LIPID COMPOSITION OF HUMAN BONE MARROW.

1. A modified method for the analysis of phospholipid mixtures by selective hydrolysis is described. 2. The phospholipid compositions of normal human bone marrow and of the bone marrows of patients who died with anaemia or various forms of leukaemia were investigated. 3. Phospholipids from normal bone marrow comprised about 44% of lecithin, 4% of choline plasmalogen, 7% of glyceryl ether phospholipid (choline base), 10% of sphingomyelin, 22% of phosphatidylethanolamine plus phosphatidylserine, 8% of ethanolamine plasmalogen and 5% of glyceryl ether phospholipid (ethanolamine base). 4. The proportion of kephalin (i.e. phosphatidylethanolamine plus phosphatidylserine) in the pathological bone marrows tended to be lower than normal. No other consistent differences were observed between the normal and pathological samples. 4. A ceramide dihexoside was isolated from normal bone marrow.