The effects of ionizing radiation upon unresorbed embryonic mesenchyme in the middle ear have not been hitherto reported. In view of the use of x-ray as a treatment modality in certain pediatric otologic problems, such knowledge is desirable. The deleterious effect of mesenchyme upon the incidence and outcome of otitis media (including hearing) has been appreciated for some time.
Wolff,1 Guggenheim,2 and Wilson3 have all emphasized the vicious cycle of cause and effect between persistent mesenchyme and otitis media and its sequelae. Their studies added a new chapter to the older interest in mesenchyme, dating from Wittmaack, which