RESPIRATION, CIRCULATION, DIGESTION DIAGRAM 1. 11 



ORGANS OF 

 RESPIRATION, CIRCULATION OF THE BLOOD, 



DIGESTION. 

 [ DIAGRAM 1. ] 



GENERAL OBSERVATIONS. 



The Neck. The neck contains the larynx, which communicates 

 with the throat above, and joins the wind-pipe below which 

 conducts air to the lungs. 



The larynx makes a projection in man, which is felt in the neck, 

 and is called Adam's apple. When the larynx is stopped up 

 suffocation ensues, and this is what occurs in the croup of children. 

 The surface of the larynx is exceedingly sensitive ; and if it is 

 touched by anything but air, a violent fit of coughing is the 

 result. This happens when we swallow anything the wrong way, 

 that is, when a drop of water or a morsel of food penetrates into 

 the larynx instead of falling into the oesophagus behind the 

 larynx. 



Below the larynx, near the wind pipe, is a gland called the 

 thyroid gland. It is not usually felt under the skin, and we only 

 mention it because it produces goitre, when it swells to a large 

 size. Goitre is very common in some countries, and seems to- be 

 caused through bad water. 



The Chest. The chest is protected in front by the ribs, and is 

 separated below from the abdomen by a partition called the 

 diaphragm. The chest contains the oesophagus and the wind- 

 pipe at the back, the heart in front, and the lungs on each side. 

 The heart is not situated wholly on the left side, as is often 

 supposed, the point only is a little inclined to this side ; and as 



