I've been reading about the 1804 Balmis-Salvany Smallpox Expedition, or Expedición de la Vacuna, and am fascinated by this sentence:

"The ship reached Puerto Rico in February 1804 with its cargo of vaccine serum preserved between sealed glass plates; also onboard were 21 children from the orphanage at La Coruña who carried the vaccine through arm-to-arm vaccinations performed sequentially during the ship’s journey . . ."

Who were these children? How were they chosen to do this? What was their life like? I think there may be a poem here.