great number 
and varying complexity, organic chemistry recognizes an- 
other class of bodies, of which vinegar is the type, and 
which receive the name of organic acids, to mark their 
resemblance to mineral acids, such as oil of vitriol or aqua- 
fortis. Now, every alcohol, on losing a certain amount of 
hydrogen, gives rise to a new body, which is called an 
aldehyde; and every alcohol, on combining with an acid, 
produces what is called anether. ‘These rapid details allow 
us to understand precisely the chemical character of the 
essences or essential oils which plants elaborate within their 
delicate tissue. Except a small number among them which 
contain sulphur, as the essences of the family of crucifers, 
they all present the same qualitative composition—carbon 
and hydrogen, with or without oxygen. Between one and 
another of them merely the proportion of these three com- 
posing elements varies, by regular gradations, but so as 
always to correspond either to a hydrocarburet, or to an 
aldehyde, or to an ether. In this case, as in almost the 
whole of organic chemistry, every thing is in the quantity of 
the composing elements. The quality is of so little im- 
portance to Nature, that, while following always the same 
laws, and constantly using the same materials, she can, 
by merely changing the ponderable relations of the latter, 
produce, by myriads of various combinations, myriads of 
substances which have no resemblance to each other. The 
strange powers of the elements and the mysterious forces 

