LIVING ORGANISMS 23 



or fluids as they were known to the chemist. 

 We now know that this is an assumption. 

 These so-called principles probably only arise 

 from the decomposition of matter that was 

 once alive. One of the characteristics of 

 these complex organic substances, whether 

 as found in the bodies of plants or animals, 

 is their instability. They are liable to split 

 up into simpler bodies, and this splitting up 

 is always associated with the liberation of 

 energy, chiefly as heat or movement. Thus, 

 in living matter two apparently opposite 

 chemical processes are continually at work ; 

 there is either the building up of simpler 

 substances into more complex ones, such as the 

 formation of starch from the elements carbon, 

 hydrogen, and oxygen, or the pulling down of 

 complex substances into simpler ones, as the 

 resolution of starch into carbonic acid and 

 water. In the upbuilding process, often termed 

 anabolic, energy is locked up, or becomes 

 latent, while in the pulling down process, 

 termed katdbolic, energy is liberated and 

 becomes kinetic. Thus starch (or oil), when 

 burnt, that is oxidised, yields carbonic acid 



