The Kolbe electrolytic cross-coupling synthesis has been employed for the synthesis of homocholic, bishomocholic, 3α:7α:12α-trihydroxy-25-L-coprostanic and the two (25-L and 25-D)-3α:7α:12α-trihydroxyhomocoprostanic acids, the latter two compounds being thus related to L- and D-β-methylglutaric acids and hence to L- and D-glyceraldehyde. The two (25-L and 25-D)-3α:7α:12α-trihydroxyhomocoprostanic acids were degraded by the Wieland-Barbier method into the two corresponding (25-L and 25-D)-3α:7α:12α-trihydroxycoprostanic acids. These latter two acids were identical with the two naturally occurring 3α:7α:12α-trihydroxycoprostan-26-oic acids (Japanese 'α-' and 'β-' trihydroxycoprostanic acids respectively), which have been isolated from the biles of various species. The formation of a new asymmetric centre by the oxidation in vivo of a methyl group in cholesterol to give bile alcohols or bile acids may be considered to be non-specific, in the sense that both optical isomers are obtained. Cytidine diphosphate glycerol, cytidine diphosphate ribitol and D-mannitol 1-phosphate have been isolated from Lactobacillus arabinosus. The method of isolation includes gradient elution chromatography on Dowex-2 resin and adsorption on charcoal. The base:phosphate ratio in both nucleotides was 1:2, indicating that they are derivatives of cytidine diphosphate.