But it is not only air, and pure air, the children must have if their blood is to be at the ‘finest quality,’ as the advertisements have it. Quite healthy blood is exceedingly rich in minute, red disc-like bodies, known as red corpuscles, which in favorable circumstances are produced freely in the blood itself. Now it is observed that people who live much in the sunshine are of a ruddy countenance — that is, a great many of these red corpuscles are present; while the poor souls who live in cellars and sunless alleys have skins the color of whity-brown paper. Therefore, it is concluded that light and sunshine are favorable to the production of red corpuscles in the blood; and, therefore — to this next ‘therefore’ is but a step for the mother — the children’s rooms should be on the sunny side of the house, with a south aspect it possible. Indeed, the whole house should be kept light bright for their sakes; trees and outbuildings that obstruct the sunshine and make the children’s rooms dull should be removed without hesitation.