Ivan Pavlov

Ivan Petrovich Pavlov, a Russian and Soviet experimental neurologist and physiologist, is famous for uncovering classical conditioning while working with dogs. His research on digestion also earned him the 1904 Nobel Prize in Physiology or Medicine.

Born on 26 September 1849 in Ryazan, Russia, Pavlov was the first of ten children. His father, Peter Dmitrievich Pavlov, served as a village Russian Orthodox priest, and his mother, Varvara Ivanovna Uspenskaya, managed the household. As a child, he helped with chores like washing dishes and caring for his siblings, and enjoyed gardening, cycling, rowing, swimming, and playing gorodki during summer breaks. Though he could read by age seven, a serious fall from a high wall onto stone pavement delayed his formal schooling until he was eleven.

From an early age, Pavlov showed intellectual curiosity and what he called "the instinct for research." He attended a Ryazan church school and then a local theological seminary. Inspired by the progressive ideas of literary critic Dmitry Pisarev and physiologist Ivan Sechenov—whom Pavlov later called "the father of physiology"—he left the seminary without graduating to pursue science.

In 1870, he entered the physics and mathematics department at the University of Saint Petersburg to study natural science. During his fourth year, his first research project on the nerves of the pancreas won a prestigious university award. He earned a Candidate of Natural Sciences degree in 1875. Driven by his interest in physiology, he continued at the Imperial Academy of Medical Surgery, where he assisted his former teacher Elias von Cyon until Cyon was replaced. Pavlov then worked as a laboratory assistant to Konstantin Ustimovich at the Veterinary Institute, studying the circulatory system for his medical dissertation. In 1878, clinician Sergey Botkin invited him to lead the physiological laboratory at his clinic. Pavlov graduated from the Medical Military Academy in 1879 with a gold medal for his research, and won a fellowship there for postgraduate work.

The fellowship and his role as director of the Physiological Laboratory at Botkin's clinic allowed him to continue his research. In 1883, he presented his doctoral thesis on the centrifugal nerves of the heart, proposing ideas about nerves and the trophic function of the nervous system. His work at Botkin's clinic also revealed a basic pattern in how reflexes regulate circulatory organs.

After completing his doctorate, Pavlov studied in Germany from 1884 to 1886, working with Carl Ludwig in Leipzig and with Eimear Kelly in the Heidenhain laboratories in Breslau. Heidenhain was studying digestion in dogs using an exteriorized stomach section, but Pavlov improved the technique by preserving the external nerve supply. This exteriorized section became known as the Heidenhain or Pavlov pouch.

Returning to Russia in 1886, Pavlov sought a new position. His application for the chair of physiology at the University of Saint Petersburg was rejected. He was offered the chair of pharmacology at Tomsk University in Siberia and at the University of Warsaw in Poland, but declined both. In 1890, he became professor of Pharmacology at the Military Medical Academy, a post he held for five years. The following year, he was invited to organize and direct the Department of Physiology at the Institute of Experimental Medicine in St. Petersburg. Over 45 years, under his leadership, the institute became a world-leading center for physiological research. He continued directing that department while also taking the chair of physiology at the Medical Military Academy in 1895, heading it for three decades.

Pavlov was nominated for the Nobel Prize in Physiology or Medicine four years in a row starting in 1901, but did not win until 1904 because earlier nominations were not tied to a specific discovery. When he finally received the prize, it was "in recognition of his work on the physiology of digestion, through which knowledge on vital aspects of the subject has been transformed and enlarged." At the Institute of Experimental Medicine, he conducted his classic experiments on digestive glands, which led to that Nobel Prize. His laboratory included a full-scale kennel for experimental dogs, as he wanted to observe their long-term physiological processes, which required keeping them alive and healthy.