THE ORGANIC AND INORGANIC KINGDOMS. 125 



presses, though imperfectly, the distinctions between the organic and 

 inorganic kingdoms of nature ; for njineral substances simply increase 

 or grow by accretion, plants and animals grow by means of living pro- 

 cesses, whilst animals surpass plants by possessing sensibility. A 

 closer inspection of the characters of organic and inorganic bodies 

 reveals, however, a series of important differences, not only in their 

 form and size, but more especially in their chemical characters, their 

 structure, the nature of the actions which take place within them, their 

 mode of formation, maintenance, and increase, their duration, and their 

 manner of production, or reproduction. 



The form of organic bodies is always determinate ; that of some 

 inorganic bodies, such as crystals, is likewise determinate, but this is 

 not an essential characteristic, the greater number of them being 

 irregular in form. Organic bodies do not present strictly geometrical 

 forms, and have more or less curved outlines and surfaces; whilst, as 

 a rule, inorganic bodies, when of determinate shape, have geometrical 

 forms, plane surfaces, and straight outlines ; but there are a few ex- 

 ceptions of crystals having curved surfaces, viz., the diamond, dolo- 

 mite, and spathic iron ; and inanimate matter sometimes presents a 

 tendency to assume a more or less spheroidal shape. The simplest 

 forms of organic bodies present a universal tendency to a spheroidal, 

 oval, or ovoid shape; but linear forms prevail in the more highly 

 developed species ; ramification and repetition of parts are common, 

 and very frequently spiral forms are seen, either in parts or in entire 

 organisms. A bilateral symmetry is likewise almost always apparent ; 

 though this also is met with in the inorganic crystalline bodies. The 

 irregularly formed inorganic bodies have irregular surfaces, and are 

 without symmetry. 



In size, organic bodies are determinate, each species within certain 

 dimensions. Inorganic bodies having crystalline forms, are also lim- 

 ited in size, but they exhibit wider individual deviations in this respect ; 

 whilst the non-crystalline inorganic bodies have no determinate bulk. 



Organic bodies contain no chemical elements beyond those which are 

 found in the inorganic world ; but the total number of elements con- 

 tained in all the organic compounds, is fewer than that of those con- 

 tained in the mineral kingdom. Organic bodies present a striking 

 uniformity of composition ; most of them being ternary, consisting of 

 carbon, hydrogen, and oxygen ; a certain number quaternary, con- 

 taining, in addition, nitrogen ; and a few only, absolutely essential to 

 organization, quinary, containing likewise sulphur or iron. Inorganic 

 bodies, on the other hand, exhibit a far greater variety in their com- 

 ponent elements ; they also present a greater variety in their atomic 

 constitution, being not only ternary, quaternary, or quinary, but fre- 

 quently binary or simple. 



The compound chemical substances contained in or derived from 

 organized bodies, are named organic compounds, and are treated of in 

 so-called Organic Chemistry. Their chemical constitution is more com- 

 plex than that of inorganic substances, and their properties are more 

 various. Though composed of but a few elements chiefly, as already 

 stated, of these four, carbon, hydrogen, oxygen, and nitrogen they 



