on Muscular Motion. 
17 
denied by others, who have written upon the subject. Haller 
has taken some pains upon this point : he found, that by pulling 
the marsupium the motion was communicated to the lens, but 
he was unable to make out the mode of union ; and all his at- 
tempts to coagulate the cells of the vitreous humour were un- 
successful ; he says, no spirits can produce such a change. I 
have found, however, that, after the eye has remained a few 
days in rectified spirits, the medium between the marsupium 
and lens is coagulated, and rendered visible. By this means I 
have detected it in the turkey’s eye ; it is connected to the 
whole anterior extremity of the marsupium, extends to the 
capsula of the lens, aud appears to be about one half the 
length of the marsupium itself. 
The union has been supposed to be extremely weak, be- 
cause after death it readily gives way ; this, however, is by no 
means the case, for when it is coagulated in rectified spirits, it 
is not easily torn ; and the reason of its giving way in the dead 
eye, is probably from dissolution readily taking place when 
surrounded by moisture. 
The anterior edge of the marsupium in some birds is nar- 
rower than its base, as in the cassuary; in others, it is of the 
same extent, as in the turkey ; and in all, I believe, it is an 
uniform line; but when it is separated from the lens the folds 
contract irregularly, and appear of different lengths. In the 
eagle the marsupium is uncommonly strong. 
From the similarity of structure in the marsupium and 
ciliary processes, as also their connection with the crystalline 
lens, I was desirous of ascertaining whether the marsupium 
was possessed of any muscular power, as this would determine 
mdccxcvi. D 
