(Above) a diagram of the 1912-4 vividiffusion apparatus designed, constructed and used by Abel Rowntree and Turner. (From Abel JJ, Rowntree LG, Turner BB. On the removal of diffusible substances from the blood of living animals by dialysis. J Pharmacol Exp Ther 1913-4 5: 275-316). Its operation is described in the text, but dialysis entered and exited the containing bath through the two tubes on the right, whilst blood entered and exited the collodion tubes at the left, using glass manifolds such as (below). (Courtesy Alan Mason Chesney Archives, Baltimore). It is not clear from Abel et al.’s description whether counter-current flow of blood and dialysate was used, or not, but clearly they did not regard this as of importance.