permeability，growth， sensory excita

permeability，growth， sensory excitation， electrical stimulation， centerfunction，etc.), would "fuse into an integrated theoretical field under theguidance of the concept of open system" [6, Vol. II, pp. 49 ff.; also 15, p.137 f.].The intuitive choice of rhe open system as a general system modelwas a correct one. Not only from the physical viewpoint is the "open sys-tem" the more general case (because closed systems can always be obtainedfrom open ones by equating transport variables to zero); it also is thegeneral case mathematically because the system of simultaneous differen-tial equations (equations of motion) used for description in dynamical systemtheory is the general form from which the description of closed systemsderives by the introduction of additional constraints (e.g., conservation ofmass in a ciosed chemical system) (cf. [46], p. 80 f.).