CONNECTIVE TISSUE. 43 



well suited to the various manipulations to which we 

 shall subject it. A frog's eye should be enucleated 

 directly after death, and placed entire in Miiller's fluid, 

 where it should remain for ten days. It is then washed, 

 and put, for a few hours, into dilute alcohol (alcohol 

 one, water two), then transferred to, and left, for forty- 

 eight hours, in strong alcohol. The cornea is now 

 excised, just within the sclero-corneal junction, and, two 

 or three short radial incisions having been made at the 

 edge, so that it will lie flat, it is embedded between two 

 bits of hardened liver, and thin transverse sections cut 

 from it. These are stained double, and mounted in 

 glycerin, slightly tinged red with eosin. 



If the sections are made so as to include the entire 

 thickness of the cornea, both the anterior and posterior 

 edges of the section will be seen to be covered with epi- 

 thelial cells. Between these two layers of cells lies the 

 connective-tissue substance of the cornea, which alone 

 concerns us here. This consists of delicate fibrillated 

 fibres, closely bound together by a small amount of 

 cementing substance, and arranged in lamellae. Between 

 these lamellae are seen the corneal cells, which, in this 

 view, seem to have the form of slender elongated spin- 

 dles, part of them being closely surrounded by the 

 intercellular substance, part lying in small elongated 

 cavities. 



Lamina of Cornea the Cells Seen on the Flat. In 

 order to determine the exact shape of the cells, which 

 in the former preparation are seen only from the edge, 

 it is necessary to look at the cornea from the side. For 

 this purpose a fresh cornea should be very carefully ex- 



