Histamine and granulocytes in the umbilical cord blood of infants at birth.

1. Histamine levels in whole blood and plasma from the umbilical arteries and veins, together with circulating basophil and eosinophil counts, were determined in two groups of healthy infants, "term" and "pre-term".2. No significant arteriovenous differences were found except in the basophil counts of the "pre-term" group. This result was consistent with the finding of significant arteriovenous correlations for all these sets of estimations except the basophil counts in the "pre-term" group.3. No significant differences were found between the mean values in either group except for the difference between the mean basophil counts for venous blood.4. Plasma histamine levels (arterial and venous) were usually less than the lowest limit of the method (1.8 ng/ml). Very small amounts of histamine were detected, however, in one venous and one arterial specimen in the "pre-term" group, but these did not produce a significant difference between the levels for the two groups of infants.