1847.] Strictures on the views of Dr. Seller. 109 



— for example, by the increase of the organic matter oi" the soil 

 often observed during the growth of plants — but also by the gen- 

 eral view of the earth's surface just taken, because there is nothing 

 in its aspect to warrant the idea that its means of maintaining the 

 organic kingdom are declining with the rapidity indicated in the 

 statement just made. 



But we may well enquire, admitting the fact that the food of 

 plants is organic, are the views really sustained by Dr. Seller's 

 reasoning; or, is it possible, under present arrangements, to ex- 

 haust the organic matter — for the living to consume all the dead 

 organic matter. The following considerations have a bearing upon 

 the question: 



1. Plants have a limited duration, and although they consume 

 food which enters into theii' bodies and is withdrawn from the soil, 

 still, in the course of a few years, or centuries at most, it must and 

 will be restored again, and will pass through those changes which 

 are necessary to fit it to become again the food of succeeding 

 generations. 



Organic matter, if resolved into inorganic carbonic acid, ascends 

 into the atmosphere,but returns to the soil again ; for in the nature of 

 its constitution it must be dissolved in the vapor of the atmovsphere; 

 and when this takes place, it ceases to obey the law of the diffu- 

 sion of gasses and descends to the earth. No accumulation of 

 this gas can ever occur so long as the earth is supplied with water 

 wherewith to form vapor, and here we infer, too, that it never did 

 accumulate in the atmosphere. However, this may be, the com- 

 pensating processes which are provided in all structures must not 

 be lost sight of in the physical arrangements of the globe — regen- 

 eration necessarily follows decay: and provision was made in the 

 original construction of things to furnish a supply for the wants 

 of life. Matter is never at rest; and when once it is liberated 

 from its connections with a given body, it soon begins to be fitted 

 for some other. Nature is balanced by compensations, and the 

 processes which, on a superficial view, seem as if they would ex- 

 haust a necessary supply of any material or any force, are found 

 to have been provided for in the operation of the very machinery 

 which seemed at first view^ to consume its own material or its force 

 by its own workings. The wheels of nature as they move along 

 may seem to exhaust all the force and material in their progress, 

 yet a return for all this expenditure is secured by the workings of 

 the apparatus and by the ministration of the materials employed. 

 But to recur once more to the accumulation of carbonic acid in 

 the atmosphere. It is a favorite doctrine with many, that this sub- 

 stance must have been much more abundant in certain geological 

 periods than it is at present. The ground of this opinion is based 

 on the fact that accumulations of carbonaceous matter either took 



