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PARASITES OF MAN. 61 
PARASITES OF MAN. 
4 BY T. SPENCER COBBOLD, M.D., F.R.S., ETC, 
[Continued from page 9.] 
The last two, or rather, I should say, three nematode parasites that 
remain for the Society’s consideration are Ascarides properly so called. 
It has long been the habit of medical practitioners and others to speak 
of the obnoxious little threadworms as Ascarides, whilst they call the 
large roundworms Lumbrici. Both terms are erroneous and misleading. 
The true Ascarides are readily recognised by their three prominent lips, 
associated with a more or less uniform thickness of the body, and a short 
tail which is not finely pointed. The Oxyurides on the other hand have 
_ @ spindle-shaped body, which is finely drawn out behind. Hence their 
generic name. As to the large roundworms, it was, perhaps, not unnatural 
that in early times they should have been called Lumbrici—on account 
of their general external resemblance to earthworms—but it is hardly 
necessary to remark that, as regards their internal organisation, they differ 
essentially from the setigerous annelids; whilst, with rare exceptions, the 
nematodes are unisexual, the oligochztous Terricole are hermaphroditic. 
In the minds of unscientific and non-professional persons the Lumbrici 
are not only still frequently regarded as genuine earthworms, but, from 
time to time, sensational paragraphs find their way into the newspapers 
asserting that live eels have been ejected by the mouth; these so-called 
“eels” being lumbricoid Entozoa. Thus it is that the undisciplined 
mind, incapable of correct observation, conjures up and gives expression 
to notions which, though uttered in times of comparative enlightenment, 
are just as absurd and untrustworthy as certain statements which I 
have previously referred to in this relation as occurring in ancient writings, 
both sacred and secular. 
NEMATODA CONTINUED. 
40.— Ascaris lumbricoides, Linneus. 
Synonymy.—Fusaria, Zeder ; Lumbricus teres hominis, Tyson. 
Larve.—As vermiform embryos, (developed within the egg,) they 
attain a length of nearly ;3, of aninch. As sexually immature 
worms they have been found by Heller in man, post mortem, up 
to the sizes of }in. and din. respectively. The intervening 
stages have not been traced. 
Intermediate host.—Probably not necessary. 
Experiments.—Davaine, myself, and others have frequently 
reared the embryos in water; and whilst still enclosed within 
the egg-shell the embryos have been kept alive by Davaine for 
five or more years. The administration of eggs by Leuckart to 
swine, dogs, rabbits, and mice gave negative results. Davaine 
* Communicated to the Microscopical General Meeting, (Birmingham Natural 
History and Microscopical Society,) February 18th, 1879. On Dr. Cobbold’s behalf Mr. 
Hughes exhibited specimens of Ascaris lwmbricoides, and an example of A. mystax 
taken from the human body. A large Ascaris megalocephala was shown, in 
order to compare the human and equine lumbricoids; other roundworms from a 
chimpanzee, and also from a cat, being likewise exhibited. Mr. Hughes also 
exhibited, from his cabinet, a slide of ova of A. lwmbricoides, put up at the 
General Hospital in 1863, 
