Things Fall Apart Chapter 9
Okonkwo was finally able to sleep for the first time in three nights when Ekwefi awakened him because Ezinma was ill. She had a fever and so Okonkwo went out to find the herbs that would help her. Ekwefi was afraid that Ezinma would die as her previous nine children had. A medicine man decided that Ekwefi was bearing the same evil child over and over again; this type of child was called an ogbanje. The only way to save a woman from an ogbanje was to mutilate the dead body of the child and then bury it in the Evil Forest across the stream from the village where twins were left.
"After such treatment it would think twice before coming again, unless it was one of the stubborn ones who returned, carrying the stamp of their mutilation - a missing finger or perhaps a dark line where the medicine man's razor had cut them." Part 1: Chapter 9, Pg. 69
Ezinma bore none of the marks of mutilation and when her iyi-uwa, the stone that was her link to the world of ogbanje, had been found and destroyed over a year before, Ekwefi was reassured that Ezinma would stay. But when the girl fell ill, Ekwefi was still afraid that her daughter might die.
Okonkwo came back with the herbs and made Ekwefi boil them in a pot and then put Ezinma under a heavy mat to sit in the steam of the liquid. After that, Ezinma slept.