Since our1 first advocacy of the value of the comparison of the specific gravities of the separate urines from the kidneys as a test of renal function, we have gained a considerable amount of experience in the use of the test and have had a large amount of surgical and postmortem material with which to check up the agreement of the preoperative or antemortem observations with the final pathologic examination. Also certain improvements in technic have been made which in our opinion appear to make the test of more practical value.
Because of the facts that subsequent observation has borne out our previously expressed belief in the value of the test, that certain technical changes are really improvements and that the skeptical urologists of our own organization have reversed their judgment of the value of the test so that now they all regard it as the best single means
TODD LC. SEPARATE KIDNEY FUNCTIONFURTHER OBSERVATIONS ON THE SPECIFIC GRAVITY TEST AND IMPROVEMENTS IN TECHNIC. JAMA. 1929;92(3):228-229. doi:10.1001/jama.1929.02700290038010