John Allen, a British physician of the eighteenth century, deserves being remembered for a series of inventions, but most importantly -- from a 'medical' point of view -- for his highly praised manuscript, the 'Universae Medicinae Practicae,sive Doctissimorum Virorum de Morbis Eorumque Causis ac Remediis Judicia', which long served as a text-book for medical students of the time, and also as a reference book for practitioners throughout European countries, for several decades after its original first publication. It contains the opinions ('Sententiae') of the most celebrated authors of all ages, from Hippocrates, Galen and Avicenna up to Allen's contemporaries, concerning a wide number of diseases, their causes, signs, symptoms, and therapeutical remedies where available. The present paper deals mostly with parts of the Synopsis concerning renal diseases and related clinical signs.