In order to study the physiological changes of total protein content related to the site of its collection, 932 cerebrospinal fluid samples were analysed by V.D.R.L.'s trichloracetic acid method. Statistical analysis of the results showed that the total concentration of protein in ventricular samples is lower than that in lumbar ones; the total protein content of samples collected from the cisterna magna (suboccipital puncture) are represented by intermediate values. Such data confirm the results registered in the literature, where other methods of protein determination are used and establish the limits of normal changes in relation to the V.D.R.L.'s method. The mean values and its deviations are shown in table 2; the limits representing the normal changes in respect to the site of collection are presented in table 3.