CAPACITY OF THE CHEST. 247 



sandtlipart of the muscles which clothe the chest; 

 and this little muscle controls them all. A sailor 

 leaning his breast over a yard-arm, and exerting 

 every muscle on the rigging, gives a direction to 

 the whole muscular system, and applies the mus- 

 cles of respiration to the motions of the trunk and 

 arms, through the influence of this small muscle, 

 that is not capable of raising a thousandth part of 

 the weight of his body : because this little muscle 

 operates upon the chink of the glottis, and is capa- 

 ble of opposing the whole combined power of all 

 the muscles of expiration. It closes the tube just 

 in the same way that the man standing on the hy- 

 draulic bellows can with his lips support his whole 

 weight. Thus it is that the muscles which would 

 else be engaged in dilating the chest are per- 

 mitted to give their power to the motions of the 

 arms. 



Some cruel experiments have been made, and, 

 for whatever intended, they illustrate the necessity 

 of closing the top of the windwipe during exertion. 

 The windpipe of a dog was opened, which pro- 

 duced no defect until the animal was solicited by 

 his master to leap across a ditch, when it fell into 

 the water in the act of leaping ; because the mus- 

 cles which should have given force to the fore- 

 legs, lost their power by the sudden sinking of the 

 chest. The experiment is sufficiently repugnant 

 to our feelings ; and I need not offend the reader 

 by giving instances in further illustration from 

 what sometimes takes place in man. 



