As Mr. Shandy continues his research into health, he reads chapters from various books to Trim, Toby, and Yorick.

While reading, Mr. Shandy comes to a sentence that begins, "The whole secret of health" lies in the mastery of two different elements, "radical heat" and "radical moisture." The long discussion that follows this statement centers on a definition or explanation of what these two elements are and how they are applied to maintain one's health.

Mr. Shandy begins his discussion by criticizing "quacks." It is not clear if this is a reference merely to uneducated doctors or to all doctors in general. However, Mr. Shady believes that all of man's problems boils down to the ignorance of "quacks."

Next, a discussion ensues about a man names Verulam, who believed that human life is shortened by man's internal spirit, which burns man's life energies away. Another factor in man's early death is the external air surrounding a man, which dries up a man's body. It is these two forces by which a man's body is turned to ashes.

To extend life, according to Verulam, one must make sure that neither the internal heat nor the external dryness prevails. Verulam's recommendation was for each man to take three and a half grams of opiates each day to maintain the internal heat and to grease one's skin with an ointment so thick one could not scrape it off even with a spatula. The grease would maintain the radical moisture needed for health.

Mr. Shandy argues against the way doctors have since interpreted Verulam's secret of health. Instead Mr. Shandy recommends that for a child to maintain perfect health, the parent needs to teach the child never to run into a fire or into water.

Hearing Mr. Shandy's discourse, Trim is inspired to speak. He begins by relating an incident that took place while he and Toby were involved in a battle in Limerick, Ireland. During this siege, it rained so hard and so long that all the tents in the encampment were flooded. To keep dry, Toby and Trim devised a plan by which they dug a ditch around the outside of their tent to draw the rain water out. Then each night, they boiled wine mixed with cinnamon. If they hadn't done this, Trim is sure they would have died there.

When Mr. Shandy hears this reference, he does not understand how it relates to what he has been saying, so Toby tries to tie Mr. Shandy's and Trim's statements together. Toby relates that at the time of the Limerick battle, both he and Trim had long, high fevers. This internal heat is what protected them from the moisture from the rain that surrounded them.

It was to maintain the balance between the radical heat and the radical moisture that they then added the hot spicy wine they drank, explains Toby, trying to make sense out of all the details that have been discussed, little of which makes any sense to anyone, except for Mr. Shandy.

It is about at this point that Dr. Slop enters the house and joins in the conversation. After listening for awhile, Slop points out that the whole concept of radical heat and moisture is the "basis and foundation" of every man's being. He then turns to Trim and states that Trim has been mislead by some "superficial empiric discourse upon this nice point." Slop's statement ends the discussion.