Although described in 1891 by Ehrlich, the function of the basophil has stood in relative obscurity these long 70 years. It is a normal member of the blood cell family, yet it is the rarest type. Failing to clear the critical 1% hurdle of the regular white blood cell count, it is often noted in the patient's record only in absentia. Should the cell appear in any quantity, one thinks of polycythemia or myeloid leukemia.
Despite the low percentile rank of this cell, the basophil is beginning now to emerge as a cell with vital functions. It is becoming possible to view the basophilic granulocyte within the physiologic framework of the body, rather than simply as a morphologic variant of the white cells which may undergo malignant changes. This has come about within the last few years as a result of 2 new areas of advance: cytochemistry and functional cytology.