Boylston first experimented on his 6-year-old son, his slave, and his slave's son; each subject contracted the disease and was sick for several days, until the sickness vanished and they were "no longer gravely ill".
Boylston一開始在他六歲的孩子、奴隶及奴隶的儿子試驗，三人都發病數天，然後病症就消失了，之後就「不再重病缠身」。