519 
ON HYDATIDS IN THE SHEEP. 
The cranium of the horse is so securely defended by the 
yielding resistance of the temporal muscle, that fracture rarely 
occurs, except at the occipital ridge ; and the depression of 
bone is there so considerable, as to produce complete coma, and 
bid defiance to all surgical skill. 
Hydatids in the Brain.—Symptoms.— One of our patients 
affords us too frequent instances of the effect of chronic com¬ 
pression of the cerebral substance. After a severe winter, and 
a cold and wet spring, many of the yearling lambs, and parti¬ 
cularly those that are weakly, exhibit very peculiar symptoms of 
disease. The malady usually appears during the first year of 
the animal’s life, and when it is about or under six months old ; 
it is far less frequent during the second year, and, after that, the 
sheep seem to have acquired an immunity against the attack of 
the hydatid. The symptoms are as follow : the sheep cease 
to gambol with their companions; they are dull; they scarcely 
graze; thev ruminate in the most languid and listlessmannei ; 
they separate themselves from the rest of the flock ; they walk in 
a peculiar, staggering, vacillating manner ; they lose themselves ; 
or, seeking out some ditch or brook, they stand poring over the 
ruffled or flowing water. They stand there until they appear to 
be overcome with vertigo, and often tumble in. In the midst of 
their grazing they suddenly stop, look around frightened, and 
start away and gallop over the field. They begin to lose flesh, 
and the countenance is haggard, and the eye wandering, and of 
a curious blueish colour. The last circumstance, although not 
observed so carefully as it ought to be, is perfectly characteristic 
of the disease, and a clever shepherd would select every stur- 
died sheep from the flock by the colour of the eyes. 
Decided Affection of the Brain.— This evident cerebral affection 
increases. The animals begin to carry the head on one side, 
and always on the same side. It is with difficulty that they can 
straighten the neck in order to graze, and then there is a pecu¬ 
liar undecided motion in the act of grazing. Their fits of wander¬ 
ing become more frequent; they are oftener frightened without 
apparent cause ; they take increasing pleasure in poring over 
the rippling brook; there is something in the playing of the 
light on the water, or in the murmuring sound, which has a 
lulling influence over them, and they often forget themselves 
and topple in and are drowned. 
Peculiar Rotatory Motion— By-and-by they commence, and 
even while grazing, a rotatory motion, and always in one way, 
and with the head turned on the same side. Then they almost 
cease to eat or to ruminate, partly because the disease, from its 
debilitating character, destroys the appetite altogether,^ and 
more perhaps because they are rapidly becoming blind. They 
