A cellular element in milk has been recognised for over a century. During the last decade there has been a renewed interest in milk cells but reports present a wide variety of methods of analysis, and the results and interpretation of findings have been inconsistent. We have devised our own techniques of collecting, storing, and analysing milk for its cellular content. Milk samples were taken from 53 healthy women who had been lactating from 4 days to 15 months. From each woman three samples

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... e analysedpre-, mid-, and postfeed from one breast. In addition 12 women gave similar samples from the other breast at the same feed, and in some of these the procedure was repeated at the next feed. Leucocytes were found in all samples. The range was 1-0-33-0 x 109/l. Most samples had counts between 3 0 and 15 0 x 109/l. There was considerable variation in cell numbers during each feed 'profile', with a tendency for the cell count to rise markedly towards the end of the feed. Differential cell counts were as follows: macrophages-40 to 90%, polymorphs-5 to 50%, lymphocytes-0 to 10%. It is evident that a fully breast-fed baby probably ingests as many viable leucocytes every day as it has circulating at any one time. Evidence of a biological role for these cells in the neonate is beginning to emerge. Fat content of bank human milk. L Carroll, D Conlan, and D P Davies. Leicester Royal Infirmary Maternity Hospital. Milk which is collected for human milk banks is heterogeneous in the method ('expressed' or 'drip') and stage in lactation of its collection. In view of considerable physiological variation in the fat content of breast milk in relation to time of the day and stage of lactation, we wished to examine the variability of fat (and therefore of energy content) in human milk as it reaches our milk bank. In 140 samples of milk (mainly collected by the 'drip' method) arriving in the milk bank of the Leicester Royal Infirmary Maternity Hospital, the fat content was estimated in each by the creamatocrit method. The results are shown in the Table. Fat concentration (gll)