NERVES OF THE CONJUNCTIVA. 



453 



the former are more sharply defined than those of the conjunc- 

 tiva bulbi, and at the same time more transparent. In many 

 animals the epithelial cells of the above-named layers of the 

 conjunctiva bulbi close to the corneal border contain dark pig- 

 ment granules in the nucleus and in the substance of the cell. 



Helfreich * has written a treatise on the nerves of the con- 

 junctiva, and the following excerpt will show the state of our 

 knowledge respecting them : 



Fig. 398. 



Fig. 398. a, Epithelium of the conjunctiva of the border of the lid ; 

 6, epithelium of the conjunctiva bulbi ; c, epithelium of the con- 

 junctiva palpebrarum ; d, epithelium of the fornix conjunctive. All 

 taken from sections of specimens prepared with chloride of gold, and 

 drawn as seen with a Hartnack's instrument, ocular 3, obj. 8. 



" We are indebted to W. Krausef for the first observation in 

 regard to the ultimate distribution of the nerves of the con- 

 junctiva. According to his description, the nerves distributed 

 to the conjunctiva, after repeatedly forming plexuses and ex- 

 changing fibres, penetrate by degrees into the upper layers <>f 

 the propria, and end in peculiar terminal organs, which he 



* Wiirzburg, 1869. 



t Ueber terminate Korperchen, 1860. 



