2 LAWS OF ENERGY 



down the wall of partition which has been reared by common 

 consent between the chemical constitution of living and non-living. . 

 They have been partially successful in that they have been able to 

 build up certain typical products of life from non-living material. 

 No one, however, has, as yet, either analysed or synthesised living 

 matter. The finest chemical technique available cannot be 

 employed without injury to the tissue studied. In spite of this 

 drawback, the science of nutrition may be classed as exact. 

 Mathematical formulae may be employed to express results, and 

 chemical response to a definite stimulus may be predicted. 



Life has been compared to a flame. The Ancients looked on 

 fire as a living thing, and is their view not, to some extent, justifi- 

 able ? The continual ringing of the changes — of form, of colour, 

 or of position — by the flickering flames of our house fires draws 

 the eye. Constantly, alterations are going on. No flame is still 

 for any length of time. All is seemingly unordered and uncon- 

 trolled change. Yet down to the most minute movement all is 

 governed by physico-chemical laws. Every flicker can be accounted 

 for, and could be recorded as due to pressiu-e of liberated gas, 

 pressure and direction of draught, temperature of fire, etc. Fire 

 — mysterious and all-powerful gift of the gods — has yielded to 

 the prying endeavours of the scientist, and can be harnessed and 

 employed in the service of man. 



Similarly, while not committing oneself to a vitalistic or to a 

 mechanistic conception of life, one may study, with considerable 

 profit, the various physical phenomena exhibited by living matter. 

 Examination of even the simplest form of life is sufficient to 

 show that a characteristic phenomenon is change. No living 

 thing is absolutely still. It is undergoing change in one way or 

 another. It may alter its position relatively to its environment ; 

 it may alter in its parts ; it may grow ; it may undergo alterations 

 in internal (atomic or molecular) structure. The physico-chemical 

 processes indicated by these changes or initiated by them are 

 studied under the term metabolism (Gr. metabole, to change). 

 Metabolism may consist in a building up of matter, anabolism 

 (Gr. ana = up) or in the reverse process, a breaking down of 

 matter, catabolism (Gr. kaia = down). If anabolism is greater 

 than catabolism, the organism grows ; if the two processes balance, 

 the organism exists. The predominance of catabolism leads to 

 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- 



