The following information is summarized from a historylink.org article by Paula Becker at http://www.historylink.org/File/10410.
Incubator baby exhibits first appeared in Seattle at the Wonderland attraction around October 1906. The proprietor was a certain "Professor" Harry Spaw, about whom little is known. Admission was 10 cents to view "chubby" babies in three incubators. Wonderland only survived about a year, and incubator babies next appeared at a new amusement arcade called Eden Musee sometime in 1907. Eden Musee was similarly shortlived, and was out of business by the middle of 1908. By spring 1909, incubators were being displayed at Seattle's Luna Park attraction, which seems to have been modeled on Coney Island's Luna Park.
In June of 1909, the Alaska-Yukon-Pacific Exposition opened, which had a incubator baby exhibit on the "Pay Streak" or Midway. The exhibit appears to have been highly successful, selling 28,000 tickets over the course of several months. More information about the Alaska-Yukon-Pacific Exposition can be found here.
|Seattle Times announcement of Wonderland Baby Incubator exhibit.|
|Luna Park "Baby Electrobator Exhibit"|