sentences:  A peculiar outbreak of Nyctalopia or night-blindness affected many of the prisoners in 1806.They became severely dyspeptic and completely blind from sunset until dawn, to the extent that their fitter companions had to lead them around the camp.Various treatments were tried and failed; finally they were cured with black hellebore, given as snuff, which relieved the dyspepsia and restored their night vision within a few days.