57 



9. What changes take place in the air breathed ? 



(1) Breathe upon a piece of cool clean glass. 



(2) Breathe out repeatedly through the vessel of lime 



water provided, and note the change produced. 



(3) Breathe out repeatedly through the weak solution of 



potassium permanganate provided, and note the 

 change produced. 



(4) Light the candle in the bottle provided, and con- 



tinue to breathe the air of the bottle through the 

 tube attached. 

 Note your results and conclusions. 



10. What changes take place in the blood in passing through 

 tJie lungs ? (See Practical Chemical Physiology, Noel Paton, 

 Cathcart and Burns, p. 20.) 



VIII. VOICE. 



(Revise the anatomy of the larynx.) 



Laryngoscope. Fix the mirror of the laryngoscope on the 

 forehead. Gently warm the small mirror on the handle. 

 Place a fellow student in one of the stalls in the dark room 

 with a light beside his head, and let him open his mouth 

 widely. Hold down the tongue in a fold of handkerchief. 

 Reflect light into the mouth by means of the mirror on the 

 forehead, and insert the small mirror through the pillars of 

 the fauces and try to see the upper opening of the larynx 

 reflected in it. 



Identify the structures seen, and then make the observed 

 person sound a high note, a low note, and take a deep 

 inspiration. 



IX. DIGESTION. 

 Swallowing. 



1. Swallow a mouthful of water or saliva and, with the 

 finger, determine the changes in the position of the tongue, 

 hyoid bone and larynx. 



2. Swallow some water coloured with methylene blue, and 

 then examine the posterior aspect of the epiglottis with the 

 laryngoscope. 



