Summary

In the spring of 2014, Mukherjee's father had a fall, showed signs of impaired memory, and developed incontinence. Though these symptoms could all be attributed to his advancing age, it turned out that he had developed a condition called normal pressure hydrocephalus (NPH) which results from the abnormal flow of fluid around the brain. NPH is thought to be a genetic disease triggered by a combination of genes and environmental or accidental triggers. Particular genetic combinations indicate a susceptibility to the illness, which is eventually determined by the relationships between genes and between genes and the environment. Mukherjee asks: "How do genes intersect with environments to cause normalcy versus disease? For that matter, what is normalcy versus disease?" (258).

Analysis

To open Part Four, Mukherjee returns to a personal family story, continuing his pattern of beginning a new section of...