Human skin epithelial-like cells (NCTC strain 2544) were grown in NCTC 135 medium. Neuraminidase and hyaluronidase were added to the growth medium. Cells were incubated 96 h at 36 degrees C. Growth rate and viscosity of cell suspensions were measured after forming single cells mechanically (mopping). With addition of neuraminidase and hyaluronidase, respectively, the growth rate remains unchanged. With neuraminidase a distinct raise in viscosity was achieved, whereas with hyaluronidase only a small effect was seen. The characteristic structure viscosity is maintained in all forms of the viscosity curves at different shear-rates.