RESPIRATION IO9 



Reserve air, supplemental air, vital capacity. Determine in your 

 own person with the spirometer the amounts of each of these, and 

 note down the results. 



Measurements of the chest and abdomen in deepest inspiration 

 and in deepest expiration. Determine these upon yourself (a) at the 

 level of the armpits, (b) at the level of the lower end of the 

 sternum, (c) at the level of the umbilicus, using a tape measure. 

 Note down the results. 



Artificial respiration in man. Place the subject flat on the ground 

 in the prone position with the head on one side. Kneel or squat by 

 the side of or across the lower part of the body, facing the head, and 

 place your hands flat on the loins with the thumbs nearly touching at 

 the spine (Fig. 83). Throw the weight of your body forward on the 

 hands, keeping your arms straight (A), and count slowly one, two, three, 

 four, five. Whilst counting four, five, swing backwards () so as to take 

 the weight off your hands. Then swing forwards again, counting, as 

 before, one, two, three ; and backwards, counting four, Jive ; and so on 

 about twelve to fifteen times a minute. The effect of the pressure is 

 to force the abdomen and lower part of the chest against the ground 

 so that the viscera are pressed against the diaphragm. In this way 

 air is driven out of the lungs. On relaxing the pressure the parts 

 resume their former position ; the diaphragm descends and air is 

 drawn into the lungs. 



The amount of air thus pumped through the lungs in a minute can 

 be measured by the spirometer in the same way as the tidal air 

 measured in natural respiration. 



Negative pressure within thorax. Introduce through an inter- 

 costal space into the pleural cavity in the human cadaver or in any 

 dead animal a sharp-pointed cannula or hollow trochar connected by 

 rubber tubing to a water manometer. Notice that as soon as the 

 trochar passes into the pleural space the water in the distal part of 

 the manometer sinks and registers a certain amount of negative 

 pressure within the thorax. 



Effects of stimulation of nerves and of asphyxia upon the respira- 

 tory movements of animals. These have been studied in connexion 

 with blood-pressure (Chapter XX.). 



