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Life and Health 



are not necessarily excited to action by an increased flow 

 of blood through the skin. In other words, the sweat 

 glands may be stimulated to increased action, both by an 

 increased flow of blood, and also by special nerve impulses 

 sent to them. 



These two agencies, while usually working in harmony, 

 may produce phenomena which are essentially independ- 

 ent of each other. Thus a strong emotion, like fear, may 



cause a profuse sweat to 

 break out, with cold, pallid 

 skin. In this case the two 

 sets of nerves act in the 

 opposite way. The sweat 

 glands secrete, but the blood 

 vessels are constricted. 

 ->294. Absorbent Powers of 

 the Skin. The skin serves 

 to some extent as an organ 

 for absorption. It is capable 

 of absorbing certain sub- 



(In each papilla are seen vascular loops stances to which ft i s freely 

 (dark lines) running up from the vas- . 



exposed. Ointments rubbed 

 in are absorbed by the lym- 

 phatics in those parts where 

 the skin is thin, as in the bend of the elbow or knee, and 

 in the armpits. Physicians use medicated ointments in 

 this way. House painters are often poisoned by the 

 absorption of lead into the body through the skin. 



A slight amount of water is absorbed in bathing. Sailors 



deprived of fresh water have been able to allay partially 



their intense thirst by soaking their clothing in salt water. 



If the outer skin be removed from parts of the body, the 



exposed surface absorbs certain substances rapidly. When 



FIG. 104. Papillae of the Skin of 

 the Palm of the Hand. 



cular network below ; the tactile cor- 

 puscles with their nerve branches 

 (white lines) which supply the papillae.) 



