XIV.] LIVING MATTER AND ITS EFFFXTS. 219 



very deep lakes ; in consequence of the deepening of the 

 existing sea-valleys, and the elevation of the intermediate 

 land areas. Or the contrary result might be brought about, 

 by the depression of the existing land areas, and the raising 

 of the sea-bottom by matter ejected from submarine vol- 

 canoes. 



Thus, so far as the mere transference of the matter of the 

 crust of the globe is concerned, the tendency of volcanic 

 action and of the elevatory forces is, on the whole, towards 

 compensating denudation and depression ; and, it is con- 

 ceivable, that the two processes should go on, for any 

 assignable time, in such a manner, that the proportion of 

 land above the sea level to that below it should remain 

 unchanged. But, in the operations of nature hitherto dealt 

 with, there is nothing to compensate for the gradual conver- 

 sion of solids into liquids by denudation ; nor for such out- 

 pouring of gases into the atmosphere as occasionally, if not 

 always, accompanies volcanic action. 



Nevertheless, an agent, by which some of the gaseous 

 and liquid constituents of the earth are, temporarily or per- 

 manently, reduced to the state of solids, is at work upon a 

 prodigious scale. This agent is what is termed living mat- 

 ter ; or less accurately, organic matter} 



The surface of the valley of the Thames is covered with 

 prodigious multitudes, and seemingly endless varieties, of 

 the forms of this living matter, some of which we call plants, 

 and others animals. But, notwithstanding their obvious 

 differences, there are so many deep-seated points of agree- 

 ment among the diversified forms of life, that any plant or 



^ Less accurately, because all forms of living matter cannot be 

 strictly said to be organised. An organ is a part of a living body, the 

 structure of which fits it for the performance of some special action, 

 which is called its function. The lowest forms of life possess no parts 

 to which the term organ can be applied in this sense. 



