Why did plague doctors have long noses?

Related questions

1. What did people think caused the Black Death?
2. When was black death?
3. Is there cure for plague?
4. Who cured the Black Death?
5. How many people did the Black Death kill?
6. How did plague doctors cure the plague?
7. How fast is SCP 173?
8. Is FTP SSL secure?
9. What spread the Black Death?
10. Can you contain SCP 173?

Tags

1. #would
2. #disproved
3. #infected
4. #principal
5. #thought
6. #which
7. #plague
8. #cause
9. #becoming
10. #known
11. #purpose
12. #believed
13. #doctors
14. #prevent
15. #miasma
16. #smells
17. #herbs
18. #before
19. #theory
20. #counter
21. #disease