Human Physiology. 



the body to be freed from its waste matter. We cannot breathe 

 the same air over and over with impunity. 



Every sleeping-room should be so freely ventilated that a 

 person entering it in the morning from the fresh air can detect 

 no closeness by the smell. This can easily be done by having 

 no blinds to the windows, or setting them three inches below 

 the top, and lowering the upper sash the same distance. This 

 will keep up a double current of air all night the warm air of 

 the room passing out at the top of the opening, the cooler air 

 from without entering below. Such an opening of two or three 

 inches can occasion no hurtful draught, and it secures a perfect 

 ventilation. The amount should be increased with the number 

 of persons in the room. 



And here I must expose another vulgar error of scientific 

 men. It is held, and the error enters into the legislation of 

 the country, that every room in which people live should con- 

 tain a certain number of cubic feet that so many cubic feet of 

 space are necessary for each person. Some medical authorities 

 require 1200 feet, or a space of twelve feet long, ten wide, and 

 ten high. A certain amount of space is convenient, but a man 

 can live better in a well-ventilated room containing 400 cubic 

 feet, than in an un ventilated one containing 1200, or one of 

 treble its dimensions; better in a hogshead with good breathing 

 holes, than a tightly-closed room of any size. It is not the size 

 of a room, but the perfection of ventilation the constant sup- 

 ply of fresh air that is in question. And what every man 

 wants is to draw his individual supply from the great reservoir 

 of the entire atmosphere, and to have the air he breathes 

 uncontaminated with the breath of any other person, or with 

 his own. The size of the room is of little consequence; the 

 quality of the air it contains is of the greatest importance. 

 This should change with every breath, and every breath of 

 man should come fresh from the outer air. 



In the crowded parts of London, the whole air is deadened 



