



BEST METHODS OF VENTILATION 409 



Do not give up work if the patient does not at once show signs 

 of recovery. Persons who have been under water for some time 

 have been resuscitated after four to five hours' work. Prompt, 

 regular, and continued effort is the thing that counts. 



Self-Testing Exercise 



In breathing there are two movements, (1) and (2). 



In the first movement the (3) are pulled up and outwards, 



and the (4) is lowered, thus making a larger space within the 



chest cavity into which (5) may pass (6) is a pas- 

 sive movement, the air being forced out by the return of the (7) 



and (8) to their former positions. We inspire about 



(9) times a minute. About (10) (11) inches of air are 



taken into the lungs during a " long " breath. To perform artificial 

 respiration by the prone-pressure method we place the patient face 



(12), kneel astride him, and slowly but strongly press 



(13) and (14) just over lower part of the (15) 



(16) at a rate of (17) times a minute. Keep this 



pressure up for (18) seconds, release suddenly, rest (19) 



seconds, and repeat. 



PROBLEM VI. WHAT ARE THE REASONS FOR, AND THE 

 BEST METHODS OF VENTILATION? 



Demonstration 6. To show methods of ventilating rooms. 



Make a grooved box 8 X 10 inches at base, 8 inches high, with 

 sliding glass door. Place on side and have 4 half-inch holes, two at 

 top and two at bottom, bored in each end and fitted with corks. 

 Place three candles in the box. Light the candles. 



With all the corks in place, how long (take exact time) do the candles 

 burn? 



Remove the upper corks from both ends. How long do the candles 

 burn? 



Remove the lower corks. How long do the candles burn? 



Remove the upper and lower cork from one end. How long do 

 the candles burn? Remove the upper corks from one end and the 

 lower ones from the opposite end. How long do the candles burn? 



Make cross-section sketches and explain the different trials. Use 

 dotted lines and arrows to represent the course of the air. 



What is the best method of ventilating a room ? Why should people 

 sleep with windows open? Make a diagram to show how to ventilate 

 a -room. How would you ventilate through a window without making 

 a draft? Can you explain the school system of ventilation? 



