Source of Carbon and Nitrogen in Plants and Animals. 361 



mch variable proportions in the atmosphere, that they may appear, from this 

 circumstance alone, to be extraneous to its composition ; and, on the other, 

 are both seen to proceed, even at the present day, from the interior of the 

 earth, in various parts of the globe. 



Every one who has made the phenomena of volcanos the subject of 

 his attention, is conversant with the fact, that volumes of carbonic acid 

 are constantly issuing- from the earth, not only in places where igneous 

 action manifests itself, but also wherever we have reason to believe that it 

 has formerly existed, though apparently in a dormant condition at present. 



Those, too, who have visited an}- active volcano, must needs have re- 

 marked, that sal ammoniac is sublimed in large quantities from the sub- 

 stance of lava currents recently ejected, and likewise from the crevices of 

 mountains in which the eruptions have taken place.* 



Professor Liebig has also pointed out, that ammonia is a constant ac- 

 companiment of the boracic acid disengaged by volcanic action from the 

 lagoons in Tuscany, and it is satisfactory to me to find that distinguished 

 chemist confirming, by his authority, the view which I had long ago held 

 and maintained, namely, that the ammonia in these eases cannot by pos- 

 sibility be derived from the decomposition of organic matter, since no 

 beings could live at such a temperature as that indicated by the steam 

 which holds it in solution. 



Hence, like the carbonic acid, ammonia must have been derived from cer- 

 tain processes taking place in the interior of the globe,t processes which 

 may have preceded the existence of living beings, and which may have 

 fulfilled some important office in the economy of nature, subservient to 

 their existence and production. Startling, indeed, as the position may 

 appear, yet, being backed by the authority of Liebig - , I shall no longer 

 scruple to suggest as a matter at least of probable conjecture, that every 

 particle of carbon, as well as of nitrogen, which enters into the constitu- 

 tion of the plants and animals, either now existing, or which have existed 

 since the beginning of time, may have been originally evolved from the 

 interior of the globe. 



The only mode that suggests itself by which we can escape from this 

 conclusion, consists in supposing, 1st, that when it first pleased the Al- 

 mighty to call plants into existence, He at once overspread the globe with 

 them, without availing himself of the operation of secondary causes to 

 bring about their dissemination ; Idly, that the amount of carbon and 

 of nitrogen contained in the plants created, sufficed for supplying the 

 entire animal kingdom, in proportion as it extended itself, with the or- 

 ganic matter which it would require ; 3dly, that no increase to the col- 



appearance of Professor Liebig's work, we maintained, on geological grounds, in our 

 lectures, a similar speculation. — Edit. 



* Sec my Memoir on the Eruption of Vesuvius In 1834, published in the Phi- 

 losophical Transactions for 1835. 



t Liebig, p. 112. 



