SKIMMER 



5400 



SKIN 



ordinary snowshoe, but in open country they 

 possess great advantages, especially in speed. 

 The ski is attached to the feet by means of 

 straps which allow the heel to rise and fall as 

 in walking, but keep the toes firmly fixed to 

 the wood. In walking uphill a zigzag course 

 must be pursued, but downhill the motion may 

 become an extremely swift slide, steering being 

 done by means of a staff. 



Consult Rickmer's Ski-ing; Fulton's With Ski 

 in Norway and Lapland. 



SKIMMER, skim'er, a name sometimes ap- 

 plied to the SCISSORBILL (which see). 



SKIN. We usually think of the skin as that 

 part of the body-covering which we can touch 

 and see. As a matter of fact, the top skin is 

 only a thick, protecting layer whiclj covers what 

 is known as the true skin, or dermis. Dermis is 



CROSS SECTION OF THE SKIN 

 (Greatly magnified.) 



(a) Scarf skin, or dead epidermis; (&) grow- 

 ing layer of epidermis; (c) layer of cells filled 

 with coloring matter; (d) true skin; (e) fatty 

 tissue; (/ g h) sweat gland and duct ; (ik) hair 

 with .follicle and papilla; (I) sebaceous gland. 



derived from the Greek word for skin, and is 

 compounded with epi, meaning over, to form 

 the word epidermis. The latter is the name for 

 the upper layer, which is also called cuticle. 

 An examination of the accompanying diagram 

 will show the structure of the skin layers. 



The Epidermis. The top layer is made up 

 of countless cells placed side by side like the 

 paving stones in a street, but instead of one 

 compact row there are perhaps twelve or fif- 

 teen rows, arranged one above the other. 



These cells grow from the bottom up. In the 

 lowest row they are columnlike in shape, and 

 their long axes are perpendicular to the cells 

 of the under skin. Above are several rows of 

 roundish cells, which grow flatter and flatter as 

 the surface is approached. They also become 

 drier as they are pushed upward by new cells 

 below, and when the surface is reached they are 

 shed off in thin flakes. This is the "dead skin" 

 one rubs off with the towel in bathing. In the 

 deeper cells of the epidermis are found nerves, 

 but there are no blood vessels in this layer. 

 That is why a man can pass the razor over his 

 face without discomfort. A cut which draws 

 blood must be deep enough to reach the der- 

 mis. In the deeper layers is also found the 

 pigment which gives color to the skin. Dark 

 races have an abundance of pigment and white 

 races little or none. It sometimes happens that 

 exposure to the sun causes an increase of color- 

 ing matter in spots, and freckles result. Hair 

 and nails are parts of the epidermis that have 

 been excessively developed for special purposes. 



The Dermis consists of a closely woven net- 

 work of connective tissue, from one-sixteenth 

 to one-eighth of an inch thick, within which are 

 embedded blood vessels, lymphatics, nerves, 

 glands and hair follicles. In its lowest part the 

 dermis passes gradually into a loose network 

 of fibers called areolar subcutaneous tissue, 

 which allows the skin to move freely upon the 

 parts below. On the outer surface of the der- 

 mis are innumerable elevations about one-two- 

 hundredth of an inch in length, called papillae 

 (from the Latin word for pimple). The papil- 

 lae fit into tiny pits on the under surface of 

 the epidermis, so that the two layers are firmly 

 molded together. In the papillae are found the 

 nerves that give the sensation of touch, and 

 they are especially well developed in the inside 

 of the hands, where they are arranged in rows. 

 The fine ridges on the balls of the fingers and 

 thumb unalterable identification marks show 

 where the epidermis falls in between adjacent 

 rows of papillae. When a small group of 

 papillae becomes overdeveloped and projects 

 above the surface of the epidermis, a wart 

 forms. People become wrinkled when the fat 

 and other soft parts beneath the dermis are 

 absorbed and the skin does not shrink at the 

 same rate. Building up fat is therefore the 

 proper way to keep the skin smooth. 



The Glands. These are among the most im- 

 portant organs of the skin. There are two 

 kinds, those that pour out sweat, or perspira- 

 tion, and those that discharge oil. The sweat 



