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.

Frederick William Twort was born in Camberley, Surrey, England, on October 22, 1877. His father, William Henry Twort, was a doctor. Frederick was the oldest of ten siblings. He studied medicine in London at St. Thomas's Hospital Medical School. He became qualified and licensed in 1900, though he never actually practiced clinically. Soon after graduation Twort began his work as an assistant to Louis Jenner in London's St. Thomas's Hospital, working in their clinical laboratory. In 1902, Twort found work with...