244 THE REASON "WITT. 



1 la the sweat of thy face shalt thou eat bread, till thou return to the ground i 



for out of it thou wast taken : for dust thou art, and uuto dust 



shall thou return." GENESIS in. 



1008. Why do persons whose legs and arms have been 

 amputated fancy they feel the toes or fingers of the amputated 

 limb ? 



Because the nervous trunk which formerly conveyed impressions 

 from those extremities remains in the part of the limb attached to 

 the body. The mind has been accustomed to refer the impulses 

 received through that nervous trunk to the extremity where the 

 tensations arose. And now that the nerve has been cut, the 

 painful sensation caused thereby is referred to the extremity which 

 the nerve supplied, and the sufferers for a time appear to continue 

 to feel the part which they have lost. 



CHAPTER LL 



1009. Why do we perspire ? 



Because the skm is filled with very minute pores, which act as 

 outlets for a portion of the water of the blood, that serves to 

 moisten and cool the surface of the body, and to carry away some 

 of the matter no longer needed in the system. 



1010. Sow is the perspiration formed ? 



By very small glands, which lie embedded in the skin. It is 

 estimated that there are about 2,700,000 perspiratory glands 

 distributed over the surface of the body, and that these glands find 

 outlets for their secretion through no less than seven millions of 

 pores. 



1011. What is insensible perspiration ? 



Insensible perspiration is that transmission of watery particles 

 through the skin which is constantly going on, but whicli takes 

 place so gently that it cannot be perceived. It is, however, very 

 important in its results, as no less than from twenty to thirty- 

 three ounces of water may pass imperceptibly throryh the skin in 

 twenty-four hours. 



1012. What is sensible perspiration f 



