THERMODYNAMICS AND KINETICS .S3' 



following essential characteristics of these systems in a form 

 borrowed from the review of Pasynsk.ii/® 



1. The stationary state of open systems is characterised by 

 a constant minimum rate of dissipation of free energy 

 and a constant minimum rate of development of entropy 

 within the system in contradiction to the state of thermo- 

 dynamic equilibrium in closed systems in which these 

 functions have a value of zero. 



2. In open systems there can occur processes leading to a 

 decrease in entropy owing to their thermodynamic associa- 

 with processes leading to an increase in entropy in the 

 external medium. 



3. In open systems there can exist an infinite number of 

 stationary states depending on the internal parameters 

 of the system (the original concentration of the com- 

 ponents, the diffusion constants, the rates of the reactions 

 and so forth), and on the external conditions (tempera- 

 ture, pressure and so forth). A change in any of the 

 conditions of a stationary state leads to a rearrangement 

 of the kinetic and diffusion parameters of the system and 

 to the establishment of a new stationary state. 



4. In open systems where alternative routes are available 

 the directions of chemical changes are determined by the 

 principle of the maximal reaction velocity. 



5. In an open system the presence of catalysts affects not 

 only the rate of the reaction, but also the stationary 

 concentrations of the reagents. 



6. When the conditions are altered in the stationary state 

 in open systems, processes occur which tend to conserve 

 the properties of the system (the dynamic stabilisation 

 of the stationary state). 



7. The transition from one stationary state to another in 

 an open system where the reaction velocities are not very 

 great does not proceed according to a smooth curve but 

 usually passes through an extreme state (through a maxi- 

 mtim or minimum). 



It is very significant in connection with our problem that 

 the principle according to which protoplasm is organised 

 in time is similar to the principle of organisation of open 



