Pasteur pipettes, also known as droppers or eye droppers, are used to transfer small quantities of liquids. They are usually glass tubes tapered to a narrow point, and fitted with a rubber bulb at the top. The combination of the Pasteur pipette and rubber bulb has also been referred to as a teat pipette. Pasteur pipettes come in various lengths and are sold in boxes of hundreds. They are named after the French scientist Louis Pasteur, who was known to have used a variant of them extensively during his research. Generally, they are considered cheap enough to be disposable, however, so long as the glass point is not chipped, the Pasteur pipette may be washed and reused indefinitely.