35 
elasticity of the lungs. 
For the purpose of these experiments, an apparatus of 
glass, of the following simple construction, was used. An 
oblong glass globe, containing nearly two quarts, had tubular 
openings at each end, A, and B. (Plate IV.) A glass tube, 
nearly three feet in length, and bent at one end, was joined by 
the blowpipe to the opening at B, and is represented by B, C. 
To the other opening at A, a shorter tube was joined in the 
same manner, and in the form A, D. A free passage was es- 
tablished from D to C, where the tubes were both open. To 
D, a piece of the dried gut of some small animal was bound, 
of a few inches in length. The other end of the gut was fixed 
to a cylindrical tube of bone, metal, or wood, also of a few 
inches in length, and of a diameter corresponding with the 
diameter of the windpipe of the animal which was to be the 
subject of the experiment. The windpipe of an animal, which 
had been recently killed, was divided across near the throat, 
and separated by dissection from the rest of the neck, nearly 
to the top of the chest. 
The first experiment was made on the 27th of August, 
1817, on a cat, which had been hanged the day before. A 
' small cylindrical tube of bone attached by gut to the end of 
the glass tube, A, D, was inserted into the windpipe, which 
had been prepared in the way described, and which was tied 
to the cylinder so tightly, that no air could pass between the 
external surface of the tube and the internal surface of the 
windpipe. An open and secure passage was thus established 
between the glass apparatus and the windpipe, and of course 
the lungs of the animal. Water was then poured into the 
apparatus at C, until it stood in the upright tube C B, at the 
height of eleven inches above the level of the water in the 
