Another great difference between the bed-room and the sick-room is, that the sleeper has a very large balance of fresh air to begin with, when he begins the night, if his room has been open all day as it ought to be; the sick man has not, because all day he has been breathing the air in the same room, and dirtying it by the emanations from himself. Far more care is therefore necessary to keep up a constant change of air in the sick room.
It is hardly necessary to add that there are acute cases, (particularly a few ophthalmic cases, and diseases where the eye is morbidly sensitive), where a subdued light is necessary. But a dark north room is inadmissible even for these. You can always moderate the light by blinds and curtains.
Heavy, thick, dark window or bed curtains should, however, hardly ever be used for any kind of sick in this country. A light white curtain at the head of the bed is, in general, all that is necessary, and a green blind to the window, to be drawn down only when necessary.