That strange petrifaction had begun in them which overtakes all very old monks and nuns who have never had very active minds.

From doing the same things, with no appreciable variation, at the same hours for fifty, sixty, and even seventy years, they become so perfectly mechanical that their bodies are always in one of a limited number of attitudes, less and less pronounced as great age advances, till they at last cease to move at all and die, as the hands of a clock stop when it has run down.
But the three old nuns belonged to a past generation, and it was not probable that the younger Sisters would ever be like them.

The Mother Superior was a small and active woman, with quick black eyes, a determined mouth, and a strangely pale face.

She seemed to be incapable of being tired.

Among themselves the novices called her the little white volcano.