GEOLOGY. 247 



pearing from the field of progress, and then from the sphere of exist- 

 ence. Death is implied in the very inception of the scheme. 



2. Death is also in every step of the process of life. For the liv- 

 ing being is throwing off effete matter during all its growth. The 

 change is constant, so that with each year a large part of the mate- 

 rial in our bodies has passed away and been replaced by new. More- 

 over, the force which had been expended in making a cell or particle 

 of tissue goes to form a new cell or particle when the former dies, 

 and was needed for the new formation going on. Force is not lost or 

 wasted, but used again. There is unceasing flow, and in this flow is 

 life ; its cessation is death. 



3. The kingdom of plants was instituted to turn mineral matter 

 into organic, that the higher kingdom of animals might thereby have 

 the means of sustenance; for no animal can live on mineral matter. 

 Now this living of animals on plants implies the death of plants. 



Again, the rocks of the globe are, to a great extent, made of the 

 remains of dead animals. 



4. The chemistry of life, also, required death. Life in the plant 

 or animal, if sustained by means of nutriment, and continued con- 

 suming, with no compensating system, would evidently end in an ex- 

 haustion of any finite supply. A perfect adjustment was therefore 

 necessary, by which nutriment should sustain life, and life contribute 

 to nutriment. Now the plant takes up carbonic acid from the atmos- 

 phere, appropriates the carbon, and gives back the oxygen. Yet there 

 is no tendency to an exhaustion of the atmospheric carbonic acid, or 

 an over-supply of the oxygen ; for death strikes an exact balance. 



The death of a plant ends in a change of all its carbon into car- 

 bonic acid again. Thus the plant, as it grows, decomposes carbonic 

 acid to get carbon, and then ends in making, in its decay, as much 

 carbonic acid, and restoring it to the atmosphere. Thus through death 

 the compensation is perfect. The atmosphere loses only what it 

 receives. Again, as just now observed, the plant, in growing, gives 

 oxygen to the atmosphere ; but in the decay of the plant the carbonic 

 acid formed is made by taking up the same amount of oxygen. The 

 same carbon that lost oxygen when becoming a part of the plant, 

 takes it again at the decay. The system is hence complete. The 

 parts play into one another in perpetual interchange. Take death 

 and decay out of the system, and it would not work. 1 



Animal life, as above stated, was made to subsist on plants. But 

 the scheme is so well managed as not to disturb the balance made by 

 the vegetable kingdom alone. For all the carbon of animals comes 

 from plants. The plants which feed an animal, and which, on decay, 

 would have turned into carbonic acid, become changed into carbonic 



1 In early geological history, as is generally believed among geologists, there 

 was an excess of carbonic acid in the atmosphere ; and this excess was removed, 

 to a great extent, by the growth of plants during the carboniferous era. Vege- 

 table material decaying under water does not undergo complete decomposition, 

 and thus part of the carbon is left behind; and so far as there is carbon left, there 

 is an actual abstraction of carbonic acid from the atmosphere, by the process of 

 growth. The coal era was a period of great marches ; and by this means the 

 needed purification of the atmosphere was effected, preparing it for land life. 

 The amount abstracted now by the same means is very small, and may be bal- 

 anced by the carbonic acid from mineral sources and volcanoes. 



