Okay, cursed history time!
So, diabetes is because the pancreas cannot produce enough insulin, or because cells do not have enough/properly functioning insulin receptors. Because of this, glucose (sugars) cannot enter the cells, and makes the blood really sugary.
Well, this excess glucose can be expelled from body through urine. Again- glucose is sugar, it makes things sweet.
Sometime around 1675, there was a method of diabetic testing introduced, in which MD's, testing their patients for diabetes, would sterilize their hands, take urine samples from said patients, dip a finger into the sample, and taste it to see if it was sweet.
MD's just dipped their fingers in your piss and tasted it. If it was sweet, congratulations, you're diabetic.
This was of course before people knew that diseases could be passed through bodily fluids.
This is also why diabetes is also referred to as diabetes mellitus. Mellitus is the Latin word for honey, so this acknowledged the sweetness of the urine, and the high glucose in the blood.










