34.3 
HELMINTHOLOGY 
compatible with the ordinations of Providence, to be¬ 
lieve, that all inteftinal worms have their origin or'germ 
formed in the foetus of every animal which produces 
them ; that their office in the inteftines mull be primari¬ 
ly to ferve fome wife and benevolent purpofes affigned 
to them by the Creator, although the difcriminating 
powers of man have not hitherto been able to penetrate 
them ; that their habitation in the body is never injuri¬ 
ous, but when other caufes predifpofe to their exceffive 
multiplication, fueh as morbid affections in the vifcera 
and parts adjacent, or the accumulation of putrefcent 
mucus in the bowels, cedemafous tumours, &c. a ten¬ 
dency to all which lies in the-conftitution, or in the in¬ 
fluence of different epidemical complaints, rather than 
in the effefl of worms; fi.nce very many people live to 
the grand climacteric, and even beyond it, and are ac¬ 
companied with worms to the very laft.” In fupport 
of this dodtrine of Goeze, it may not be improper to 
notice, that Dr. Heberden found worms in the inteftines 
of an infant born dead. 
The immortal naturalift, fir Charles Linnaeus, availed 
himfelf of all the difcoveries of his cotemporary la¬ 
bourers in this field of fcience, in order to form that ad¬ 
mirable compendium of the ftupendous works of the 
Creator, known by the title of Syjlema Natures-, but to 
which, tince that great man funk into the grave in the 
year 1778, prodigious numbers of newly-difcovered in¬ 
teftinal worms have been added, by the well-known edi¬ 
tor of the late editions of that excellent work, Dr. I. 
Frederic Ginelin, of Gottingen. But of all the animals 
of this clafs now brought within the fphere of our know¬ 
ledge, none are found to be fitch general inhabitants of 
the human race, as 
The ASCARIDES. 
Thefe generally exift in the greateft numbers in 
children ; whenceit has beeninferred, that by theirceafe- 
lefs irritating aCtioa upon the interior membranes, they 
promote the periftaltic motion of the inteftines, by which 
the'excrements are preffed down and excluded, and the 
paffages of the body kept open ; which is fo effential to 
its healthful ftate. Their proper nidus, according to 
Dr. Heberden, is in the mucus or flime deftined to lu¬ 
bricate the bowels; which flime, he thinks, ferves them 
for food. He further obferves, that it is this mucus 
which preferves them unhurt, though furrounded with 
many other liquors, the touch of which would be fatal. 
It is hard to fatisfy ourfelves by what inftindt they find 
it out in the human body, or by what means they get at 
it; but it is obfervable in many other parts of nature, 
as well as in this, that, where there is a fit foil for the 
hatching and growth of animals and vegetables, nature 
has taken fufficient care that their feeds fhould find the 
way thither. If the afearides are taken out of their 
mucus, and expofed to the open air, they become mo- 
tionlefs, and die in a very fhort time ; but in general 
they are fo well defended'by the mucus from the imme¬ 
diate adtion of whatever paffes the inteftines, that they 
are rarely incommoded in their nidus, unlefs they exift 
in great numbers. From thefe obfervations'of Dr. He¬ 
berden, we may eafily perceive why it is fo difficult to 
deftroy thefe animals ; and why anthelmintics, though 
greatly celebrated, are far from always being fpecifics. 
As the worms which refide in the cavities of the body 
are never expofed to the air, by which all other living 
creatures are invigorated, it is evident, that in them- 
felves they nnift be the moll tender and eafily deftrudti- 
ble creatures imaginable, and much lefs will be requi- 
fite to kill them than any commoninfedt. “Yet, (fays 
Dr. Heberden,) by beingimmerfed in flime, thefe worms 
are the moft difficult to kill of any, and are yet the leaft 
dangerous of all. They have been known to accom¬ 
pany a perfon through the whole of a long life, without 
any reafon to fufpedt that they had haftened its end ; 
and as in this man’s cafe there was no remarkable indi- 
geftion, giddinefs, pain of the ftomach, nor itching of 
of the nofe, the ufual prognoftics of worms, poffibly 
thefe fymptoms, where they have happened to be joined 
with the afearides, did not properly belong to them, 
but arofe from fome other caufes. There is indeed no 
one fign of thefe worms, but what in fome patients will 
be wanting.” 
In the human body, only two fpecies of afearides have 
as yet been found, viz. the vcrmicularis, or fmall kind ; 
and the lumbricoides , generally about a fpan in length, 
but fometimes a foot, or more. “This long round 
worm of the human inteftines, (fays Dr. Hooper,) has, 
for many centuries, been confidered of the fame fpecies 
as the earth or lob-worm ; the fallacy of which I have 
therefore thought proper to demonftrate. The lumbri-. 
cus terreftris, or earth-worm, has but one veficle at its 
head, in the middle of which is its mouth ; it is flatten¬ 
ed towards the tail, and is fiirnifhed with fliarp briftles 
on its under furface, that ferve it for feet, which the 
animal can eredt or deprefs at pleafure ; its annular 
mufcles are very large and ftrongly marked, and its co¬ 
lour is a dulky red. Whereas the afearis lumbricoides 
has none of, thefe phenomena. Its colour is a pale yel¬ 
low ; its mufcles very delicate, and its head is furnifhed 
with three vejicles inftead of one. Upon the under furface 
of the earth-worm there is a large femilunar fold in the 
Ikin, into which the animal can draw its head, or thruft: 
it out at will; but there is no fuch form in the afearis 
lumbricoides ; the former alfo has an elevated belt in 
its middle, but in the latter there is a depreffed band. 
On each fide of the afearis lumbricoides there is a lon¬ 
gitudinal line very diftindtly marked; on the earth¬ 
worm there are three lines upon its upper furface. 
“ With refpedVto the other fpecies, afearis vermicularis , 
this is not, as is the generally-received opinion, herma¬ 
phrodite ; but the male and female are diftindt worms. 
The male, when expofed to the magnifying power, does 
not exhibit any of the gyrated apparatus, which, in the 
female, is decidedly for the purpofe of bringing the 
young to perfection. The ftomach and inteftinal canal 
have, apparently, a different arrangement from thofe of 
the female, and are the only vifcera I have been able.to 
detedt. I have fearched for the male organs of gene¬ 
ration, but have never been fortunate enough to find 
them. Perhaps they are fo very minute as to elude our 
refearches. The female has, upon its external furface, 
about the eighth of an inch from the head, a fmall • 
pundtiform aperture through which the young are pro¬ 
truded. When the worm is very much magnified, its 
internal cavity appears filled with the convoluted appa¬ 
ratus ; and I have feen upwards of a hundred of the 
young efcape through the external aperture, all alive, 
and very vivacious, feveral hours after the death of the 
mother, upon making a flight preffure with the finger.” 
So widely diffufed are the worms of this genus, that 
befides the two deferibed above as proper to man, no 
lefs than feventy-eight other fpecies have been afeer- 
tained, as proper to the inteftines of different animals ; 
for particulars of which fee the article Ascaris, yol. iij. 
p. 251, and the correfpondent Engraving, whereon fif¬ 
teen of the-mqft curious and interefting fpecies* are cor- 
redtly delineated. 
The TAENIA, or TAPEWORM. 
This genus is confeffedly the moft furprifing of all 
the worm tribe, and demands the ftridteft ferutiny of 
phyfiologifts and phyficians. They are extremely tena¬ 
cious of life, and very difficult fo remove ; and when ■ 
broken, have the power of reproducing the part. They 
appear to inhabit the inteftines of moft of the animals 
which have hitherto been dilledteu for the purpofe of 
detecting them ; in all of which they are perfectly ana¬ 
logous to thofe found in the human fubjeCT, though all 
differing in their ftrudture. There are two divilions of. 
of them; one round or globular, and from the fize of .a 
4 grain- 
