Eluates of 13 malignant and 17 normal tissues were prepared at 56 degrees C using the continuous flow technique. Albumin was detected in all the eluates. IgG, IgA, C3 or haptoglobin were detected in most of the malignant and some of the normal tissues. Carcinoembryonic antigen, beta 2-microglobulin, alpha 1-antitrypsin or alpha 1-antichymotrypsin were detected in some of the eluates of the malignant tissues only. IgM, IgD, C1q, C4, Cl-INH, alpha 1-macroglobulin, beta 2-lipoprotein, fibrinogen and alpha 1-foetoprotein were not detected in any of the eluates. The ratio of the concentration of albumin to the concentration of IgG was similar in extracts and eluates of all the normal tissue and in 3 of the malignant tissues indicating non-specific binding of IgG.