“All cells come from cells. Every cell is born of a previous cell, which was born of a previous cell. Life comes from life. Life begets life begets life begets life.”

“Omnis cellula e cellula," he said again. "All cells come from cells. Every cell is born of a previous cell, which was born of a previous cell. Life comes from life. Life begets life begets life begets life begets life.”

“The tragedy is that every brain cell devoted to belief in the supernatural is a brain cell one cannot use to make life richer or easier or happier.”

“Life is a solitary cell whose walls are mirrors.”

“It is not a simple life to be a single cell, although I have no right to say so, having been a single cell so long ago myself that I have no memory at all of that stage in my life.”

“Life is precarious and improbable, a flame in matter, easily snuffed out. Nature shows no regard for the individual spark, in this creature or that, but only for the spreading of the fire, like an ember passed from cell to cell.”