No doubt my uncle Toby had great command of himself, - and could guard appearances, I believe, as well as most men; - yet any one may imagine, that when he could not retreat out of the ravelin without getting into the half-moon, or get out of the covered way without falling down the counterscarp, nor cross the dyke without danger of slipping into the ditch, but that he must have fretted and fumed inwardly: - He did so; - and these little hourly vexations which may seem trifling and of no account to the man who has not read Hippocrates, yet, whoever has read Hippocrates, or Dr James Mackenzie, and has considered well the effects which the passions and affections of the mind have upon digestion, - (Why not of a wound as well as of a dinner?) - may easily conceive what sharp paroxysms and exacerbations of his wound uncle Toby must have undergone upon that score only.Mackenzie (1680-1761) was a Scottish physician, and author of The History of Health and the Art of Preserving it (1758).
Sterne's hunch is backed up by contemporary research. On page 239 of our book we mention a study which showed that when holes were punched into the roof of the mouths of dental students, on average the wound took 40% longer to heal during a period prior to examinations than during a vacation period.
Uncle Toby's condition starts to improve when he draws up a map of Namur, and immerses himself in the theory of military engineering until he is quite fluent. The cure gains enormously when he removes himself to his country house to have his servant reconstruct Namur and its environs on what had been a bowling green.