(j TIME IS AN ELEMENT OF LIFE. 



seas undergoes change changes, however, which require long periods of time, and 

 which, in the course of human existence, are, for the most part, imperceptible. Com- 

 mencing with the inorganic world, which we see is included in this law of unceasing 

 variation, we discover that each of its component structures passes through its trans- 

 mutations more rapidly according as its constitution is more complicated. For the 

 same reason it is that bodies which are organized and organization in itself implies 

 complicated structure are of all forms most liable to these mutations. The dead car- 

 cass of an animal speedily disappears under the forms of water, ammonia, and carbonic 

 acid, its elemental atoms breaking up into simpler and more enduring groups. It is a 

 vulgar error that a living being possesses a principle of resistance to external agents, 

 while a dead one submits itself to them ; both equally change, or, of the two, the living 

 one putrefies and changes the more rapidly ; but, then, for each of the several systems 

 of dead and dissevered atoms, appointed routes of passage are prepared. The carbonic 

 acid escapes by the lungs, the nitrogenized compounds through the kidneys, and water 

 through both those organs and the skin. The putrefaction of an organized being is a 

 constant event ; it commences before birth, and continues after death ; but, though 

 constant, it is regulated in life, and after death the avenues of discharge are all closed, 

 and the mechanism appointed for removing the decaying atoms broken down. 



18. Time, therefore, enters as an element in animal life. Individuals, after the prog- 

 ress of a few years, pass away, and, during each moment of their existence, their va- 

 rious parts are undergoing incessant change. There is a constant removal of all the 

 carbon compounds from every part of the system ; a removal which necessarily arises 

 in conducting locomotion, and various other functions. If an electric current is to be 

 passed along the wire of a voltaic battery, and is required to evolve a certain amount 

 of light or heat, or to produce a certain amount of electro-magnetic motion, a fixed 

 amount of zinc must be consumed. If a steam engine has a given quantity of work to 

 perform, a given quantity of coal must be burned. So also in animal systems, the pro- 

 duction of motion can only be effected by the consumption of the parts of the animal 

 machine. In the higher races, in which an elaborate development of these functions 

 has been accomplished, the processes of transmutation go on with the greatest rapidity. 

 Among insects, which are constantly upon the wing, the combustion of the organic 

 atoms is at a maximum, as is also, consequently, the production of heat ; but at night, 

 or when they rest, the rate of respiration diminishes, the heat declines, and the trans- 

 mutation is checked. In the existence of an animal, as also in the existence of its 

 constituent atoms, time, therefore, enters as an element. 



19. There is a constant washing away of mountains into the sea, and rivers contin- 

 ually tend to fill up their beds. In one region the detritus of the land, brought down 

 by streams, encroaches on the ocean, and makes new countries ; in another, the ocean 

 invades the shores, and makes changes in the shape of continents. In the vegetable 

 world, the leaves are organized in spring, and decay in autumn ; and among animals, 

 each has its own period of duration. Among all these organized structures the parts 

 are undergoing unceasing change. Physical forces are at work, physical phenomena 

 have to be originated, and physical ends to be gained. The death, therefore, of an or- 



