42 
Structure of the 
TMonthly Microscopical 
L Journal, July 1, 1869. 
in thickness,* is observed, at the margin of the cornea, to become 
fibrous and to divide into three parts. One part encircles the rim 
of the anterior chamber, limiting the fluid which it contains, and 
passes into the base of the iris and into the ciliary body, in the 
j^^^ ^ latter of which situations it 
becomes blended with the 
fibrous processes of the zone 
of Zinn. Of the other 
parts, the greater gives 
origin to the ciliary mus- 
cle, which is also inserted 
into the ciliary body ; while 
the lesser portion (E) enters 
the sclerotica, enclosing the 
canal of Schlemm. By the 
latter attachment the scle- 
rotic is indirectly connected 
with the cihary circle. 
Again, the hyaloid mem- 
brane (B), after encircling 
the posterior hemisphere 
as a thin transparent mem- 
brane, is firmly bound down 
to the ciliary body, where 
it increases in thickness, 
and goes under the name 
of the structureless mem- 
brane of Zinn (C), from its 
discoverer. This union is effected by strong fibres which are given 
off" from the external surface of the latter, pass into the substance 
of the ciliary body, and meet those, already referred to, coming 
from the posterior elastic lamina of the cornea. Thus, then, these 
two membranes become united in the ciliary circle, and form a 
structureless sphere, the fimction of which is essentially that of 
limiting the humours which it encloses. For brevity of description 
I shall call this sphere the aqueous capsule of the eye. 
The parts contained within the aqueous capsule are, the aqueous 
humour, iris crystalline lens, and vitreous humour. It is divided 
into two segments by the lens (F) and its ligaments (G H) ; but the 
division is such as to admit of a certain amount of imbibition between 
the two hemispheres. This latter fact is of the less importance, as 
the fluid in the two hemispheres is chemically and physically alike, 
comes from the one source, distends both hemispheres with an equal 
degree of force, and its amount in both is regulated by the same 
principles. 
* Bowman : ' Lectures on the Parts concerned in Operations on the Eye,' p. 19. 
Diagram of the Aqueous Capsule of the Eye. 
A, Posterior elastic lamina of the cornea ; B, Hyaloid mem- 
^ brane ; C, Structureless membrane of Zinn ; D, Union 
of the membranes of the two hemispheres in the ciliary 
body ; E, Faslculus of fibres which enclose the canal of 
Schlemm ; F, Crystalline lens ; G, Ligament of the an- 
terior capsule ; H, Ligament of the posterior capsule. 
