152 NUNNELEY, ON THE CRYSTALLINE LENS. 
figs. 11 and 12), but this I think results from mutual 
pressure, for when detached and allowed to expand by 
immersion in water they become circular, or nearly so. 
These cells appear to form the connecting medium between 
the capsule and the lens itself. Were it not that similar cells 
are found in Petit’s canal, I should feel inclined to think they 
are not merely the means of nutrition to the lens, but that 
they are lens-fibres in process of development. Any wound, 
however small, in the capsule during life, almost invariably 
leads to opacity and absorption of the lens. The anterior por- 
tion of the capsule is considerably, three or four times, thicker 
than the posterior half of it. ‘This probably arises from the ex- 
pansion of the suspensory ligament over it; or, if we suppose 
the latter to be an extension from the capsule, from it passing 
off from the capsule, just anterior to the margin of the lens, 
to form the anterior wall of Petit’s canal, where it is striated, 
from the continuation of the folds, which are received be- 
tween the ciliary processes (zone of Zinn). At this point of 
the capsule, just anterior to the margin of the lens, there is a 
sudden thinning of it, and after turning over the edge of the 
lens, the posterior capsule, though in other respects identical 
with the anterior, is much thinner and weaker. 
In a few hours or days after death the capsule is found 
separated from the lens by one or two drops of interposed fiuid. 
This is the Aguor Morgagni, and until very lately has been 
considered as a normal condition of the living eye. This, 
however, it certainly is not, for if the lens of any creature be 
examined immediately after death no fluid whatever is found; 
indeed, we can hardly understand how the vitality of the lens 
could be maintained, or the lens be kept steadily in situ, which 
for the purpose of vision would appear to be absolutely neces- 
sary, were it surrounded by a bath of aqueous fluid, however 
small. The least pressure of the muscles of the eyeball would 
induce an oscillatory motion of the lens. The fluid is a post- 
mortem effect; it is derived from the breaking down of the 
epithehal cells, and by endosmose,from the aqueous and 
vitreous humours. 
In the adult neither vessels nor nerves can be traced in the 
lens or its capsule; they are therefore regarded as extra- 
vascular; but during foetal life, up to the period of birth, 
and even some little time aftérwards, both contain vessels ; 
indeed, the capsule is then covered with a beautiful network 
of blood-vessels, derived, principally, from the central artery 
of the retina, by means of a considerable branch, which 
passes directly through the vitreous humour to the centre of 
the posterior capsule, where it minutely subdivides, the 
