ABSTRACT
From the physical point of view the characteristic state of the living organism is that of an open system. A system is closed if no material enters or leaves it; it is open if there is import and export, and, therefore, change of its components. Living systems maintain themselves by the exchange of materials with their environment and by the continuous building up and breaking down of their components. An open system may attain a time-independent steady state where the system remains constant as a whole, and in its phases, though there is a steady flow of materials through at A characteristic of an open system is that the system exerts forces to attain, and then maintain, a steady state. Self-regulation is a general property of open systems. 1 In field theory the self-regulated steady state is referred to as a quasi-stationary equilibrium. 2
