  It is shown, that spontaneous ultraviolet radiation of cells (infusoria)
plays the role of agent, restricting the upper limit of the quantity of cells
in quasi-stationary phase of cultire's development. The spectral region of this
radiation defined experimentally occurred to be in the range of 200-290 nm. As
the filter cutting off the short wave length part of the spectrum (below 290nm)
1 mm thick plexiglas has been used, while as the filters transmitting short
wave part of the spectrum - 5 mkm thick fluorostatic film or 1 mm thick optical
quartz has been selected. It has been shown, that dynamics of development of
the cells in the culture depends on transparency of nutrient medium to
spontaneous ultraviolet radiation of the cells. Conclusion has been made, that
superweak chemiluminescence of the cells is not a worthless metabolism product,
but plays significant biological role.
