55 



2. What sounds are produced during breathing ? With a 

 stethoscope listen (a) over the windpipe and (6) over the middle 

 of the right side of the chest in the axillary line while the per- 

 son breathes, and describe the sounds heard at each place, 

 timing their relationship to inspiration and expiration. 



3. What is the rate of respiration? Count the number of 

 respirations in a person who has been and is sitting still and 

 whose attention is directed to something other than his 

 breathing, and again in the same person after taking violent 

 exercise. 



4. Why do the lungs collapse when the thorax is opened ? 



Distend the rabbit's lungs given you by blowing into the 

 trachea and then observe their elastic collapse. Measure the 

 force of this with a water manometer. 



5. How to record the movements of respiration. 



(1) To record the movements of the air. Arrange a very 

 slowly moving drum. Connect a recording tambour by means 

 of a piece of rubber tubing with a short piece of glass tube. 

 Insert the glass tube into one nostril, and breathe with the 

 mouth closed, recording the movements of the lever. Now 

 put a time record in seconds on the drum and measure the 

 duration of inspiration and of expiration. 



(2) To record the movement of the chest wall. Insert in 

 the course of the rubber tube a glass T tube with a clamp. 

 Connect the glass tube with a toy balloon, and place it under 

 the waistcoat or a bandage round the chest, and slightly 

 distend the balloon. Take a tracing. 



These records should be taken with the subject sitting 

 still. 



6. What is the influence of CO, on the respiration ? 



(1) Examine the pulse (p. 53, 4). Record the rate. Run 

 several times up and down stairs to increase the C0 2 in the 

 blood, and again record the respiration from the nostril and 

 examine the pulse, recording the rate. 



(2) While taking a trace of normal breathing by means of 

 a tube in the nostril, hold the breath till a marked desire to 



