tubes are stood side IW sidle, “100” on the Haldane-Gower scale corresponds to “52” on the Wintrobe scale. In view of the relation of plasma trapping to the height of the packed cell column, both types of tube were filled with the same blood
to the same height. Samples of different P.C.V. were used and sets of both types
of tube were spun together in the same centrifuge at. 3000 r.p.m. for 30 minutes.
The results are illustrated in figure 2 and it cats be seen that. if plasma trapping
is plotted against the height of the packed red cell column in mm., identical
values are obtained for both types of tube.