20 
HYDATIDS WITHIN THE BRAIN AND 
tion. No sooner was the vertebral theca of the tumid part slit 
open than out sprang an ovoid vesicle, which, dilatation of the 
opening showed to belong to a larger cerebral hydatid lodged 
within the middle of the posterior part of the spinal marrow, 
separating its two component chords; so much so that when 
stripped of their membranous envelopes they were perfectly 
disunited. The parietes of the cavity excavated by the hydatid, 
were covered with yellow spots, looking like adhesions sticking 
to the folds of the arachnoid where it divides the two spinal 
chords. 
Although this occurrence stands as yet unparalleled in the 
annals of veterinary medicine, we do not believe that the pre¬ 
sence of hydatids within the spinal marrow can be so rare as 
might be imagined : in truth, so seldom is the marrow examined 
that its diseases are perfectly novel to us. The case puts us 
in possession at least of two facts : vi%, that hydatids are not 
confined to the brain ; and that, notwithstanding their presence 
within the cerebrum or cerebellum may be indicated, we have 
no guide to direct us to the place where we ought to operate. 
Before we can arrive at a certain diagnosis we must learn to 
distinguish the symptoms arising from the lesion of any particu¬ 
lar part of the brain by the worm. Such observations might prove 
curious in relation to physiology, at the same time that they 
afforded a prospect of success to the operation, and particularly 
when undertaken before the brain had sustained much injury : 
for, such are the ravages already made in most of these cases 
that the number of animals that die after the operation greatly 
surpass probably the number of recoveries : at least, the num¬ 
ber and variety of operations that have been proposed, without 
any one of them coming into general adoption, and the paucity 
of recorded cures, taking no notice of the number and nature of 
-the complicated and more fatal forms of the disease, lead me to 
this conclusion. An instance of complication occurred in a 
sheep, belonging to the flock of the Institution, which had pined 
away to a weight of not more than from 25 to BOlbs.' Two at¬ 
tenuated flexiWe points having, after frequent examination of 
the head, been detected, one on the right, the other on the left 
side, I perforated them with the actual cautery, making two 
holes about the size of pins’ heads, through, which issued a 
little drop of serum : the perforated places were afterwards co¬ 
vered with Burgundy pitch plasters. For seven or eight days 
after the operation, the animal ate little or nothing, continued 
to turn round from right to left as before, and manifested consi¬ 
derable vertigo and uneasiness. On the eighth day both plasters 
had become displaced : that on the left side however was only 
