ABOUT five years ago, because of the large number of orbital deformities associated with war injuries, investigation was initiated of various products which offered possibilities as substitution materials in restoration of fractures of the orbital floor. A preliminary report was made concerning the use of glass wool.1 Sufficient time has elapsed to permit a more thorough evaluation of this substance and its behavior in orbital tissues. I have been able to obtain from my own records and from those of surgeons who have sent me résumés of their own cases a total of 19 cases in which glass wool was implanted in the orbit or adjacent structures. In 10 of these, to the best of my knowledge, there have been no untoward effects. Since most of these cases represented war injuries and the patients-were treated in Army or Veterans hospitals, follow-up studies have been difficult, and it is quite