XXIV.] SKIN AND TOUCH. 253 



one which is not surrounded by fat, cut it out 

 and mount it in normal saline solution. With 

 a little care the mesentery covering it may be 

 removed with needles. Observe 



a. The medullated nerve-fibre and the thicken- 

 ing of its connective- tissue sheath as it 

 approaches the Pacinian body. 



h. The division of the connective-tissue sheath 

 to form the numerous concentric capsules, 

 which become closer together towards the 

 centre. At intervals on the capsules elon- 

 gated nuclei will be seen. 



c. The loss of medulla as the sheath splits up. 



d. The hyaline core inside the innermost capsule. 



e. The axis-cylinder penetrating the core, and 

 ending in it in a slight enlargement. 



To observe the manner in which a small bundle 

 of nerve fibres separate and run to the Pacinian 

 bodies, a piece of the mesentery containing a 

 number of them should be stretched over a 

 slide, the piece cut out and the edges allowed 

 to dry, so that the part containing the Pacinian 

 bodies is kept stretched. The outlines of the 

 flat cells of the capsules can easUy be made 

 obvious by placing a Pacinian body freed from 

 the mesentery as in § 6 in '5 p.c. nitrate of 

 silver for a quarter of an hour, then exposing 

 to light as usual and mounting in water. They 

 are not easy to preserve, the best plan is 

 perhaps to irrigate with dilute glycerine after 

 treatment with osmic acid or gold chloride. 



