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 time on proteins—proteins were considered as unlikely to have such highly specific physiological activity shown by a hormone such as insulin. In 1927, he was published in the journal Science for this work with a paper entitled "Chemistry in Relation to Biology and Medicine with Especial Reference to Insulin and Other Hormones". At the time, Abel's laboratory was no doubt the center of insulin research in the United States. A lot of young scientists came to his lab and worked under Abel to study the newly crystallized hormone. Abel himself gradually withdrew from the actual experimental work on insulin after