SYSTEMATIC SYNTHESIS OF TISSUES INTO ORGANS. 285 



ferent parts from a twenty-fourth to a sixth of an inch ; the 

 basement is one thing everywhere ; the thickness of the 

 cellular layer (cuticle) varies very much, as does the dry- 

 ness of its cells ; in some places, as the palm, heel, &c., 

 they become quite horny by the time they are at the 

 surface, while in other places the cells retain considerable 

 of their moisture and pliability at the very surface. 



Remark. CORNS ARE PRODUCED by pressure upon cells at some point, 

 by which the fluids they contain are caused to exude, leaving them one 

 under another mere horny scales matted together, pressing on the nerves 

 and even down into the dermis. A sharp-pointed instrument can be used 

 to take them out without pain, as cutting the cuticle devoid of nerves 

 cannot cause pain ; and, if the instrument is carried no deeper than the 

 corn, it cuts no nerves. If the pressure is not renewed the corns will not 

 return ; if it is, they will. 



712. TOUCH is the name given to the sense, when 

 used in a general or passive manner ; when used inten- 

 tionally, and for special purposes, it is CALLED TACT, and 

 also implies some training and acquired skill. 



713. TACT AND THE MUSCULAR SENSE often work to- 

 gether to get knowledge for the mind, that neither alone 

 could well obtain. 



714. THE ORDINARY SENSATIONS PRODUCED THROUGH 

 TOUCH are neither particularly pleasant or unpleasant. 

 They may be called neutral, since they are neither essen- 

 tial nor injurious to our welfare ; when they are either, the 

 skin rouses itself and is the cause of intense sensations ; 

 entrancing the mind with pleasure, as when it receives a 

 refreshing bath, or the gentle breeze of summer is waft- 

 ing away its accumulating heat ; or irritating and vex- 

 ing the soul most unpleasantly, as when the cold, driz- 

 zling, raw air chills it through ; in all cases proving equally 

 a precious friend and worthy of being maintained in the 

 highest condition of health and activity. 



715. OUR WELFARE REQUIRES that attention be giv- 

 en to provide seats that are easy, beds that are comfort- 



Rem. How ? 712. What is ? 718. What do ? 714. What is said of? 

 What of the extraordinary ? 715. What does ? 



