XXIV.] SKIN AND TOUCH. 251 



4. Cut out the cornea of a recently killed cat or 

 rabbit, taking care not to drag it, and place it 

 in gold chloride "5 to 1 p.c. for an hour. Wash 

 well and expose to light as usual, but do not 

 remove its epithelium. When it is well stained, 

 if necessary harden with alcohol, imbed a piece 

 of it vertically in paraffin, and cut sections as 

 thin as possible. Observe 



a. The bars of the primary plexus cut across, 

 and becoming finer and more numeroi^s 

 towards the anterior membrane; from this 

 superficial layer of the plexus single axis 

 cylinders or small bundles of fibrils (rami 

 perforantes) run through the anterior mem- 

 brane and separate into a brush of fine 

 varicose fibrils which spread out immediately 

 underneath the epithelial cells , forming the 

 sub-epithelial plexus. Probably the sec- 

 tion in some part will be a trifle oblique, 

 here a fragment of the sub-epithelial plexus 

 will be seen having small meshes and very 

 fine varicose nerve fibrils, elsewhere similar 

 fine fibrils will be seen running a longer or 

 shorter course underneath the cells. (To 

 see the sub-epithelial plexus well, sections 

 should be cut from the surface of the cornea 

 and a section which includes the anterior 

 surface of the basement membrane picked 

 out.) 



b. Between the epithelial cells of the cornea, 

 the epithelial plexus of very fine varicose 



