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January 14, 1933


JAMA. 1933;100(2):120. doi:10.1001/jama.1933.02740020038015

Diseases once regarded as clinical rarities have come into prominence as more commonly occurring disorders when attention has been explicitly directed to their nature and detection. Sometimes the unexpectedly large comparative prevalence owes its discovery to the introduction of new methods of examination. Heart blocks and arrhythmias are far more familiar to the physician of today than they were to his predecessors of a generation ago, because he has become accustomed to look for their symptoms. It is not long since hyperinsulinism was an unrecognized disease entity. This is true likewise of carotenemia, as distinguished from jaundice. The illustrations could readily be multiplied. Enough have been mentioned to explain the reference here to a rarely recorded type of chronic cyanosis properly designated as methemoglobinemia.

Methemoglobin is not entirely unfamiliar to the biochemist. He can form it in blood through treatment with a variety of chemical compounds: permanganates, chlorates, nitrites, nitrobenzene,