A simple method of inducing ascites in the laboratory white rat by intraperitoneal administration of Freund's complete adjuvant is described. Female rats were found to produce ascitic fluid more reliably than males with an average volume yield of 60 ml per rat. The performance of immune rat ascitic fluids in complement fixation, hemagglutination-inhibition, neutralization and immunodiffusion tests was found to be excellent.
Present address: Asa Wright Nature Centre, P.O. Bag 10, Port of Spain, Trinidad, West Indies.