Touch. 425 



ingly in a dozen other places. In each corpuscle there is the termination 

 of a nervous filament. Their uses are not known. ( Med. Dictionary. ) 

 Underneath this sensitive layer imbedded in thecorium is an abundant net- 

 work of arteries, veins, nerves, and lymphatic vessels. These are all pro- 

 ducts by development of the corium or dermis. Besides these there are 

 also imbedded in the corium, or below it, the sebaceous follicles (or suet 

 bags ), the perspiratory glands, the milk glands, the tear glands, the 

 wax glands ( of the ear ) and the hair follicles ; all of which originate by 

 development from the epidermis or horn plate. They begin as ingrowths 

 or projections from the epidermis, and penetrating inward, bury them- 

 selves in the corium or in some cases below it. In these positions they 

 develop into their several varieties of glands or follicles and open their 

 ducts through both layers of the skin to the surface. The ducts of the 

 sebaceous or oil glands generally open into the hair follicles. The sweat 

 ducts are very long, and much coiled at their lower ends and open by 

 pores on the surface. 



The epidermis, or horn plate, is composed of nucleated cells, which 

 are formed at the bottom of the epidermis and in contact with the 

 blood vessels of the corium, from which they receive their substance, 

 furnished originally from the general circulation. They fill up the hol- 

 lows between the papillae. They increase their numbers by fission, and 

 as they grow they make room by raising the cells above them. As 

 layer after layer of these is pushed up they become flattened and hard- 

 ened into scales of horn, which are constantly being worn off the out- 

 side of the skin. These lower live cells constitute what is sometimes 

 called the mucous layer. Among these cells are. to be found the pig- 

 ment cells that give color to the skin when it has color, from which cir- 

 cumstance this layer is sometimes called the color stratum, or pigment layer. 



The sense of touch, like every other sense, is the result of active 

 movements, of some sort, in the environment. Without movement 

 there is no sense. The movements concerned in this sense are friction, 

 pressure and temperature. Some authors make a 'distinction between 

 "touch " and "tact," regarding the former as an active sense residing 

 in the active touch organs, fingers, tongue, &c. , and the latter as a pas- 

 sive sense. This distinction is hardly proper, since all parts of the 

 skin are sensitive, in some degree, to friction, temperature and pressure, 

 and all parts are alike dormant and senseless when not under one or 

 the other of these stimuli. If we put our hands in water warmed to their 

 own temperature, and hold them still, we do not have any sense of 

 touching the water. But if we move them, the friction conveys a sense 

 of touch. We are not ordinarily conscious of touching the air, but if it 

 move or we move in it, we feel the friction. If it be warmer or colder" 

 than our skin, we feel it through the sense of temperature. If our 



