Propositiones de lithiasi tōn nephrōn

...the right kidney is affected, or the left side if the left kidney is affected. Likewise, there will generally be a numbness of the thigh directly corresponding to the affected kidney. For if numbness occupies the right thigh, the right kidney will be in a bad state; if the left, the left kidney.

XIIX.
To this pertains what Paul noted in book 3, chapter 45: that the right kidney is suffering if the right testicle is retracted, and the left if the left is retracted. Both occur (if we believe Galen, On Epidemics book 6, and the author of the book On the Diagnosis and Cure of Renal Affections) because of the consensus of the vessels lying upon the spine, namely the vena cava and the great artery, by whose mediation both the legs and the testicles sympathize with the kidneys, as dissections testify.

XIX.
Pain in nephritis is irritated, as Hippocrates teaches in On Popular Diseases book 6, at the time when patients are filled with food; which Galen testifies in the same place.

XX.
During the initial stages, there is phlegmatic vomiting, especially if those suffering have been of a phlegmatic nature. But in the increase of the disease, due to pain and sleeplessness (and this most especially when they have been feverish and worn out by fasting), bilious vomiting also supervenes, as Galen testifies in the places already cited. The patients feel lighter after vomiting, and they are freed from the affection when the food has been evacuated and reddish sand has subsided. For although a stone is not expelled by the evacuation of food alone, it sometimes becomes quiet after being moved.

XXI.
Urine is thin at the beginning due to obstruction. In an inveterate affection, however, it is often voided bloody. For a rough or angular stone, driven in the kidneys, wears down their substance...