MGM would have loved to have had Shirley Temple, the #1 box office attraction of 1935, 1936 and 1937, as Dorothy in THE WIZARD OF OZ, but she belonged to 20th Century-Fox, and Darryl Zanuck refused to loan her out.

Ray Bolger was originally to be the Tin Woodman, but begged off, saying he was too fluid a performer. What he really wanted was to play the Scarecrow, but Buddy Ebsen had been cast in that role. (Rent CAPTAIN JANUARY sometime and watch Ebsen and Temple dance in "At the Codfish Ball.")

Eventually, Bolger would play the Scarecrow, although how he managed this trick is uncertain; Ebsen would be replaced as the Tin Woodman by Jack Haley two weeks before shooting began; and Bert Lahr would play the Cowardly Lion.

What Ebsen suffered was probably an allergic reaction to the pure aluminum dust which had been powdered onto his face and head. He spent two weeks in the hospital under an oxygen tent, his skin at first bright blue, then spent a month recuperating. Haley's makeup was painted on, not powdered.

The above from THE MAKING OF THE WIZARD OF OZ, by Aljean Harmetz