Exposure to chickenpox
Garrett explores the idea of deliberate exposure of children to disease in wealthy nations, especially the deliberate exposure of children to chickenpox. She uses this as a metaphor for how different first world and third world countries react to disease, as many poorer nations struggle to deal with chickenpox outbreaks.
Earth as a stage
When talking about various creatures and microorganisms, Garrett emphasizes the strength of bacteria. She says that they will "doubtless continue to colonize and alter the face of the Earth long after we and the rest of our cohabitants have left the stage forever." Here, she uses a metaphor to describe the earth as a stage.
Reaching the moon
Garett uses the fact that humanity reached the moon as a metaphor for the vast achievements made in the 20th century. She also suggests this was part of a general attitude of fearlessness at this time in history.
The scars of slavery
In her discussion of 20th Century history, Garrett argues there was a belief that "civil right legislation could erase the scars of slavery." This is a metaphor used to describe the violent consequences of slavery as being "scars."
A beacon
Garrett argues that first world countries in the 20th Century were under the impression that "democracy could shine in startling contrast to communism and produce a beacon to which the nations of the world would quickly flock." In this metaphor, Garrett compares democracy to a beacon that provided hope to other nations.