Mounting and storage of gastrocamera films.

The various models of the Olympus gastrocamera use film of either 4 or 5 mm size, with 32 exposures per roll of film. The developed film is returned from the processing laboratory, therefore, as a film strip, 4 or 5 mm in width, and approximately 34 cm in length. The Olympus Camera Company supply a viewer with a magnifying power of x 10 with each instrument, and this is of some value in examining the returned film, although not suitable for demonstration purposes. They also produce, as an accessory, a projector, complete with a small screen 14-5 x 23-7 cm in size, which can be used for studying films, and for demonstrating them to a small group of people. The lens and lighting system of this projector are not, however, equal to the task of projecting on a large screen, such as in a lecture room, and only a few exposures can be seen at any given time. A further disadvantage of both these instruments is that they involve repeated handling of the film strips which become defaced very easily by finger marks and dust. In addition, in our experience, the film is readily scratched, particularly with the use of the projector. Gastrocamera film is usually stored and filed by using a special filing book obtainable from the Olympus Company, in which each film strip is filed in a slotted plastic envelope. Each page of envelopes is interleaved with a ruled page (with Japanese headings) in which details of each film may be recorded opposite the slot in which the film strip is filed. There is, therefore, a great need for a means of easy projection for demonstrating and teaching, and for a method of filing and handling which avoids damage to these small film strips. Griffiths (1967) described a method whereby the films were cut into five small pieces, each containing five or six exposures, and mounted in a paper mask as a composite lantern slide between 2 x 2 in. cover glasses. This technique fulfils the requirements as regards easy projection using a standard 2 x 2 in. slide projector, and storage, safe from dust and scratches. Its disadvantage lies in the use of 2 x 2 in. cover glasses. The films are returned from the processing laboratory as a roll, and consequently when cut up for mounting the segments are still curled in their long axis. They are difficult to handle on this account, and to mount them neatly in parallel strips by Griffiths' method requires considerable patience, dexterity, and time. It is necessary for the clinician conducting the gastric photography to select personally those exposures which can be expended in the course of cutting the film for mounting. He must, therefore, either be present to supervise the process, or do