LAUGEL'S PROBLEMS OF NATURE AND LIFE. 337 



hydrogen, and in those which attend and follow its 

 exclusion from the alloy. 



This discovery, if we may so deem it, has much 

 value, not solely in itself, but also in the collateral 

 suggestions it affords. Familiar as we seem to be with 

 oxygen, there are still certain anomalies regarding 

 this greatest element of the natural world which are 

 awaiting further solution. Such are its allotropic 

 states, and the true theory of ozone. The same may 

 even more especially be said of that other great 

 element, nitrogen, so wonderfully associated with 

 oxygen in the atmosphere of our globe not chemi- 

 cally, we are told, and yet everywhere, and always 

 present in such exact proportion that it is difficult not 

 to suppose some atomic relation beyond that of mere 

 admixture. But taking nitrogen singly, as an element 

 to our present knowledge, we know few chemical ob- 

 jects better fitted to stimulate and reward research. 

 Considered in its simplest state as a gas, it is chiefly 

 defined by negative qualities ; while in its compounds 

 it furnishes some of the most violent agents, explosive 

 and poisonous, which nature or art has produced. 

 These explosive actions are explained by the phrase of 

 instability of combination applied to them ; but no 

 explanation has yet reached those by which living 

 organisms are affected. The natural relations, indeed, 

 of this element to animal life, both in its structure and 

 functions, are matter of high interest. Nor must we 

 omit those recent discoveries which give to nitrogen a 

 cosmical existence in planetary space, together with 

 hydrogen and the several metals which have yielded 



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