1. The important factors causing albumin denaturation in the presence of sodium sulfite when shaking with ether or ether-Span, are the method and time of shaking, and the free air space available for shaking. 2. Gentle inversion with ether-Span for 30 seconds or less, and a free air space of about 1.3 cm.3 gave results with the Wolfson-Cohn procedure (10) which were in close agreement with the electrophoretic method in 42 normal and pathologic sera. 3. There is little or no albumin denaturation from shaking with ether in the presence of 21.2% sodium sulfate as used in the procedure of Wolfson-Cohn (10)for albumin plus α-globulins.