An extract from a book with the following text: General hygiene. Pure air and sunshine. The question as to whether the injury done by living in closed rooms is mainly a physical or a chemical effect does not concern us here. Throughout this section I assume for the sake of simplicity that the damage is toxic. Keep the baby in the open air as much as possible. A sun-bath does not stop at the surface - radiant energy penetrates the body and stimulates the vital processes. When the baby is in the house, let the room (whether bedroom or sitting room) have an ample current of pure cool outside air flowing through it all the time. Keep baby out of direct line of draught, but don’t be frightened of the air being cold. Pure cold air is invigorating and prevents ‘catching cold’. Warm stuffy air is poisonous and devitalising, and makes babies liable to ‘catch cold’ when taken out in the open. There is no danger, but actual safety, in free-flowing night air. N.B. At the Karitane Harris Hospital the babies live out of doors all day, and a broad stream of pure old outside air flows through the sleeping rooms all night long: tiny, delicate babies, after a week or more of gradual habituation, sleep well, grow and flourish in rooms where the temperature may sometimes fall almost to freezing point. Of course the babies are properly clothed and covered …