RESPIRATION 39 



Greek words signifying "bad breathing;" when it is 

 totally arrested, the condition is called asphyxia and 

 when there is an excess of oxygen or too little carbon 

 dioxide in the blood, so that respiration can be sus- 

 pended without injury, a condition of apnea exists. 



Modifications of respiration are seen in sighing, yawn- 

 ing, laughing and sobbing, snoring, hiccoughing and 

 coughing. 



Sighing is a slow, large inspiration, followed by an 

 audible rapid expiration. 



Yawning is practically an involuntary sigh accom- 

 panied by a widely opened mouth. It may be caused 

 by stomach pain (hunger) as well as the torpor which 

 precedes sleep. 



Hiccough is a spasmodic contraction of the diaphragm 

 accompanied by closure of the glottis. It is often patho- 

 logic and uncontrollable. 



Coughing is a reflex act caused by irritation of the 

 nerves of the larynx. The mechanism of the act is a 

 full inspiration followed by a sudden strong expiration. 



Laughing and sobbing are, mechanically, identical. 

 The diaphragm is the muscle employed in each act and 

 the face is the organ of expression. 



Snoring is the vibration of the soft palate. 



CHEMISTRY OF RESPIRATION 



If two or more gases are confined in the same vessel 

 they will mix or diffuse throughout the space. If water 

 or other fluid be in the space, some of each gas will en- 

 ter the fluid, or be dissolved in it; and, under some con- 

 ditions, some of the gases may enter into chemical com- 

 bination with the liquid. The amount of gas dissolved 

 ;ni (I the amount in combination, will vary somewhat 



