It may frequently happen that the clinician requires the result of a blood test before the patient leaves the dispensary or within an hour ot two after the collection of the sample. Particularly in the tropics, where outpatients are difficult to follow up, an easy and rapid test for syphilis and yaws is of value. For general survey work, such as might be undertaken by a travelling Medical Officer, a rapid test requiring no elaborate technique is required. In such work the Rosenthal test, as described by Tulipan and Director (1) seems especially suitable, always provided that the relative accuracy of the test is appreciated. The test is also applicable when only a small amount of blood can be obtained. (Actually 4 drops only of serum are used in each test.) When possible sufficient blood should be taken to allow of a control test being performed.