VELOCITY OF REACTIONS 



away nor added. The characteristic stage of 

 equilibrium of the reaction has been reached. 

 We express this rule by writing the chemical 

 equation connected by a double arrow instead of 

 the sign of equation : 



C 2 H 5 OH + CH 3 COOH ^ C 2 H 5 OOC-CH 3 +H 2 O 



Ethyl alcohol + Acetic acid^I^ Ethyl acetate + Water 



or C 6 H 12 6 +C 6 H 12 6 ^ C 12 H 22 O n +H 2 O 



Glucose + Fructose ~^~^[ Saccharose + Water 



This theory involves the condition that all these 

 reactions may be reversed under certain circum- 

 stances. It only depends upon the external con- 

 ditions in which direction the situation of the 

 stage of equilibrium is displaced, either [in the 

 direction of composition or in the direction of 

 decomposition. We may draw the further con- 

 clusion that many chemical processes in living cells 

 may obey this kind of law. Under certain circum- 

 stances cells may contain more grape sugar and 

 fructose, under other circumstances more cane 

 sugar. Only chemical or physical agents influence 

 this relation, and we need no longer take refuge 

 in mysterious " vital forces " when we want to 

 explain these facts. Just such chemical reaction- 

 complexes occur most frequently in living cells. 

 The digestion and dissolution of organic matter in 

 the cell on the one hand, and the storage of organic 

 matter on the other, must be ruled by analogous 

 G 81 



