For the next twenty years, Credé used his incubator to treat pre-mature infants at a public institution for children that had been abandoned, called the Moscow Foundling Hospital or Vospitatelnoi Dom in Moscow, Russia. Instead of keeping the incubator on the floor, Credé placed it on a stand with a hose attachment that connected to a hot water faucet, making it easier to replace water as it dissipated the heat. Credé's incubator was also a double-walled metal tub, but it differed from Denucé's model in that it circulated warm water to heat the surrounding walls. Credé built and implemented his incubator model in 1861 while serving as the director of the Leipzig Maternity Clinic, later renamed as the Leipzig University Gynecological Clinic in Leipzig, Germany. However, Credé created his model independently of Denucé. Pediatrician Julius Hayes Hess, in his 1922 book Premature and Congenitally Diseased Infants, noted that writers from France often attributed the origin of the infant incubator to Denucé. In the 1860s, obstetrician Carl Credé in Germany built his first infant incubator. The incubator also had a drain at the bottom to drain water that had cooled.
In Denucé's description, both tubs were welded at the top edges with a small opening near the top where warm water could be poured inside. In 1857, physician Jean-Louis-Paul Denucé published a description of an infant incubator consisting of a large zinc metal tub with a smaller metal tub set inside. The function of an infant incubator is to provide a stable environment in which pre-mature infants can be cared for during the remainder of their development. Infants born pre-maturely are often unable to maintain a constant body temperature and are at risk for hypothermia. The infant incubator technology provides a stable environment for premature infants and helps keep them alive. Carl Credé released his incubator model in Germany in 1860 and Stéphane Tarnier further developed the model in 1884. However, Jean-Louis-Paul Denucé, a physician who worked in Bordeaux, France, first published about incubator technology in 1857. Records show that physicians had used infant incubators since 1835.
The infant incubator is a medical device that maintains stable conditions and a germ free environment for premature infants born before the thirty-seventh week of pregnancy. In the nineteenth century, obstetricians in Europe began to construct devices to incubate infants in increasingly controlled environments. The Infant Incubator in Europe (1860-1890)