on Muscular Motion. 
21 
that vascular membrane, which may extend itself upon the 
cornea; for it is impossible that the vessels of the cornea, 
which naturally cany only lymph or serum, can be made to 
carry red blood, unless the irritation extends to some neigh- 
bouring part supplied with red blood. 
That vessels carrying red blood have been met with upon 
the cornea in a diseased state, is doubted by Haller; he does 
not altogether deny it, but the assertion, he says, requires 
proof, as he is not satisfied with the authorities of Petit and 
others whom he quotes upon that subject. 
It is so common a thing in inflammations of the eye to have 
the branches of the arteries of the tunica conjunctiva continued 
upon the cornea, that every practical surgeon must have met 
with it. In some instances of this kind, which have come imme- 
diately under my own care, I have examined these vessels with a 
magnifying glass, and have seen distinctly small arteries from 
the tunica conjunctiva, uniting upon the cornea into a common 
trunk larger than any of the branches that supplied it, and this 
trunk has sent off other branches distributed over the cornea. 
These vessels may, by some physiologists, be supposed to 
be continued upon the lamina of the tunica conjunctiva, which 
is spread over the cornea; this, however, is not the case, as 
they pass behind it, and therefore belong as much to the la- 
mina under them as that which is over them ; and, in many 
instances of disease, vessels carrying red blood are met with 
in the substance of the cornea still deeper seated. This has 
been seen by Professor Richter,* who says, he has divided a 
* Richter Med. Doctor, et Professor publicus Or dinar ins Soc. Reg. Scient. Gotting. 
el Acad. Reg. Scient. Suecice Mem . in Novis Comment. Soc. Reg. Gotting. T. vi. ad 
annum 177 s- 
