The hexasaccharide was subjected to partial acid hydrolysis (0.1N H2SO4, 80 deg C), further hydrolysis (0.5N, 100 deg C), oxidation by periodic acid and methylation. In each case the products were passed through an ion-exchange column and identified by paper chromatography. The hexasaccharide consisted of D-galactopyranose, N-acetyl-o-pyranoglucosamine, D-glucopyranose and N-acetyl-neuraminic acid in the proportions 2 : 1 : 1 : 2. The structure was that of lacto-N-tetraose (see DSA 25 : 447) with the addition of 2 neuraminic acid residues on position 3 of the terminal galactose and position 6 of the N-acetyl-glucosamine. JK.