The Estimation of Protein in Cerebrospinal Fluid Using the M.R.C. Photometer

Turbidometric methods are widely emp!oyed for the estimation of protein in cerebrospinal fluid (C.S.F.). Precipitation is generally effected using salicylsulphonic acid, and subsequent com-parison made with standard reference tubes, e.g., of the formazin gelatin type (King, 1951a). Un-fortunately these suffer "ageing, " and matching in artificial light is often difficult. The following technique has been employed in this laboratory for the past two years. Method To 1 ml. of C.S.F. in a 6 in. bvx in. test-tube is added 3 ml. of ',. aq. salicylsulphonic acid solution. mixed, and allowed to stand for five minutes. At the end of this time the turbid suspension is introduced