ON THE NATURE OF LIFE 221 



happen. So water does not rraf uphill ; a piece of brick put into 

 the fire does not generate heat; and water and carbonic acid do 

 not, of themselves, combine to form carbohydrate, because in 

 such processes entropy would necessarily increase. Our inor- 

 ganic concept is, therefore, the entropy of the universe tends 

 towards a maximum value. 



On the other hand, things do happen in the course of which 

 energy is not degraded, but, on the contrary, becomes elevated, 

 so to speak. Water and carbonic acid react together and utilise 

 the degrading energy of sunlight, producing carbohydrate. 

 Proteid, carbohydrate, and fat, when aggregated in the form of 

 living protoplasm, do not decompose, but increase in quantity 

 by reproduction. In these energy transformations entropy 

 decreases, and unavailable energy becomes available.* Some 

 adaptations among wild animals clearly tend to reduce the waste 

 of available energy (as when change of coat colour or the accumu- 

 lation of blubber beneath the skin minimises the loss of heat), 

 and all adaptations have the same general tendency. Human 

 operations may lead to degradation (say by war, by the cutting 

 down of forests, the extinction of seals and whales, or the de- 

 pletion of coal resources), but they may also have the opposite 

 tendency (as in afforestation, the cultivation of the land, the 

 breeding of domestic animals, the increase of populations, and 

 the invention of antifriction machinery). A man may expend 

 his energy in rolling stones downhill, when he dissipates potential 

 energy in useless friction; or he may by the same expenditure of 

 energy carry stones uphill, so that they are in a position to roll 

 down again, thus accumulating potential energy. In such 

 " vital " processes and tendencies available energy accumulates 

 and entropy decreases. 



Therefore the concept by which we explain truly inorganic 

 happening fails to explain organic happening, for in the latter 

 the inorganic concept is reversed. 



In living processes the increase o! entropy is retarded this is 

 our " vital " concept. 



* The reader must not misunderstand this statement. Starch accumu- 

 lates in the green leaf exposed to sunlight, but the whole system is the 

 green leaf + the C0 2 and OH 2 + the degrading sunlight. In the system 

 thus denned entropy increases very slowly. The system is one in which 

 there are coupled energy transformations, (1) the degrading sunlight: and 

 (2) the photo-synthetic process. If there were no coupling, the solar 

 energy would degrade, with a maximum entropy increase; if there is a 

 coupling, the entropy increase becomes minimal. The coupling is always 

 the mark of life activity. 



