OP BODIES CONTAINING NITROGEN. 283 



formation, while this necessary condition to the transposition of 

 their atoms is absent. Even the compounds of nitrogen most 

 liable to change, such as those found in animal bodies, do not 

 enter into a state of putrefaction when dry. 



The result of the known transformations of azotized substances 

 proves, that water does not merely act as a medium in which 

 motion is permitted to the elements in the act of transposition, 

 but that its influence depends on chemical affinity. When the 

 decomposition of such substances is effected with the assistance 

 of water, their nitrogen is invariably liberated in the form of 

 ammonia. This is a fixed rule, without any exceptions, what- 

 ever may be the cause which produces the decompositions. All 

 organic eompounds containing nitrogen evolve the whole of that 

 element in the form of ammonia, when acted on by alkalies. 

 Acids and increase of temperature produce the same effect. It 

 is only when there is a deficiency of water, or of its elements, 

 that cyanogen or other azotized compounds are produced. 



From these facts it may be concluded, that ammonia is the 

 most stable compound of nitrogen ; and that hydrogen and nitro- 

 gen possess a degree of affinity for each other surpassing the 

 attraction of the latter body for any other element. 



Already in considering the transformations of substances des- 

 titute of nitrogen, we have recognised the great affinity of carbon 

 for oxygen as a powerful cause for effecting the disunion of the 

 elements of a complex organic atom in a definite manner. But 

 carbon is also invariably contained in azotized organic com- 

 pounds, while the great affinity of nitrogen for hydrogen fur- 

 nishes a new and powerful cause of change, and thus facilitates 

 the transposition of their component parts. Thus, in the bodies 

 destitute of nitrogen we have one element, and in those contain- 

 ing that substance, two elements which mutually share the ele- 

 ments of water. Hence there are two opposite affinities at play, 

 which mutually strengthen each other's action. 



Now we know, that the most powerful attractions may be over- 

 come by the influence of two affinities. Thus, a decomposition 

 of alumina may be effected with the greatest facility, when the 

 affinity of charcoal for oxygen, and of chlorine for aluminium, 

 are both put in action, although n< ither of these alone has any 



