For the first time since the introduction of Thormahlen's test in 1887, a biography of its creator has been written and it is presented here. It reveals the tragic fate of a young doctor ill with tuberculosis towards the end of the last century. At the same time, an historic evaluation of the Thormahlen's test and its place in the history of clinical chemistry is attempted. A urine test is taken as an example of the wide range of possible diagnostic methods; starting with the very basic observation of dark urine, followed by rudimentary chemical analyses, leading up to the most modern laboratory procedures. Nowadays, the urine test for melanoma must be considered as obsolete.