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May 1, 1926


Author Affiliations

From the Laboratory of Physiological Chemistry, University of Illinois College of Medicine, the Presbyterian Hospital, and the John McCormick Institute for Infectious Diseases.

JAMA. 1926;86(18):1333-1334. doi:10.1001/jama.1926.02670440007004

Crystalline proteins have been isolated from the urine up to the present time in only eight cases.1 In the course of work on human blood proteins, difficulty was experienced in obtaining blood for the preparation of sufficient quantities of albumin. This led to an attempt to separate this protein from the urine of patients with nephritis that were eliminating large quantities of protein. In the course of this work it was discovered that, under certain conditions, proteins in the cases studied tended to become crystalline.

As a preliminary treatment, the urine was saturated to 25 per cent with ammonium sulphate, left standing for a few minutes until flocculation had taken place, and then filtered. The filtrate was placed back on the filter paper until a clear fluid was obtained, which was completely saturated with ammonium sulphate. The precipitate was dissolved with the requisite amount of distilled water giving a