1883 .] 
AMERICAN AGRICULTURIST. 
363 
The Liver-Fluke and Prevention of the 
Rot in Sheep. 
The liver-rot. fluke, or “ bane ” lias been known 
among sheep, and its ravages dreaded, from early times. 
There have been many theories as to the nature of the 
..‘■y 
Fig. 1.— THE MATURE FLUKE. 
fatal disease ; but of late years it has been shown that 
it is due to a parasitic animal which inhabits the bile 
ducts of the sheep's liver. For the last two years re¬ 
searches into the natural history of the pest have been 
carried on by Prof. A. P. Thomas on behalf of the Royal 
Agricultural Society of England, and the completed in¬ 
vestigations are given in Part I. of the Journal of the 
Society for the present year. From this we condense 
the more important facts discovered and reproduce most 
of the engravings herewith given. 
The fluke, fig. 1, is a sucking worm somewhat re¬ 
sembling the common leech, of a flat, oval shape, pale 
brown or flesh-colored, and an inch to an inch and a 
third In length. Near the head is a sucker, y , by means 
of which the fluke attaches itself to the surface of the in¬ 
fested part. The mature fluke produces a large num¬ 
ber of eggs, which are 1-200th of an inch in length. In 
one case observed, 7,000,000 eggs were obtained from 
the gall-bladder of a single diseased sheep. Figure 2 
shows the fluke's egg, much magnified, as it comes from 
the sheep’s liver. It is an oval body, with a transparent 
shell, which allows the rounded masses of the contents 
being seen. The eggs are carried with the bile into the 
intestine, and at length are voided with the droppings 
of the animal. If they fall upon wet ground, or are 
washed by rains into pools or streams, other changes 
•occur. With the temperature at 75° to 80°, an embryo 
forms in about two weeks. Figure 3 shows an egg with 
the embryo fully formed, and fig. 4 represents the same 
when hatched, both highly magnified. The broader end is 
directed forward in swimming, and in its centre is a 
^peg-like projection which is used as a boring tool. 
When the embryo meets with any object, it feels 
screw, by means of the many hair-like paddles, cover¬ 
ing its surface. The objective point is the snail's lung, 
in which the embryo fluke soon develops farther at the 
expense of the juices of the host. The form of the 
body of the embryo soon changes to an oval shape, shown 
in fig. 0. This is distinguished as the first generation 
in the snail, and is termed the sporocyst , which means a 
bag of germs. These sporocysts grow rapidly, and de¬ 
velop offspring which are the second generation, and are 
called redia. Figure 7 shows a magnified mature sporo¬ 
cyst, containing a number of redia. The largest one at 
the lower end is well developed, and will soon force its 
way through the walls of the parent—the wound heal¬ 
ing up and the remaining germs continuing to grow. 
The redia are more active than the sporocysts and 
migrate from the lung to other organs of the snail. A. 
full grown redia is shown in fig. 8 ; it has a mouth and 
an intestine, and produces the third generation. The 
offspring of the redia are tadpole-shaped, and called the 
cercaiice. It is this third generation of the snail parasite 
that is destined to enter the sheep and produce the liver 
fluke. The cercarhe, one of which is shown in fig. 9, 
leave the snails, swim around for a time, and then be¬ 
come attached to and encysted upon grass stalks. 
These cysts remain dormant until picked up and swal¬ 
lowed by sheep feeding on the grass. The number of 
cercari* descended from a single fluke egg is not less 
than two hundred, and under the most favorable condi¬ 
tions, over a thousand. A single live fluke may, through 
the medium of the alternation of generations above de¬ 
scribed, give rise to more than a hundred million de¬ 
scendants within a single season. 
About six weeks elapse, from the swallowing of the 
tadpole animal, before the fluke becomes adult, and be¬ 
gins to produce eggs in the liver of the diseased sheep. 
It is seen that the fluke alternates between a particular 
snail and the sheep. The latter voids the eggs, and the 
developed embryos enter the snails, which, in turn, har¬ 
bor them through three distinct forms, the last attaching 
itself to herbage, conveys the infection to the sheep. 
Now that the life-history of the parasite is known, 
the conditions for its existence may be understood. 
Prof. Thomas’ summary is condensed as follows: For the 
production of liver-rot in sheep, there must be—1. Fluke 
eggs on the ground; 2. Wet ground or water during 
drugs. Sheep that are badly infested soon fall away in 
condition: the eyes lose their brightness, and become 
tallowy; the skin grows moist, and the wool loosens. 
As the disease advances, dropsy sets in, and soon after 
this, the animal dies in a state of rottenness. Sheep 
may live and thrive when only slightly infested with the 
Fig. 8. —YOUNG AND MATURE REDIA. 
fluke, if well fed and otherwise cared for ; but the shep¬ 
herd should be on his watch for the disease. If there 
is reason to think a flock is attacked, one of the most 
suspicious should be killed, and its liver examined for 
the flukes. If “rotted” sheep are kept, let them run 
Fig. 9.— A CERCARIA. 
warm weather; 3. The Snail, Limnceus truncatulus; 4. | 
Sheep to feed on the ground infested by the fluke. 
The eggs may be introduced in manure, in earth ad- I 
hering to the feet of animals, or by running water, 
especially floods. Rabbits and hares are often infested 
only on dry ground, that the eggs voided may not meet 
with the water necessary for their development. The 
manure from fluked animals should not be placed on 
wet ground, and the livers of all infested sheep ought 
to bo destroyed or deeply buried. The obvious remedy 
for wet land is thorough drainage. When not practica¬ 
ble to drain, salt or lime may be scattered on the sur¬ 
face, as these substances destroy the embryos, the cysts 
of the fluke, and also the host snails. Sheep feed¬ 
ing upon salt marshes are free from the disease. 
They should not be allowed to graze closely, as the ma¬ 
jority of the cysts are near the roots of the grass. Salt 
is a preventive when given to sheep, acting injuriously 
upon the swallowed fluke germs, and improving the 
general health of the animals. Dry food is much better 
than green for infested sheep. 
The annual loss of sheep from liver-rot in the United 
Kingdom is not less than 1,000,000 head, and an equal 
number die annually from the same cause in Central 
Europe. The “rot” occurs in most parts of the world. 
It is found in both our native and imported flocks, and 
many thousands of our sheep die every year without the 
owners having any knowledge of the cause. 
Fig. 2.— THE FLUKE EGG. Fig. 3.— EGG WITH EMBRYO. Fig. 4.— THE EMBRYO. Fig. 5.— SNAIL ENLARGED. 
about, and if not satisfied, darts off; but if the surface 
met is that of a certain kind of snail —Limnceus trunca¬ 
tulus (fig. 5), it begins at once to bore into it. The young 
fluke spins around on itself like the handle of a cork¬ 
with liver fluke, and may be a means of introducing it. 
The production of eggs is prevented by killing all sheep 
suffering from the disease. There is no cure for the 
fluke, as it inhabits an organ not easily reached by 
A White rsirin. —A property belonging to 
Lady Abingdon, of England, is thus called, in conse¬ 
quence of her eccentric fancy to have every animal on 
it of a white color. Horses, cows, sheep, swine, dogs, 
