FIRST LAW OF THERMOD YNAM I ( S ;j 



disintegration. Complete immobility denotes death. Change 

 indicates the utilisation of energy, which obviously must have 

 come from some source outside the organism. ; ' The mechanistic 

 notion of life, the representation of the body as primarily and 

 fundamentally a machine, is often bitterly and not very intelli- 

 gently opposed. We are told that the machine the scientists' 

 imitation of life is not merely a purely inanimate mechanism. 

 In its cunning combination of valves and regulators it has a 

 brain, part of the brain of its designer. The partial likeness is 

 that of the machine to the man, of the limited imitation to the 

 original, not the other way about, which is true enough. But 

 let us bear in mind one essential and undeniable fact. Machine 

 or man, inanimate mechanism with the mechanical imitation of 

 a brain, or brain controlling an animate mechanism, what of the 

 power ? The power to live, the power to do work is not in the 

 brain nor in the body, not in the valves nor the moving parts. 

 The power, whether of life or of mechanism, is external. This is 

 the real ground of analogy " (Soddy). We must determine the 

 source of this energy, study its laws, see how it is made available 

 for living matter, and then see how it operates in living matter. 



Energy is the underlying cause of all changes in matter. This 

 does not seem a very satisfactory definition but, so far, it is the 

 only one possible. It is a very striking fact that the two funda- 

 mentals of our external world, matter and energy, have for us 

 no existence apart from their effect on us. We cannot prove 

 that there are such things except in so far as they manifest them- 

 selves, matter by being changed, and energy by producing changes, 

 which in turn alter our sensation-complex. 



There can be no change of any sort without free energy. Energy 

 exhibits itself in many forms heat, light, movement of matter, 

 electricity, radio-activity, etc. 



In 1798, Count Rumford, who was engaged in boring cannon, 

 showed that movement or kinetic energy could be transformed 

 into heat. Later, Joule demonstrated the equivalence of these 

 two forms of energy. 427 kilogrammetres of work always pro- 

 duce (under standard conditions) one Calorie of heat. Con- 

 versely, heat may be transformed into mechanical movement. 

 Indeed, any form of energy may be converted into any other 

 form of energy. (Radio-active matter evolves energy which 

 manifests itself in various forms, yet all attempts to change 

 other forms of energy into radio-active energy or even to influence 

 the rate of transformation have failed. Chap. XI.) 



