Final answer:
Joseph Lister's antiseptic practices using carbolic acid significantly reduced postsurgical infections, endorsing germ theory and advancing surgical safety.
Step-by-step explanation:
The work of Joseph Lister was important because it paved the way for safer surgical practices by introducing antiseptic procedures. His utilization of carbolic acid (phenol) as a disinfectant greatly reduced the incidence of postsurgical infections. This innovation was a significant advancement in the acceptance of the germ theory of disease and transformed how surgeries were conducted, establishing new standards for hygiene in medical practices during the late 19th century.