2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/52291String (membrane) theory could be considered as degenerate case of relativistic continuous media theory. The paper presents models of media, which are continuous distributions of interacting membranes, strings or particles.6 pages, LaTeX, The paper is based upon talk at SQS'03 (Dubna); Discussion of different string fluid models and some references are addedHigh Energy Physics - Theorytext