Acetate injected into rat brains is rapidly oxidized, a small part, however, is incorporated into the brain lipids. Already after six hours the total fatty acids show a maximum activity, which is highest for palmitic acid. As there is practically no more acetate available after this time, we have to explain later changes of activity as transformations. Cerebrosides were isolated from rat brains 3 and 72 hours after injection. Their fatty acids were separated by gas‐chromatography. Palmitic acid had a high initial activity, acids with 18, 20, 22, 23 and 24 C‐atoms at the beginning had a low one, which increased remarkably later on. The conclusion may be drawn that palmitic acid has a rapid turnover in brain. It is the precursor for the higher saturated and unsaturated, evennumbered fatty acids, whose rate of synthesis is lower.

An approximately quantitative method for the isolation of pure brain cerebrosides is reported. Crude cerebrosides are obtained out of total lipids by chromatography on an alumina column, pure cerebrosides are subsequently eluted with chloroform‐methanol from a silicagel column. Those are free of phosphatides, sphingomyelines, gangliosides and sulfatides.

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