The platoon school is an effort, through a rather complicated type of organization, to take care of the greatly expanded and overcrowded elementary-school curriculum and at the same time provide broad social training. It has grown out of various attempts that have been made to reorganize the school. Most noted of these is the "work-study-play plan" as developed by William A. Wirt at Gary, Indiana. The fundamental principle of the plan from an administrative point of view is the duplicate idea, which has been experimented with in various forms in some eighty-one cities of the United States. Scientific principles have been applied as to organization, building, equipment, and curriculum until today the plan is beyond the experimental stage. In such cities as Detroit, Akron, Pittsburgh, and Newark it is meeting with marked success, and the movement is attracting nation-wide attention from educators and boards of education.