1. Paul-Louis Simond was a French physician, chief medical officer and biologist whose major contribution to science was his demonstration that the intermediates in the transmission of bubonic plague from rats to humans are the fleas Xenopsylla cheopis that dwell on infected rats.
Paul-Louis Simond was born in Beaufort-sur-Gervanne, on 30 July 1858.
Paul-Louis Simond's father was a pastor of the Reformed Church.
From 1878 to 1882 Simond was an assistant in Medical and Biological Sciences at the School of Medicine and Pharmacy in Bordeaux, and he began his medical training there.
Paul-Louis Simond returned to Bordeaux in 1886 and the following year he received his medical doctorate with a prize-winning thesis on leprosy.
In 1897, when Alexandre Yersin was transferred by the Pasteur Institute to a post in Vietnam, his position in Bombay was filled by Paul-Louis Simond, who was to test the efficacy of an experimental antiserum against the outbreak of plague in that city.
Paul-Louis Simond's findings were not initially accepted by the scientific community, but were validated later by others and by 1907 his conclusions were accepted as scientific fact.
From 1898 to 1901 Paul-Louis Simond served as director of the Pasteur Institute in Saigon organizing a modern vaccine service; he received the distinction of Knight of the Legion of Honour.
In 1917, Paul-Louis Simond was installed in Valence to study tuberculosis.
Paul-Louis Simond had a keen interest in botany; during his stay as a colonial doctor in Indochina from 1914 until 1917, he collected orchids and had a local artist create watercolor paintings of them.
Paul-Louis Simond amassed a collection of 226 watercolor paintings of 3,226 different species of orchids which were presented to the Phanerogamie of the Museum national d'histoire naturelle on 1947.
Paul-Louis Simond died in Valence on 3 March 1947 at the age 88.