113 



ORGANIC CHEMISTRY. 



ORGANIC COMPOUNDS. 



instance, as to discover that it consists of silver, steel, and glass, 

 nay he might even without difficulty make his research a quantitative 

 one, and ascertain the weights of these different materials, which enter 

 into the composition of the instrument, but such an investigation 

 would obviously leave the most interesting part of the history of the 

 watch untouched ; it would tell him nothing either of the arrangement 

 of these materials or of the respective functions of the wheels, the 

 springs, the hands, Ac., the investigation of which would obviously 

 involve a much more laborious and especially a much more intellectual 

 inquiry. So in chemistry, the mere determination of the composition 

 of a compound stops short of the more interesting attributes of the 

 body its internal arrangement and the functions performed by its 

 several constituents. Hence the higher problem, difficult as its solu- 

 tion undoubtedly is, has never been lost sight of by the chemical 

 investigator. With a view to its solution he on the one hand submits 

 organic compounds to various processes, in order to take them to 

 pieces ; and on the other, he brings together what he conceives to be 

 their proximate constituents, in order if possible to build up the 

 substance he is investigating ; and thus he endeavours from both the 

 points of view thus afforded to arrive at some conclusion as to their 

 internal constitution. 



It is quite unnecessary here to notice the various views of a more 

 general character which, with a greater or less amount of this kind of 

 labour, have been arrived at by different chemists; it will be here 

 sufficient to mention one such general view, which has for some years 

 found very extensive acceptance amongst chemists. This view, which 

 might be called the doctrine of types, regards all organic bodies as 

 constituted in conformity with certain inorganic types, as being cast, 

 so to speak, in the moulds of these inorganic compounds. The four 

 principal types are 



Hydrogen 

 Tjpe. 



Hydrochloric 

 ncid Type. 



Water Type. 



HI HI 



Hj Cl) 



Ammonia 

 Type. 

 (H 

 { II 

 II 



The radicals, both positive and negative, belong to the hydrogen type. 

 The haloid compounds of these radicals are formed upon the hydro- 

 chloric acid type. The alcohols, ethers, acids, and ethereal salts belong 

 to the water type ; whilst the ammonia type includes the organic bases 

 and the amides. In this Cyclopaxlia the formula! of organic bodies are 

 generally written in accordance with these types. 



In the concluding remarks of the article ORGANOMETALLIC BODIES, 

 an endeavour is made to show that these bodies throw considerable 

 light upon the nature of the so-called organic radicals, and hence also 

 upon the constitution of organic compounds in general. If the views 

 there expressed as to the nature of organotnetallic bodies and their 

 compounds be correct, the extension of those views to the organic 

 compounds of carbon becomes inevitable. Regarded from this point 

 of view the double atom of carbon, like that of tin, i quadratomic 

 in perchloride of carbon and carbonic acid 



Cl 



C 



C \C1 



Cl 





 



and biatomic in protochloride of carbon and carbonic oxide : 



C f 01 

 c lCl 



(0 

 '10 



In other words, the quadratomic stage in carbon compounds is the 

 stage of maximum saturation, whilst the biatomic stage is one of 

 exalted stability. If we substitute an atom of chlorine in perchloride of 

 carbon by one of ethyl, we produce a body having the formula of 

 trichlorhydrin : 



/ C TT 

 I C H I 



c. g 



\Cl 



If now a second atom of chlorine be substituted by one of hydrogen, 

 we have a body exhibiting the composition of bichloride of propylene : 



H 



a 

 ci 



The treatment of this body with alcoholic potash remove* hydro- 

 chloric acid, and reduces it to the protochloride type 



C,H, 



i i 



+ KO = C, 



+ KC1 + HO. 



* / ' Chloride of Allyl. 



Bichloride of propylenc. 



The substitution of a third atom of hydrogen for chlorine, gives the 

 formula of chloride of propyl : 



'C.H. 

 II 



ARTS AMD 801. DIV. VOL. VI. 



whilst the substitution of the last atom of chlorine by hydrogen yields 

 hydride of propyl, or by ethyl, the so-called double radical ethyl propyl : 



Hydride of propyl. Ethyl-propyl. 



In like manner, if we substitute an atom of oxygen in carbonic acid 

 by ethyl, we have propionic anhydride 



( (C 4 H S ) 



C / C ) 



<M c ". j o 



(o 



* Carbonic acid. Fropionic anhydride. 



A second atom substituted by hydrogen yields propionic aldehyde : 



Propionic aldehyde. 



The replacement of a third atom of oxygen by hydrogen produces 

 propylic ether : 



C.H 5 



^H 



[a 



v 

 Propylic ether. 



Whilst the replacement of the last atom of oxygen by hydrogen, 

 produces hydride of propyl, and by uniatomic peroxide of hydrogen, 

 propylic alcohol : 



C,U S / C t Hj 



C 5 U 



i (HO, 



Hydride of propyl. Propylic alcohol. 



The glycola are also constructed upon the carbonic acid type : 



C 2 II, 

 H 



HO, 

 110. 



Carbonic acid. Glycol. 



And to the same type belongs also the teracid alcohol glycerin 



c I" ** 

 c HO, 



I no, 



Under the influence of iodide of phosphorus, glycerin yields iodide 

 of allyl : 



Iodide of allyl. 



Here we have a reduction from the carbonic acid to the carbonic oxide 

 type, of precisely the same nature as that which occurs when cacodylic 

 acid is reduced to oxide of cacodyl. Allylio compounds are therefore 

 constructed upon the carbonic oxide type : 



Carbonic oxide* Iodide of allyl. 



C f c n 

 1 '. HO, 



Allylic alcohol. 



It would be easy greatly to extend this view of the constitution of 

 organic carbon compounds, but the above examples are sufficient to 

 indicate its general application. It is from carbonic acid, water and 

 ammonia that nature constructs her most complex organic compounds ; 

 these inorganic substances are the essential food of plants, which thus 

 find ready formed in the air and earth the moulds in which to cast 

 their most complicated chemical compounds, just as animals find ready 

 formed in their vegetable food, the plastic constituents which they 

 employ for the construction of the various parts of their organisms. 



ORGANIC COMPOUNDS, A rtifiaal Production of. Under ORGANIC 

 CHEMISTRY allusion is made to the production of urea, acetic acid, and 

 methyl (three essentially organic compounds), by purely artificial 

 methods, and without any assistance, direct or indirect, from vital 

 action. The recent ingenious researches of M. Berthelot have greatly 

 extended this branch of chemical inquiry, and have in a most important 

 degree increased the number of bodies capable of artificial formation. 

 The production of chloride of methyl, and the members of the olefiant 

 gas family up to amylene (C JO H >0 ), furnishes us with the whole series 



