I would be happy to help you with that question. The doctor who can be thanked for introducing the practice of handwashing to reduce the transmission of diseases in medical settings is Ignaz Semmelweis.
1. Ignaz Semmelweis was a Hungarian physician who advocated for hand hygiene in the mid-19th century. He noticed that the mortality rate of women giving birth in hospitals where doctors and medical students worked was significantly higher compared to those attended by midwives.
2. By implementing handwashing with chlorine solution before examining patients, Semmelweis was able to reduce the mortality rate drastically. His work laid the foundation for modern antiseptic practices in healthcare.
Therefore, in the context of the question, Ignaz Semmelweis is the doctor who can be credited for the standard practice of surgeons washing their hands thoroughly before interacting with patients.