SUMMARY 393 



with oxygen at the lungs. White corpuscles are like amebas. They 

 destroy bacteria. 



The coagulated material of a blood clot, which closes a wound, is 

 fibrin, formed out of one of the proteids of the blood. 



Lymph is a form of blood that exists outside of the organs of rapid 

 circulation. It has no red corpuscles. In supplying the cells, the 

 capillaries give their food material to the lymph, and this gives it to the 

 cells. 



Excretion is the secretion of waste solutions, so that they may be 

 removed from the body. The chief excreting organs are the kidneys. 

 The skin excretes waste in the perspiration. 



Respiration brings oxygen to the blood, and removes carbon dioxide 

 from the blood. 



The chief organs of respiration are the two lungs and the air pas- 

 sages. The pleurae are sacs that surround the lungs. The lungs 

 contain a multitude of air cells. 



In the lungs the air loses about 34 of its oxygen, and takes up car- 

 bon dioxide in its place. 



In inspiration the chest is enlarged, and the outside air rushes into 

 the lungs. 



In expiration the diaphragm and ribs are crowded against the lung 

 cavity, and force out the air. 



The air passages include the nasal passages, the pharynx, the larynx, 

 the trachea, and the bronchial tubes. All are lined with mucous mem- 

 brane. 



The larynx contains the vocal cords. In speaking and singing we 

 make sounds with the throat, tongue, lips, teeth, and nostrils, as well 

 as with the vocal cords. 



We should have good habits of breathing, and should breathe good 

 air. Mouth breathing is dangerous. 



Colds, tobacco, alcohol, and tight clothing are all sources of danger 

 to the organs of respiration. 



The skin consists of epidermis and dermis. The sense of touch is 

 in the papillae of the dermis. 



Perspiration is secreted (excreted) by the sweat glands of the 

 dermis. 



