XV. 

 THE SKIN AND BODILY TEMPERATURE. 



A. The Gross Structure of the Skin. 



I. THE SKIN ON THE HAND. 



Apparatus. A magnifying glass, 



Examine with a magnifying glass the skin of the palm 

 of the hand. 



Notice : 



a. The larger furrows, or creases. What is their cause ? 



b. The smaller ridges, or papillae, and the small furrows. 

 How are they arranged ? 



c. The small openings. These are the openings of the 

 perspiratory, or sweat, glands. How are they arranged? 



d. Sketch. 



II. THE Two LAYERS OF THE SKIN. 



Apparatus. A sewing needle. 



Carefully insert a needle under the outer skin of your 

 finger. 

 Notice : 



a. The two layers of the skin. 



b. The outer, dead skin, or epidermis. 



1. What is its color ? 



2. Has it blood-vessels or nerves ? 



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