How was Ivan Petrovich Pavlov awarded the Nobel Prize in Physiology or Medicine?

Name: Ivan Petrovich Pavlov.
Country: Russia.
Date of Birth: 26 September 1849.
Died: 27 February 1936.
Education: Saint Petersburg University.
Subjects Of Study: Pavlovian conditioning, Conditioned reflex, Nervous system secretion.
Known as: Dead Water, Nansen Bottle, Nansen Ice Sheet, Nansen Passport, Nansen’s Fram expedition, Oceanography, and Polar meteorology.
Noble Prize Year: Nobel Prize for Peace in 1904, his work on digestive secretions.