Studies on diffusing factors

Abstract
Comparison of testicular diffusing prepns. with kallikrein (a vasodilator material from pancreas and urine) indicates that, contrary to the statement of Christensen (1938), the 2 materials are quite unlike one another in their effects on the rate of spread of injected fluids through rabbit skin. Rattlesnake venom, filtrates of Clostridium welchii and Vibrion septique, staphylococcal toxoid. leech extracts and diazo-benzenesulphonic acid-serum globulin all resemble the testicular diffusing factor in producing a very rapid increase in the rate of spread of fluids through skin. Purification of the testicular diffusing factor by means of fractional precipitation with ammonium sulphate and dialysis is described. (Madinaveitia, 1938.) The evidence shows the active material has protein properties and that its biological action, which does not depend on circulation, is not due to a surface tension effect.