PRACTICAL EXERCISES 291 



5. Measurement of Volume of Air inspired or expired Vital 

 Capacity. A spirometer (Fig. 101, p. 220) of sufficient accuracy for 

 this experiment can be made by removing the bottom of a large 

 bottle with a capacity of not less than 4 litres. A good cork, through 

 which passes a glass tube connected with a rubber tube, is fitted 

 into the neck. The bottle is fixed vertically, mouth downwards, 

 the glass tube being closed for the time, and graduated, by pouring in 

 measured quantities of water, say 100 c.c. at a time, and marking the 

 level. The divisions are then etched in. If the cork does not fit 

 air-tight, it is covered with wax. The bottle is swung on two pulleys, 

 counterpoised and immersed, bottom down, in a large glass jar or a 

 small cask nearly full of water. A smaller bottle may be used for 

 the determination of the tidal air, so as to reduce the error of reading. 



1 i ) Submerge the bottle to the stopper, after opening the pinchcock 

 on the rubber tube. Breathe into the bottle, close the cock, adjust 

 the bottle so that the level of the water is the same inside and outside, 

 and then read off the level. Determine the volume of air expired in : 



(a) A normal expiration after a normal inspiration (tidal air) ; 



(b) The greatest possible expiration after a normal inspiration 

 (supplemental air plus tidal air) ; 



(c) The greatest possible expiration after the greatest possible 

 inspiration (vital capacity). 



(2) Open the cock and raise the bottle till it is nearly full of air. 

 Determine the volume of air inspired in : 



(a) A normal inspiration after a normal expiration (tidal air) ; 



(b) The greatest possible inspiration after a normal expiration 

 (complemental air plus tidal air) ; 



(c) The greatest possible inspiration after the greatest possible 

 expiration (vital capacity). 



Make several observations of each quantity, and take the mean. 



(3) Count the rate of respiration for three minutes, keeping the 

 breathing as nearly normal as possible ; repeat the observation ; and 

 from the mean result and the amount of the tidal air calculate the 

 quantity of air taken into the lungs in twenty-four hours (pulmonary 

 ventilation) . 



6. Cardio-Pneumatic Movements. Fill a U-tube with tobacco- 

 smoke. One end of the tube is placed in the nostril of a fellow- 

 student, and made tight with a little cotton-wool. The other nostril 

 and mouth are closed, and respiration suspended. The column of 

 smoke moves in and out at each beat of the heart. By feeling the 

 apex-beat, try to verify the fact that during systole the cardio- 

 pneumatic movement is inspiratory, and in diastole expiratory. 



7. Auscultation of the Lungs. Make the following observations 

 on a fellow-student, who should strip to the waist, and should be 

 seated on a stool, so that the back can be easily examined as well 

 as the front of the chest : 



(a) Vesicular Breathing. Place the stethoscope 2 or 3 inches 

 below the axilla. The rustling vesicular sound will be heard. It is 

 more intense in inspiration than in expiration, and much more 

 prolonged, being heard during the whole of the inspiratory act, but 

 in health only at the beginning of expiration. Another position in 

 which to listen for the typical vesicular sound is below the angle of 

 the scapula. Study the sound in deep and in ordinary breathing. 

 Now go over the whole chest systematically, noting the positions 

 where the typical vesicular sound can be clearly heard and the 

 positions where it^is not heard or is obscured by 



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