The widely increasing work among surgeons in the treatment of bone lesions by direct methods has created a demand for motor-driven instruments, several of which are now on the market. All of these, however, aside from being very expensive, lack several essential qualities which we have tried, in a measure, to develop in the instrument described below.
The instrument consists of a 1/15 horse power motor connected with a driving shaft, 4 inches long, at the end of which is screwed a chuck for securing the surgical bits. Around these parts there is a snug fitting, detachable metal case permitting free and easy access to the motor mechanism. At the posterior end of the case there is fitted a permanent hollow grip in which are stored the resistance coils and control mechanism. In addition to this grip, there is a detachable handle which can be fastened to the shell around