CHEMICAL REACTIONS CAN BE INDUCED 137 



the energy set free in one reaction is used to cause another reaction 

 to proceed away from the direction of its equilibrium point, as 

 in the reduction actions often induced by oxidising agents. For 

 example, in the action of hydrogen-peroxide upon certain metallic 

 oxides, such as silver, gold, and peroxide of lead. Here the reaction 

 of formation of water and oxygen from hydrogen -per oxide which 

 goes on slowly by itself, and gives out free energy, is actually 

 enormously increased in velocity l by another reaction which 

 absorbs energy in the process. The induced reaction runs the 

 inducing reaction backwards away from its equilibrium point by 

 means of the energy which would be otherwise set free. The 

 reason for the increased velocity is the same as in the case of 

 catalytic action ; although free energy from the induced reaction 

 is taken up by the inducing reaction, the resistance in the process 

 of the intermediate stage due to setting free of nascent oxygen is 

 removed, and in this respect, although undergoing alteration itself 

 with absorption of energy, the metallic oxide acts as does a 

 catalyst in catalysed reactions. 



But it is in the metabolism of the living cell that we meet with 

 examples of such linked and induced reactions in greatest numbers. 

 Even in the animal cell, although the balance-sheet of metabolism 

 is in favour of oxidation with liberation of free energy, it is 

 a mistake to suppose that there are no reactions running in the 

 reversed direction. We have seen earlier, that with the varying 

 conditions of concentration in the cell the equilibrium point may 

 alter so that syntheses forming the reversals of simple hydrolytic 

 cleavages may readily occur in the cell, simply by the action of 

 enzymes. Such, for example, as maltose formation from glucose, 

 of glycogen formation from glucose, of proteid from albumose, 

 or even of neutral fat from fatty acids and glycerine. Such 

 syntheses demand little or no energy, because the chemical energy 

 of the substances upon one side of the equation is practically 

 identical with that of the substances upon the other, and hence 

 variations in osmotic energy with changes in concentration may 

 easily make the balance, so that an enzyme which adds no energy 

 may affect the conversion. But in such cases of metabolic change, 

 as, for example, the conversion of carbohydrates to fats, where, 



1 We cannot say catalysed, because the inducing substance does not remain 

 unaltered but takes up energy, but the difference is only in definition, for, as 

 far as chemical kinetics go, the action is virtually catalysed. 



