38 



NERVOUS SYSTEM. 



pancreas. They sometimes exist in the mesentery, and have 



been observed near the coccygeal gland. 



The structure of the cor- 

 puscles consists simply of sev- 

 eral layers of connective tis- 

 sue enclosing a central bulb 

 in which is found the terminal 

 extremity of .the nerve. This 

 bulb is finely granular, nucle- 

 ated, and is considered by most 

 anatomists to be composed of 

 connective tissue. At the base 

 of the corpuscle is a pedicle 

 formed of connective tissue sur- 

 rounding a medullated nerve- 

 fibre which penetrates the cor- 

 puscle and terminates in the 

 central bulb. 



The only really important 

 point of discussion with refer- 

 ence to the structure of the 

 nerve-fibre in the central bulb, 

 and this is purely anatomical, 

 is whether or not the medul- 

 lary substance extends into the 

 corpuscle itself. Probably the 

 fibre is here reduced simply 

 to the axis-cylinder. Kolliker 

 thinks that there is a very thin 

 layer of medullary substance, 

 but he states that this is a ques- 



and extremities of the fibre. ' (KOLLIKER, + ,. J'ffi T, j -i i i A n 

 Handbuch der Gewelelehre Leinzi- 1S6T tlon CUmCUit tO deClCle. All 

 8.108.) . . , . 1 



anatomists agree that a single 



thin, flat fibre penetrates the corpuscle and terminates near 



its summit in two or three branches, with slightly enlarged 



1 Op. tit., p. 143. 



