For those scientists who study urine the saying is quite literal–pee is a treasure-trove of scientific potential. It can now be used as a source of electric power. Urine-eating bacteria can create a strong enough current to power a cell phone. Medicines derived from urine can help treat infertility and fight symptoms of menopause. Stem cells harvested from urine have been reprogrammed into neurons and even used to grow human teeth.
But a quick look back in history shows that urine has always been important to scientific and industrial advancement, so much so that the ancient Romans not only sold pee collected from public urinals, but those who traded in urine had to pay a ‘urine tax’. The tax was placed on the collection of urine, since the lower classes of society had to urinate into small pots that were then emptied into cesspools. Liquid could then be collected from these cesspools, as well as from the public toilets of the upper classes, and recycled for a number of chemical processes: animal skins could be soaked in urine to remove the hair fibers before tanning, and Roman launderers could use urine as a source of ammonia to bleach and clean wool garments.
Originally published in Smithsonian Magazine.