TECHNIQUE OF EYE DISSECTIONS 



faces and the layers, as they are taken off, 

 will show the arrangement of the lens fibres, 

 and will also show plainly their directions. 

 (Fig. 19.) To get another view of the onion- 

 like layers of the lens, cut through it with a 



Fig. 20 Section through lens show- 

 ing its concentric layers. 



safety-razor blade, either longitudinally or 

 equatorially. (Fig. 20.) The better way is to 

 have enough lenses to make one of each kind. 

 Never try to work with only one piece of 

 material. If the lens is first stained with chro- 

 mic acid the layers may be seen better, or, a 

 simpler way is to drop the lens, before cutting 

 it in two, into a, carmine solution; red ink 

 slightly diluted, will do. 

 A lens that has been boiled and partly dis- 

 57 



