LESSON XXVII. 



SKIN. ENDINGS OF SENSORY NERVES 1 . 



1. Vertical section of human scalp. (Alcohol ; 

 picrocarmine.) Observe 



a. The epidermis formed of: 



The horny layer, consisting of much flattened 

 cells, without visible nuclei; possibly the inner part 

 only of this will remain. 



The stratum lucidum, a thin layer of transparent 

 cells (stained yellow by picric acid). 



The granular layer, one or two cells deep, probably 

 stained deeply with carmine. Examine under a high 

 power for the eleidin granules of the cells. 



The Malpighian layer, consisting of (a) polyhedral 

 cells (prickle cells), and of (6) a row of columnar or 

 elongated cells (the germinal layer). 



b. The dermis, consisting of white, fibrous, and 

 elastic tissue, which becomes coarser and has larger 

 spaces in passing inwards. Note the papillae, conical 



1 For sensory endings in Muscle and Tendon, see Lesson xvi. 



