Corporal Trim enters with the copy of Stevinus' book, which Toby had sent him after. Toby tells the corporal to take the book back home, but first Walter jocularly asks him to look through the book for a "sailing chariot." As Trim shakes the book, out fall some papers that turn out to be a sermon. Walter asks Trim to read some of it, and he is delighted to have the chance to perform. Walter asks Dr. Slop if he objects; he doesn't, saying "it may be a composition of a divine of our church" (the Catholic church). Trim says that since it is on Conscience, "'Tis wrote upon neither side."
Tristram describes in fine detail the corporal's stance, the position of his legs, the angles of his body; he has the posture of an expert orator.
The way Trim reads the first sentence of the sermon provokes Dr. Slop into an argument with the others: "For we trust we have a good Conscience." Dr. Slop defends the Inquisition, which would persecute anyone who took exception to the text of the Bible, and Trim tearfully speaks about his brother who has been imprisoned by the Inquisition for fourteen years.
Trim continues reading, with comments by both Dr. Slop and Walter on the meaning of the sermon. It turns out to have an anti-Catholic bias, and Dr. Slop falls asleep in the middle. Toward the end, in a description of the practices of the Inquisition, Trim takes the sermon literally as an account of what is happening to his brother Tom, and he cannot read without commenting at each line. Walter finishes the reading.
The sermon, they decide, was written by Parson Yorick, who had borrowed Toby's copy of Stevinus and left the sermon between the pages.
Obadiah returns with Dr. Slop's bag of instruments, and Walter informs Dr. Slop that he is to be merely an auxiliary; unless the midwife sends for him, he is to remain downstairs. Dr. Slop says that there have been such improvements in obstetrical knowledge, especially in "the safe and expeditious extraction of the foetus," that he wonders "how the world has — " and he is interrupted by Uncle Toby, who says, "I wish . . . you had seen what prodigious armies we had in Flanders."
Tristram in turn interrupts, dropping "the curtain over this scene for a minute." There are two things to say that he should have said 150 pages ago; after that, the scene will continue.
First, he reminds us of his father's character, referring us to what we learned about him from his theory of names. Then he tells us of Walter's elaborate "Shandean hypothesis" — supported by references to many learned authorities — that the most important center in the brain is the medulla oblongata. This part of the head is during birth "compressed and moulded into the shape of an oblong conical piece of dough, such as a pastry-cook generally rolls up in order to make a pye of." To protect his child's brain, Walter suggests to Mrs. Shandy that she have a Cesarean delivery; "but seeing her turn as pale as ashes at the very mention of it, . . . he thought it as well to say no more of it."
The next best thing to protect his child's medulla oblongata is Dr. Slop and his "new-invented forceps." They will act as armor against the medulla's being compressed like the pastry-cooks' pie dough.
Tristram asks the reader to conjecture about how Uncle Toby got his modesty from a wound upon his groin, how Tristram "lost" his nose because of the marriage articles, how he came to be called "TRISTRAM" in opposition to his father's hypothesis, and "fifty other points." But the reader will never unravel these mysteries by himself; he must be content to wait for "a full explanation of these matters till the next year."
The insertion of the sermon on Conscience is somewhat artificial; it was one of Sterne's sermons, a popular one, and he felt it would provide good reading even in the context of Tristram Shandy. But the use that he puts it to is in complete harmony with the story. The occasion that it provides for the arguments between Walter and Dr. Slop and the emotions it provokes in Corporal Trim make it an organic part of the novel.
Tristram leaves us suspended with Uncle Toby's wish about our seeing the "prodigious armies" in Flanders. It will turn out to be another demonstration of Toby's childlike reasoning — direct and very simple. The interruption in which Tristram outlines his father's theory about the brain and his trust in Dr. Slop's forceps is important; we know that it will play a role at the right time, and we suspect that since it is a cherished theory of Walter's, something is going to go wrong.
Before ending the second volume, Tristram tells us what we still have to find out, matters that he has raised but not resolved yet. This final paragraph functions like a cliff-hanger; the interested reader will be sure to buy — and read — the next installment.
In this last chapter, there is a strange and very interesting footnote that has a most important function. Apropos of the title of a "learned" work on childbirth, we find this at the bottom of the page: "The author is here twice mistaken. . . . Mr. Tristram Shandy has been led into this error" by such and such — more learned jargon. Sterne, the author of the novel, is pretending to be merely the editor of Tristram Shandy's Life and Opinions, putting distance between himself and "Mr. Tristram Shandy." There are two or three other such footnotes, and they remind us — Sterne wants us to know — that the person doing the "internal" writing is not Laurence Sterne, but Tristram Shandy.