IN HYGIENIC PHYSIOLOGY. 159 



below the skin, induce neuralgia and numbness in the fingers. 

 A rigid constriction about the arm-pit will frequently result in 

 a swollen hand. Tight elastics should never be worn upon the 

 lower limbs. Aside from all the discomforts and maladies at- 

 tendant upon the wearing of tight garments, the natural ease 

 and grace of bodily movement are always more or less ob- 

 structed. 



4O. Why should we take special pains to avoid clothing 

 that is colored by poisonous dye-stuffs ? 



(See Physiology, p. 62.) 



Because the particles of the poisonous coloring are liable to 

 be absorbed by the skin, and thus taken into the system. The 

 dangerous agent is usually arsenic, which is employed in dyeing 

 bright reds, magentas, aniline reds, and certain greens. Par- 

 ticular care should be taken in the selection of hose. Unfortu- 

 nately, the pure white stocking has gone out of style, though 

 hygienically it is greatly preferable to the highly (often poison- 

 ously) dyed one that has succeeded to fashionable favor. 



4:1. WJiat general principles should guide us as to the 

 length and frequency of baths in salt or fresh water ? 



(See Physiology, pp. 66, 291.) 



Sea or river baths should never be prolonged to the extent 

 of sensible fatigue, and consequent inability of reaction. A 

 daily swim taken before breakfast, and limited to twenty min- 

 utes at the outside, is to most people the best of tonics. Per- 

 sons with pale skins (technically termed anaemic, or bloodless), 

 or those who are suffering from heart disease, should not at- 

 tempt sea or river bathing, or, indeed, any cold bath, except 

 under medical advice. 



42. What is the beneficial effect of exercise upon the 

 functions of the skin ? 



(See Physiology, p. 62; also note, p. 42.) 



Increased muscular action calls for an extra supply of blood. 

 The heart responds by more rapid beating, the lungs take in 

 more oxygen, and the bodily heat is heightened. To dispose of 

 this superfluous warmth, the oil and perspiratory glands are 

 stimulated to greater activity, the impurities which naturally 



