82 



RESPIRATORY MECHANISMS 



This supposes the seal to be absolutely quiet during the 

 dive, but, as we know, the seal like the other divers does its 

 swimming and catches its prey under water. The seal must 

 therefore contract a very considerable oxygen debt in addition 

 to that represented by the depletion of the stores. Scho- 





mgr % 

 Lact.acid 

 l20lVbl% C02% 



Jz, C 

 tQ'tO 



ccRQ 



3000 j 1 - 5 



2000 



1000 



Fig. 48. Influence of 15 min. dive on respiration, blood gases and lactic acid, 

 expired air and metabolism in seal. Explanation see text. (Scholander.) 



lander worked out methods for accurately measuring the 

 respiratory exchange in seals and graphically recording the 

 respiration. The curves (Fig. 48) tell the story of one experi- 

 ment in which the seal remained under water with suspended 

 respiration for 1 5 minutes. On top we have the actual record 

 showing before the dive periodic breathing of the so-called 

 "Cheyne-Stokes" type. The diving begins with an expiration 

 and when the seal comes out there is a deep inspiration fol- 

 lowed by a period of continuous and very deep breathing, 



