Stepped into Dr. Keep's and had a double tooth extracted under the ethereal vapor. On inhaling it, I burst into fits of laughter. Then my brain whirled round, and I seemed to soar like a lark spirally into the air. I was conscious when he took the tooth out and cried out as if from infinitely deep caverns, 'Stop;' but I could not control my muscles or make any resistance, and out came the tooth without pain.
Longfellow was often willing to try novel medical techniques. Throughout his life, he suffered from neuralgia and poor eyesight, both of which he treated with the water therapy and other treatments. He was happy to advocate these medical techniques with others. In fact, just the day before Longfellow's visit to the dentist, on April 7, 1847, his wife Frances Appleton gave birth to the couple's first daughter, whom they named Fanny, after her mother. Dr. Keep administered ether to Mrs. Longfellow — making her the first woman in the United States to give birth under anesthesia. Friends were worried when she agreed to use ether but she reassured them because her husband felt confident about it. He was fairly impressed she went through with it. Longfellow wrote about it to his friend Charles Sumner:
The great experiment has been tried, and with grand success! Fanny has a daughter born this morning, at ten. Both are well. The Ether was heroically inhaled.
We know it was controversial even among family members, judging by allusions made in letters in the few days after the birth. Longfellow tries to laugh off their concern, noting that if his wife had been asked if she would prefer a boy or a girl, "she would have replied, I will take ether." Alas, young Fanny did not survive more than a couple years.
*The image above shows Henry Wadsworth Longfellow and Frances Appleton Longfellow with their first two children, Charles (center) and Ernest. After the birth of baby Fanny, they would have three more daughters.