360 



PKACTICAL HISTOLOGY. 



[XXXII. 



adjoining cells, not only in the same plane, but with cells lying in 



planes above and below them. 



(6.) The Nerves. If a part of the sclerotic is adherent to the 



cornea, the fine medullatcd nerve-fibres, deeply stained, are seen in 



the sclerotic and passing 

 into the cornea, where 

 they lose their myelin 

 and become non-medul- 

 lated. The larger 



non- 



medullated fibres have 

 nuclei in them, and unite 

 with other fibres to form 

 a coarse plexus the 

 ground or primary nerve 

 plexus. 



(c.) From this plexus 

 finer bundles of fibrils 

 proceed to form a finer 



jftG. 335 . Sub-Epithelial Nerve-Flexus, Cornea of plexus, and from the 

 Frog. n. Non-medullated nerve with nerve- i ff nr T1 , irn oT>rma fiVmilo 

 fibrils ; a. Nerve-fibrils, x 300. 



often with varicose swel- 

 lings running chiefly in the planes of the laminae are seen.^ 



(d.) (H) Fine fibrils are seen in the larger branches of the non- 

 medullated nerves (fig. 335). 



If the cornea of a rabbit be used, then tangential thin sections 



must be made and mounted 

 in Farrant's solution or 

 balsam. 



3. Inter-Epithelial Ter- 

 mination of the Nerve- 

 Fibres. The cornea of a 

 rabbit is stained in i per 

 cent, gold chloride (25-30 

 minutes) and reduced in 

 slightly - acidulated water 

 (acetic acid) by exposure to 

 light (p. 79). The lemon- 

 Fia. 336. v.s. Cornea of Frog. n. Nerve-fibres ; juice and formic-acid method 



a. Perforating fibrils; r. Nucleus ;#&. Inter- , i i , 4 i 



epithelial plexus of fibrils. Gold chloride. Dltlfit not be used, as the 



formic acid removes the 



epithelium. Make V.S. either by freezing or free hand and mount 

 them in glycerine (L and H). 



(a.) Observe sections of the lamellae and corneal corpuscles, and 

 between these, parts of the primary nerve-plexus cut across, more 

 or less obliquely, the branches being finer towards the anterior 



