Satan's Incubator by Randolph Craig

WHEN Dr. Skull came back to his office that morning, the dust was unusually thick on his desk. He looked about him with oddly young brown eyes. The bust of Galen on his bookshelf, the books themselves. No, Mrs. Timiny had not been in to clean, which was strange, for she had not missed a morning before in six years. Absently, then, Dr. Skull employed the black sleeve of his neat and ancient coat to rub the city grime from his desk top.

The old man frowned. He had seen much dust that morning during his calls, dust that lay unheeded in houses where misery had ended all thought of daily chores. He thought too, while his back straightened as against some invisible burden, that thus it must have been at the destruction of other cities, with the dust at last burying outraged ruins from the eyes of the future.