230 Histology of the Eye. [^rS ?Il>Triff 
but never co-extensive with more than a very small fraction of the 
entire corneal area. (Fig. 2.) 
Fig. 2. 
Vertical Section of the Cornea. 
The cell-nets extend in planes which intersect one another at 
every possible angle, preserving always more or less parallelism to 
the corneal surfaces. 
Corpuscles lying in the same plane intercommunicate very 
freely through their branches, and less freely with those in the 
neighbouring more superficial and deeper planes ; and in this way 
they collectively form a system of plasmatic canals, which pervades 
the entire cornea. 
The interstitial fhrous tissue consists of broad flat lamelliform 
bundles, interwoven vdth Jihe cell-nets, necessarily also in planes more 
or less parallel to the corneal surfaces — an arrangement of the 
tissues which gives the quasi-laminated appearance observable in 
vertical sections of the cornea. In the foetus, the fibrillation of the 
bundles is very distinct ; and in the adult it is also evident. 
Blood-vessels are entirely absent from the healthy adult cornea, 
the nutrition of which is wholly carried on by the corpuscular 
system, which draws its plasma from the vessels of the sclerotic and 
conjunctiva. Its nerves, however, are numerous. The distribution 
of the coarser bundles is easily demonstrable. They enter the 
circumference of the cornea, and converge towards its centre, 
repeatedly dividing and uniting in a plexus, most of the bundles of 
which tend towards the anterior surface. Near here they recom- 
bine in a plexus of very fine bundles, from which minute branches 
are detached towards the anterior elastic lamina, which they per- 
forate, and reach the anterior epithelium. (Fig. 3.) The exact 
relation of the nerve-fibres to the epithelium is so delicate a subject 
of inquiry, that it cannot surprise us that difierent opinions have 
