126 



THE HUMAN BODY 



back by the sides of the blue ones, joining, constantly, 

 other tubes, until all are united in two large ones on the 

 main stem of our bunches of grapes. The blue tubes are 

 the pulmonary artery and its branches. The net-works 

 on the grapes are the capillaries, and the red tubes are 

 the pulmonary veins. 



Bronchial 

 tubes. 



Larynx. 



Fig. 49. 

 SECTION OF THE LUNGS, PARTLY SHOWING THE COURSE OF THE BRONCHIAL TUBES. 



Ill such a figure we have the air-tubes and air-cells: we 

 have the blood-vessels, and we have the fibrous tissue. If 

 we add the lymphatic vessels and nerves, we have all that 

 makes up the lung. 



