ON HYDATIDS IN THE SHEEP. 
527 
myrrh has been used. An injection, composed of unknown in¬ 
gredients, was sold at a great price in France ; but it was soon 
found that inflammation was the almost inevitable result ot this 
practice, and that death speedily succeeded. 
^ Comparison between the Operations .—The operation by the 
trephine has usually been an unsuccessful one, and more so on 
the continent than in our country. It has been imagined, that 
two out of five may, at the most, have been saved by this ope¬ 
ration, conducted by a skilful practitioner. But he had mucu 
to contend with: the enormous vacuum in the cranium suddenly 
formed by the removal of the hydatid, and the cerebial dis m ' 
ance which must be the necessary result of this;—the rush ot 
blood which would follow when the vessels, relieved from the 
compression of the brain, were rapidly dilatedthe admission 
of the atmospheric air into such a cavity, and the irritation it 
must inevitably occasionthe previous impairment ot nervous 
power, both animal and organic, by the destruction ot so great 
a portion of the cerebral substance, and the almost total suspen¬ 
sion of the most important of the nervous functions. I here is 
somethino-, then, quite as formidable in the concomitants ot the 
operation” with the trephine as in that of the wire as practises 
by Mr. Ho°-°-; and there might be thought to be this advantage 
on the side of the latter, that the fluid is more slowly evacuated— 
drop by drop—and that the surrounding parts have a somevyhat 
better chance of adapting themselves to the change, while theie 
is not so free an opening for the atmospheric air. 
Both deferred too late. —The efficacy of both operations is pro¬ 
bably diminished, and that to a very material degree, by their 
beini>' employed at too advanced a period of the disease. When 
the skull begins to soften, sad ravages must have been com¬ 
mitted in the cranial cavity. Before the solid roor will yield, a 
considerable portion of the brain must have disappeared, and 
the chance of saving the animal will have very materially dimi¬ 
nished. It is not necessary to wait so long in order to ascertain 
the existence of the hydatid, for the separation of the sheep from 
its fellows, its peculiar gait and manner, and the evident impair¬ 
ment of intellect, will plainly mark him out as a sturdy ; and then, 
if he is carefully watched, it will soon be seen on which side his 
head seems to incline; and on that side the hydatid is lodged. 
It probably will not then have attained any great size. Father 
operation may then be resorted to with far bettci piobabihty o 
success. I should prefer the trephine—comparatively little 
danger attends the application of it, if the brain is not previously 
too 'much disorganized ; and the examination of the heads 01 
several sturdies tells me, that the residence ol the hydatid is 
