NORMAL HISTOLOGY. 



lial lining of the lymph-cavity. The outer surface of the sclera 

 throughout a large part of its extent takes part in bounding the 

 episcleral space, where it is likewise covered with endothelium. 



The blood-vessels distributed to the tissue of the sclerotic coat 

 are meagre, although the tunic is pierced by numerous trunks related 

 with the supply of the underlying parts ; such small vessels as are 

 present break up into capillaries passing among the bundles of fibrous 

 tissue. 



The lymphatics are represented by the intercommunicating cell- 

 spaces which connect with the larger lymph-cavities. 



The nerves, terminating within the sclera constitute fine twigs 

 given off from the larger trunks passing between the sclerotic and 

 choroid coats ; they break up into fibrillae which end as naked axis- 

 cylinders between the bundles as an interfascicular plexus. 



THE CHOROID. 



The choroid consists of a connective-tissue stroma supporting 

 numerous blood-vessels. Dependent largely upon the size and 

 arrangement of the blood-vessels, certain layers are distinguished, 

 these being, from without inward : 



1. The layer of choroidal stroma containing large blood-vessels. 



2. The layer of dense capillary net-works the choriocapillaris. 



3. The homogeneous glassy lamina, or vitreous membrane. 



The stroma-layer, with its large blood-vessels, constitutes the 

 greater part of the choroid. Within a supporting tissue made up 



FIG 



Section of human choroid : a, retinal pigment adhering to vitreous mem- 

 brane (i>) c, capillary layer, or choriocapillaris ; d, e, large blood-vessels 

 of stroma-layer (_/) ; g, lamina suprachoroidea ; h, tissue of sclera. 



of closely united connective-tissue lamellae, elastic fibres, and 

 branched pigmented cells, the freely branching arterial and venous 

 trunks take their course, appearing as lighter-colored channels within 

 the darker surrounding matrix. The blood-vessels and the stroma 



