“…The gangliosides (for nomenclature see McIlwain, 1961c) contain fatty acids, sphingosine, N-acetylgalactosamine and glucose as well as the N-acetylneuraminic acid by which they are most frequently determined (Svennerholm, 1957;Klenk & Gielen, 1960;Rosenberg & Chargaff, 1960;van Heyningen & Miller, 1961); they comprise more than one molecular species (Meltzer, 1959;Folch & Lees, 1959;van Heyningen & Miller, 1961). Cerebral tissues also contain derivatives of N-acylneuraminic acids (sialic acids) which either are not gangliosides or are further derivatives or complexes of gangliosides (Svennerholm, 1956;Rosenberg & Chargaff, 1958; and see below), and the particular distribution of gangliosides between aqueous salt solutions and non-aqueous solvents, investigated by Folch, Lees & Sloane-Stanley (1957), gives valuable means of obtaining additional specificity in methods for their determination. Long & Staples (1959) applied such distribution in a method for separating and determining the gangliosides, which forms the basis of that studied below.…”