192 THE. HYGIENE OF RESPIRATION 



lead to narrowing of the nasal passages and upper jaw, 

 and eventual closing of the tube to the ear, which re- 

 sults in defective hearing. It is therefore important that 

 adenoids should be removed before the deformities have 

 time to develop. "Whenever mouth breathing is habitual 

 or head colds with closure of the nose are frequent, 

 the presence of adenoids should be suspected and a phy- 

 sician consulted. 



Enlarged tonsils. The throat is affected by much the 

 same conditions as the nose and requires much the same 

 treatment. The tonsils frequently become chronically 

 enlarged, sometimes so much so that swallowing and 

 breathing are difficult. When markedly enlarged, they 

 should be removed, since the general health may suffer 

 greatly through them. 



EXPERIMENTS AND DEMONSTRATIONS 



Materials: Whips or light rods, 5 to 6 ft. long; down or 

 delicate feathers ; spool "A" sewing silk ; ball of lead weighing 

 about 1 oz. ; dry and wet bulb thermometers (psychrometer) ; 1 

 [Fitz COa apparatus 2 ]. 



1) Test of purity of air: 



a) By odor: Make an independent test of the air of 2 oc- 

 cupied rooms by entering them from outside fresh air and 



1 Select cheap tin-cased thermometers by noting that the three 

 scratches on side of glass stem of each coincide respectively with 

 the graduations for 32, 62 and 92. Match them by putting 

 them into a glass of water of about 60 temperature and selecting 

 the pairs which register the same. A slight variation may be 

 adjusted by sliding one stem up or down on its scale the required 

 amount. Slip thermometers out of tin cases and secure each stem 

 in its proper position on scale by means of sealing wax, applied 

 to back of scale where tip of glass stem projects through. Care- 

 fully cut off lower portion of metal scale where it surrounds bulb 

 and fasten thermometers to a grooved piece of wood, as shown in 

 fig. 107. Upon bulb of one, tie a piece of thin linen cloth and 

 attach a stout cord 12 in. long to top of wooden support so that it 

 can safely be whirled. 



2 L. E. Knott Apparatus Co., 15 Harcourt Street, Boston, Mass. 



