The theory of the partition column is extended to include a compressible mobile phase of a permanent gas and a method of determining the height equivalent to a theoretical plate of such a partition column is given. A convenient apparatus making use of a gasliquid partition column for the separation of volatile acids or bases and an automatic recording burette for their detection and estimation by titration is described. With 4-foot columns having a stationary phase consisting of a mixture of a liquid silicone and stearic acid, all n-and iso-acids from formic to hendecanoic acid can be ..

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1. Fatty acid synthesis from [2-(14)C]acetate by Chlorella vulgaris cells grown and incubated in the dark is limited almost entirely to the production of saturated and monoenoic acids. 2. In light-incubated cells, both saturated and polyunsaturated fatty acids are rapidly synthesized. 3. Two groups of lipids can be distinguished in both dark- and light-incubated cells. The first group, consisting of phosphatidyl-glycerol, monogalactosyl diglyceride, lecithin and neutral glyceride, has a very high turnover rate for certain fatty acids. The second group, consisting of digalactosyl diglyceride, sulpholipid, phosphatidylethanolamine and phosphatidylinositol, has a slow turnover of fatty acids. 4. The lipids with rapid fatty acid turnover may be involved in the sequences of saturated and unsaturated fatty acid synthesis. A classification of lipids is made on the basis of their suggested functions.

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The incubation of trans-3-hexadecenoic acid with cells of Chlorella vulgaris, and with lettuce leaf slices, resulted in reduction of the substrate to palmitic acid.Before this reduction was complete, the trans-acid entered all the acyl lipid classes present in the cell.Consequently, the specific location of trans-3-hexadecenoic in the phosphatidyl glycerol fraction of photosynthetic tissues cannot be explained on the basis that lyso-phosphatidyl glycerol is the only lipid capable of 'accepting' this acid. It is more likely that phosphatidyl glycerol or lyso-phosphatidyl glycerol is a required substrate or cofactor for the synthesis of trans-3-hexadecenoic acid from palmitic acid. . The trans-3-hexadecenoic acid is located at the 2-position of phosphatidyl glycerol [8,10] and the major molecular species of this lipid in spinach has been shown to be l-linolenoyl-2(trans-3-hexadecenoyl)-glycerol-3-phosphoryl-l'-glycerol (nomenclature according to Hirschman [ll]). trans-3-Hexadecenoic acid also occurs in some seed oils [12] but in such cases is presumably associated with the triglyceride fraction.