Chapter Three, ‘Piss Prophets and Urine Matters’, shows that physicians repurposed chemistry from the general diagnostic tool of uroscopy to serve the specialised, pathological study of urinary diseases.
For centuries uroscopists used patients’ urine both as a diagnostic and a prognostic tool. By means of distillation some practitioners believed to be able to diagnose patients more precisely than ever before. But for physicians like Hieronymus Gaubius the chemistry of urine was not so much a diagnostic instrument applicable to any disease; rather, it was a means for investigating the changing properties of urine in the course of a patient’s condition. These doctors explained specific urinary disorders like bladder stones in terms of the chemical elements in urine and their cohesive powers.
Chapter 3 demonstrates, therefore, that the method and practice of urine chemistry, though apparently similar in practice to chymical uroscopy, had very different aims and applications, and moved from diagnostics to pathology. These new goals and methods would prove to be paramount for the development of modern medicine at the turn of the nineteenth century.