DIAGNOSIS OF POSITION OF CCENURUS CEREBRATES. 
131 
injuries are treated on general principles. In cases of necrosis, separa¬ 
tion of the periosteum or horns from underlying tissues or secretion of fluid 
products, free use of the' knife is called for. Every effort must be made 
to preserve the horns and to ensure the resulting cicatrix being as small 
as possible. If it is imperative that the animals continue at work, 
circumscribed injuries may be shielded by surrounding them with pads . 
and so relieving them of pressure. Extensive disease of the yoke bed 
necessitates either entire rest or the use of a collai. 
(7.) TREPHINING THE CRANIAL CAVITY IN SHEEP 
OR CATTLE, OR OPENING BY THE TROCHAR. 
The cysticercus form of the tape-worm of dogs (Taenia ccenurus) 
often develops in the brain of the sheep, and occasionally in that of 
cattle and other animals. It usually attains the size of a, duck s egg, 
and animals may die from the resulting disturbance. So-called gid 
or sturdy generally appears in the first or second year of the sheep s life, 
producing significant phenomena. No treatment short of operation is 
effectual. Picric acid and other chemicals, cauterisation, and refrigera¬ 
tion of the skull with ice, recently recommended in England, and usually 
requiring to be persisted with for three weeks, are of no avail. Tiephining 
or opening the skull with a trochar is the only satisfactory treatment. 
Even in the previous century this was attempted by laymen in a primitive 
way with the pocket-knife, but success could only be satisfactorily attained 
when proper instruments had been constructed. These consist of a 
small trephine about § of an inch in breadth, or of a special set of 
trochars, which have been perfected by Zehden. 
It is of primary importance to fix the position of the cysticercus. 
This is usually in the neighbourhood of the surface of one hemisphere 
of the brain. Sometimes it can be recognised by the softness and 
yielding of the bone on strong pressure. Percussion gives a dull, less 
loud sound over the affected spot, a symptom to which Yillborg directed 
attention last century. But these appearances are often entirely wanting, 
and the position of the parasite can only be conjectured from noting the 
peculiarities of the patient’s movements. 
(D Where the patient shows rotary movements, the cyst generally 
lies on the surface of one hemisphere, and on that side towards which 
the animal turns. Though this symptom, according to Holler’s experience 
is by far the most reliable, exceptions occur, especially where the cyst 
is large, and presses on the deeper-lying portions of the brain. 
(2) Twisting of the head towards the hind-quarters points to the cyst 
lying in the depth of the hemisphere of the same side, or in the base of 
the opposite ventricle. 
