1. Cellophane was effective in the formation of a new subdeltoid bursa in twenty-eight out of thirty cases, in which two previous operations had produced only scar tissue which had obliterated the bursa. In the two cases in which new bursae were not formed, the cellophane had coiled up and had been extruded.
2. Grossly, the new bursae were lined with a shiny, glistening wall. The cellophane lay in this new bursa with no gross evidence of foreign-body reaction in the tissues or of destruction of the cellophane.
3. Microscopically, the lining of these newly formed bursae differed in no way from the lining of normal bursae. There was no microscopic evidence of foreign-body reaction, or of fragmentation or destruction of the cellophane.
4. It is concluded that cellophane is a safe inert substance to use in the tissues. It will allow the formation of a new synovial membrane in areas where scarring is to be expected.