52 HIS, ON THE CORNEA. 
is attached. In these animals vessels may run immediately beneath the 
epithelium, while in the others they are always covered by the anterior 
lamina.”’—pp. 11, 12. 
The constituents of the substantia propria are the cells and 
intercellular substance, which form a continuous whole. 
After discussing the various theories which have been enter- 
tained with regard to the normal and unaltered structure of 
the intercellular substance, Dr. His brings forward evidence, 
both embryological and histological, to show that neither 
lamelle nor fibrils, as such, exist in the cornea; but that it 
is a continuous substance which possesses a tendency to 
cleave with great readiness in particular directions—the 
planes of separation of the fibres and lamelle which are so 
readily produced artificially. The cornea, then, is laminated 
and fibrous only in the sense that wood or slate may be said 
to be so ; and it would be more proper to say that it possesses 
a lamellar or fibrous cleavage. In vertical sections of a 
fresh cornea prepared with the precautions described above, 
Dr. His asserts that “not a trace of lamellar or fibrous disin- 
tegration is visible,” p. 21. Dr. His, however, continues to 
use the word “lamelle” in the sense of “those portions of 
intercellular substance which are cleavable in one direction 
(the length of the lamella) ; and in speaking of the interlace- 
ment of lamelle all that is meant is, that at different levels 
the substance splits in different directions.” 
The corneal cells le between the lamellz, and send out 
processes between these last much as the osseous lacune send 
their processes between the lamelle of bone. Dr. His dis- 
tinguishes three forms of these cells—the stedlate cells, which 
are found throughout the greater part of the cornea ; those of 
the superficial layer of the cornea; and those of its marginal 
zone. ‘The first kind are flattened and typically quadripolar ; 
their processes branch out and anastomose abundantly, and 
they contain a single flattened “nucleus.” The superficial 
cells are like the stellate kind, much branched ; but the body 
of the cell and the nucleus are so very small that they appear 
almost like mere thickenings, and their processes form a very 
peculiar system of arched meshes, concave externally. From 
these peculiarities the superficial cells at first seem to con- 
stitute a network of curved fibres, and their true nature is 
only to be made out readily im young cornez or im those 
which are in an early stage of inflammatory alteration. 
The marginal cells lastly, are elongated and fusiform and 
their long terminal. processes commonly remain distinct and 
parallel for a great distance, so as to give rise to a false 
appearance of fibrillation in the intercellular substance. 
