HISTOLOGY OF THE LENS. 



359 



the surface of the lens. Still farther backwards the cells 

 become yet longer, and their direction still more oblique, and 

 their anterior extremities curve to meet the ends of the 

 adjoining above-described cells. All these relations may be 

 much better understood from the adjoining fig. 371, and still 

 better from fig. 372 B, which shows the parts just described 

 under a high power. Thus originates the junction of the ante- 

 rior thin layer of the body of the lens with the thicker posterior 

 layer. The transition of the epithelial cells of the anterior 

 layer into the fibres of which the posterior is composed, results 

 therefore simply from the elongation of the cells of the former. 

 In successful preparations the epithelial cells of the anterior 

 layer preserve at all points, whatever changes they may un- 

 dergo in form, the characters of true cells ; that is to say, they 

 always possess a well-marked nucleus surrounded by proto-- 



Fig. 372 A. 



Fig. 372 A. Meridianal section through the margin of the lens of 

 the Rabbit, showing the transition of the epithelium into the fibres of 

 the lens. 



plasm. Neither I nor Dr. Sernoff,* who by his investigations 

 under my inspection has materially assisted in explaining the 

 true structural relations of the lens, were ever able to discover 

 at any part of the lens, in place of true cells with well-marked 

 protoplasm and nucleus, " the sharply defined irregular nuclei 

 of various sizes," the so-called formative cells of Becker,*)* 

 which, according to his description, lie in close apposition at the 

 point of attachment of the zonula, have but little surrounding 

 protoplasm, and often exhibit distinct indications of fission. 



* Ueber den Mikroskopiachen Bau der Linse bei Menschen und ll'ir- 

 belthieren (On the microscopic structure of the lens in Man and other 

 Vertebrata), Dissert, inaugural., 1867. 



t Becker, ArchivfUr Opkthalmologie t 1863. 



