SKIN 



SKINK 



surface. These glands are also outgrowths of the 

 epidermis, and they are lined l>y epithelial cells. 

 They are most numerous where there i- no hnir, 

 but they occur everywhere in connection \\iili the 

 skin, rvrause state* that 2800 open on a square iiu-h 

 of skin from the palm ; half as 

 many on a similar area on the 

 back of the hand; fewer mi tin 1 

 surface of the forehead: 1100 on 

 breast and forearm ; while from 

 400 to 600 are found on the square 

 inch of the lower limbs and back 

 of the tnink. The sweat is 

 naturally alkaline, although it 

 may be found acid owing to the 

 presence of fatty acids derived 

 from the decomposition of sebum. 

 In prolonged sweating the secre- 

 tion becomes neutral and again 

 alkaline. It is colourless, of a 

 salt i-h taste, and its odour, which 

 is due to volatile fatty acids, 

 varies with different parts of the 

 body. Coloured sweat is among 

 the phenomena of nervous affec- 

 8. Magni- tions, and instances of blue and 



d view of bloody sweats are on record. In 



a Sweat-gland, jaundice the sweat may contain 

 with its duot bile-pigment. 



(Wagner): ,//. its glands are found in 



, the 8J n j 1 a- the auditor}' passage, and have 

 c*5 tm iu 8ucn ft dose resemblance to sweat- 

 duct,' pawing glands that the former may be 

 through cerium regarded as modifications of the 

 and epidermis. latter. They yield an adhesive 

 bitter secretion the wax which 

 protects the drum of the ear from insects, <lnst, &c. 

 The most important function of the skin, 

 Touch (q.v. ), is separately treated. Regarded as 

 a protective covering, the skin possesses the com- 

 bined advantages of toughness, resistance, flexi- 

 bility, and elasticity ; the connective framework 

 iH'ing the part which mainly confers these proper- 

 ties, although the epidermis co-operates with it. 

 The subcutaneous layer of fat, and the modifica- 

 tions of epidermis in various forms, as hairs, wool, 

 feathers, scales, &c., serve for the preservation of 

 warmth, and occasionally (when they occur as 

 claws, talons, &c. ) as means of offence or defence. 

 The skin is the seat of a twofold excretion vi/. 

 of that formed by the sudoriparous glands and 

 that formed by the sebaceous glands. The llui.l 

 secreted by the sudoriparous glands is usually 

 formed so gradually that the watery portions of it 

 escape by evaporation as soon as it reaches the 

 surface ; hut in certain conditions, as during strong 

 exercise, or when the external heat is excessive, or 

 in certain diseases, or when the evaporation is pre- 

 vented by the application of a texture impermeable 

 to air, as, for example, oiled silk, or the material 

 known as mackintosh, or imlia-rublier cloth, the 

 secretion, instead of eva]>orating, collects on the 

 skin in the form o' drops of fluid. When it is 

 stated that the sweat contains urea, lactates, ex- 

 tractive matters, &c., and that the amount of 

 watery vapour exhaled from the skin is, on an 

 average, 24 Ib. daily, the importance of the sudo- 

 riparous glands as organs of excretion will lie at 

 once manifest. Moreover, there is reason to IM-- 

 lieve, from the experiments of Scharling, (icrlach, 

 and others, that the importance of the skin as a 

 iratary organ is far from inconsiderable, very 

 appreciable quantities of carlionic acid being ex- 

 haled hourly by the external surface of the body. 

 In the amphibia, in which the skin is thin and 

 moist, the cutaneous respiration is extremely 

 active; and that the respiratory function of the 

 kin in the higher animal* is also considerable is 



proved not only by measuring the excreted carlmnic 

 acid, but by the fact that if the skin is covered 

 by an impermeable varnish, or if the body is en- 

 closed, all but the head, in a caoutchouc dress, 

 animals soon die, as if asphyxiated, their heart and 

 lungs being gorged with blood, and their tempera- 

 ture before death gradually falling many degrees. 



The skin is, moreover, an organ of absorption : 

 mercurial preparations, when niblied into the skin, 

 have the same action as when given internally. 

 Tims potassio-tartrate of antimony, rubbed into 

 the skin in the form of ointment or solution, may 

 excite vomiting, or an eruption extending over the 

 whole body. The effect of rubbing is probably to 

 force the particles of the matter into the orifice- of 

 the glands, where they are more easily almorlied 

 than they would l>e through the epidermis. It has 

 been proved by the experiments of Madden, \\> r 

 tholil. and others, that the skin has the power of 

 absorbing water, although to a less extent than 

 occurs in thin-skinned animals, such as frogs and 

 lizards. This fact has a practical application. In 

 severe coses of dysplmgia difficult swallowing - 

 when not even fluids can lie taken into the stomach, 

 immersion in a h.-it h of warm water, or of milk and 

 water, may assuage the thirst. Sailors, also, when 

 destitute of fresh water, find their urgent thirst 

 allayed by soaking their clothes in salt water. 



The diseases of the skin are classified af 

 DISEASE (q.v.) ; the more important affections are 

 noticed in special articles. See also ALHINO-. 

 BATH, NERVOUS SYSTEM. The colour of the skin 

 as a means of distinguishing race is dealt with at 

 ETHNOLOGY. Peculiarities in the skins of various 

 animals are treated in the articles on those animals 

 ( HIPPOPOTAMI'S, ItHlNOTEltos, ix;c.). For skins as 

 articles of commerce, see FURS, LEATHER. For 

 the stuffing of animals, see TAXIDKHMY. 



SKIN -CASTING is a imimlar term for processes 

 which vary not a little in degree and even in nature. 

 In most cases the outer layer of the epidermis tends 

 to die away, and is separated off either very gradu- 

 ally and in small pieces at a time, or in large 

 shreds, or in a continuous slough (see SNAKES}. 

 The moulting of feathers anrl the casting of hair 

 are analogous. In the moulting or ' ecdysis ' of 

 Crustaceans and other Arthropods, what is cast 

 is the cuticle a product of the underlying epider- 

 mis. See CRAB, CRAYFISH, CRUSTACEA. 



Skillk i,sv//ir//v officinalia), an African lizard, 

 which lives in sandy places, and burrows with great 

 rapidity. It is from six to eight inches long, 

 generally of a reddish dun colour, with darker 



Skink (Scineui offcinalu). 



transverse hands, a wedge-shaped head, and four 

 rather strong limbs. For ages it has l>een in great 

 repute for imaginary medicinal virtues ; it was 

 largely imported on this account into ancient 

 Home., and is still in high esteem in the East, 

 dried skinks finding a ready sale in many places, 

 as Cairo and Alexandria. There is almost no 

 disease for which skink-powder has not been 

 supposed to be a cure. The Skink in typical 

 of the family Scincido;, of which Eumeces with 



