De Urinis was not one of the books translated at Toledo; the Latin version that was used in the Middle Ages was translated by Constantine the African, a Benedictine monk and physician who spent the first part of his life in Ifriqiya, then brought Isaac's work and others from Tunisia to his retirement at the Benedictine Abbey of Monte Casino. Unfortunately, Constantine often did not include in his translation the name of the original author, leading many to think that he himself wrote the medical texts. It took other references to these works to be able to affix the proper author's name. (The illustration here shows a dog's head added to the margin by a bored copyist.)
There are ten sections to De Urinis, as follows:
- The science of uroscopy, placing it in context of the four temperaments*, particularly in relation to the blood;
- The importance of nocturnal urine;
- Types of urine in relation to pathology;
- Urine as humor-discharging fluid;
- Types of urine by colour;
- The state of the body judging by its colour;
- Types of urine based on clarity and viscosity;
- Sediment in relation to pathology;
- Types of urine in coherence with sediment;
- Different types of urine and sediments and their meaning.
This text influenced islamic medicine to a great extent (where uroscopy was of great importance) and contributed to the rise of uroscopy as one of the most important branches of medicine in the Middle Ages (Prioreschi 2001). Ms. 690 is a remarkably early witness of this.