218 Mr. Home's Lecture 
To ascertain whether any such action could he demonstrated 
in the membranes of the quadruped, I made the following 
experiments. 
These experiments were made upon the internal membrane 
of the urinary bladder of a dog, which, in consequence of the 
animal dying a violent death, was in a very contracted state; 
the whole of its contents having been expelled in the act of 
dying. 
The method I have adopted to ascertain the muscular power 
of this membrane, is similar to that taken by Mr. Hunter in 
his very ingenious investigation of the structure of blood-ves- 
sels, which was laid before this Society ; the same mode being 
equally applicable to the present subject.* 
The bladder was carefully laid open, and a portion of its in- 
ternal membrane, which was corrugated into folds, was dis- 
sected off. This portion was spread out, so as to be completely 
unfolded ; it was then laid upon a piece of plate glass wetted, 
to prevent, as much as possible, any friction ; its exact length, 
in this contracted state, was three quarters of an inch ; it was 
now stretched out, and found to be i-| inch, upon being left 
to itself, it contracted so as to be only 1 inch, so that in this 
state it had gained of an inch, which must have been lost 
by some actionjn the living body, and entirely independent 
of its elasticity. This portion of membrane then had two 
powers of contraction, one which was muscular, and equal to 
f- of an inch, the other elastic, and equal to of an inch. 
Another portion of the same membrane, an inch long and 
* Mr. Hunter’s experiments on the arteries of the horse are published in his trea- 
tise on the Blood, Inflammation, and Gun-shot Wounds. 
