Tristram opens this volume with epigraphs from Horace and Erasmus and then immediately inveighs against plagiarism and literary borrowing. He complains, "Shall we for ever make new books, as apothecaries make new mixtures, by pouring out of one vessel into another? Are we forever to be twisting and untwisting the same rope?"
He then returns to the scene in which his father is digesting the news of Bobby's death. Walter's grief takes the oblique and impersonal form of a catalogue of literary and historical cases of parents who have lost children. Mrs. Shandy, overhearing the word "wife," listens at the door. Meanwhile, in the kitchen, Corporal Trim makes a speech on the subject of death that parallels Walter's oration in the parlor. Tristram compares the rhetorical styles of these two men of such different education and upbringing. Obadiah and Susannah respond still differently: he thinks of all the work that will have to be done on the ox-moor, and she thinks of a green satin gown and the preparing of the mourning clothes. Tristram then digresses in order to recall that he still owes chapters on chambermaids and buttonholes, hoping that the previous chapter might adequately discharge his debt. Trim's speech-making continues while Tristram returns to Mrs. Shandy, whom he has left listening at the parlor door, in time to hear Walter's closing speculations on Socrates and his children.
Walter determines to devote himself, now that his oldest son is dead, to preserving what is left of his unfortunate remaining child. He sets out to write a "Tristra-paedia," a book outlining the system under which Tristram is to be educated. After three years of work, Walter is almost halfway through with the project; unfortunately, the child's education is being neglected all the while.
At the age of five Tristram suffers his next major catastrophe, in which he is accidentally circumcised by a falling window sash in the nursery. "'Twas nothing," he says, "I did not lose two drops of blood by it." But the house is thrown into an uproar. Susannah, who was supervising the child, flees the scene for fear of reprisal. Trim, hearing of the incident, takes the blame onto himself; he dismantled all the sashes to collect lead for Toby's fortifications. Trim's valiant defense of Susannah reminds Toby of the Battle of Steenkirk. Toby, Yorick, Trim, and Susannah march in formation to Shandy Hall to tell Walter about the accident. Walter's eccentricity makes him unpredictable, and nobody is sure how he will react.
Tristram, arguing for his right to backtrack, returns to the moment of the accident. The child screams most impressively, and his mother comes running to see what is the matter just as Susannah slips out the back. Walter also proceeds to the nursery, learning what has transpired from the servants, who have already heard the story from Susannah. He surveys the scene without a word and walks back downstairs. He soon returns again, equipped to facilitate matters with a Latin volume on Hebrew circumcision practices. Walter and Yorick confer and pronounce that no harm has been done to the child.
Walter then begins to read from the Tristra-paedia. Toby and Trim take up among themselves the question of "radical heat and radical moisture." They generate and then present an alternative theory to Walter's. This free-for-all is interrupted by the entrance of Dr. Slop, who has been tending to little Tristram. Slop offers his diagnosis, and then the others return to their debate. Walter promises to refrain from reading the Tristra-paedia for twelve months--as soon as he finishes airing his theory about the importance of auxiliary verbs. He demonstrates their utility by means of the extended example of a white bear.