OF ORGANIC COMPOUNDS. 277 



Inorganic compounds differ from organic in as great a degree 

 in their other characters as in their simplicity of constitution. 

 Thus, the decomposition of a compound atom, as of sulphate of 

 potash, is aided by numerous causes, such as the power of cohe- 

 sion, or the capability of its constituents to form solid, insoluble, 

 or at certain temperatures volatile compounds with the body 

 brought into contact with it, and nevertheless a vast number of 

 other substances produce in it not the slightest change. Now, in 

 the decomposition of a complex organic atom, there is nothing 

 similar to this. 



The empirical formula of sulphate of potash is SK0 4 . It con- 

 tains only 1 eq. of sulphur, and 1 eq. of potassium. We may 

 suppose the oxygen to be differently distributed in the compound, 

 and by a decomposition we may remove a part or all of it, or re- 

 place one of the constituents of the compound by another sub- 

 stance. But we cannot produce a different arrangement of the 

 atoms, because they are already disposed in the simplest form in 

 which it is possible for them to combine. Now, let us compare 

 the composition of sugar of grapes with the above: here 12 eq. 

 of carbon, 12 eq. of hydrogen, and 12 eq. of oxygen, are united 

 together, and we know that they are capable of combining with 

 each other in the most various ways. From the formula of sugar, 

 we might consider it either as a hydrate of carbon, wood, starch, 

 or sugar of milk, or further, as a compound of ether with alcohol, 

 or of formic acid with sachulmin.* Indeed we may calculate 

 almost all the known organic compounds destitute of nitrogen 

 from sugar, by simply adding the elements of water, or by re- 

 placing any one of its elementary constituents by a different sub- 

 stance. The elements necessary to form these compounds are 

 therefore contained in the sugar, and they must also possess the 

 power of forming numerous combinations amongst themselves by 

 their mutual attractions. 



Now, when we examine what changes sugar undergoes when 

 brought into contact with other bodies which exercise a marked 

 influence upon it, we find that these changes are not confined to 



* The black precipitate obtained by the action of hydrochloric acid on 

 sugar 



