Dutch scientist (1857-1930) who in 1888 invented the olfactometer, an instrument used to gauge the odor detection threshold of substances. In addition to his work on the sense of smell, he also conducted research on the human heart, discovering that salts of potassium and other radioactive elements stimulated the heart. Untranslated ALS in German, signed “H. Zwaardemaker,” one page, 8.5 x 10.75, April 28, 1907. In fine condition. Accompanied by the original mailing envelope, addressed in his own hand.
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