MATERIALS AND METHODS Material. Normal human adult brains were obtained from the Institute of Pathology I, Sahlgren's Hospital, Gothenburg. They were all obtained from persons killed in road accidents. Infant human brains were from stillborn fullterms. Brains from human foetuses were obtained after legal abortions carried out for medico-social reasons at the Gynecology Clinic, Sahlgren's Hospital, Gothenburg. The foetuses were 4-5 months old. The brain from one patient with infantile amaurotic idiocy (Tay-Sachs), studied earlier by SVENNERHOLM and ZETI'ERGREN (1957), and one six-year-old patient with juvenile amaurotic idiocy (Vogt-Spielmeyer-SovRANDER and SVENNERHOLM unpublished), were also studied. The brains had been preserved in formalin for 1.5 years and 0.5 year, respectively, before the lipids were extracted. The lipids had been extracted into chloroform-methanol (2: 1, v/v) and stored at+ 4" for 4 and 2 years, respectively, before the present study was undertaken. Zsulatiun ufgangliosides. The brain material was homogenized in a Turmix blendor and extracted twice with 10 volumes of chloroform-methanol (1: 1, v/v) and finally extracted with chloroformmethanol (1: 2, v/v) in a Quickfit Soxhlet apparatus (Quickfit & Quartz Ltd., Staffordshire, England). Total gangliosides were isolated by partition distribution and repeated chromatography on silicic acid (SVENNERHOLM, 1963) or by chromatography on cellulose (SVENNERHO~~, 1956). In the latter procedure the bulk of the lipids was eluted with the solvent phase of chloroform-ethanol-water (16: 4: 1, v/v/v). The gangliosides were then eluted with chloroform-methanol-water (5: 15: 1, v/v/v) and methanol-water (9: 1, v/v). Generally about 5-10 per cent of the total gangliosides were eluted in the first eluate. It was rechromatographed once. The eluates containing gangliosides were combined, evaporated to a smaller volume, dialysed against water and freeze-dried. The final purification of the gangliosides and their separation into a monosialoganglioside and a disialoganglioside fraction was achieved by chromatography on silicic acid (SVENNERHOLM, 1963) or on a pressurized paper roll column (LKB 3504 ChroMax, LKB-Products, Stockholm, Sweden). The paper roll column was rinsed with several litres of water and organic solvents before use, otherwise the fractions were contaminated with some yellow-coloured material which moved rapidly in the solvents used for the analytical chromatography. After this preliminary rinsing, the column was run with 1 litre of n-propanol-water (3: 1, v/v). The maximum loading forthecolumn wasabout 600 mg crude gangliosides. The sample to be run was dissolved with some difficulty in the developing solvent in the following manner: The crude gangliosides were first dissolved in water and three volumes of propanol were then added. At least 1 ml of water was necessary for each 100 mg of gangliosides. The extract was applied to the top of the column and washed down with several rinsings of n-propanolwater (3: 1, v/v). The column was then developed with 1-5 litres of n-propanol-water (3: 1, v/v), 1 1. n-propanol-water (7: 3, v/v), and 11. n-propanol-water (3: 2, v/v). When chromatography was completed, the paper roll column was regenerated with 2 litres of water, 11. n-propanol and 1 1. n-propanol-water (3: 1, v/v). The same paper roll has now been used for more than a year. Find separation of gangliusides. The monosialoganglioside fraction was separated into its com-ponents by chromatography on silicic acid of fine particle size (SVENNERHOLM, 1963). Silicic acid (60 g) was suspended in chloroform-methanol (CM)(4: 1, v/v). 300 mg …