Abstract
As a part of effort to physically define what is the living state, we describe process of regeneration of a hydra animal from a tendem graft and a dissociated cell aggregate. Particularly, a transition from a dissociated cell aggregate which is nothing but a mechanically gathered cells to an animal which is an organically interacting cell system is, in a sense, similar to an nonequilibrium system undergoing a transition to an ordered state. Also a fundamental difference between measurement of the physical systems and the biological systems are discussed.
