84 HISTOLOGY. 



three large groups, viz.: the cardiac ganglia, the epi- 

 gastric ganglia and the hypogastric ganglia. These 

 ganglia are located in front of the spinal column. 



NERVE ENDINGS. 



There are three varieties of nerve endings : free 

 nerve endings occurring in the skin, mouth, spinal 

 cord, etc., terminal corpuscles occurring in the skin, 

 and neuro-epithelial, occurring in the perceptive or- 

 gans, viz. : mouth, eye, nose and ear. 



Exercise No. 48. Examine the skin T. S. 



Technic : Harden in alcohol, embed in celloidin, and 

 stain with haematoxylin and eosin. 



I. Search for the four layers of the cutis-notha, hair 

 follicle, hair in place, hair muscle, sweat gland, se- 

 baceous gland, nerve endings and pigment of the skin. 



In what layers are all these objects found? 



A sweat gland is a simple tubular gland. 



What lesson do you get from the skin bearing on the 

 nervous system? 



