96 THE HUMAN LUNGS. 



description will convince us. Every time that we draw in the air, 

 our brains fall, from the venous blood being sucked out of the head 

 to fill the threatened vacuum in the chest ; and when we breathe 

 out the air, the brains rise, from the return of the blood from the 

 head to the chest being impeded. The same also takes place with 

 the heart. During inspiration, the lungs breathe up the venous 

 blood into that organ, and retard the passage of the arterial blood 

 from it ; during expiration they keep the venous blood away, and 

 increase the onward impulse given to the arterial blood. So like- 

 wise in the belly. Largely emptied, as it is of venous blood in 

 inspiration, and subject to the movements of the superincumbent 

 lungs, it necessarily undergoes great motion during breathing. 



Now, that movements like these have a universal part to play, it 

 would be idle to deny. They actuate the body some fourteen times, 

 or more, every minute of our lives. If we watch our neighbor as 

 he sits upon his chair, we see, not his wind chest only, but the man 

 himself, expand and contract each time he breathes. If we watch 

 the face, we see a corresponding change : if we lay the hand upon 

 the stomach, we feel it rise and fall as plainly as the chest. And 

 common sense ordains, that in a machine divinely economic, the 

 use of any motion is co-extensive with the motion itself, and if the 

 motion be universal, the end it serves is likewise universal. 



As we have seen, the pressure of the atmosphere distends the 

 lungs and produces inspiration : the living contraction of the lungs 

 causes expiration. The result is, to engender a power which 

 alternately stirs the frame. As a familiar instance of what this 

 power is, I appeal to those who have sat to the sun for a daguerreo- 

 type portrait. You know that the greatest stillness is needed to 

 bind down that quick artist to the execution of single portraits ; 

 to make his successive ideas or touches fall in identical lines; other- 

 wise, he will paint you not one, but a chaos of likenesses, equal in 

 number to your variations of position. In the painfulness of your 

 anxiety to sit still, to suppress the breath, you find that you are a 

 frame which verily exists in motion j you ascertain what a struggle 

 it is to combat your life's progress, to wrestle with the moving 

 lungs. To the fingers' ends, to the toes' ends you pant and swell, 

 and sink again, with irrepressible heavings ; and the voice which 



