removed and the papillary body then separated 
by a shaving cut through the surface of the 
conjunctiva. The papille are seen under a 
microscope magnifying three hundred diame- 
s, as yellowish red corpuscles standing close 
ther, of an arched conical shape and pre- 
ing a round nucleus in their interior. 
any of the papille have short pedicles. Many 
resent at their extremity a small point or fila- 
tous prolongation which runs towards the 
thelium. Henle* thinks Valentin’s papille 
‘are nothing but the corpuscles of the epithe- 
um, presently to be noticed, distorted by the 
ction of the compressorium. Itappears to me 
lat Valentin’s papillary body constitutes a 
‘Structure of the same nature as the corpus 
Malpighianum of the skin. We know that 
‘$uch exists in the sclerotic conjunctiva from the 
tircumstance that in negroes and many of the 
Tower animals it is tinged of a black or brown 
~ colour, whilst in Isabella horses and in Swiss 
Taces among oxen it appears yellowish. 
Epithelium of the conjunctiva. The dis- 
covery of a characteristic structure in epithe- 
Tium enables us to determine its existence even 
en so delicate as not be separable as a dis- 
{ layer. It may appear merely as a tena- 
_ cious mucus little more than perceptible to the 
_ naked eye, but examined under the microscope 
it is found to consist of minute polygonal 
tells, flat and containing a central nucleus. 
ese corpuscles aggregated together more or 
less closely and in greater or less quantity con- 
stitute the substance of epithelium. The epi- 
dermis is essentially of the same structure ; as 
also the corpus Malpighianum, only when this 
is coloured, the cellules are found to contain 
colouring particles, as is remarkably the case 
im the black pigment of the eye, the small 
_ hexagonal bodies composing the membrane of 
| which belong to the same category as the cor- 
_ puscles of the epithelium or corpus Malpi- 
anum. 
__ According to Valentin the epithelium of 
the conjunctiva consists of rhomboidal or quad- 
e@ cells lying close together, the boundaries of 
yhich are formed by simple lines. In every 
there is found without exception a some- 
' 
what darker and more compact nucleus of a 
Tound or largish form. The average diameter 
‘of these cells, in the human eye, is about the 
two-thousandth of an inch. The nuclei are 
about half the size. 
Thickening of the epithelium takes place in 
opium and callous granulations. What is 
ee led cuticular conjunctiva is at the same time 
4 general contraction of the whole conjunctiva 
ith a thickened and dry state of the epi- 
_ thelium. 
_ _ Does the conjunctiva extend over the cornea ? 
Every one admits the existence of a layer on 
the anterior surface of the cornea, quite dif- 
ferent from its proper substance, and apparently 
a continuation of the conjunctiva covering the 
Sclerotica, but this layer on the anterior surface 
wal 
oD 
4. ™ Symbole ad Anatomiam Villorum intestina- 
um, imprimis eorum epithelii et vasoruam lac- 
teorum, p. 8. 4to, Berolini, 1837. - 
| i 
4 
; 
LACRYMAL ORGANS. 
87 
of the cornea does not present exactly the same, 
or at least all, the anatomical and chemical 
characters as the sclerotic conjunctiva. What 
of it can be raised is like epidermis or epithe- 
lium, coagulated and rendered white by the 
heat applied to separate it, and moreover it is 
not vascular, the vessels seen ramifying on the 
surface of the cornea in some inflammations 
being situated underneath it. 
What is the nature of the superficial layer of 
the cornea? It is composed of two lamelle. 
The more superficial constitutes a very fine but 
firm epithelium. According to Valentin, after 
sixteen or twenty-four hours’ maceration, the 
epithelium separates from the cornea. The 
cells have in this case lost a little in transpa- 
rency and are somewhat distended. The nuclei 
appear more or less swollen by the action of 
the water. The other lamella situated under- 
neath the epithelium is more loose in its co- 
hesion, and is What Valentin considers the 
same structure as the papillary layer described 
by him in the ocular conjunctiva. Valentin 
says that a chorion or fibrous layer does not 
exist in the conjunctival extension over the 
cornea. The bloodvessels derived from the 
sclerotic conjunctiva run merely betwixt the 
papillary body and the surface of the proper 
substance of the cornea. They are very deli- 
cate and extremely difficult to inject. 
Romer* has described the arteries of the con- 
junctiva corner from injections. The fine 
twigs of the arteries of the sclerotic conjunctiva 
unite together around the margin of the cornea 
into a vascular wreath or circle. From this 
there arise very numerous branches which run 
from the circumference towards the centre of 
the cornea, and in their course make two or 
three very fine subdivisions. Their ends bend 
distinctly inwards, and appear to penetrate the 
proper substance of the cornea. 
Having thus shown on the surface of the 
cornea the existence of an epithelium and a 
structure, called by Valentin a papillary body, 
similar to what is found on the surface of the 
sclerotic conjunctiva, as also a stratum of blood- 
vessels, we must admit a cellular support for 
those vessels, however delicate. If so, the 
bloodvessels and cellular tissue would consti- 
tute the essential elements of a chorion.t We 
can only explain the development of those ex- 
tensions of membrane like sclerotic conjunctiva, 
over the cornea by supposing an irregular and 
undue development or hypertrophy of these 
elements. 
The question, “ Does the conjunctiva’ ex- 
tend over the cornea?” may be considered as 
answered in the affirmative by the above ana- 
tomical demonstration. Morbid anatomy 
now comes in advantageously with its corro- 
borative evidence. ‘ Nothing is more in 
favour,”’ says Eble, “ of the existence of a con- 
* In Ammon’s Zeitschrift Bd. v- p- 2], Table I, 
Fig. 9 and 11. See also Miiller’s Archiv, 1836; 
Jahresbericht, p. 28; and Henle De Membrana 
Pupillari, &. Bonne, 1832. 
+ Medico-Chirurgical Transactions, vol. xxi. p. 
414, London, 1838; London Medical Gazette, vol. 
xxiil, pp. 571, 702, 815. 
