Abstract

It is generally believed, that when the surface/volume ratio is high, fractal structure is expected to exist. The branched fractal structure of the lung has been cited as a classical example of this statement. In this short paper I would like to demonstrate that an alternative lung structure (namely sponge-like fractal) is at least as good as, or even better than the branched one, concerning this ratio, therefore, the cause of the lung''s fractality lies elsewhere.