A series of experiments has been carried out on the flowing of suspended human erythrocytes into glass-tubes whose diameters varied between 30 mum and 1 mm. Thus, the Fahraeus and Fahraeus-Lindqvist effects emergence fields have been drawn, and it has been shown that, contrary to a widely admitted hypothesis, the Fahraeus effect does not account for the Fahraeus-Lindqvist effect.