Initially, the incubators failed to catch on. In 1888, another Parisian obstetrician, Pierre Budin, began publishing reports detailing Tarnier’s success, but most medical professionals at the time dismissed the technology as pseudo-scientific at worst, ineffective at best. Determined to change the medical community’s perception of the incubators, Budin asked his protégé, the physician Martin Couney, to accompany him to the Berlin World’s Fair in 1896 to supervise a display of six premature babies in incubators. The “Kinderbrutanstalt” or “child hatchery” was such a success that Couney, hoping to introduce the technology to a broader audience, raised enough money to kick off a world tour.

Over the next seven years, Couney showed off the incubators at the Victorian Era Exhibition in London, the Trans-Mississippi Exposition in Omaha, the 1900 Paris Exposition, and the Pan-American Exposition in Buffalo, New York. In 1903, he decided to permanently relocate to America, and settled in a place with an insatiable appetite for the new and unusual: Coney Island.

The Coney Island exhibit was, for all intents and purposes, a small-scale hospital, a sterile environment staffed by doctors and nurses constantly attending to the infants. Couney hired a staff of wet nurses to feed the infants, and a team of cooks to feed the nurses, with the instructions that they were forbidden to prepare hot dogs or any of the other typical boardwalk fare of the neighborhood. He also tried to minimize the nurses’ stress levels as much as possible, often offering them advice and gifts out of fear that unhappiness would impact the quality of their milk.

Aware that he operated on the fringe of accepted medical practice, Couney implemented strict guidelines for all aspects of his Coney Island operation, including a no-joke policy for the exhibit guides who shepherded curious onlookers past the babies. “We run this place ethical,” he informed his staff, “not like a sideshow.”

Even so, he was a talented showman. He positioned Coney Island “barkers”—including a young Cary Grant—outside the exhibit to urge people inside, and instructed the nurses to dress the infants in unnecessarily large clothing so as to highlight their small size. He also ran frequent publicity stunts, holding “graduation” ceremonies for babies who had outgrown the incubators, and reunions for former patients, the first of which was held in Coney Island in 1904 to allow curious crowds to see the longitudinal effects of his treatment. Eventually, Couney took his incubator show back on the road to destinations like Portland, Mexico City, Rio de Janiero, Denver, San Francisco, Chicago, and Atlantic City.

The visitors at Coney Island approached Couney’s incubators with a combination of excitement and confusion; the doctor was frequently asked where he obtained the “eggs” gestated in the incubators, and he got the occasional request to have sexual intercourse with the incubator device in an attempt to conceive. Despite being one of the most costly attractions at Coney Island, the incubators saw a substantial number of return visitors, many of whom came regularly to check in on the development of a particular infant to whom they’d taken a liking.