IN HYGIENIC PHYSIOLOGY. 167 



ally cleaned, especially if the water in them is not freely ex- 

 posed to the oxygen of the air. If one must depend upon well- 

 water, the safest reliance is upon a deep-driven well. 



1 47 ! Why does a dry, cold atmosp7iere favorably 

 affect catarrh ? 



It tends to diminish inflammation in the mucous membrane 

 lining the nose and nasal passages. 



2. Why should we put on extra covering when we lie 

 down to sleep ? 



The respiration and the circulation are then less active. 

 The fire in our corporeal stoves being low, we need extra cov- 

 ering to preserve the warmth of the body. 



3. Is it well to throiv off our coats or shawls when we 

 come in heated from a long walk? 



No. "We need, instead, to put on extra clothing at such times 

 to keep the body from cooling too rapidly. The best hygienic 

 teachers commend the throwing of a shawl about the shoulders 

 whenever we sit down to rest after fatiguing labor. 



4. JFliy are close-fitting collars or neck-ties injurious ? 



They impede both respiration and circulation. 



5. Which side of the heart is the more liable to inflam- 

 mation ? 



The left ; because that contains the red blood just oxygenated 

 in the lungs. 



6. What gives the toper his red nose ? 



(See Physiology, p. 126.) 



The congested state of the capillaries. 



7. Why does not the arm die when the surgeon ties the 

 principal artery leading to it ? 



The anastomoses of the arteries enable a collateral circula- 

 tion to be established, whereby blood is supplied to the arm. 



8. Wlien a fowl is angry, ivhy does its comb redden^ 



