[Various theoretic principles of geriatrics and their application to aging of arteries. A. Aging on different organizational levels of living organisms].

At all times "theories of ageing" have played a leading part in gerontology. The experimental theoretic gerontology has elaborated interesting findings on monocellular organisms and insects as well as on small laboratory animals. Recently, models of cells and ageing at cellular and molecular level play an increasing part. Also the physico-chemical alteration of the condition of macro-molecules has contributed to the clarification of ageing processes. It will be a task of future to clarify the ageing of higher organisational forms of life (organs, systems of organs, organisms) better than up to now. The laws of systems active in these cases are complex and cannot be explained by simple addition of cellular or subcellular ageing mechanisms.