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 numerous 

 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 



