164 



PEEIPHERAL NERVE TERMINATIONS: END ORGANS 



its ultimate division makes several spiral turns about the corpuscle. The 

 course of the nerve fiber gives the corpuscle a peculiar spirally striated 

 appearance. Within the corpuscle the nerve fiber breaks into a plexus 

 of varicose fibrils, many of which end in knobbed extremities. The cor- 



FIG. 178. TACTILE CORPUSCLE OP 

 MEISSNER. 



b, epithelioid cells; e, nerve endings; 

 e, connective tissue capsule. (Maxi- 

 mow, after Van de Velde.) 



FIG. 179. TACTILE CORPUSCLE OP 



MEISSNER. 



a, nerve fibrils which enter the corpuscle 

 and supply its nerve skein. Methylene 

 blue. Very highly magnified. (After 

 Dogiel.) 



puscles also contain many flattened or cuneiform epithelioid cells which 

 are interspersed among the nerve fibrils. 



Tactile corpuscles occur in largest numbers in the cutaneous papillce 

 of the finger tips, where there may be as many as twenty to the square 

 millimeter. They are found in considerable abundance also in other 

 highly sensitive regions, including especially the corium of the toe tips, 

 the lips, nipple, conjunctiva, glans penis and clitoris. The cutaneous 

 senses comprehend four different qualities of sensation : pressure, warmth, 

 cold and pain. These are mediated by two distinct groups of sensory 

 fibers ending in the skin: the one conveys the impulses for pain and 

 extremes of temperature (protopathic sensibility), the other for light 

 pressure and small changes of temperature (epicritic sensibility). The 



