In December of 2006, Dr. Selma Calmes (left) sent what she called a “Christmas present” to the Wood Library-Museum of Anesthesiology. Her gift was a holiday-wrapped “mystery inhaler” (right) that she had purchased from a vendor in southern California. After Museum Registrar Judith Robins unwrapped this item, it was curatorially identified as a Hayes Anaesthetic Apparatus No. 3, the final and most sophisticated “Generator” designed by 1895 by Dr. Samuel J. Hayes of Pittsburgh. (Copyright © the American Society of Anesthesiologists, Inc.)

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