126 RELATIONS OF MAN WITH EXTERNAL NATURE. 



are characterized by the high number of atoms of those elements? 

 which enter into their composition ; so that, e. g., whilst only one atom 

 of carbon, or two of hydrogen, are combined with oxygen to form car- 

 bonic acid and water, no less than six atoms of carbon, twelve of 

 hydrogen, and six of oxygen, enter into the formation of grape sugar. 

 The molecules of organic substances, i. e., the aggregate of all the 

 atoms of each element which they contain, are therefore larger than 

 the molecules of inorganic chemical compounds. In both organic and 

 inorganic chemistry, certain radicals are supposed to enter into com- 

 bination in fixed proportions, with some single element, such as oxy- 

 gen, chlorine, or even a metal. In organic chemistry, such radicals 

 are always compound, consisting themselves of two elements, as for 

 example, cyanogen, which 'is a compound radical containing carbon 

 and nitrogen ; but such compound radicals also exist amongst inor- 

 ganic bodies, as e. g., cyanogen itself, when made synthetically from 

 inorganic matter, and also ammonium, which is composed of hydrogen 

 and nitrogen. Until comparatively recent times, a broad distinction 

 was supposed to exist between all organic chemical compounds, or the 

 substances immediately derived from their decomposition, and purely 

 inorganic chemical substances, the former being believed to be alone 

 producible by vital actions. But the distinction has, in regard to 

 many substances at least, been completely effaced by the discoveries 

 of Wohler, and more especially by the labors of Bcrthelot and others. 

 The former chemist first showed that urea is identical with cyanate of 

 ammonia, which can be artificially produced, and hence is named arti- 

 ficial urea. Ammonia, formerly supposed to be producible only from 

 the decomposition of previously organized matter, can now be obtained 

 from inorganic materials, by first making carbon and nitrogen unite 

 artificially, under the influence of carbonate of potash, to form cyano- 

 gen (in cyanide of potassium), which, decomposing with water, yields 

 ammonia. Again, tartaric and oxalic, and some other organic acids, 

 and even alcohol, have been made artificially by a series of synthetic 

 steps, without the intervention of any vital process, or the employment 

 of any organic substance, or the product of any previous vital action. 

 Thus, acetylene (C 2 H 2 ) is formed by electric sparks passed from car- 

 bon points through hydrogen gas; this acetylene is made to combine 

 with copper, and then, when subjected further to the action of nascent 

 hydrogen, produces ethylene (C 2 H 4 ) ; the ethylene, united with sul- 

 phuric acid, forms a compound (C 2 H 4 S0 4 ), which, when diluted with 

 water and distilled, gives off alcohol (C 2 H 6 0). It would therefore seem 

 possible that other and higher so-called organic compounds, such as 

 sugar, quinine, and even albumen, may hereafter be artificially pro- 

 duced from inorganic materials only. These researches already suffice 

 to show that the synthetic actions, by which plants build up organic 

 substances from inorganic elements, are similar in nature to those 

 which have been devised by man ; and that, accordingly, the chemical 

 molecular attractions employed or operating in each, are identical. 

 So, also, the analytic or decomposing processes of the chemist, are 

 paralleled in the laboratory of the living organic world ; for sugar in 

 solution, at certain temperatures, under the influence of the yeast 



