CHAPTER XVI. 



FURNITURE, AND ITS USES CONTINUED. 



Purifying the Blood. The Lungs. Capa- 

 city of the Lungs. Breathing. Uses of 

 Breathing. Nature of the Air. Breath- 

 ing Air twice. Ventilation. Free motion 

 of the Lungs. Tight Lacing. 



WE are now prepared to enter upon another 

 subject the study of the process by which 

 the purity of the blood is promoted, in defiance 

 of many causes which are continually in opera- 

 tion to render it impure. 



PURIFYING THE BLOOD. This is done by 

 means of air. But how is air to be introduced 

 into the human body ? Can we eat it ? Can 

 we drink it ? Can it enter by means of the 

 eyes, or the ears, or the nose ? Not in either 

 way exactly. It can indeed enter into the 



