368 CONTRIBUTIONS TO COMPARATIVE PATHOLOGY. 
After the first operation, the mare had for a time improved 
remarkably fast in fat and general appearance; but from the 
obstruction to breathing so frequently taking place from the 
ejection of the pipe, although every means were taken to prevent 
it, she had become much reduced, and nearly suffocated. Very 
soon, however, after this third dilatation, she ate and drank, and 
was as comfortable as before she met with the accident. 
19M.—The pipe having been again forcibly and very fre¬ 
quently ejected, and the parts immediately collapsing, adhesions 
between the divided surfaces had taken place. It having been 
seen to what extent the operation was likely to succeed, the mare 
was destroyed. 
The trachea was thickened where the pipe was inserted, and 
the structure of the cartilage much softened. The lungs were of 
a lighter colour than usual, and a small quantity of air was extra- 
vasated under the pleura. 
A very remarkable circumstance is the easy manner in which 
the introduction of so large a pipe into the trachea was borne, 
so long as a free passage, sufficiently large, was kept open. 
Although the orifice was nearly opposite to the point of the 
sternum, breathing went on with as much freedom and apparent 
ease as in the most healthy and perfect state. The lining of the 
trachea scarcely shewed common irritability; and it was only 
when blood flowed into the lungs that coughing was induced.' 
The relief produced by the operation was immediate, and for a 
time perfect; and the final failure arose from the accumulation of 
pus and mucus in the pipe (which precluded the possibility of 
its remaining permanently in the trachea), the strong disposition 
in the parts to collapse, and the rapid manner in which the new 
substance was formed. Whether these circumstances can be 
overcome by ingenuity and surgical treatment remains to be 
shewn : they are, however, formidable impediments in the way 
of a succesful termination to extensive openings of the trachea. 
The Farrier and Naturalist, vol. ii, p. 226. 
