METHOD

The method includes determination of both total protein and its fractions. Total protein is precipitated at 55-65" C., after addition of trichloracetic acid to 9.4 % concentration. The precipitate is centrifugated, suspended in trichloracetic acid and repeatedly centrifugated and washed in order to remove all non-protein nitrogen. Globulin is defined by IZIKOWITZ as that part of the protein which precipitates at 56' C. in a sample of lumbar fluid after the addition of an equal volume of neutral ammonium sulphate saturated at room temperature. The globulin precipitate is centrifugated and washed with neutral semi-saturated ammonium sulphate and afterwards with trichloracetic acid in the same way as the total-protein precipitate. By adding trichloracetic acid up to 7.6 % concentration to the centrifugate from which the globulin has been removed, the albumin is precipitated. This precipitate is then washed in the same way as the total-protein precipitate. All the precipitates are combusted at about 29.0" C . for at least 10 hours with concentrated sulphuric acid in a specially constructed combustion oven, and, after the addition of hydrogen peroxide, for a further 3 hours at 310' C . Precipitatio-1, centrifugation and combustion take place in the same tube of Pyrex glass, which has a oonically prolonged bottom accommodated to the small precipitates. These tubes require a specially constructed centrifuge. Finally, the nitrogen is determined iodimetrically by TEORELL'S micro-method (1928), slightly modified.