i8 
Mr. Home's Lecture 
the same point with respect to the ciliary processes, and might 
lead to an explanation of the use of both these parts. 
With this view I made the following experiments. The 
marsupium and crystalline lens of a goose's eye were exposed 
immediately after death ; and the lens was pushed forwards, 
by which means the marsupium was elongated, and measured 
of an inch ; upon taking off the pressure, it again contracted 
to ; this was repeated several times. The parts were then 
left, till it was supposed that all remains of life were gone, and 
the same experiment was repeated. In the stretched state it 
measured as before, of an inch, but in the contracted state, 
; this change arose from the elasticity of the ligament 
connecting the marsupium to the bottom of the eye ; and there- 
fore the contraction of ^ , which was now lost, must have 
arisen from some other cause. 
The result of this experiment favours the idea, that the 
marsupium possesses a muscular power, but in matters where 
we are so liable to be deceived, it seemed not a sufficient proof ; 
I therefore made several other experiments, but they were all 
liable to some objections ; the following, however, appears sa- 
tisfactory, and shows that there is a power of contraction in 
the marsupium independent of elasticity. 
The crystalline lens of a turkey's eye was extracted, and 
immediately afterwards the turkey was killed, by wounding 
the spinal marrow ; the two eyes were taken out, and put 
into spirits.* In the one, the marsupium had nothing to pre- 
* In the act of dying, the muscles are found to contract to their utmost, where 
there is no resistance to prevent such action ; this is also found to take place in the 
greatest degree, when the animal is killed by any violence committed upon the brain 3 
or spinal marrow. 
