564 ELEMENTARY PHYSIOLOGY append. 



in the capillaries at the rate of 1-2 inches (25-50 milli- 

 metres) in a mimite. The shortest time taken up in per- 

 forming the complete circuit would probably be about ;:50 

 seconds. 



The left ventricle would probably establish a blood- 

 pressure in the aorta equal to the pressure (per square 

 inch) of a column of blood about 6 feet (1*8 metres) in 

 height ; or of a column of mercury 5-6 inches (140 milli- 

 metres) in height. 



Sending out 80 grammes of blood at each stroke 

 against this pressure the left ventricle does 80 x 1800 

 gramme millimetres or 144 gramme-metres of work at 

 each stroke : in 24 hours, at 72 strokes per minute, the 

 total work done is about 15,000 kilogramme-metres. 

 The work of the ricjlit ventricle is about one quarter of 

 that done by the left, since it works against a smaller 

 blood -pressure in the pulmonary artery. The total work 

 of both ventricles is therefore about 20,000 kilogramme- 

 metres, or 68 foot-tons. 



IV. Respiration. 



Such a body would breathe about 17 times a minute. 



The lungs would contain of residual air about 1,500 c.c. 

 (100 cubic inches), of supplemental or reserve air about 

 1,500 c.c. (100 cubic inches), of tidal air 500 c.c. (20 to 

 30 cubic inches), and of complemental air 500 c.c. (100 

 cubic inches). 



The vital capacity of the chest — that is, the greatest 

 quantity of air which could be inspired or expired — would 

 be about 3,500 c.c. (230 culiic inches). 



There would pass through the lungs, per diem, about 

 10,000 litres (350 to 400 cubic feet) of air. 



In passing through the lungs, the air would lose from 

 4 to 6 per cent, of its volume of oxygen, and gain 4 to 5 

 per cent, of carbonic acid. 



During 24 hours there would be consumed of oxygen 

 about 450 litres (16 cubic feet) or 640 grammes (1^ lb.) ; 



