450 MODEEN CHEMISTRY. 



absolute line of distinction exists between organic and 

 inorganic chemistry; but, nevertheless, this division seems 

 practically justified by the diversity of the objects they 

 respectively offer to us. 



Of more than sixty undecomposed elements now known, 

 and which enter into the combinations of inorganic nature, 

 sixteen may be numbered as more or less essential to the 

 products of organic chemistry. Among these, however, the 

 four elements of carbon, oxygen, hydrogen, and nitrogen 

 are so largely predominant in quantity, if not more essential 

 in their presence, that to them the name of Organic Elements 

 may especially be applied. Every organic compound con- 

 tains three of these elements a large proportion, especially 

 among animal substances, all the four. The other elements 

 concerned in Organic Chemistry (including sulphur, phospho- 

 rus, chlorine, iodine, the metallic bases of the alkalies and 

 earths, iron, &c.), though comparatively of small amount, yet 

 appear to be necessary to the organised bodies in which they 

 are severally found. Out of these various materials, but 

 mainly from the four first mentioned, are formed the countless 

 combinations which the chemist has subjected to his science ; 

 analysing those which nature has so profusely presented 

 in the animal and vegetable world; forming new com- 

 pounds by intermixture and varied proportions of these 

 elements; and in some cases, by a still higher art, even 

 producing certain of those organic compounds, which were 

 known before only through the occult chemistry of living 

 beings. We should despair of giving those of our readers 

 who are new to the subject, any adequate idea of the vast 

 labours, and not less vast results, which illustrate this de- 

 partment of the science. Scarcely is there a principle or 

 product of organised existence which has not been submitted 

 to rigid examination, and tried in all its relations of affinity 

 with other bodies ; and nomenclature has been taxed to its 



