Oswald Avery (1877-1955), Canadian-born American physician and bacteriologist, who is best known for his discoveries in the field of genetics. Oswald Theodore Avery was born in Halifax, Nova Scotia, and earned his medical degree at Columbia University's College of Physicians and Surgeons. Avery was the first to show that the agent responsible for transferring genetic information was not a protein, as biochemists of his time believed, but the nucleic acid deoxyribonucleic acid, or DNA (see Nucleic Acids). Avery and his coworkers extracted a substance from a type of bacterium with a smooth surface and introduced the substance into a rough-surfaced type of bacterium. When the rough-surfaced bacteria transformed into the smooth-surfaced type, he knew the substance he had extracted contained the gene that coded for the smooth surface. Avery's team purified this substance and found it was pure DNA. Avery published the results of his research in 1944. The paper led to more intensive studies of DNA, which eventually revealed it to be the common agent of heredity, present in all animal cells.