A device (10) for conducting chemical and/or biological reactions includes a base member (12) and a cover member (14) joined together and together defining sealed test chambers. One of the members (12) is of flexible material which is releasably and sealingly joined to the other member (14) to provide access to the test chambers. Lens elements (30) are included on one of the members (14) to image the test chambers. The walls of the test chambers may be made of flexible material so that they may be deformed to permit different portions of the test chambers to be imaged by the lens elements (30). A plurality of conically shaped cavities (20) are formed in the base member (12) so that reaction products accumulate in V-shaped lower portions (20a) of the cavities (20) for better visualization.
