Observations on the Relation of Urea to Uremia

One of the earliest theorfes of the causation of uremia was a chemical theory put forth by Wilson in 1833, in which the symptoms were ascribed to the retention of urea in the blood.But discrepancies were soon noted between the amounts of urea in the blood and the severity of the symptoms in patients, and later workers, Frerichs, in 1852, Feltz and Ritter, in 1880, Bouchard, in 1887, Herter, in 1898, and many others, found that urea was relatively nontoxic, when injected into animals.In fact, Bouchard, using rabbits, found that the amount of a concentrated urea solution necessary to produce severe symptoms was equal to the toxic dose of distilled water itself.