John Jacob Abel to successfully isolate the neutral base of epinephrine by adding ammonium to highly concentrated extract, a method Abel himself tried but failed due to the use of low concentration of extract. After Takamine's success, Abel himself remarked, with great candor, "The efforts of years on my part in this once mysterious field of suprarenal, medullary biochemistry, marred by blunders as they were, eventuated, then, in the isolation of the hormone not in the form of the free base but in that of its monobenzoyl derivative." Together with L.G. Rowntree and B.B. Turner, Abel devised what they called a "vividiffusion" apparatus,
John Jacob Abel consisting of a series of tubes surrounded by fluid. They first demonstrated the apparatus at the Physiological Congress in Groningen in 1914. By allowing arterial blood to enter at one end of the connection, and later return to circulation through the venous connection after dialysis, they were able to demonstrate the existence of free amino acids in blood. By isolating these amino acids from blood circulation, Abel conducted various subsequent researches on the structure of proteins in the blood. Not only did Abel use the apparatus for his research work, he also realized the great clinical potential such dialysis machine