19 
HYDATIDS WITHIN THE BRAIN AND SPINAL 
MARROW OF THE SHEEP. 
OF all animals the sheep is the most subject to verminous 
disorders, and at the same period of life when others have them, 
namely, during growth: it is between the first and second 
years that cerebral hydatids commonly manifest themselves, oc¬ 
casioning a giddiness or staggers, which, though a symptom 
of several other affections, is not always attended with the fatal 
result of which it is indicative in this disorder. 
This inevitably fatal termination has induced farmers, on the 
appearance of the malady, to sacrifice the sheep before they 
have lost their condition ; though in other cases every means 
have been tried to get at the hydatids, such as trepanning, per¬ 
forating the skull with a file, an awl, a hot iron, &c. Sheep 
previously destined, or at the time of their attack fit for the 
butcher, are wisely so disposed of: such only become subjects 
worthy of our endeavours to preserve as are kept for their wool, 
or as breeders, or on account of some peculiar estimation. 
Prior to the performance of any operation, the seat of the 
hydatid must be ascertained. Now, up to the present day, so 
vaguely has this point been determined that our directions are 
to wait until the hydatid by augmentation and extensive ra¬ 
vages has attenuated the skull so as to render it flexible under 
the finger. Some assert, and rightly enough, that the worm 
' will generally be found on that side of the brain towards which 
the animal staggers. But the information we want is that 
which will direct us to the precise spot to be operated on. And 
what renders this problem more embarrassing is the fact of hy¬ 
datids having been found not only within different parts of both 
the cerebrum and cerebellum, but even within the spinal mar¬ 
row. At least, such was the case of a Merino sheep, brought 
to us in July, 1827, on account of paralysis of the hind quar¬ 
ters, on w'hich M. Girard had intended to investigate the na¬ 
ture of another species of verminous disorder that had proved fa¬ 
tal to many of the same flock. Within the cerebrum was found 
an undeveloped hydatid, of the size of a nut, growing between 
the brain and the arachnoid membrane, over the corpus stria¬ 
tum, at the anterior extremity of the left hemisphere. 
/ The posterior third of the spinal marrow, inordinately in¬ 
creased in volume, completely filled the canal, all the way from 
the last dorsal vertebra but one to the sacro-vertebral articula- 
c 2 
