amino acids glycine and proline, respectively, for his research on elastin. With the conclusion of his academic career, Stein went on to work under Bergmann. Late Life and Death William H. Stein and his wife traveled around the world and hosted many prominent scientists in their own home in New York City throughout his scientific career. In addition to Stein’s long-term professorship at Rockefeller Institute, he served as a visiting professor to the University of Chicago in 1961 and Harvard University in 1964. Stein also lectured at the Washington University in St. Louis and Haverford College. In 1969, Stein suffered from sudden paralysis, diagnosed as Guillain-Barré syndrome, after developing a fever several days prior during a symposium in Copenhagen. Despite remaining quadriplegic the rest of his life, Stein’s colleagues alleged that his spirit and sense of humor endured. He continued to be a guiding presence at the Rockefeller Institute to his younger colleagues and their work on the study of RNase. At the age of sixty-eight, Stein experienced unexpected heart failure. William H. Stein died 2 February 1980 in New York City. Scientific career Early work Following the completion of his formal education, Stein became a researcher under Bergmann at Rockefeller Institute, where much of his most important work was done. Stanford Moore joined Bergmann's lab in 1939, where he and Stein began research focusing on amino acids. According to Moore, "During the early years of our cooperation, Stein and I worked out a system of collaboration that lasted for a lifetime." Their work in this area was disrupted with the beginning of World War II, and they temporarily parted ways to aid the war efforts, Stein staying with Bergmann to research the molecular scale effect of blister agents on the human body. They began collaborating again, however, after Bergmann died in 1944 and they were given an opportunity by the Director of the Rockefeller Institute, Herbert S. Gasser, to continue Bergmann’s work in amino acids. Chromatography Stein and Moore developed a method to quantify and separate amino acids with column chromatography, using potato starch as the stationary phase. The fractions, originally collected manually, were collected in their newly developed automated fraction collector, and the amount of each amino acid was determined by an adjusted color reaction with ninhydrin. They began testing other methods of separation, such as ion exchange chromatography, to reduce the analysis time, as it took two