THE DIAPHRAGM, &C. 615 
When Mr. Castley saw him, “his breathing and attitude indi¬ 
cated the greatest distress. The prominent symptom, however, 
was a convulsive motion or jerking of the whole body, accom¬ 
panied by a dull thumping noise, audible at several yards dis¬ 
tance, and evidently proceeding from his inside. The beats 
appeared to be about forty a minute. On my placing my hand 
over the heart, the action of that organ could be felt, but very 
indistinctly ; the beating evidently came from behind the Ireart, 
and was most plainly to be felt in the direction of the diaphragm. 
Again, placing my hand upon the abdominal muscles, the jerks 
appeared to come from before backward: the impression on my 
mind, therefore, was, that it was a spasmodic affection of the 
diaphragm, brought on by violent distress of breathing.” Mr. 
Castley pursued a very judicious mode of treatment. He ad¬ 
ministered stimulants. He refrained from bleeding until the 
horse began to rally, and the animal did well. 
Caution. —This case, gentlemen, deserves to be treasured in 
your memories, not only as an illustration of the connexion be¬ 
tween comparative anatomy and comparative disease, but as a 
most useful guide against an error that may be fatal to your 
patient. Had he mistaken this “audible thumping” for carditis, 
he would have bled copiously at the first, and nature would have 
sunk. 
Use of the Appendices. —The use of the appendices will now 
be evident. They are placed under the loins ; at a part at which 
there will be considerable motion, when the animal is in rapid 
progression, and more especially if he is carrying weight. The 
alternate rising or falling of this portion of the spinal column 
would, if the diaphragm were continued straight around, inter¬ 
fere very materially with its action. It would often tighten the 
diaphragm when we wanted it relaxed, and relax it when we 
wanted to have it to press with considerable and uniform force 
against the abdominal viscera. It would cause uncertainty and 
confusion in the action of this muscle. Now these appendices, 
inserted so much farther back, and going to join the diaphragm 
with the obliquity that we here observe, will act as springs beau¬ 
tifully and efficiently. The spinal column may rise and fall, but 
comparatively little of that motion will reach the diaphragm; it 
will be neutralized or spent as it is communicated along the 
fleshy columns which proceed for awhile almost parallel with, 
but separate from, the spine. We shall see another use of them 
presently. 
7 he Openings through the Diaphragm. —There are three. 
Superiorly you will perceive that through which the posterior 
aorta passes into the abdomen, and observing it in the space be- 
