I have recently completed two cameras for laboratory use, and in describing them also include two others which have been in use for some time previously.
I. CAMERA FOR USE WITH PROCTOSCOPE
This camera (Fig. 1) consists of a cylindrical barrel (A) to the front end of which is attached a rapid, short-focus, photographic lens (B) and to the other end of which is attached a simple photographic shutter (C) and small metal receiver (D) for taking a plate-holder (E) which carries an ordinary photographic plate 4.5 by 6 cm. in diameter.In use, when a desirable field is found through the direct-vision proctoscope (F), the camera is inserted with the shutter closed and set for time exposure and the dark slide of the plate-holder drawn. The patient's buttocks are steadied, the shutter snapped and an exposure of from 2 to 5 seconds given. The shutter is then closed and