256 PRACTICAL HISTOLOGY. 



tinuous network by the junction of their branches ; 

 and nervous fibrils may be seen intercalated amongst 

 the corpuscles, but never actually joined to, or con- 

 tinuous with, the cells. 



Preparation 13. Nerves of the rabbit's cor- 

 nea. For exhibiting the nerves of the cornea with- 

 out at the same time staining the corpuscles and 

 the epithelium, the following modification of the 

 gold method may be used (Klein). The cornea of a 

 rabbit or guinea-pig is put into half per cent, solu- 

 tion of chloride of gold for an hour and a half. It 

 is removed from the gold into distilled water and 

 placed in the light (without warmth) for from 

 twenty-four to thirty hours, or until the larger 

 nerve trunks begin to be visible near the circum- 

 ference, converging towards the centre as irregular, 

 branching lines. When the staining has arrived 

 at this stage, and before the corneal substance gene- 

 rally begins to acquire a violet appearance, the 

 cornea is removed from -the water and placed in a 

 mixture of glycerine and water (one part glycerine 

 to two parts distilled water). After it has been in 

 this for twenty-four hours, or longer, the corneal 

 substance should be very little darker than before, 

 but the nerves much more distinct, and on holding 

 the cornea between the finger and thumb, and mak- 

 ing sections from the anterior surface, including the 

 epithelium, and a little of the substantia propria, 

 these, when covered in the glycerine mixture, will 

 show not only the fine and close plexus of nerves 

 which lies immediately underneath the epithelium, 

 but also the far more minute network of varicose 

 ultimate tibrils which extends between the epithe- 

 lium cells almost to the anterior surface of the epi- 

 thelium. If not at first sufficiently evident, these 

 intra-epithelial nerves may generally be brought 

 more clearly into view by placing a section for a 

 few minutes in the strong caustic potash solution. 

 From this it is transferred by a section lifter to 



