The rapid development of chemistry during the nineteenth century and its application to the analysis of mineral medicinal waters imposed significant challenges in the formation of a medical bath doctor if he wanted to perform his functions well. The excellent studies, increasingly abundant, on concrete spas lacked sufficient theory. The need for treaties that would systematize the hydrological knowledge of the moment moved to the publication of many books in the mid-nineteenth century. The interest of those physicians who wanted to pass the exams in order to enter the yet prestigious Medical Corps of Baths also added publications. If Garcia Lopez's recognized, award-winning publication proves the first purpose, Aguilar Martinez's job confirms the second.