Private organizations directly funded federal education until 1919 made it illegal.

Evidence

To no small extent their policy reflected the guidance of Frances Kellor … Her National Americanization Committee’s longstanding subsidization of the United States Bureau of Education ceased in March 1919. The connection would shortly have become illegal under a statute prohibiting the federal government from accepting financial aid from private organizations; °* but Miss Kellor was already absorbed in another project. — John Higham, Strangers in the Land, 1548