Abstract: A capillary tube (10) is provided with ends that are initially open. The capillary tube (10) is preferably constructed from a plastic material that will allow the contents of the tube (10) to be analyzed by x-raying the tube (10). Plural fluid segments (20, 28, 30, 32) are introduced into the capillary tube (10) through one end of the tube (10). Then, the ends of the capillary tube (10) are closed, such as fusing them shut (34, 36) or by providing them with closure caps (40, 42). Different capillary tubes (10) contain different combinations of the fluid segments. The contents of each capillary tube (10) forms a distinct sample. The samples are viewed and evaluated while they are in the sealed capillary tubes (10).