vi HYGIENE OF RESPIRATION 71 



10. Clothing tight about the waist, careless postures of the 

 body, improper school desks, and a naturally small and weak 

 chest are conditions that make it difficult to supply the blood 

 with a sufficient amount of oxygen. 



11. Alcohol tends to reduce the breathing capacity of the 

 lungs by causing the capillaries of the lungs to dilate, thus 

 diminishing the size of the air sacs. It also predisposes the 

 tissues of the lungs to certain diseases. 



