As a pioneering bacteriologist, Frederick Twort was responsible for several important advances in his field. He discovered what would be known as bacteriophages, bacteria-attacking viruses. This discovery led to the advent of molecular biology. Twort was the first scientist to grow the organism that caused Jöhne's disease, a deadly cattle infection, and his efforts contributed to its elimination. Twort also discovered a nutritional element later identified as vitamin K.

Twort was born in Camberley, Surrey, England, the son of William Henry Twort, a physician. Frederick was the oldest of ten siblings. He studied medicine in London at St. Thomas's Hospital Medical School. Twort became qualified and licensed in 1900, although he never practiced clinical medicine. Soon after graduation, Twort began his work as an assistant to Louis Jenner in London's St. Thomas's Hospital, working in the clinical laboratory. In 1902, Twort found work with William Bullock as an...