XIII 



KESPIEATOEY EHYTHM 



481 



animal before and during experimental apnoea, Ewald found that 

 the O 2 content of the arterial blood was hardly increased ( + O'l, 

 + 0'9 per cent) while that of the venous blood was considerably 

 reduced ; hence after apnoea the blood, as a whole, is poorer in 



FIG. 215. Increase of respirations after cessation of the apnoea produced with artificial respiration, 

 before and after section of vagi, in rabbit and dog. (Luciani.) A, A', Adult rabbit, tracheo- 

 tomised and given artificial respiration with the bellows ; A. respiratory tracing consequent 

 on apnoea, the trachea being connected with a receiver of 12 litres air, which in its turn com- 

 municates with a Marey's writing tambour ; A', the same, after section of both vagi. 

 B and B', Puppies of 3*800 kgrms. anaesthetised with 2 c.c. laudanum injected into a vein, 

 tracheotomy and artificial respiration with bellows ; B, respiratory tracing after apnoea, the 

 trachea being joined to a receiver of 30 litres air, communicating with a writing tambour ; 

 B', the same, after cutting second left vagus. 



oxygen. On the other hand, the C0 2 of the arterial blood 

 diminished by more than half, while that of the venous blood 

 increased. This fact is readily explained on the assumption 

 that forced pulmonary respiration, by compressing the alveolar 

 VOL. I 2 i 



