834 SCOTTISH METROPOLITAN VETERINARY MEDICAL SOCIETY. 
troduced manually, or by the animal voluntarily drinking water, into 
the stomach or intestines are imprisoned. Eventually gas is evolved, 
the stomach and intestine are distended to the utmost; the gas, by its 
own diffusive properties, passes into the oesophagus, anti-peristalsis takes 
place, and forces the fluid also into the oesophagus, thus producing the 
regurgitation and borborygmal sounds already alluded to. ^ Death in 
these cases is produced purely by exhaustion and by interference with 
the normal functions of organs. 
The cause of death in these three special forms of colic torsion and 
displacement is that which I have assigned; but, while saying this, I 
must call your attention to a recent translation, by Mr. Steele, of some 
remarks made by M. Bouley, to the effect that death is produced by 
putrid infection, i. e. absorption of the products of putrefaction from the 
alimentary canal. I cannot agree with the statement, as I think it is 
highly impossible that such absorption could take place with the intes¬ 
tinal parietes in the condition I have described, and the symptoms accord 
with the conditions I have pointed out. 
Now, as to the use of the trocar and canula in tympany, I have 
adopted this method of giving relief to horses for the past seven years, 
sometimes affording immediate and permanent relief at the first in¬ 
troduction of the canula, at others failing to obtain the slightest benefit, 
though introducing the canula a dozen times in different parts of the 
abdomen—wherever, in fact, it has appeared to me that the greatest 
amount of gas was imprisoned. The conclusion is natural that relief 
will be most certainly and rapidly afforded in those cases in which the 
tympany is circumscribed and due to decomposition of food, in which 
condition the gas passes freely through the canula without blocking it 
up, whereas in fermentation, with the ingesta, fluids, and gas forming a 
seething mass, the canula is completely blocked, and the quantity of gas 
liberated is comparatively small. 
In my early experiments in this operation I found that very frequently 
I entirely failed to relieve my patient, and discovered that, in some 
cases at least, my canula was too short. For the past five years I have 
employed a large curved trocar and canula, of about a quarter inch in 
diameter and seven inches long, the advantages of which are—1st, that 
owing to the curve the open extremity does not pass into the ingesta 
and become blocked, but, by remaining in the upper part of the intes¬ 
tinal tube, it allows the free exit of the gas; 2nd, it is not so liable to 
become displaced by the peristalsis of the intestine and the movements of 
the animal. 
In introducing the trocar and canula when the animal is on his back 
or side it must be borne in mind that the relative positions of the injesta 
and the gas are altered, the former gravitating to the lower part of the 
intestinal cavity, the latter ascending to its upper; due allowance must 
also be made for the thick layer of abdominal fat, which is always present 
in fat animals. 
The removal of the hair and the making of a small incision in the skin 
facilitate the introduction of the trocar, but in making this incision 
an unlooked-for accident may happen, viz. the infliction of a large 
wound by the sudden contraction of the muscles at the moment the 
lancet is introduced; hence the necessity of gathering up a small fold 
of skin, where practicable, between the finger and thumb, before making 
the incision. 
The canula may, if it is thought advisable, be left in situ for several 
hours with impunity; but if any sign of displacement is observed it 
should be withdrawn, as its free extremity would produce considerable 
