153
This vesicle is enclosed in a cyst which belongs directly to the host and is
formed of connective tissue, muscular fibre and blood vessels, its dimensions
vary from that of a pea to that of a man's head, it is filled with a serous liquid
which is transparent and does not contain albumen.
The scolices of young tapeworms are formed from the proligerous of vesicles
originating from the germinal membrane. Each vesicle may contain as many
as 1,000. The liver attacked becomes enlarged, its volume may increase 5 or
even 10 fold. It presents an irregular surface, the salient parts of which cor-
respond with the echinococcus. More than 1,000 have been found in a single
liver. Perroncito found a liver weighing 158 lbs. the normal being about 10.
The serous membrane which covers the organ is often thickened and may
be adherent to the neighbouring organs. On section the liver is found to
contain a number of caverns between which the parenchyma remains in the
shape of islands. When the echinococei die their contents are transformed
into a yellow fatty pasty material which sometimes seems to be composed
exclusively of lime; pus may be found in it. In the lungs the echinococci are
of a size varying from that of a pea to that of a man's fist; the surface of
lobes is uneven. When the hydatids die the cysts become filled with a
detritus which gives them a caseous tuberculous aspect. In most cases when
the heart is invaded there is but one vesicle which is generally found at the
inferior extremity of the median septum near the apex.
In the bones mainly at the lower maxilla the echinococcus sometimes
produces tumors, they have been found also in the femur and tibia.
Symptoms.—The symptoms caused by the echinococcus naturally vary
with the organs affected, but they have nothing characteristic about them.
When these echinococci are few in the liver and lungs there are seldom
any symptoms of disease shown, and we often notice on post-mortem exami-
nation that the liver is considerably increased in volume without any func-
tional disturbances having been caused. When any symptoms are produced
by the hepatic echinoccoccus they are digestive troubles and progressive
emaciation. The rupture to superficial cysts sometimes leads to peritonitis
owing to the fluid escaping into that sac.
Pulmonary echinococcus resembles tuberculosis in its symptoms; the
animal falls away, the skin sticks to the bone and respiration may be inter-
fered with. When the echinococci exist in great numbers in both lungs
we get difficulty in breathing, and an abrupt inspiration with a weak hard
cough. On percussion we find a dull tympanitic sound. On ausculation we
find that the vesicular sound has disappeared from the parts where the
changes of resonance are found. Pain is evinced on pressure over the back ribs.
If one percusses the chest with the closed fist a peculiar fremitus or vibration
will be perceived by the other hand spread out on the chest wall. It is really
time some attempt be made to limit the ravages of this disease by prophylactic
measures at least in our own slaughter-houses. All organs which are attack-
ed by this parasite should be destroyed. They should on no account be
given to dogs as this is the way the disease progresses naturally. Useless
stray dogs should be made away with.
Oesophogotma columbianum causing nodular disease of the intestines
of the sheep.
555. Although the sheep is an animal of very secondary importance to us
in this country still I think it is of interest to note the occurrence of parasites
in it in order that their geographical distribution may be known, hence
I describe the occurrence of an interesting worm in the sheep in this
country which is also common in America where it has been investigated.
The parasite has been fully described by the American Department of
Animal Industry by Cooper Curtice.
It has been found to be very common in the sheep seen in the districts
visited during my tour this year and most probably a brief notice of it
39