Read it through once

This man carved the walls of his prison house from floor to roof with all manner of figures of men and animals grouped in intricate designs. He had toiled there year after year, at his self-appointed task, while infants grew to boyhood--to vigorous youth--idled through school and college--acquired a profession--claimed man's mature estate--married and looked back to infancy as to a thing of some vague, ancient time, almost. But who shall tell how many ages it seemed to this prisoner? With the one, time flew sometimes; with the other, never--it crawled always. To the one, nights spent in dancing had seemed made of minutes instead of hours; to the other, those selfsame nights had been like all other nights of dungeon life and seemed made of slow, dragging weeks instead of hours and minutes.