XXVI.] THE EYE. 269 



in the same row, but also with those 

 below and above. 



7. The fibrous laminae between which the 

 cells are placed ; here and there bundles 

 running obliquely from one lamina to 

 another may be seen. 



c. The membrane of Descemet or posterior 

 basement membrane : a thick hyaline mem- 

 brane, with very sharp outlines. 



d. The posterior epithelium, consisting of a 

 single layer of large nucleated tesselated 

 cells. In this section they are seen in pro- 

 file, covering the membrane of Descemet. 



Lens. 



3. Take an ox's or sheep's lens which has been 

 in potassium bichromate "2 p.c. for a week ; 

 observe 



a. The junctional ILaes of the lens fibres as a 

 star. 



b. The fibres readily peel off in laminje. 



4 Place the eye of a rabbit or cat, with the cornea 

 and sclerotic cut through, in MuUer's fluid for 

 three weeks or longer; then cut out the lens 

 with its capsule, and cut vertical sections through 

 its centre and mount them in glycerine. The 

 sections are best cut with a freezing microtome ; 

 neither the lens nor the sections of it should 

 be touched with spirit. Observe 



