138 
The Rot in Sheep. 
with their number, r/c, that on the death of the animal, whose 
body they inhabited, taking place, they leave their original loca- 
tion, as if making an effort to escape from their own consequent 
death. Many of the intestinal worms, the ascares lumhricoides, the 
tcenicc, tricliocephali, &c., comport themselves in this manner ; and 
in so doing they often form large masses or knots in a part of the 
intestinal canal foreign to their ordinary dwelling. The lumbricoid 
worms have been known, under such circumstances, to enter the 
stomach, and even to pass up the oesophagus into the mouth to 
effect their escape. We have occasionally found them crowded into 
the duodenum so as to literally block it up throughout the greater 
portion of its length, being arrested in their effort to enter the 
stomach ; two remarkable specimens of which are preserved in 
the Museum of the Royal Veterinary College, one from the horse 
and the other from the pig. 
Sliould the same thing take place with regard to flukes, a search 
for them in the intestinal canal will prove successful. That their 
number, however, is often very large within the biliary ducts, we 
have daily proof; and it is said that Leeuwenhoeck took no 
less than " 870 out of one liver, exclusive of those that were 
cut to pieces or destroyed in opening the various ducts." * 
Tracing the smaller ducts onwards, exit is ^given to a dark- 
brown and thickish fluid, among which are masses varying in size 
from the head of a pin to a pea, or occasionally larger — collections 
of the ova of the distomata held together by the mucus of the 
ducts and inspissated bile. A drop of the fluid, or a minute 
portion of one of these masses, placed under the microscope, 
reveals the fact that in the small ducts, especially, the ova are 
to be met with in countless myriads. We obtain evidence also 
of another very instructive circumstance, to which attention 
has been previously directed, by simply putting a little of 
the matter upon the edge of a plate or slip of glass and lightly 
pressing it with the point of a scalpel — namely, that the 
ova have remarkably hardened shells or cases, which doubtless 
enables them, when out of the body of the sheep, to long retain 
their vitality by resisting all ordinary causes of decomposition. 
We feel them as so much gritty matter, and we hear them crack- 
ing under the pressure of the knife. 
The gall-bladder itself is not much altered in structure, nor 
does it in general contain many distomata ; but the bile within 
it is mixed with a considerable quantity of mucus, and its 
colour is altered from that of the greenish-yellow which normally 
belongs to it. Ova are also met with here, but in scanty quan- 
tities compared to the biliary ducts. 
* Youatt on Sheep, p. 449. 
