THE RESPIRATORY SYSTEM. 365 
(absorption). The undigested remnant of food and the excre- 
tions of the intestine make up the feces, the latter being ex- 
pelled by a series of co-ordinated muscular movements essen- 
tially reflex in origin. 
THE RESPIRATORY SYSTEM. 
In the mammal the breathing organs are lodged in a closed 
cavity, separated by a muscular partition from that in which 
the digestive and certain other organs are contained. This 
Fig. 295.—Lungs, anterior view (Sappey). 1, upper lobe of left lung; 2, lower lobe; 3, fissure ; 
4, notch corresponding to apex of heart ; 5, pericardium ; 6, upper lobe of right lung ; 7, 
middle lobe ; 8, lower lobe ; 9, fissure ; 10, fissure ; 11, diaphragm ; 12, anterior mediasti- 
num ; 13, thyroid gland ; 14, middle cervical aponeurosis ; 15, process of attachment of 
mediastinum to pericardium ; 16, 16, seventh ribs ; 17, 17, transversales muscles ; 18, linea 
alba. 
