762 INTUSSUSCEPTION OF THE SMALL INTESTINES. 
bowel being twisted upon itself, or from a knuckle of it 
having passed through a rent in the mesentery, or from the 
pedicle of a tumour being twisted around the gut, thereby 
producing a like result. Within the last few days two 
very remarkable cases of strangulated bowels have come 
under my notice, but in neither of them did the symptoms 
indicate, so far as I could judge, the precise nature of the 
disease. The direct cause of the strangulation was very 
unusual, each case being found to depend upon the mesentery 
being firmly twisted upon its own axis. 
Again; interruption to the free passage of the ingesta 
through the intestinal canal, which may be produced in 
various ways—as, for instance, by a calculus or calculi, or by 
impaction of hardened foecal matter—may produce similar 
symptoms. Spasm of the muscular coat of the bowels will 
also not unfrequently give rise to very nearly the same class 
of symptoms. The two affections, however, last alluded to, 
are, by the aid of therapeutic agents, somewhat under 
our control. Still it is not always that we can effect a 
cure, and in making a post-mortem examination of the 
animals which die, we not unfrequently discover, to our sur¬ 
prise, that the bowel is invaginated in one, or even more 
places. Intussusception may, and often does, happen during 
the struggles of the animal just previous to death, and it may 
even occur, I believe, immediately on death taking place. 
Indeed, I have seen one portion of intestine slip into another 
after the viscera had been removed from the abdomen; but 
of course the parts involved in any of the latter-named 
instances would not present the same pathological changes 
which are observed in those cases in which death actually 
depended upon the intussusception. This is so self-evident 
that it needs no comment; nevertheless, these facts should 
be borne in mind, or the cause of death may be attributed to 
such a circumstance, and the true one be entirely over¬ 
looked. 
The causes which give rise to intussusception are by no 
means well defined; indeed, they are at best only con¬ 
jectural. Irritating substances in the alimentary canal, or 
the existence of parasites, are believed to be exciting causes, 
and I think it not at all improbable that the presence of worms 
might have had much to do w T ith the invagination of the 
intestines of the puppies in question. 
In commenting on this lesion I may be permitted to 
digress from these particular cases, and make a few ob¬ 
servations on the immediate cause of intussusception, and 
explain why it usually proves fatal. To understand the 
