Daily Richmond Whig. [volume] (Richmond, Va.) 1861-1862, 1862-01-03

proyed that very many Of the forms hitherto held to be
distinct epecies are nothing but different stages in the
DEVELOPMENT. Of one species, as egg, caterpA guo ana
butte Ay ere different stages OF one species; and nna
w. il has been proved that the Larvae Of parasites MI
gate from one animal to another, and must migrate
their development is to be completed.
Tbess three positions enable attack 10 be made on
the array Of faculties which only spontaneous genera
ton Is thought ,mpeent to explain Let the difficult
ties be stated Toe parasites quite distinct in or
ganzsion from all animals living elsewhere. They not
only constitute peculiar fauna, bat mary OF them are
peculiar to certain animals and even TO certain organs
In the brain there are forms found in the ines-
tine Ia the liver there are forms never found in the
muscles in the muscles there forms never found In
the blood Nor Is this all How they got from without
into some Of the places where they have been detected
Is quite inerplicsbe They have been found in closed
sacs such as the chambers Of the eye They are outd
in the embryo while in the womb This last fact has
been doubted, but it has been frequently witnessed
by very Competent observers We have ourselves found
parasites in the fetal kitten, and in the of new
born kitten they will generally be found Nay, Dr. Bur-
nett OF America states tina. he has found vegetable para
sites even in the human ovun they belonged to species
Of conferva similar to yeast one fourthousandth oil an
inch in diameter It Is remarked by Allen Thomson, in
bis enumeration Of the corroboatiye facts, that animals
living In the situations and feeding on the same
substances have fsrent kinds OF entozoa parasites
The ova Of some Of the entozo for example those Of
the common worm not so large that they could not
pass through the largest Of the capillary bloodvessels
the oya heavy that they could not be transmitted
through the atmosphere; and the suppositon OF the
passage of the ova from the parent 10 the opring is
opposed by the mechanical difficulty Of the transmits.
sion well as BY facts that parent and child are not
always ST -cted with the kind Of worms, and that
though the complaint Of worms may be said TO run M
families vet many escape and one or more generations
in the hereditary succession frequently tHemp! from
it, 81
We have ourselves too strongly felt the difficulty
usy, the impOss.bty-of explaining many OF the facts
relating parasites not % admit thai In them sponts-
generation hnds powerful support; nevertheless
as We hated be attacked from the present stand
ing point of science The pscMiiariy Of the parasitic
fauna offers no argumen. Of value the peculiarly is not
greater than that Of the fauna OF the compared
With that Of tho atmosphere and II only certain forms
are found inhabng particular regions of the body, this
Is no more than what hld on the shores aud noun
tains where certain wemarked OF life admit only
particular FORMS As the base Of 4 mountain presents
coud ions which admit the development Of plants that
could not develop its summit will the brain Of an
animal present conditions for the development OF para
site which would sver develop in the liver. Moreover
the whole difficulty Il greatly lessened that ii has
been proved that many OF the parasitic species ars only
different saSes Of species. The naturalist who had
never seen gna quit its lArvA envelope, would never
suspect that the delicate winged creature living only in
the air. was the unganly wormlike animal bobbpg
through the water would he suspect this ungainly
arya was only advanced form Of the active pred
a,ory animal he had noticed in the water day or two
before Unless actual observation had established the
identity Of these three FORMS the naturalist would neces
sary suppose them be three distinct animals 10 like
IN amer until investigation had shown that
ca agrgS systereIT and sehnOcoceus which bad been
supposed TO be three distinct genera were nothing but
/ forms of the common tapeWorm. such suspicion could
hardly have been entertained But is now known that
the parasite which in the Grain Of the sheep produces
"he s,sEgcs" and the parasite which IN the cellular It's
of the pig produces "meAy pork are aIVsi forms
of the tapeWorm which infests the Intestine Of man.
Startling this may sound It IL fact as well estab-
shed as facts in biology. Experiment has proved
that If you wish TO ufest an animal with particular
parasite you have only feed the animal with the eggs
or the known lar,e Of that parasite found IN some df
Cerent Anis and he result will be certain as the ap
pearapce of plant after sowing the seed. Pigs may
/ be made msasly" and sheep may be made TO stag
/ GER" or and dogs be infested with worms" In
nineteen cases out Of twenty. Tue following amusing
ory will wildly impress the reader the esrtGsy OF
| the experiment:
In bis splendid monograph on Les Vrs Iatss inanz,
the Beg an naturalist Van Beneden relacs that be al
minsered 10 puppy several parasites taken from the
body of rabbit. These parasites were OF what was
formerly called the genus Cg'tieereu, now known TO
be the laryal form Of tSpeWorn. This tapeWorm "a
never found 10 the rabbit but always In some annual that
bis eaten the rabbit With this puppy kept another
Of the sAm age to whom none OF these parasites were
administered no died not many weeks Afterwards and
on dissection il thst he had no iapeworm =
was replaced BY another pup vhs gss also reared with
Bde (he pup which bad been fed with pisssiies) and
shared bis oOd Two other pups, Tina and OIio were
then purchased from litter and being taken from
the mother reared carefully by Van Bentden, WHO
adm cred parasites to Cao but none to Tina These
four dogs VIu Benedsn brought with him to Paris and
ia the presence OF yalencienn6s Milne Edward, Qnatre
! fages and Jules HAime he made the following clara
ton Here four dogs: in two oil them you will ind
single specimen Of IGRid SuTdth, and ID two OF them
you will fad sp cme1s not only So but, Of these
tao you will fad that BlGe has specimens in four diff
fere1, Stages OF deyelopn Mt whereas Gao has them
oaly ia three different stages and in Eos they will be
| more nu nerous" He enabled to make tbs very
specific declaration, because he kew that two OF the
dogs had not eaten the parasites OF the rabbit which
would become elias and thai the other two had eaten
them in different quantities and a. different nterVals-
The dogs were then killed and examined, ard what Urn
Bsneden had foressen found 10 be strictly correct
Modern Investigations have traced the singular migrS
tons OF several paraes Thus the eli Ited animalca ale
| which ssu from the egg Of Distoma penetraUs the
body Ct fish; the asa ia Caen by bird and In the
ntestines Of this bird the llrva becomes developed into
ma ure DstOHad, with reproductive organs This hnal
development would take in the fab, but only
| in the intesnes Of some oarnverous animal; here II
aoushes here il produces eggs, which once more 60
through the migratory eirth. Thousands upon thous.
and Of thef egg' aud these rte never attain maur-
y The 40 dies before it is eaten. end with dies tho
parasite or the animacue dies before Il reach the
6h. Il is not every which has es,tieaess, nor
every that eaten by cat but uules' the cat
eats mouse with cy'tieseu' the cat will have no
raa al tbs lsrval eystiereus will reach ma
turity Thus as Van y neden pleasantly puts IL, lie
cysticerQue est piluis doree par un llmbeau de
chair"
In the present condition Of know ledge It seems 10
very legitimate conclusion sly that all those Isra'
sites which are found n various animals and various or
gsns without reproductive apparatus simply arvai
forms Of some parasite which reprOduces IDS kind in
the ordinary wsy. We may boi vet be able TO trace
their parentsge may never trace the parentage Of
all Of them but inssmnCh we positively know that
many Of them have been produced by the ordinary iws
of generation have right to assume that all so
produced There Is no more jusEcliion for supposrg
tina, those parasites in which reproductive organs are
absent have been developsdby spontaneous generation
tan there would be in assuming that the caterpillar land
or b. in which reproductive orga's absent we're
Or dccec Il would be contradictory to all zoology 10
assume without proof that some parasites were repro
duosd in the ordinary way and others by law only
seen in their exceptional And there is another
obi ,con of still stronger force II the parasites are