USING the micro-technique of James and Martin1, it has been established that bovine muscle phospholipids contain small amounts of volatile fatty acids, and it is possible that this finding can be extended to animal phospholipids in general. Hitherto, in the absence of techniques for the micro-estimation of the low molecular-weight fatty acids, it has generally been accepted that the fatty acids of phospholipids tend to be of high molecular weight only. A con-secutive series of normal fatty acids from C2 to C10 has been identified in ox perinephric fat2.