Mechanical transformations of living cavitary bodies

Abstract

All living organisms and many of their parts are organised in an essentially similar manner: they are closed cavitary bodies consisting of 1) the inner mass and 2) a relatively thin sheath enclosing it. This organisation allows living bodies to change shape by employing hydrostatic forces. These forces are generally recognised to govern changes of shape in walled cells. To explain transformations of other organisms, other factors are usually sought. In this paper, the hydrostatic mechanism is represented as a universal mode of shape formation. It acts in all kinds of organisms, determining the course of diverse processes such as development of cell outgrowths, limb buds, gut derivatives and sense organs; endocytosis; cell division; branching of capillaries; gastrulation; cell locomotion; muscle contraction etc.