Oxalate was determined by the method of Munro and Basir (1969). Oxalate was extracted from the sample (1:5 W/V) with 0.15% citric acid and treated with tungstophosphoric acid. Precipitated oxalate was solubilized with 1 % hot diluted H2SO4 and titrated against KMnO4 as equivalent to 0.3 g/100 ml of calcium oxalate.