The intumescence continued till it seemed to burst, and exhibited a shocking sight of foam and blood, during which the quack appeared in extreme agonies, and excited the commiseration of all the bye-standers.
"Travels in China, Containing Descriptions, Observations, and Comparisons, Made and Collected in the Course of a Short Residence at the Imperial Palace of Yuen-Min-Yuen, and on a Subsequent Journey through the Country from Pekin to Canton"
John Barrow
intumescence is the swelling of the substance upon heating.
"The Elements of Blowpipe Analysis"
Frederick Hutton Getman