,, THE BUTYRIC ACID GROUP. 35 



subject, we employ this mode of representation, arid arrange the 

 formulae of these bodies so as to substitute chlorine in the place of 

 hydrogen. 



But putting out of the question the practical advantages afforded 

 by this mode of viewing the subject, and independently of the cir- 

 cumstance that Berzelius's mode of indicating the composition of 

 such bodies is very far-fetched, and cannot without great difficulty 

 be brought in accord with other experiments, this mode of investi- 

 gation is recommended by the circumstance that, in most cases, not- 

 withstanding the loss of atoms of hydrogen, and the introduction 

 of negative chlorine, bromine, or iodine, or of the complex atom=: 

 N O 4 , corresponding to hyponitric acid, the new body retains the 

 chemical character of the original compound ; that is to say, if the 

 mother-substance were an acid, the newly-formed substance would 

 be so also ; if it were neutral, the new compound would likewise 

 be neutral ; and it is very remarkable, that basic bodies, like the 

 alkaloids, continue bases when the above elements, or hyponitric 

 acid, are substituted for the atoms of hydrogen. 



All the acids of this group likewise form amide-compounds. 

 The term amide is known in inorganic chemistry. The atomic 

 group H 2 N, which cannot be exhibited in an isolated state, is 

 found in many metallic preparations produced by treating com- 

 pounds of the metallic oxides with ammonia. It might thence be 

 assumed, that the atom of oxygen of the metallic oxide, as for 

 instance of the oxide of mercury, has united with an equivalent of 

 hydrogen of the ammonia to form water, and that the metal then 

 unites with what remains of the ammonia =:H 2 N to form the 

 so-called amide. In organic chemistry the amides are produced in 

 a similar manner, with this difference only, that in this department 

 it is chiefly acid substances which have a tendency to enter into 

 such combinations. We can best realise the production and 

 decomposition of organic amides, by assuming that the hypothetical 

 anhydrous ammonia-salt of the organic acids loses an equivalent of 

 water, while an equivalent of hydrogen is withdrawn from the am- 

 monia, and an equivalent of oxygen from the acid. Thus acetamide 

 is equal to acetate of ammonia, minus 1 atom of water, since 

 H 3 N. C 4 H 3 O 3 HO=H 2 N. C 4 H 3 O 2 =:C 4 H 5 NO 2 . 



According to the theory of substitutions, one atom of the 

 oxygen of the acid in these combinations is replaced by the 

 complex atom H 2 N, but this mode of viewing the subject cannot 

 be adopted, since the acids, by this union, entirely lose their acid 

 character, and even basic bodies, on their entering into combina- 



D 2 



