Stéphane Tarnier (born in 1828) was a French obstetrician who studied and practiced medicine in Paris. He is mainly remembered for his work involving the treatment of premature infants.
At the time, the infant mortality rate was incredibly high - 1 in 5 newborn babies died in the first couple of months. Tarnier was acutely aware of this problem and wanted to find a solution.
On a visit to the Paris Zoo, Tarnier noticed a chicken incubator which was being used to keep new hatchlings warm.
Tarnier wondered if this principle of a machine being used to regulate the temperature of newborn chicks could be copied, and adapted to regulate the temperature of newborn infants.
So with the help of the zookeeper, he created a special "baby-warming device" which cut the infant mortality rate at his hospital by half.
Today, modern incubators have revolutionized maternity wards all over the world.