110 



CROSS-SECTION OF THORAX. 



extend about half-way down the jar. Tie the balloon on the 

 lower end of the glass tube. 



EXPERIMENT 1. Inflate the balloon. Consider that it 

 requires some expenditure of energy to do this. When the 



Triangularis Sterni 

 Internal Mammary Vessels 



Pleura 

 Pulmonalis 



Lett Phrenic 

 Nerve 



ura Costalii 



( Sympathetic Nerve 

 Mediastinum < 



( Thoracic Duct 



Pneumogastric Nerves 



Posterior 



Fig. 43. A Transverse Section of the Thorax, Showing the Relative Position of the 

 Viscera and Reflections of the Pleurae. 



mouth is taken away from the tube the balloon immediately 

 collapses. 



EXPERIMENT 2. Insert the balloon and tube into the jar, 

 but do not cork, and repeat Experiment 1. The same results 



