348 
HELMINTHOLOGY. 
'furface of a bag or fac, which is firmly attached to the 
neighbouring parts, and covered with a firong outer 
coat. It is obvious that the progrefs of growth is very 
unequal in thofe two, and indeed inverted; for in the 
firft the young ones are as large as the heads ot pins, 
while the parent bag is not larger than a walnut, and 
floats unattached; but on the contrary, in the fecond 
there is a large fac with a ftrong cuter coat, and a more 
tender inner one, adhering itrongly to the furrounding 
parts, while the young ones, that are very ilightly at¬ 
tached to its.fides, are not of a larger diameter than a 
2^5 part of an inch. Whether thefe are merely acci¬ 
dental differences in the growth, or depend upon fome 
more effential diftin&ion, muff remain to be determined 
by future obfervations. However their growth and de¬ 
cay evidently explain the inc-reaf'e and diminution of tu- 
motirs in the abdomen containing them.” In the pre- 
fent cafe, Dr. Hunter thinks that their origin was pro¬ 
bably in the fpleen, and that one .of the bags there hav¬ 
ing burft, they fell by their own gravity into the pelvis, 
and there adhered and multiplied, till they deftroyed 
the life of the patient ; which probably might have 
been faved by giving them an outlet, or by the intro¬ 
duction of mercury. 
Since the difcovery of hydatids in the cellular fub- 
ftance, Dr. Adams lias endeavoured, with fome fuc- 
cefs, to (flow that cancer is owing to the introduction of 
an animal of this kind. If fo, its ftraCture muff form 
the fepta fo often defcribed in fuch maladies ; and the 
power of reproducing its parts will account for the ob- 
flinacy of the cure, and of the growing again, unlefs the 
whole fcirrhiis be clean cut out. Subfequent to this 
ftateinent by Dr. Adams, a cafe'has occurred of a can¬ 
cerous tefticle, which was extirpated in 1S01, and pub- 
1 ifired in the (ixtli volume-of the Medical Journal, p. 194. 
'1 his cancerous fubltance contained a hydatid, about 
the fize of a walnut, almoft furrounded by tranfparent 
fpherical veficular bodies, about the fize of fmall peafe, 
perfectly detached from the adjacent fubftance, and from 
each other; and were evidently young hydatids. 
In the Helminthology Plate II. at fig. z. are given, 
three views of the tcenia vifceralis, or vilceral hydatid : 
the firft fhows the animal with its head protruded, and 
the coronet of laciniae or retractile holders exferted ; thi 
fecond exhibits the hydatid in a quiefcent ftate, with its 
head drawn within the veflcle, broad on the forepart, 
and pointed behind ; the third is a longitudinal feCtion 
of the veflcle. 
Fig. 2, is a very beautiful reprefentation of the tcenia 
cersbralis kominis, as given in the pofthumous volume 
of Goeze’s Eingeweidewiirmer. It was extracted from 
the brain>of a young woman difieCted by profeffor Mec¬ 
kel of Halle. This patient had been afflicted with vio¬ 
lent head-ach, vertigo, and confequent derangement, in 
.which condition (lie died, after baffling every kind of me¬ 
dical aid. The veflcle was about the fize of a walnut, 
and on tiiat fide attached to the brain there appeared to 
tie about fif ty young hydatids'w ith their mouths and laci¬ 
niae or hooks protruded through the membranaceous coat 
of the parent veflcle, and fromtwhich many of them had: 
the facility of withdrawing themfelves interiorly.- May 
not this curious circnmfiance ferve to throw fome light 
upon the phenomenon of ruptured onclgcayed hydatids, 
as noticed above, diicovered by Mr. j. Hunter ? May it 
not, with great probability, be inferred, that thefe mi¬ 
nute hydatids, at a.certain period of their growth, pierce 
the delicate veflcle - of the p.aren/t, which becomes dead 
matter in order to forward the efcape of its young ? 
Thefe young are harcely larger than a mufturd feed, 
yet are furnifhed with a (cries of hooks, by which they 
firmly attach thepift Ives to the fubftance-of the brain. 
In the figure, thefe hooks are (flown magnified, juft as 
they appeared through the co.at of the large hydatid.; at 
the lower extremity of w ivieh a young one is growing out. 
At a , is fhown one of the young taken out of. the parent. 
bag; and at b, two others, Thefe have been known to 
grow in a mafs to the fize of a clenched fill, until the 
fubftance of the brain has been quite abforbed, and the 
patient faid to have died, (in common language,) "of a 
“ water-bladder, formed upon the.brain.” 
Fig. 3, exhibits the tcenia cerebralis ovinis, a hydatid 
of nearly the fame frze with the preceding, and with 
duffers of its young ; which prey upon the brain of 
flieep, and occafion the difeafe call d Jlaggevs, duns, or 
rickets. In this fpecies, there is a double row of pi ickles 
or hooks, amounting to from thirty-two to thirty-fix ; 
but in the hominis there is only a (ingle row. 
Fig. 4, repreients two of the tcenia ovilla ,. exactly as 
they were found in the omentum ot a.-fheep, diffeCted by 
M. Goeze. Fig. 5, the tcenia granulofa , found in the 
liver of fheep, and occafions the rot, the iame as the faf- 
ciola hepatica, or-gourd-worm. Thef e hydatids are from 
the fize of a nut to that a hen’s egg, containing each 
many thoulands of animalcules fwnnuring in the fluid 
with which it is filled, and are fcarcely vifible to the 
naked eye. A mafs of thefe animalcules is figured at c. 
Fig. 6, fhows the head of this hydatid, as it appears 
under the microfcope. 
Fig- 7* L the tcenia globofa, or large hydatid, from 
the fize of a pigeon’s egg to that of an orange, found in 
the abdomen of dropfical people. Fig. 8, the tcenia 
apri, or hydatid found in the liver of the boar, juft as 
it appeared in.a diflecStion made by M. Goeze. Fig. 9, 
tli c tcenia vervecina, a hydatid found in the peritoneum 
of fat fheep. Fig. 10, a duller of hydatids, (tcenia 
pififormis,) found on the liver of a hare, differed by 
Goeze. At d, one of thefe hydatids is fhown detached. 
Fig. 11, 12, and 13, exhibit the hydatids, (tcenia mu- 
rina,) found in the rat, moufe, and dormoufe: thefe are', 
generally about the fize of a pea, but fometiines as large 
as a hazle nut.—For more on the fubject of Hydatids, fee 
the article T.*nia, and the correfpondent engravings. 
Of the TRICHOCEPHALUS, SCOLEX, and 
other INTESTINAL WORMS. 
The trichocephalus rs an elaftic worm, poflefling the 
fame kind of motion as the afcarides j.and is nearly of 
the fame colour. See the article Ascaris, vol. ii. 
p.252. Its body is round, and curioufly twifted ; the 
head or forepart is much the thickeft, and is furnifhed 
with a (lender exfertile probofcis, which the animal has 
the power of thrufting out and drawing in at pleafure. 
About two-thirds of this worm confifts of its tail, which 
is capillary, and tapering to a fine point; on which ac¬ 
count the French call it le vtr a queue. The fpecies 
called trichocephalus hominis, (the trichuris vulgaris of 
Dr. Hooper,) inhabits.the inteftines of th.e human race ; 
but is not often found amongft the people of England. 
In Germany it is very common; and, according to 
Blumenbacli, oppreffes lickly children with their num¬ 
bers, occupying the inteffinum rectum, the inferior part 
of the ileum, and alfo the jejunum. They are ufually 
about two inches long; but that delineated in the an¬ 
nexed Engraving, at fig. 21, as given by M. Goeze, is 
very confideraLly magnified, in order to (flow its cre- 
nated conformation, probolcis, &c. The ftomach and 
inteftines confift of a long greenifh canal, which is con¬ 
tinued in a ftraigju tube from head to tail, where it ter¬ 
minates in the anus. The convoluted or zigzag vifcus 
is the ovarium, found to contain a limpid fluid, the 
accompaniment of the ovula. Befides the hominis , there 
are- five other fpecies of this worm,-found in the intef¬ 
tines of the horfe, boar, fox, moufe,-and lizard; for 
which fee the article Trichocephalus. 
There appears to be only one more worm, at prefent 
known, that inhabits the human inteftines; though there 
are a great variety of others found in the inferior ani¬ 
mals. I l:is ;s tlie Fajciola hepatica, the well-know.ri gourd- 
worm or fluke, found in rotten flieep. See the article 
Fasciola, vol. vii. p, 267. It is ailo found in the de- 
2 . cayed 
