Abstract: An apparatus for testing the effects of an antibiotic of chemical on a bacterial or biochemical substance of the type having a plurality of side-by-side test chambers each separated from the other by a side wall and having a common reservoir disposed adjacent each test chamber and separated therefrom by a barrier having a height less than the height of each side wall is characterized by an array of guide walls disposed in the reservoir, each guide wall merging into one of the side walls and cooperating with next-adjacent guide wall to define an array of channels. Each channel communicates with one of the test chambers and each channel is adapted to conduct a liquid disposed in the reservoir into the test zone with which it is associated upon rotation of the apparatus about an axis of rotation.

Abstract: An apparatus for testing a substance is characterized by a substantially planar base member carrying a reservoir extending lengthwise thereon. A plurality of test zones, each having a chemical substance therein, are carried by the base and are disposed in a side-by-side relationship with each other and in a substantially perpendicular relationship with the reservoir. Each test zone is separated and isolated from the next adjacent test zone by a sidewall of a predetermined height. The test zones are each separated from the reservoir by a barrier having a height less than the height of the sidewall. A clear plastic cover is provided to enclose the reservoir and the test zones so that fluid communication is permitted only between each individual test zone and the reservoir through a clearance space defined between the interior of the cover and the top of the barrier.