The narrator disassembles their own brain using a periscope to see the back of their head with a microscope to see the tiny mechanical parts. Looking at the disassembled brain, the narrator wonders where their body is. The narrator's brain is on the table. The narrator's eyes are still in their head but the narrator is looking through a microscope fastened to a periscope so that the point of view is radically shifted from the usual position to be outside of the body, looking back at the body.
The short story "Exhalation" (published in a collection of the same name) tells the story of a world where people are made of metal. The first person narrator is an "anatomist" who uses a specially designed periscope and tools to perform an auto-dissection, a dissection of the narrator's own mechanical brain, in order to discover how memories work and why people don't remember much more than a hundred years back. Understanding the process of memory, which involves the constant movement of air across tiny gold lattices, leads the narrator to discover that the air pressure people depend on is running out.