Cats and dogs, I believe, are usually excluded from the nursery; if not, they ought to be. For though the apprehension of cats "sucking the child's breath," is wholly groundless, yet they may be provoked by the rude attacks of a child to inflict upon it a lasting injury. Besides, they assist, by respiration, in contaminating the air, like all other animals. If there are, in the nursery, objects which, from the vivacity or brilliancy of their colors, attract the attention of the child, they should never be presented to them sideways, or immediately over their heads. The reason for this caution is, that children seek, and pursue almost instinctively, bright objects; and are thus liable to contract a habit of moving their eyes in an oblique direction, which _may_ terminate in squinting. Many parents seem to take great pleasure in indulging the young infant in looking at these bright objects; especially a lamp or a candle. If the child is naturally strong and vigorous, no immediate perceptible injury may arise; but I am confident in the opinion that the result is often quite otherwise. For many weeks, if not many months of their early existence, they should not be permitted to sit or lie and gaze at any bright object, be it ever so weak or distant, unless placed exactly before their eyes; and even in the latter case, it were better to avoid it. Heat is also injurious to the eyes of all, and of course not less so to children than to adults. But when a strong light and heat are conjoined, as is the case of sitting around a large blazing fire--the former custom of New England--it is no wonder if the infantile eyes become early injured. No wonder that the generation now on the stage, early subjected to these abuses, should be found almost universally in the use of spectacles. This may be the most proper place for observing that great care ought to be taken, at the birth of the child, to prevent a too sudden exposure of the tender organ of vision to the light. We believe this caution is generally omitted by the American physician, though it is one which accords with the plainest dictates of common sense. Who of us has not experienced the pain of emerging suddenly from the darkness of a cellar to the ordinary light of day? The strongest eyes of the adult are scarcely able to bear the transition. How much more painful to the tender organs of the new-born infant must be the change to which it is so frequently subjected? And how easy it is to prevent the pain and danger of the change, by more effectually darkening the room into which it is introduced! But we have testimony on this point. A distinguished German physician states that he has known many cases of permanent blindness from this very cause to which we have referred. The Principal of the Institution for the Blind, at Vienna, says he is confident that most children who appear to be born blind, are actually made blind by neglecting this same precaution. CHAPTER II. TEMPERATURE.