260 



RESPIRATION 



general circulation rate is considerably increased during muscular 

 work, so that, in spite of the enormous increase in consumption of 

 oxygen and production of CO 2 in the body, there is still a good 

 deal of oxygen in the venous blood. 



Other very interesting experiments were made on man by 

 Loewy and von Schrotter. 2 They succeeded in introducing a 

 modified Pfliiger lung catheter (Figure 68) into a branch bron- 

 chus or one of the two main bronchi in man. The supply of fresh 



Figure 68. 



Lung-catheter as used by Loewy and von Schrotter. The lung-catheter con- 

 sists of a central inner tube open at the lower end, and an outer tube ending 

 below in a distensible bulb which can be blown up by the rubber bag when the 

 end of the catheter is placed in position in a bronchus. By means of the syringe 

 and glass sampling tube a sample of gas from beyond the bulb can be collected 

 over mercury free of air. 



air to the corresponding part of a lung, or whole lung, was thus 

 completely cut off and remained so for long periods. The breath- 

 ing, however, went on quite quietly and naturally, just as before, 

 even though all the air usually distributed to the two lungs was 

 going to only one lung. It is very significant that so little dis- 

 turbance in breathing, etc., was produced; but the fact is quite 

 easily intelligible now in the light of the preceding chapters. The 



2 Loewy and von Schrotter, Die Blutcirculation beim Menschen, 1905. 



