"Dr. Avery was a true scientist with an insatiable curiosity and a powerful and unremitting urge to discover the innermost mechanisms of the biological facts that came under his observations."
Oswald Theodore Avery was born on 21 October 1877 in Halifax, Nova Scotia, the second of three sons of Elizabeth Crowdy and Joseph Francis Avery. A Baptist minister in England, Joseph Avery and his wife emigrated to Canada in 1873. After establishing himself as a well-respected pastor in Halifax, he moved his family to New York City in 1887, where he was appointed the pastor of the Mariner's Temple Baptist mission church on the lower East Side. Each member of the family participated in the church: Elizabeth was involved with charities and the newsletter while young "Ossie" and his oldest brother, Ernest, often played their clarinets on the church steps to attract new attendees. Ernest died early in 1892, at the age of eighteen, probably from tuberculosis. Several months later, Reverend Avery also passed away. Following their deaths, the then fifteen-year old Oswald assumed the paternal role for his youngest brother, Roy, a part he would also play some years later to his cousin, Minnie Wandell, who Roy often affectionately referred to as "little sister."
After attending the New York Male Grammar School, Avery went to the Colgate Academy and then Colgate University, where he excelled in literature, public speaking, and debate. While at Colgate, he was a classmate of Harry Emerson Fosdick, who would become one of the most notable clergymen in America; it is likely that when Avery started at Colgate he also intended to enter the ministry. Avery received a BA in the humanities in 1900. For reasons that are not clear, and despite the absence of any scientific background, after college Avery chose a career in medicine and entered the College of Physicians and Surgeons in New York. He received his medical degree in 1904.
Desiring greater intellectual stimulation and frustrated by his inability to help some of his patients, Avery moved in 1907 to laboratory work at the Hoagland Laboratory in Brooklyn, the first privately endowed bacteriological research institute in the country. Since the laboratory was also associated with a Long Island hospital, Avery's duties included teaching courses for student nurses. It was here that he acquired his best known and most enduring nickname, "The Professor," which was often affectionately shortened to "Fess." The Hoagland Laboratory's director, Benjamin White, instructed Avery in laboratory techniques and biochemistry. Avery initially worked on the bacteriology of yogurt, but soon developed an interest in tuberculosis after White suffered a severe case of the infectious pulmonary disease. It was during this time that Avery established what his biographer René J. Dubos called the pattern of his career, the "systematic effort to understand the biological activities of pathogenic bacteria through a knowledge of their chemical composition."
Avery's work came to the attention of Rufus Cole, the director of the Hospital of the Rockefeller Institute for Medical Research, through one of his papers on secondary infections in pulmonary tuberculosis. One of Cole's goals was to develop a therapeutic serum--like that which had been developed for diphtheria--for pneumonia, and to this end he asked Avery to join the Hospital's pneumonia research program. Avery moved to the Rockefeller Institute in 1913, where he focused most of his research for the next thirty-five years on a single species of pneumonia-creating bacteria, Diplococcus pneumoniae. There, he worked with scientists that were widely recognized as being among the elite in their fields, including Alphonse R. Dochez, René Dubos, Harriett Ephrussi-Taylor, Michael Heidelberger, Rebecca Craighill Lancefield, Maclyn McCarty, and Colin MacLeod. His research career culminated in 1944, when, with McCarty and MacLeod, Avery published his seminal paper proving that the "transforming principle," or hereditary material, was DNA and not protein as most scientists had assumed.
In the early 1940s Avery and McCarty, a colleague at the Hospital, concentrated on the phenomenon of pneumococcal transformation, in which "R-form" (non-virulent) pneumococcus bacteria changed into the virulent "S-form" after killed S-form bacteria were added to the culture. The changed bacteria were identical in virulence and type to the killed bacteria, and the changes were permanent and inheritable. Utilizing refined versions of MacLeod's preparation techniques, Avery and McCarty soon isolated active "transforming substance" from samples of pneumococci, and found that the substance was deoxyribonucleic acid, or DNA. In 1944, Avery, MacLeod, and McCarty published their discovery in the Journal of Experimental Medicine. Their conclusions in this paper were cautious, and they presented several interpretations of their results. The phenomenon of transformation, they wrote, was "interpreted from a genetic point of view." Yet they also gave another interpretation, that there might be an "analogy between the activity of the transforming agent and that of a virus." They concluded that, "Assuming that the sodium desoxyribonucleate and the active principle are one and the same substance, then the transformation described represents a change that is chemically induced and specifically directed by a known chemical compound. If the results of the present study on the chemical nature of the transforming principle are confirmed, then nucleic acids must be regarded as possessing biological specificity." Although some of their peers initially questioned this conclusion, in 1952, Alfred Hershey and Martha Chase proved DNA was the hereditary material through their work with a bacterial virus (phage). In 1953, James Watson and Francis Crick determined the double helix structure of DNA. Thus, Avery played an early and critical role in the molecular revolution in biology.
Soon after starting at the Rockefeller Institute, Avery began to share an apartment with Dochez, who was then a colleague in the respiratory disease department at the Hospital. The two life-long bachelors continued as roommates for most of the following thirty-five years. They made complementary housemates and friends, as Avery was somewhat introverted and retiring whereas Dochez was gregarious and outgoing. He would often return home from a night out and engage Avery with his thoughts on an aspect of microbiology which had occurred to him earlier in the evening. Both men acknowledged that they derived a great deal from these late night discussions. They used each other as sounding boards for trying out new ideas or better defining works in progress.
In the early 1930s, Avery underwent treatment for Graves' disease. He took a brief leave from the Hospital in 1934 following a thyroidectomy, but did not fully recover for several years. In 1943, at the mandatory retirement age of 65, Avery became a member emeritus at the Rockefeller Institute; however he continued his research there until 1948. He then moved to Nashville to be closer to the family of his brother, Roy, a bacteriologist at the Vanderbilt School of Medicine. Avery rented a home down the street from Roy, and quickly became a fixture in the neighborhood. Avery's cousin, Minnie Wandell, who was very close with him, acted as his housekeeper. While vacationing on Deer Isle late in the summer of 1954, Avery experienced terrific pain in his abdomen, and subsequent surgery revealed extensive cancer of the liver. He died in Nashville on 20 February 1955 at the age of 77.
Avery achieved many honors during his career. He served as president of the American Association of Immunologists, the American Association of Pathologists and Bacteriologists, and the Society of American Bacteriologists. He was elected to the National Academy of Sciences and the Royal Society of London. He received honorary degrees from McGill University, New York University, the University of Chicago, and Rutgers University, as well as awards from organizations such as the Royal Society of London, the American College of Physicians, the Association of American Physicians, and the New York Academy of Medicine. Avery received the Lasker Award in Basic Medical Research in 1947.