Filamentous bodies which are longitudinally extended and other film-like constructions are made by combining liquid siliceous precursors with air and extruding them. Distinct types or grades of fibers, strands, and other film-like constructions are produced which have a multiplicity of useful applications and indications for use owing to their inherent memory, compactability, tensile strength and density. A prosthetic device for a mastectomy bra is constructed with filamentous bodies. It can be sewn permanently into the bra cup. The device can be refilled to counteract volume loss.