LESSON XXIV. 

 SKIN AND TOUCH. 



A. SKIN. 



1. Prepare vertical sections of human scalp which 

 has been hardened by placing it in chromic acid 

 2 p.c. for a week. Stain the sections with 

 picrocarmine, mount them in glycerine and 

 observe 



A . The Epidermis : proceeding from the outside 

 will be seen 



a. Non-nucleated cells, the cell substance of 

 which is no longer protoplasmic but has 

 become transformed into horny keratinous 

 material ; they are much flattened especially 

 near the surface of the skin, where they may 

 present the appearance of a number of fibres. 

 This is the horny layer; in the stained 

 sections it will be yellow. 



6. Nucleated cells, spheroidal in form: the 

 peripheral part of these cells may appear 

 striated or closely serrated (the expression 

 of fine projections of the surface). 



