You could say that the living substance which is on the interior of the membrane regenerates the membrane, but it’s the membrane that makes the living being alive at each moment, because this membrane is selective: it maintains the milieu of interiority as a milieu of interiority in relation to the milieu of exteriority. You could say that the living being lives at its own limit, on its limit; it’s in relation to this limit that there is a direction toward the inside and a direction toward the outside, in a simple unicellular organism.