In "Gulp: Adventures on the Alimentary Canal," Mary Roach reflects on her experience measuring saliva production while chewing on cotton wads with a friend, Silletti. Despite both participating for the same duration, Roach only produced 0.78 milliliters of saliva compared to Silletti's 1.4 milliliters. This difference sparks feelings of inadequacy in Roach, who jokingly refers to herself as a "dried up husk."

However, Silletti attempts to comfort her, emphasizing that these measurements do not define their worth or abilities. This moment illustrates the lighthearted exploration of bodily functions that Roach often employs in her writing, blending humor with scientific inquiry.