462 
HYDATID IN THE BRAIN OF SHEEP. 
worms, but at the present time it is considered as nothing 
more than the larva of the taenia serrata . It is met with in the 
brain of the sheep, ox, and pig ; sometimes, also, in that of 
the horse, and the human subject. Its presence produces 
the disease known by the term vertigo. In making investi- 
gations upon the mode of the development of this entozoon, 
MM. Kiichenmeister and Haubner have thrown much light 
upon the etiology of one of the most interesting and serious 
diseases. The experiments which they instituted at the 
veterinary school of Dresden, have, at their request, been 
repeated at Giessen, Berlin, Vienna, and several other towns 
in Germany, and everywhere they have been these experi- 
ments have been attended with the same result. 
By causing sheep to eat the fecundated or terminal seg- 
ments of the taenia serrata , these animals at the end of one or 
two weeks have presented symptoms of cerebral congestion, 
and which has quickly terminated fatally in many instances 
by inducing encephalitis. On the contrary, if the animals 
pass through this congestive stage of disease, then there takes 
place the formation of an hydatid in the cavity of the skull, 
and soon afterwards the symptoms of vertigo will be 
observed. 
On making a post-mortem examination of these subjects of 
experiment, vesicles, varying both in number and size, are 
found in the cranial cavity. These vesicles, or young hydatids, 
which may either occupy the surface or the substance of the 
brain itself, are always found near to a blood-vessel. They 
are at first surrounded with exudated matter, and are always 
found at the extremity of a more or less tortuous and minute 
canal. This perhaps is the road or passage which the 
hydatid followed before becoming fixed. Similar vesicles are 
also found in the tissues of the liver, diaphragm, heart, lungs, 
muscles, &c. These, however, are met with in a desiccated 
state, and often enclosed in a capsular envelope, the hydatid 
embryos having died from not being situated in the nervous 
centres ; the only part of the body, at least in the sheep, 
where they can fully develope themselves. 
MM. Roll and Giirlt have found that the tapeworms 
which have been passed from the intestines of the dog for 
some days have been better, and more generally developed 
into hydatids, than taenia which are fresh. The former of 
these veterinary surgeons has even allowed them to become 
putrid, when covered with mould, and has thus obtained 
more complete and speedy results. 
How is it (ask the editors of the Lyons Journal) that these 
entozoons, on being expelled from the intestinal tube, are 
