As early as 1947, Polge, Smith, and others1-3 showed that tissues exposed to glycerol and other polyhydric alcohol subsequently could be frozen and thawed without significant harm. The implication of this observation to blood banking was readily apparent, but practical considerations prevented its immediate translation to methods of red cell preservation. This was chiefly because glycerol must be removed from the red cells before transfusion.
The Cohn fractionator, developed in 1951, for the separation of blood into its component parts4 was found to possess certain features which made it uniquely applicable to the glycerol processing of red cells prior or subsequent to preservation in the frozen state. This Cohn-ADL fractionator contains a sterile centrifuge that operates at fixed temperatures with no limitations on the volume of solutions that may be perfused through the cellular mass revolving inside the centrifuge bowl.5
Preliminary studies with this apparatus by Tullis