PLANTS AND ANIMALS 27 



are the major products set free. This may be said with 

 equal truth of the animal and it may be pointed out that 

 if the candle is an old-fashioned one, made of tallow, the 

 fuel is the same that might have been used by the animal 

 if its life had not been cut short. 



When we deliberately cause fuels to burn, our object is 

 usually to make some use of the energy which has been 

 latent in them. We light the candle or the lamp that it 

 may give us light. Fires are maintained to warm our 

 houses, to bring about desirable changes in our food, 

 or to keep machinery in motion. In every case the 

 object is secured through the release of stored energy. 

 It has been potential before and it now becomes kinetic 

 or active. The service of oxidation to the animal is not 

 essentially different. It is the source of animal heat 

 and muscular power. It is hard for the elementary 

 student to grasp the truth that decomposition is not dis- 

 aster, but a necessary condition of living. It is only by 

 expenditure, by the sacrifice of resources, that the organ- 

 ism can react and prove itself alive. The stores of the 

 body are like money, useful not in themselves, but be- 

 cause of the results obtained in exchange for them. 



If it were possible to suspend oxidation in the body of 

 one of the higher animals it might be thought that it 

 would remain motionless and cold but perfectly preserved 

 for an indefinite time. Such a suspension of animation is 

 unknown among higher forms; in them the restriction of 

 oxygen supply perverts the life processes before it stops 

 them and the result is the poisoning which we call as- 

 phyxia. Lower down in the scale we find such modifi- 

 cations of living matter as the seeds of plants, the spores 

 of bacteria, and the encysted forms of certain aquatic 

 animals which do represent, approximately at least, an 

 arrest of respiration, and so of activity, which may be 

 continued for a long while. A German writer has com- 

 pared the state of such forms with that of a clock which 

 is wound up but not going. There is the capacity for 

 action but the mechanism remains under restraint. 



