THE SKIN OR ORGAN OF TOUCH. 385 



a more refined character, a proportionate refinement of 

 organization seems necessary, and this is found in the tips 

 of the fingers. 



The skin is also an organ of secretion and absorption. 

 The secretion is of two kinds, of which one is a separa- 

 tion from the blood of a very fine halitus, the insensible 

 perspiration, or exhalation. When this exhalation is in 

 excess and forms drops, it constitutes the sweat. This is a 

 very important function, as it relieves the blood of a large 

 amount of water, saline matters, carbonic acid and other 

 substances, which, if retained, would be injurious to the 

 system. The perspiration by evaporation acts as a cooling 

 process, and is thus highly useful in carrying off the excess- 

 ive heat of the body. The other secretion of the skin is of 

 an oily nature, which keeps it in a soft and pliant condition, 

 protects it from the drying agency of the air, and shields it 

 from external moisture. It is also an organ, as stated, of 

 absorption. 



The skin performing so great a variety of functions, must 

 necessarily possess a very complex organization. Its anato- 

 my has been given already in detail, under the head of the 

 "cutaneous tissue," in the first part of this work. It is 

 there stated to consist of three membranous layers super- 

 imposed the one upon the other, and called the cuticle, 

 rete mucosum, and cutis vera, of numerous glands and 

 follicles, with a most minute and extensive capillary net- 

 work of arteries, veins, nerves, and lymphatics. In addi- 

 tion to these there are also the appendages of the hair and 

 the nails. 



The only part of the structure of the skin, therefore, 

 necessary to make any additional remarks upon, is the pa- 

 pillary layer or that portion directly connected with the 

 sense of touch. This layer abounds with numerous papillse 

 spread every where over its surface, but more distinct 

 and of greater size in some places than in others. The 

 fingers and toes, and the palmar and plantar surfaces 

 of the hands and feet have them most highly developed. 

 The skin upon the ends of the fingers, where the sense of 

 25 



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