A practical application of the pneumatic hammer to bone surgery is presented, together with a detailed description of the author's outfit, as installed at the Massachusetts General Hospital, and a summary of its advantages and disadvantages. The essential features of the apparatus are—
1. An adequate supply of compressed air.
2. A reducing valve which maintains any desired working pressure.
3. A satisfactory air cleaner.
4. A light, compact pneumatic hammer of convenient shape and easy control.
5. Tools which may be used with either the pneumatic hammer or a hand mallet.