私醫聯招 英文歷屆試題｜第 524 題

An equally significant breakthrough resulting from Pasteur's work was the idea of  (21) —killing bacteria on surgical instruments and other surfaces rather than introducing them into a patient's body during surgery. After several years of hard work, Louis Pasteur's long career  (22)  in an enormously significant contribution to humankind—the vaccine. The concept of vaccination had existed at least since the end of the 18th century, when the English physician Edward Jenner noticed that people who had come down with a disease from cattle called cowpox were less likely to  (23)  smallpox. Jenner began to introduce material from infected cows into people, with some positive results. Pasteur pursued Jenner's idea and took one step forward by studying fowl cholera, a disease fatal to chickens. His experiments were interrupted by a summer vacation, and when Pasteur returned to the laboratory, he found that his cholera cultures were no longer lethal. In addition, he found that chickens  (24)  this new weakened strain of the disease were not killed when they were later exposed to a lethal cholera culture. Pasteur's work with weakened forms of diseases soon resulted in a vaccine against rabies. The vaccine famously saved the life of a shepherd boy named Joseph Meister when it  (25)  after an attack by a rabid dog. Eventually, the knowledge that microscopic germs were the source of disease and infection led to vaccines to fight typhus, polio, measles, and other deadly diseases.