Holder for Reading Results of Tube Tests.

A number of bacteriological and serological procedures require the use of a series of test tubes. The size of the tubes, as well as the racks used to hold the tubes, may vary. Tubes 12 to 15 mm in diameter and 75 to 100 mm in length are most commonly used. observed at one time. Ambidextrous people can become quite adept at this, while others constantly appear to have five thumbs. With the proverbial thought of a better mousetrap in mind, a holder was designed and working models were made by hand (Fig. 1). (Detailed