Physiologically, when brain cells are activated by the memory process, the nerve cell coating, known as the glial sheath, increases in thickness and becomes thicker and thicker with each repetition, strengthening the electrical pathway in brain that constitutes memory.
— from Sequential Problem Solving A Student Handbook with Checklists for Successful Critical Thinking by Fredric B. Lozo

The banana exhausts the soil with extraordinary rapidity, so that every three years they must lay out a new plantation, manured by the ashes of the jungle, which they cut down and burn.
— from On the Edge of the Primeval Forest Experiences and Observations of a Doctor in Equatorial Africa by Albert Schweitzer