Analysis of information sources in references of the Wikipedia article "Guy de Chauliac" in English language version.
"Some prescribe medicaments which send the patient to sleep, so that the incision may not be felt, such as opium, the juice of the morel,254 hyoscyamus, mandrake, ivy, hemlock, lettuce. A new sponge is soaked by them in these juices and left to dry in the sun; and when they have need of it they put this sponge into warm water and then hold it under the nostrils of the patient until he goes to sleep. Then they perform the operation."
