Accustomed as we all are by now to the rapid expansion of medical knowledge, nevertheless even the most phlegmatic among us cannot help but be impressed from time to time by occasional, truly explosive spurts in the usual orderly progression. Recent developments as regards the inherited abnormalities of human hemoglobin would seem to represent just such a spurt. Ten years ago hemoglobin, despite relatively intensive studies of its properties by the biochemist, appeared to be much the same from one person to the next. Today we recognize no less than nine different hemoglobin types, some of which, in specific parts of the' world, contribute significantly to the total disease picture.
The first of the hematological entities associated with an abnormal hemoglobin, the sickling phenomenon, was actually recognized as long ago as 1910, by Herrick, although the fact that an abnormal form of hemoglobin was involved did not become clear until