"I suppose no person ever enjoyed with more relish the infusion of that fragrant leaf [tea] than Johnson. The quantities which he drank of it at all hours were so great, that his nerves must have been uncommonly strong, not to have been extremely relaxed by such an intemperate use of it. He assured me, that he never felt the least inconvenience from it; which is a proof that the fault of his constitution was rather a too great tension of fibers, than the contrary."
James Boswell c. late-18th Century
James Boswell, Life of Johnson (London: Oxford University Press, 1966), p. 222