The external and internal parasites of [man and] domestic animals

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[From the Kcport S^j^X^ftW^ of Agriculture for 1870.]

The External Parasites of Domestic Animals,

THEIR EFFECTS AND REMEDIES.*

BY A. E. YERBILL.

The external parasites of our domestic animals nearly all
belong to the great class of animals which we call Insects, but
the internal parasites are, with few exceptions, representatives
of the class of Worms. The division of the subjects of these
lectures is, therefore, both convenient and natural.

The class of Insects includes a far greater number of spe-
cies than any other class of animals, the number actually
amounting to several hundred thousands, each country having
a vast number peculiar to itself. They are also exceedingly
diverse in habits, as well as in form and structure.

In order to show the affinities of the insect-parasites and
their position among other insects, it will be necessary to give
a brief sketch of the whole class, with a few remarks on the
more important peculiarities of their anatomy.

All insects, like the other articulated animals (worms and
Crustacea), have a body composed of a series of segments or
rings, placed one behind the other, and together forming a
sort of irregular tube, which incloses in one cavity all the in-

* In the preparation of the reports of these lectures on the parasites of domes-
tic animals, we are greatly indebted to Dr. A. S. Packard for the use of many
cuts of insects from his excellent "Guide to the Study of Insects" and the
"American Naturalist," published at Salem, Mass.; and to Donald G. Mitchell,
Esq., editor of the "Hearth and Home," published by Pettingill, Bates & Co., New
York, for the use of several excellent cuts of parasitic worms, prepared to illus-
trate a series of articles on parasites of man and domestic animals by the writer.
Without this assistance the lectures could have been illustrated only imperfectly.
In addition to these we have added, so far as the available funds would admit, fig-
ures of the more important parasitic insects and worms, copied from Cuvier, Gue-
rin, Clark, Leuckart, Cobbold, and others. — A. E. Verrill.

Fig. 2.

z BOARD OF AGRICULTURE.

ternal organs. The nervous system consists of
a double nerve-centre or ganglion in the upper
part of the head, connected with another below
by nerves that pass around the gullet on each
side, so as to enclose it as in a ring, and this
lower double ganglion is connected by a double
nervous cord with a series of similar ganglions
or nerve-masses, which are arranged along the
lower side of the body, below the intestine, each
ganglion sending off small nerves to the adja-
cent organs (figure 2). The rings of the body
are thickened in certain parts, and in the head
and middle region of the body are more or less
consolidated. They thus form a somewhat firm
external skeleton, composed of
a peculiar substance, called
chitin. When the rings are
movable this outer covering,
where it connects the rings to-
gether, is thinner and flexible,
and often folded inward so as
to form peculiar joints. The
legs, jaws, and other external
organs, are merely hollow out-
foldings of the outer covering,
and contain, like the body, the
muscles that move the various
parts, while their cavities com-
municate freely with that of
the body, and thus receive their
supply of blood, nerves, etc.
Each joint of the legs and other
appendages is also formed by
a thinner portion of the outer
covering, which is folded in
upon itself in various ways.
The wings, when present, are
also outfoldings of the integu-

For description of Figures see next page.

Fig. 1.

PARASITES OP ANIMALS.

Fig. 3.

ment, which appear at first in the form of
little sacks containing fluid, but finally ex-
pand into broad membranes and the sides
of the sack unite so as to appear like a
simple membrane, supported by little
branching, hollow rods, or tubes, which
communicate with the cavity of the body,
and also form the joints of the wings. The
legs and jaws originate from the lower part
of the sides of each ring that bears such
appendages, so that there must be as many rings or segments
in any part of the body as there are pairs of such organs, but

Fig. 4.

FIGURE 1. — " Hundred-legs," ( Scolo^ocryptops sexspinosa Say), natural size; color
deep orange, with yellow feet. From Packard's Guide.

FIGURE 2. — Nervous system of Corydalus cornutas, a large neuropterous insect;
a and b, ganglions of the head; c, the three ganglions of the thorax, which send
nerves to the three pairs of legs ; d, d, the eight double ganglions of the abdomen.
From Packard's Guide, after Leidy.

FIGURE 3. — Portion of one of the tracheae or breathing tubes, prepared so as
to show the spiral fibre a, a part of which has been unwound; c, a secondary
branch. From Packard's Guide.

FIGURE 4. — Transverse section of the thorax of a bee; a, one of the nervous
ganglions ; 6, breathing pore or spiracle, opening into the tracheae, which branch
in the interior, and send small tubes into the legs and wings; c, the dorsal vessel
or pulsating organ, which circulates the blood; d, the intestine. From Packard's
Guide.

4 BOARD OF AGRICULTURE.

the wings originate from the upper part of the same rings that
bear legs below (fig. 4). Most insects breathe air by means of
a complicated system of finely branched air tubes, having a
sort of spiral spring to keep them open (fig. 3), which are con-
nected with valvular openings, called spiracles, along each side
of the body. Some species of spiders have respiratory cavities
that somewhat resemble lungs, and contain numerous thin
membranes, arranged like the leaves of a book. These are,
however, connected with openings in the lower side of the
body, and may be regarded as a peculiar modification of the
air tubes or tracheae found in other insects. In many flying
insects the air tubes expand in certain parts into large hollow
vesicles, which give greater lightness to their bodies. In all
insects we can distinguish three regions of the body: the
head, composed of several rings closely united together, and
bearing the organs of the mouth and senses — as many pairs
as there are rings ; the thorax, composed of either three or
four rings, which bear as many pairs of legs, and sometimes
one or two pairs of wings above ; the abdomen, composed of
numerous rings, which are not consolidated, and generally bear
only the external reproductive organs ; but in the spiders they
bear the spinnerets, in many Iarva3 several pairs of fleshy legs,
in centipeds, etc., numerous legs, (figures 1 and 6), and in
some insects long, slender, feeler-like organs (figure 5).

Insects are naturally divided into three great
groups or sub-classes,* founded on important
differences in their internal anatomy and the
arrangement of their external parts.

I. — HEXAPOD INSECTS.

The highest sub-class contains the Hexapod
or six-legged insects, including all the flying
insects, and many that are destitute of wings.
In these the head, thorax, and abdomen, are
distinctly separated as three regions of the body.

* According to some writers these divisions are called orders.
FIGURE 5. — "Furniture-bug," or Shiner, (Lepisma), natural size. A smooth,
shining, neuropterous insect, covered with minute silvery scales, but destitute of
wings. It lives in houses among books, papers, clothing, or in furniture, etc.,
eating them in various ways ; it is very fond of the paste of books, and will often
loosen wall-paper.

PARASITES OP ANIMALS. 5

The head appears to be composed of seven rings, and there
are three pairs of mouth organs. They all breathe by means
of air tubes or tracheae.

II. — ARACHNIDS.

The next sub-division, called AracJtmda, includes the spi-
ders, scorpions, " daddy-long-legs," or harvest men, mites, etc.
In these the head is generally more or less united to, or sunken
in, the thorax, as in the spiders, which have the abdomen very
distinct; or the abdomen may be closely united to the thorax,
Fig. 6. as in the mites (figure 48). When mature they
have eight legs. The head bears but few organs.
There are no antennas. The eyes are simple, but
often numerous. Many breathe by tracheae, but
some spiders by lung-like organs, and others by
both combined.

III. — MYRIAPODS.

The lowest sub-elass, called Myriapoda, includes
the centipeds, "thousand-legs," etc., (figures 1
and 6.) These have the rings of the thorax and
abdomen all very similar, and the rings of the ab-
domen in some become very numerous, sometimes amounting
to several hundred. Each ring usually bears a pair of legs,
aiid contains a nerve ganglion. The head is similar to that of
the six-legged insects, and bears antennae, and sometimes com-
pound eyes. They breathe by air tubes or tracheae. This
last sub-class contains no parasites, but in both the others
there are numerous examples. Yet in those they are confined
to particular orders and families.

Among the Arachnids we find parasites only in the lowest
order, which includes the mites, the true ticks, the itch-insect,
etc., but among the Hexapod insects we find that the parasites
belong mostly to two of the seven orders into which they are
naturally divided.

The seven orders of six-legged insects are based on many
anatomical differences, but they are characterized, also, by

FIGURE 6. — Lithobius Americanus Newport, natural size; color yellowish brown.
From Packard's Guide.

6 BOARD OP AGRICULTURE.

differences in their transformations, and peculiarities in their
habits. The most obvious distinctions are found in the
structure of the organs composing the mouth, and in the
wings, when these exist. Their names are derived from the
character of their wings. The orders are as follows :

I. Hymenoptera, (membrane-winged). This order includes
the bees, wasps, ichneumon-flies, saw-flies (figures 7, 7 a), etc.

Fig. 7 a.
Fig. 7.

They have four small but strong membranous wings, the front
pair largest. The body is compact, the head large, and the
three regions of the body very distinct. • The head (figure 8)
usually has three simple eyes Fig. 8.

in front, forming a triangle ; a
pair of slender antenna3 or
feelers, and a pair of very large
compound eyes ; connected
with the mouth we find a pair
of powerful, often toothed,
mandibles or jaws; a pair of
orceps-like maxillce, bearing
near the base a jointed palpus
or small feeler ; and finally the
labium or lower-lip, which bears
a pair of palpi or feelers, and
the. ligula or tongue, which is
long and highly developed and
covered with hairs in the bees.
They have, therefore, all the
parts of the mouth symmetri-

FIGURE 7.— The Pear-slug or Saw-fly (Selandria cerasi Peck), enlarged. Color
black, with white spots on four anterior legs and feet.

FIGURE 7a. — Larvae of the same on leaf of pear, natural size ; and a, enlarged.
It is covered with sticky slime. Both from Packard's Guide.

FIGURE 8.— Head of wild Bee (Anthophora), much enlarged ; a, compound

PARASITES OP ANIMALS.

cally developed. The jaws are used for biting and cutting the
materials used in constructing their nests ; the maxillae are
used in manipulating and arranging ; the tongue is used for
lapping up honey and other liquid food. The Iarva3 are gen-
erally soft, footless, and white, but those of the saw flies re-
semble caterpillars, and have numerous abdominal legs.

II. Diptera (two-winged). Insects belonging to this order
have but one pair of wings. The three regions of the body
are very distinct. The common house-fly, meat-flies, mos-
quito, Hessian-fly, wheat-midge, onion-fly (figure 9), bot-fly,
Fig. 9. horse-fly, and the fleas

are examples. The
mouth organs- corres-
pond in number with
those of the Hymen-
optera, but the mandi-
bles and maxillce are
usually formed like
long sharp lancets, as
in the horse-fly (fig.

10), or have the shape of slender and
sharp piercing organs, as in the mosquito.
The labium and tongue together generally
form a long proboscis, often with the
tongue curiously bilobed and expanded at
the end as in the horse-fly and house-fly.
The sharp mandibles and maxillaB are used
to penetrate the skin of animals, or the
bark of plants, and rind of fruits, and the fleshy tongue is
used to suck up the blood or other liquid food. The larvae

eyes ; b, clypeus ; c, the three simple eyes or ocelli ; d, the antennae ; e, labrum or
upper lip ;.f, mandibles ; h, maxillary palpi, borne upon the base -of the maxillae
i, which are slender and hairy ; j, labial palpi ; k, ligula or tongue ; /, palpifer ;
m, paraglossae or lateral lobes of the ligula. From Packard's Guide, after New -
port.

FIGURE 9. — Onion-fly (Anthomyia ceparum), considerably enlarged, with larvae,
a and 6. From Packard's Guide.

FIGURE 10. — Head of Green-head fly or Horse-fly (Tabanus lineola Fabr.), much
enlarged ; a, antennae ; m, mandibles ; mx, maxillae ; mp, the large, two-jointed
maxillary palpi ; /, the ligula or tongue ; lb, the labrum. From Packard's Guide.

Fig. 10.

8 BOARD OF AGRICULTURE.

are usually soft, white, and footless, and generally pass under
the name of maggots. In this order we find many parasites,
of which the fleas, sheep-tick, bat-ticks, horse-tick, forest-flies,
bot-flies, etc., are examples. This order contains some bene-
ficial and very many injurious insects.

III. Lepidoptera (scaly wings). This order includes the
butterflies, moths, millers, army worm (figure 11), canker-
worms, cut-worms, silk-worms, etc.

The wings are four in number, usually
broad, and covered with minute scales,
looking somewhat like beautiful feath-
ers under the microscope, but appear-
ing like fine dust to the naked eye.
The mandibles are nearly abortive, but
the maxilla3 are usually very long, slen-
der, and hollowed out on the inside, so that when fitted to-
gether they form a long hollow tube or proboscis, through
which they suck up their liquid food. The proboscis can be
rolled up beneath the head when not in use. The larvae
mostly feed upon plants, and are generally known as cater-
pillars. They are often bright colored, sometimes hairy, and
usually have, in addition to three pair of small true legs, two
or more pairs of fleshy legs under the abdomen. Most of the
insects of this order are injurious to vegetation.

IV. Coleoptera (shield-wings). Insects of this order are
known as beetles, weevils, etc. The front wings are thick-
ened and stiff, not used in flight, but serve to protect the
hinder wings, which are larger and thin, and can be folded up
and tucked away under them. The mandibles and maxilla
are both used as jaws for biting and chewing. The larvae
have usually three pair of legs, and many are well known as
grubs and borers in wood. The apple-tree borer (figure 12),
is an example. This great order includes many beneficial
carnivorous insects, as well as many that are injurious to
vegetation.

Y. Hemiptera (half-wings). This order embraces those

FIGURE 11. — Southern Army-worm (Leucania) imago; and larva, a, natural
size. From Packard's Guide, after Glover.

PARASITES OF ANIMALS.

9

insects properly called bugs, such as the squash-bug (figure
13), strawberry-bug, bed-bug, and also the cicada or "seven-
Fig. 12.

teen-year locust," the plant-lice, bark-lice, cuckoo-spits, the
true lice, bird-lice, etc. In this order we find, therefore, the
greatest number of external parasites. The wings, when
present, are often crossed upon the back, and the front wings
are often thickened toward the base, but in other cases, as in
the cicada and plant-lice, the wings are transparent and not
crossed. The mouth organs form a sharp hollow proboscis,
for piercing the bark of plants or skin of animals, in order to
suck up the blood or sap. When not in use the proboscis can
be folded down upon the breast, by means of three joints.
The mandibles and maxillae are four, long, slender, very
sharp, piercing organs, often barbed near the points. These
are enclosed in the jointed proboscis, as in a sheath, but can
be thrust out through the opening in the end. The proboscis
is formed mostly by the lower lip or labium, but the opening
in the upper side is covered by the shorter upper lip. The
larvae of many Hemiptera resemble the adults from the first,
except that they lack wings ; the pupae are also active and
have the same habits. They therefore undergo less remark-
able transformations than those of the preceding orders.
Many of these insects are beneficial by destroying other in-
sects, but most are injurious to vegetation by sucking sap.

FIGURE 12. — Apple-tree Borer (Saperda Candida Fabr.), natural size. Color
light brown with two white stripes ; the lower figure represents the larvas. From-,
Packard's Guide.

FIGURE 13. — Squash-bug ( Coreus tristis DeGeer.), natural size. Color dart
brown. From Packard's Guide.

2

10

BOARD OF AGRICULTURE.

VI. Orfhoptera (straight-wings). This order includes the
grasshoppers, true locusts, katydid, crickets, cockroaches, etc.

Fig. u. The front wings are generally

long and straight, somewhat
thickened, and in the male often
have some sort of musical ap-
paratus, as in crickets, katydids,
etc. The hind wings are broad,
fan shaped, and can be folded
up like a fan beneath the front
wings, which when folded gen-
erally lie lengthwise of the body,
forming a sort of roof.

The mandibles and maxillae
are chewing organs. The larva&
have nearly the same form as the
adults, but lack wings ; they have
similar habits; the pupae are also active. Most of these
insects, except the Mantis, are injurious to vegetation by eat-
ing the leaves.

VII. Neuroptera (nerve-winged). The dragon-flies, lace-
winged flies (Figure 15), May Kg. is.

flies, Lepisma (Figure 3), and
white ants, belong to this order.
The wings, when present, are
thin, membranous, and subdivided by very numerous rods or
nervures into small spaces, which are often squarish. The
mandibles and maxilla are chewing organs. The abdomen
is generally long. The larvae are of many forms, often
aquatic, generally carnivorous and predacious in habits, and
usually undergo a complete metamorphosis ; the pupae are
mostly inactive. Most insects of this order, excepting the

Figure 14. — Katydid ( Cyrtophyllum concavum Say), male, natural szie. Color
bright green. From Packard's Guide.

Figure 15. — The Lace-wing Fly (Chrysopa oculata Say), natural size, with the
eggs attached to the tips of slender pedicels. Body light green. This insect
lays its eggs among plant-lice (Aphis), which the larvae, when hatched, destroy.
From Packard's Guide.

PARASITES OP ANIMALS. 11

white ants and Lepisma, are beneficial by destroying noxious
insects.

To those who desire more information upon the struc-
ture, habits, and classification of insects generally, we would
especially recommend Packard's Guide to the Study of In-
sects, Salem, Mass., 1869, and Harris' Treatise on Insects
Injurious to Vegetation (illustrated edition), Boston, 1862.

PARASITES BELONGING TO THE DIPTERA.

The Fleas.

PULICI D^B.

It is somewhat singular that parasites are almost always
degraded species of the orders and families to which they
belong. This is very evident in the case of parasitic insects,
for they are mostly destitute of wings, and are imperfectly
organized in other respects when contrasted with their self-
supporting allies. The fleas furnish us with examples of
degraded diptera, and the sheep-tick is even more degraded
than the fleas. Of fleas there are several species that attack
man and domestic animals ; but the species do not appear to
be so strictly limited to particular animals as are the lice and
some other parasites ; for the common dog-flea and cat-flea
will attack man without hesitation, and in New England ap-
pear to be far more troublesome to the human race than is
the species commonly regarded as the real human flea (Pulex
irritans), which so far as I have observed, is comparatively
rare, though in some localities it may be sufficiently common,
as it is in parts of Europe.

In the genus Pulex, which includes the common species of
fleas, the body is compressed and the integument is very firm,
so that they are well adapted for gliding among hairs or
feathers, and are not liable to be injured by any ordinary
pressure. The wings are represented only by two pairs of
short, stiff scales, which have little or no power of motion.
The posterior legs are large and powerful, enabling them to
leap with remarkable agility. The head is small ; the eyes

12 BOARD OP AGRICULTURE.

are simple, in some species very minute ; the antennae are curi-
ously constructed with three broad, flat, singularly lobed
joints, and are, in nearly all species, closely folded away out
of sight, in a socket or cavity behind the eyes ; though in
the males of the mouse-flea and pigeon-flea they are exposed
and carried erect. The mouth organs are peculiarly con-
structed and well adapted for piercing the skin and sucking
the blood. The maxillae (Figure 16, a), are a pair of broad,
flat, thin, somewhat lance-shaped organs, bearing at base the
long, four-jointed feelers or palpi (5). The mandibles (#)
are slender, flattened, sharp, piercing organs, finely serrated
along their sides, like a minute saw. The Figure IG.

labium (tT) is a round, slender, piercing
organ, forming the central lancet. The
lower lip and labial palpi (<?) form to- a,
gether a sort of sheath, with a groove on
the inside, which receives the mandibles
and labium, when in their natural posi- d*
tion ; the labial palpi are four-jointed in the cat and dog
fleas, if not in all, though some writers say they are three-
jointed. The mandibles (c) and labium (d) form together
three slender lancets, and it is by means of these that the
flea perforates the skin. The blood is then drawn up through
the channels or spaces between these organs and the labial
palpi and lower lip, by means of a sucking stomach.

The Gat-flea (Pulex felis Bouch4). Figures IT, 18.
This species of flea is perhaps the best known and most
common kind in New England. It not only infests nearly all
cats and the places where they sleep, but is also more or less
common in dwellings of all classes, especially when cats are
allowed to roam about over the carpets. It often becomes
exceedingly troublesome in sleeping rooms, for it prefers to
spend the day about the floor, in and beneath the carpet,
or in some similar place of concealment ; but when oppor-

Figure 16. — Head of the dog-flea (Pulex ranis Curtis), highly magnified; a,
the hroad, thin maxillae ; b, their four-jointed palpi ; c, the mandibles ; d, the
labrum or central seta of the proboscis ; e, the labium and labial palpi. From
Duges.

PARASITES OP ANIMALS.

13

tunities offer it is always ready to jump upon the naked feet
or ankles, and may thus gain entrance to the bed. Many
persons, especially ladies and children, are badly poisoned by

Figure 17. Figure 18.

them, and may suffer severely for several days from the bite
of a single flea; for, unlike the mosquito and other blood-
sucking insects, they are never satisfied with a single bite, or
with one spot, but must travel about and bite as they go,
literally " biting on the run." In these respects, however, it
agrees closely with the so-called human flea (Pulex irritans).

The cat-flea (Figure 17) is dark chestnut-brown in color,
and is stouter and thicker in the thoracic region than Pulex
irritans, which has a rather slender waist and darker color.
There is a row of sharp spines along the lower side of the
head on each side, and another row of similar spines on the
posterior edge of the first segment of the thorax; but the
human flea lacks both these sets of spines. Other good dis-
tinctions are found in the joints of the feet or tarsi, and in
the mouth organs. In all fleas the males and females differ
considerably in form and size, the males being smaller and
shorter.

The female cat-flea lays her eggs among the fur of the cat,
to which they are but slightly attached ; these eggs are very
small, white, and long-oval. As the cat walks or runs about,
the eggs are constantly being scattered around, often in great
numbers. On one occasion I was able to collect fully a tea-
spoonful of these eggs from the dress of a lady in whose lap a
half-grown kitten had been held for a short time. The places

14 BOARD OF AGRICULTURE.

where cats sleep become well filled with the eggs. These
hatch in about two weeks into little, white, footless, maggot-
like larvae (Figure 18), which have small tufts of hairs along
the sides. They are at first about one-sixteenth of an inch
long. The head is pale yellow, and the posterior end of the
body bears two spines. These larvae feed upon the decaying
particles of animal and vegetable matter always to be found
in the dirt in which they live. They move about by means of
their hairs and spines. They grow rapidly in warm weather,
and in about twelve days, when they mature, spin a slight
silken cocoon and change to a pupa, which is inactive.
This looks more like the mature flea and has the legs free.
In a short time, varying from ten to sixteen days or more,
according to temperature, the pupa matures, and the full
formed flea comes forth from the cocoon, ready and willing
to take care of itself. This it does by leaping upon the first
living creature that comes within range ; but no doubt it is
better suited with the cat than with other animals. This
mode of increase and the habits of the young will explain the
reason why fleas are often obtained out of doors, especially in
gardens frequented by cats or dogs. Such fleas are often
called " sand-fleas," but they are simply the progeny from eggs
of cat or dog fleas that have been hatched and lived in the
dirt or soil. They pass the winter both in the mature and
larval states, and perhaps also as eggs and pupae. There are
several broods each season.

The Dog-Flea (Pulex canis Curtis). Figure 19.
This species is very similar to the last, and is considered
the same by several writers. It has the same form and color,
and the same TOWS of spines below the sides of the head and
on the thorax. But there appears to be some difference in
the mouth organs. The posterior tarsi in this species are

Figure 17.— -Cat-flea (Pulex felis Bouche), much enlarged; a, the maxillary
palpi arising from the bases of the maxillae, b ; c, the labial palpi ; d, the slender
mandibles. The labrum is not shown. From Packard's Guide.

Figure 18. — Larva of Cat-flea (Pulex felis Bouche), much enlarged; a, one of
the antennae more highly magnified; 6, posterior end of the body, showing the
two spines. From Packard's Guide.

PARASITES OF ANIMALS. 15

said to have the fifth joint longer than Figure 19.

the second, while in the cat-flea the second
is longer than the fifth. The habits are
essentially the same, except that tins one
seems to prefer the dog's blood. It will
also attack human beings when oppor-
tunities offer.

The Hen-Flea (Pulex gallince Schank) lives upon the hen
and about poultry-houses and yards.

The Pigeon-Flea (Pulex columboe Gervais) lives upon do-
mestic pigeons and in pigeon-houses.

Other species infest rats, mice, bats, rabbits, swallows, and
various other wild animals and birds.

Remedies for Fleas.

From the description of the habits of the larvae given above,
it is evident that dirt and filth of all kinds afford facilities for
the increase of fleas, and that dogs and cats are the means of
diffusing their own peculiar species, and also, no doubt, the
true human flea. The first care, therefore, should be to see
that the dogs and cats, if such are kept, are freed from their
parasites. To this end they should be made to sleep. on some
material like shavings or chips, that can be easily burned,
and their sleeping places should be often cleaned and their
beds renewed. To remove the fleas themselves from the
animals a wash of water containing 6 to 10 per cent, of petro-
leum, naphtha, or benzine, well shaken together, may be used.
A weak solution of carbolic acid in water, about 2 or 3 parts
of the acid to 100 of water, will also be efficacious for fleas
and other parasites. Decoctions of tobacco and strong soap
suds are also recommended.

When fleas are troublesome in dwelling houses, a thorough
cleaning of the floors and an equally thorough beating and
cleaning of the carpets, rugs, etc., will generally be effectual.
When cracks or crevices exist in the floors, a thorough wash-
ing with the petroleum, naphtha, or carbolic acid water, will
be useful to destroy the eggs and young. Persian Insect

Figure 19. — Head of Dog-flea (Pulex cants Curtis), much enlarged. The parts
are the same as in Figure 16. From Duges.

16 [BOARD OF AGRICULTURE.

Powder, which is a preparation from the flowers of a plant, is
often used to expel fleas both from carpets and the fur or
hair of animals. It appears to be particularly obnoxious to
them. But after applying the powder to an animal it should
soon after be thoroughly washed off.

It often happens that there are really but few fleas, perhaps
less than a half dozen, in a room that is supposed to be over-
run by them ; for owing to their habit of biting repeatedly, a
single one may do the mischief attributed to a large number.
In such cases a careful search for and capture of the of-
fenders will soon remedy the evil. When caught, a drop or
two of benzine will kill them instantly.

The Sheep-Tick, Forest-Flies or Horse-Ticks, etc.

HlPPOBOSCID-SJ.

These are degraded Dipterous parasites, and must not be
confounded with the true ticks, which have eight legs. Some
of them are destitute of wings, like the sheep-tick ; others
have long, narrow, simple wings, like the species infesting the
horse, and those of the swallow and other birds, bats, etc.
The body is flattened from above, and is hard and firm, with
a horn-like or leathery texture. The head is somewhat
sunken into the front edge of the thorax, without a distinct
neck. The antennae or feelers are Tery small and near to-
gether. The eyes are large and often occupy most of the
sides of the head. The proboscis consists of two lateral, nar-
row, elongated, bristly plates (regarded as maxilla by some
authors), which project in front of the head. Below and
between the bases of these there is a small orifice from which,
when about to draw blood, three, long, slender, piercing
organs are protruded; but these can be withdrawn when not
in use. These are unequal in size, but equal in length. The
lower one, which is largest and channeled along the upper
side and dilated at base, receives the two smaller ones into
its groove. These organs penetrate deeply into the skin,
and through the channel formed by the setae the blood is
sucked up.

They live like lice among the feathers of birds or hairs of

PARASITES OP ANIMALS. 17

animals, and run with agility either forward, sideways, or
backward, somewhat like a crab. Their feet or tarsi are fur-
nished with powerful denticulated claws, with which they
cling securely. Their most remarkable peculiarity is their
mode of reproduction. Each female produces but one or two
young at a time, but these are born as living, fully developed
larvae, which are enclosed in a smooth oval skin, notched at
one end, within which they change to pupae immediately
after birth, the enclosing case becoming dark colored. The
female has an uterus-like enlargement of the oviduct, in which
the eggs hatch, and this organ has the power of secreting a
milk-like substance for the nourishment of the larvae until
full grown.

The Horse-tick or Forest-fly (Hippobosca equina). Figure 20.

This species is almost as large as the house-fly, nearly black,
with conspicuous yellow markings on the thorax. It some-
Figure 20" . times infests the horse

to such an extent as to
be very troublesome.
It attacks by. prefer-
ence those parts where
the hair is thinnest
and the skin softest,
especially under the
belly and between the
hind-logs. Their bites
cause severe pain, and will irritate the gentlest horses, often
rendering them almost unmanageable, and causing them to
kick dangerously. When found they cling so firmly as to be
removed with some difficulty, and they are so tough as not to
be readily crushed. If one escapes when captured, it will in-
stantly return to the horse, or perchance to the head of its
captor, where it is an undesirable guest. Another species
sometimes infests the ox.

Figure 20. — The Horse-tick (Eippobosca equina Linn.), enlarged. From
Cuvier.

18 BOARD OP AGRICULTURE.

The Sheep-tick (Melophagus ovinus Linnaeus). Figure 21.

This insect never acquires wings. It has a broad head,
wider than the thorax. The abdomen is roundish and hairy,
not showing distinct rings, and in the gravid female becomes
much enlarged. The legs are short and stout, and the claws
very strong. The proboscis is as long as the head. Like the
horse-tick, it is viviparous, producing a full-grown larva, en-
closed in an oval case, as shown in Figure 21.

It is often very troublesome to sheep, especially lambs.
There have been numerous remedies proposed. In general,
when there are but few, they can easily Figure 21.

be removed by hand when the sheep are
sheared ; but when numerous on lambs,
they may be destroyed by various washes
or baths. Snuff, or sulphur in powder,
rubbed thoroughly in to the wool, is some-
times used with good results. A bath
made by steeping tobacco in water, about
2 pounds to 10 gallons of water, in which the lambs are
entirely immersed, with the exception of the face, is said to
be effectual, but in some cases, has proved injurious to the
health of the lambs. Probably the same solutions recom-
mended for fleas would be equally effectual for these ; but
the strength of petroleum water, or naphtha water, or car-
bolic acid water, ought to be adapted to the age and strength
of the animals to which it is applied, young lambs having a
much more tender skin than dogs or old sheep.

The Sot-flies of Horses, Cattle, and Sheep.

The insects belonging to this family are much less degraded
than the other parasitic Diptera. But in reality these are not
parasites, except in the larval state. They pass the pupa state
in the soil, and in the winged state are powerful fliers, seek-
ing the quadrupeds only for the purpose of depositing their

Figure 21. — Sheep-tick (Melophagus ovinus Linnaeus), enlarged. The figure on
the left represents the puparium when first born. From Packard's Guide.

'PARASITES OP ANIMALS. 19

eggs. There are numerous genera and species, each of which
lives, in the larval state, upon some particular species of
mammalia, and usually in some particular part of the ani-
mal. In the tropical parts of America there are species which
live beneath the human skin, in tumors that they cause. The
larvas are usually thick, fleshy grubs, destitute of feet, but
generally provided with rows of hooks or spines, by means of
which they move about in their burrows. The breathing
pores are in one or two scaly plates at the thick posterior end
of the body. In those that are parasitic in the stomach, the
mouth lias horny hooks by means of which they cliii^ to the
lining membrane ; but in those that live in tumors under the
skin, there are no hooks to the mouth, but only fleshy
tubercles. They live on the matter, or pus, which is caused
by the irritation that they produce.

The flies generally have a stout, hairy body, sometimes
looking somewhat like humble-bees. The female has a more
pointed abdomen, with an extensible ovipositor. The an-
tenna3 are very small, and placed in little pits. The mouth
organs are almost abortive, and the mouth very small, for
these flies take little or no food in their winged state, this
period of their lives being wholly devoted to the reproduction
of their kind. The species that infest cattle, sheep, and
horses have been transported to nearly all parts of the world
where these animals are reared ; but there are many native
species that are found only in the wild animals. *

The Bot-fly of Cattle (Hypoderma bovis Latr). Figures 22, 23.
This fly is densely covered with hairs, except upon the
thorax, which is partially naked and black, broadly banded
with white and yellow. The abdomen is banded alternately
with yellowish white and black, and with reddish orange at
the end. The front of the head is dirty ashen, with yellowish
white hairs. They appear from June to September, and the
females lay their eggs on the backs of cattle. According to

* One species, Cuterebra emasculator, described by Fitch, lives in the scrotum of
squirrels, and destroys one or both testicles. In some parts of .the country it is
often quite common, and doubtless greatly diminishes the number of squirrels.

20

BOAED OF AGRICULTURE.

some writers, they pierce the skin, by means of their peculiar
gimlet-like ovipositor ; but others deny this, and say that the
eggs are merely attached to the skin, and that the young
larvae, which very soon hatch, eat their way in. At any rate

Figure 22. Figure 23.

the cattle are often greatly alarmed by their attacks, and run
frantically about, sometimes even taking to the water for
safety, which would hardly -be the case unless they had suf-
fered pain from their attacks. Working oxen, when thus
attacked, sometimes cause serious trouble.

The larvae having entered the skin increase the size and
depth of their burrows as they grow larger, but always keep
up an opening with the exterior, and keep the posterior end
of the body, in which the breathing pores are situated, near
this opening to get air. In this way they cause, by the irrita-
tion and inflammation that they produce, tumors or abscesses
of considerable size beneath the skin, and live upon the
matter formed by the inflammatory action. When young,
they are white, but afterwards become brownish ; when ma-
ture, deep brown.

They have transverse rows of minute hooks ; the narrower
rows are on the posterior part of each segment, and the hooks
point backward ; those of the wider rows, point forward. These

Figure 22. — The Bot-fly of Cattle (Hypoderma bovis Latreille), considerably en-
larged.

Figure 23.— The full grown larva, enlarged. Both from Packard's Guide.

PARASITES OF ANIMALS. 21

hooks are used in moving about, and no doubt cause consid-
erable irritation. The mouth is small and inconspicuous,
with small papillae. • The posterior end of the body bears two
small plates in which the spiracles or breathing pores are
situated ; and this end of the body is kept next to the external
orifice of the tumor. When the larva is mature, which hap-
pens from May to July, it is about an inch long (Figure 23).
It then works its way out of the opening backward, and falls
to the earth, where, in a day or two, it changes to a pupa,
the dried-up skin of the larva serving as a covering for the
pupa. They remain in the pupa state from four to six weeks
during summer, when the end of the pupa-case comes off,
like a lid or cap, and the mature fly comes forth. The sores
caused by them heal very soon after the larvae leave.

Although these insects probably cause some pain, especially
at first, they do not appear to cause any permanent injury,
and but little inconvenience, unless in large numbers. They
can usually be pressed out of their burrows with the thumb ;
but care should be taken not to crush or burst them in the
burrows. Or the openings of the tumors may be enlarged with
a sharp knife or lancet, and then they can be easily removed
and the wounds will soon heal. They attack by preference
young and healthy or fat animals, perhaps because the skin
is softer and thinner in these. They frequent chiefly the
uplands, and especially the vicinity of trees, and seem to
particularly avoid water or damp localities — a fact that cattle
seem to learn by experience. Owing to this habit, cattle that
graze upon meadows are generally free from them, or nearly
so, although those upon the neighboring hills may be at-
tacked. The eggs are laid soon after the flies emerge from
the pupa ; but as there is considerable variation in the time
when the larvae mature, the flies may occur from June to
September. The larvae live during the entire winter in the
tumors, and perhaps some of the pupae remain over winter.

The Sheep Bot-fly (CEstrus ovis Linn.). Figure 24.
This species somewhat resembles the preceding in form,
but is considerably smaller, with a rounder abdomen in the

22 BOARD OP AGRICULTURE.

male, and the color is lighter. The thorax is ash-colored,
with four black lines and small black spots. The abdomen is
light ash, more or less spotted with blackish. The female has
a tapering abdomen, with a long ovipositor, which is curved
forward when about to deposit the eggs.

The flies appear during the whole summer, and according
to Mr. Riley, deposit the young larvae previously hatched in
the oviduct, on the margins of the nostrils of
sheep. u The moment the fly touches this part of
the sheep, they shake their heads and strike the
ground violently with their fore-feet ; at the same
time holding their noses close to the earth, they
run away, looking about them on every side to
see if the fly pursues. They also " smell to the
grass " as they go, lest one should be lying in
wait for them. If they observe one, they gallop back, or take
some other direction. As they cannot, like the horses, take
refuge in the water, they have recourse to a rut or dry,
dusty road, or gravel pits, where they crowd close together
during the heat of the day, with their noses close to the
ground, which renders it difficult for the fly conveniently to
get at the nostril." (Clark, 1796). This description, al-
though written long ago, applies equally well to the habits
both of the fly and sheep, as observed at the present day.
The young larvae at once proceed to ascend into the nostrils
by means of their hooks and writhing motions, thus causing
great irritation and an increased secretion of mucus, upon
which they feed. They finally reach the frontal and maxil-
lary sinuses and other cavities, connected with the nose, and
attach themselves securely to the mucus membranes by means
of the two sharp hooks upon their heads. They thus cause
great inflammation, if in considerable numbers, and severe
illness, or even at times convulsions and death result. This
disease is often known as " grub in the head " among farm-
ers. The disease is indicated by loss of appetite, frequent
coughing or sneezing, unusual discharge of matter from the
nose, slow and weak gait, dullness, inability to stand, tossing

Figure 24. — Larva of the Sheep-bot ( (Estrus ovis), natural size. From Clark.

PARASITES OF ANIMALS. 23

or turning of the head, inclination to butt and push with the
head, fits of frenzy, and general appearance of suffering and
weakness, which sometimes goes so far as to render the animal
unable to rise, when death generally results. The gums, back
part of mouth, and lining of the nasal cavities are often red and
inflamed. Sometimes the larvae even force their way, by the
openings through which the nerves pass, into the brain, when
death quickly follows.

These Iarva3, when full grown (Figure 24) are about an
inch long, and have lost more or less of the white color which
they had when younger, and each ring is crossed above by two
dark brown bands ; there are also small, round, raised brown
spots on the sides of each segment. The small end, or head,
has two sharp hooks and two papillae ; but the posterior seg-
ment bears two small brown plates, in which the spiracles
are placed, and this segment can be drawn into and con-
cealed by the next, which give a truncated appearance to
the posterior end. The under side is flattish, and each seg-
ment has a median row of minute brown spines, which are
directed backward.

When full grown, they descend from the nostrils and fall
to the earth, where, in the soil or among the roots of grass,
they change to pupae in about two days. They remain in
this state from six weeks to two months, when a sort of lid is
forced off from one end of the pupae cases, and the mature
flies come forth, pair, and immediately proceed with the work
of perpetuating the race, for in the winged state they seem to
have no other instinct ; and not having any mouth, they take
no food. When not engaged in depositing the eggs, they
seem sluggish and lazy. The flies appear irregularly in June,
July, and August, and larvae of all sizes may be found at one
time in the same sheep. Each female produces several hun-
dreds of young. According to Mr. Riley, * Over 300 living
larvae have been taken from one female fly, by Mr. Cockrill.

The amount of injury which these insects do to the sheep
has long been a matter of discussion among veterinary sur-
geons and others ; but it appears to be the universal testi-

* First Annual Keport on the Noxious Insects of Missouri, p. 164, in Report of
of Agriculture, 1868.

24 BOARD OF AGRICULTURE.

mony of those who are most immediately interested — the
breeders of sheep — that their effects are evil, and evil only,
and that the amount of injury is in direct proportion to their
numbers, as is the case with all other parasites. That, when
as abundant as they often are, they are capable of causing
death, seems to be well established. As a preventive, it
has been recommended to move the sheep to distant pastures
after most of the grubs or larvae have left the sheep and are
in the earth in the pupae state, which happens during June or
July, according to locality. In this State probably the latter
half of June would be the best time for this. Others smear the
noses of the sheep with tar, or make them do so themselves
by boring large augur holes in logs to contain salt, and fre-
quently smearing the adjacent wood with tar. Many provide
spots of light, dry soil into which the sheep may thrust their
noses when pursued by the fly. When the larva? have ac-
tually entered the nostrils in large numbers, they may be
removed to a considerable extent by a feather wet with oil of
turpentine, camphor, or a weak solution of carbolic acid, or
of creosote. Lime, in fine powder, is sometimes used; for
by sniffing it, they sneeze, and thus expel the larvae. Salt
water or diluted carbolic acid solution may also be injected
into the nose with a syringe. It is doubtful, however,
whether any remedies will reach the larvae which have taken
up their abode in the more remote cavities in the bones of the
forehead and beneath the bases of the horns. Therefore it is
better to apply these remedies early and often, if necessary.

Another species of bot-fly (Hypoderma lineata Brauer),
lays its eggs upon the backs of sheep and cattle, and the
larvae live in tumors beneath the skin, like the more com-
mon Hypoderma bovis of cattle. It appears to be rare in this
country, but has been observed in Kentucky. This fly may
be known by three, longitudinal, naked, black stripes on the
thorax. The abdomen is very hairy, blackish, with three
bands, the base whitish or yellowish, the middle black, the
apex orange-red. The wings are transparent, somewhat
brownish, unspotted. In New Grenada another species, the
Dermatobia noxialis Goud., has the same habits, and also at-

PARASITES OF ANIMALS. 25

tacks men in the same way, forming painful tumors beneath
the skin. The same or a similar species also infests the dogs
in the tropical parts of America.

Several peculiar species of Hypoderma live beneath the skin
of the moose, elk, and other species of the deer family. These
animals are also infested by several species of the genus
CepTienomya, which live in the larval state in the throat, or at
the root of the tongue.

The goat is attacked by a species of Hypoderma, which
makes tumors under the skin, and by a species of (Estrus,
that enters the frontal sinuses, and has the same habits as the
common species of the sheep ; but these two species have not
been determined and are little known. The camel is infested
by the larvse of Cephalomya maculata Wd., which lives in. the
nasal cavities, like the larvae of the sheep-bot. Even the ele-
phant and rhinoceros have their peculiar parasites of this
kind. The latter is attacked by a bot-fly, allied to that of the
horse, which lives in the stomach in its larval state.

Bot-fly of the Horse (Grastrophilus equi). Figures 25, 26.

The " bots " of horses are the larvae of several species of
flies, belonging to the genus called Gf-astrophilus. The largest
and most common kind is Gr. equi, the female of which is
represented in Figure 25. This species is very hairy, and has
dark spots on the wings. The eyes are black and distant ; the
top of the head is brown, the front whitish ; the thorax is brown,
with a darker brown or blackish central spot ; the abdomen is
brown with the transverse divisions and spots blackish. The
male has a rounder or broad-oval abdomen, which is browner.
This fly lays its eggs by preference upon the hairs about the
knees of horses, especially on the inside ; it also frequently at-
taches them to the hairs of the side and back part of the shoul-
der, and occasionally to the tips of the hairs of the mane. These
eggs are of considerable size, of a long oval form, pointed at
one end and blunt at the other, and adhere firmly by one
side. They may easily be seen and can be removed either
by thorough washing and brushing, or by cutting the hairs
off with scissors. A wash of carbolic acid soap has been re-
commended to destroy them. Sometimes 500 or more may
4

26 BOARD OF AGRICULTURE.

be found on one horse. In depositing the eggs, the female
fly hovers around the horse, and as each egg is ready to be
deposited, she quickly advances and bends the abdomen for-
ward, with the egg at the end, and applies it to the hair, to

Figure 26.
Figure 25.

which it instantly adheres by the glutinous secretion which
covers it. She then retreats and prepares another egg Jo r
the same operation. This does not disturb the horse, unless
by a tickling sensation, causing the muscles of the skin to
contract with a tremulous motion. The eggs contain more
or less perfectly developed larvae when laid ; and when they
are mature, or have been a few days attached to the hair,
they burst open and allow the young to escape almost instan-
taneously, when moistened. Thus, when the horse licks itself
or its companions, the moisture hatches the eggs, and the
young larvae are transferred to the mouth by the tongue or
lips, and thence to the stomach, where they fasten themselves
to the lining membrane by their two hooks. They generally
occur in clusters, and are most common in the vicinity of the
pylorus, but are found attached to all parts of the stomach.
In this situation they slowly grow to be large fleshy larvae,
with a round body, about an inch long (Figure 25). The
segments of the body are provided with double rows of spines,
pointing backward. These are reddish with black tips. The

Figure 25. — Bot-fly of the horse ( Gastrophilus equi Leach), female, natural
size.

Figure 26. — Larva of the same, enlarged. From Packard's Guide.

PARASITES OP ANIMALS. 27

two last segments do ftot show -the spines, and the posterior
end of the body is rather truncate, with two fleshy lobes,
which cover, more or less completely, a chitinous plate, in
which the spiracles are situated. The mouth is at the small
end, between the hooks, which represent the maxillae ; the
mandibles, above and between these, are small and slender.
At the places where they attach themselves there are found
small pits or depressions ; but they do not appear to cause
ordinarily much irritation or inflammation, unless in great
numbers, as they sometimes are. They have been accused of
perforating the walls of the stomach, and this may possibly
be the case in very rare instances ; but the perforations of
the stomach, so often found in post-mortem examinations,
are generally caused by the digestive action of the gastric
juice after the death of the animal ; for after death this fluid
will attack the stomach as quickly as any other flesh.

When full grown they loosen their hold, and passing
through the intestine, fall to the earth. But they often fix
themselves for a few days upon the lining of the intestine,
and then cause considerable irritation and pain. Probably
most of the acute symptoms of " bots " in horses are caused
in this way. They often attach themselves in and about the
anal orifice, and in that situation cause much suffering and
trouble to the horses, which under these circumstances, re-
fuse to travel rapidly, and even after whipping, soon relapse
into a slow walk, as if lazy. But the bots can be easily re-
moved from this location, much to the relief of the horse.
The bot-larvge get their growth and leave the horses from the
latter part of May to July, or even later. They enter the
surface of the soil and change to pupae within the shrunken
skins of the larvae. They remain in the pupa state forty or
fifty days, and emerge in the same way as the preceding spe-
cies ; consequently the flies may occur from the last of June
till September, or later.

The amount of injury caused by the bots of horses has long
been a matter of dispute, many writers claiming that they are
very injurious, and evert at times, fatal ; while others deny this,
and consider them as harmless, or even beneficial. This can

28 BOARD OP AGRICULTURE.

be definitely settled only by experiment; but most reasonable
men would be content to forego any possible benefit, and be
satisfied with a healthy horse destitute of bots. No doubt
many diseases due to other causes are commonly attributed
to these insects, but that they are frequently the cause of
serious trouble is generally believed and admitted. In this
instance prevention is comparatively easy, while all writers
admit that there is no reliable cure, no mattter how much
they may differ in other respects. The means of prevention
consist chiefly in frequently removing or destroying the eggs,
as mentioned above, and also in removing and destroying the
full-grown Iarva3 when observed attached to the rectum. In
some countries the grooms frequently wash out the mouths
of the horses with a suitable brush in order to remove the
young larvae. Many drugs have been recommended to re-
move bots from the stomach, but none that do not endanger
the life of the horse can be relied upon ; and in cases where
they bring away the larvae, it is possible that those that are
already in ' the intestines are the only ones affected. Spirits
(or oil) of turpentine is a remedy in common use, but should
be used with caution, if at all. A better plan, under ordi-
nary circumstances, is to keep the horses in good health in
other respects, so that they can the better sustain the attacks
of the larvae until they naturally pass away, which will usually
take place without serious injury. In exceptional and severe
cases only, resort should be had to special medicines of a dan-
gerous or doubtful character ; and then they should be given,
if possible, in accordance with the advice of a competent phy-
sician. There are several other species of bot-flies of the
horse, which are less known, however, in this country.

The Gastrophilus nasalis is a smaller species, densely
hairy, with the thorax yellowish red or rust-colored. The
abdomen is either whitish at base, with the middle black and
the apex yellowish-brown and hairy ; or the base is whitish
and all the rest brown ; or the middle is black, with the base
and apex whitish, with grayish hairs. The wings are un-
spotted. The larvae are much like tliose of the preceding,
except that they are smaller, and also live in the stomach of

PARASITES OF ANIMALS. 29

horses. They change to pupae beneath the manure, and the
flies appear from June to September. It also infests the ass
and mule, and some authors say that it lives even in cattle.

The Gaslrophilus pecorum is densely covered with yellow
hairs, with a band of black hairs on the thorax behind the
suture, in the male. The female is yellowish brown, the
abdomen black, with yellowish hairs at its base, as well as
on the thorax. The wings are grayish or light brownish,
clouded with yellowish brown. The larvae are similar to
those of the more common G-. equi, and have similar habits.
The flies appear at the same time.

The Gastrophilus hcemorrhoidalis, or red-tailed bot-fly, is
a small species, easily distinguished by the bright orange-red
tip of the abdomen. The thorax above is olive-gray and hairy,
with a black band behind the suture. The base of the abdo-
men is whitish and the middle blackish, in strange contrast-
with the orange-red of the end. The larvae have the same
habits and are found in the same situations with those of
the common bot-fly, which they much resemble, except that
they are whiter and smaller, their length not exceeding one-
half or five-eighths of an inch. They change to pupae within
two days after leaving the horse, and the pupae are deep red.
They remain in the pupa state about two months, and the flies
appear from the last of June till the cool weather of autumn.
In depositing the eggs, the female fly differs in habit from
the common bot-fly, for she selects the lips and nose of the
horse as the most suitable place for this purpose. In deposit-
ing her eggs she therefore causes the horse much trouble and
uneasiness. Mr. Clark described the operation as follows :
" At the sight of this fly the horse appears much agitated,
and moves his head backwards and forwards in the air to
baulk its touch and prevent its darting on the lips ; but the
fly, waiting for a favorable opportunity, continues to repeat
the operation from time to time ; till at length, finding this
mode of defence insufficient, the enraged animal endeavors
to avoid it by galloping away to a distant part of the field. If
it still continues to follow and tease him, his last resource is
in the water, where the (Estrus is never observed to follow

30 BOARD OP AGRICULTURE.

him. At other times, this (Estrus gets between the fore-legs
of the horse whilst he is grazing, and thus makes its attack on
the lower lip. The titillation occasions the horse to stamp vio-
lently with his fore-foot against the ground, and often strike
with his foot, as if aiming a blow at the fly. They also some-
times hide themselves in the grass, and as the horse stoops to
graze, they dart on the mouth or lips, and are always observed
to poise themselves during a few seconds in the air, while the
egg is preparing on the point of the abdomen." The eggs are
darker colored than those of the common bot-fly, and contain
a nearly developed embryo, so that they very soon hatch, and
the young larvas are transferred to the mouth by the tongue,
and thence get into the stomach.

In other countries there are still other species of bot-flies
that infest the horse, ass, and mule ; among them Gast-
rophilus inermis Br., which lives in the horse ; 6r. flavipes
Oliv., which inhabits the stomach of the ass and mule ; and a
species of Hypoderma, which lives beneath the skin of all three.
But I am not aware that either of these has been observed in
this country.

The Meat-fly, Blowflies, etc. Figure 27.

These flies are not true parasites, but naturally feed, while
in the larval state, upon decaying flesh and other animal
matter. Their larvae are, however, frequently Fio. 07
found in wounds and sores, both of animals
and men, feeding upon the purulent matter,
and when allowed to live undisturbed, not uii-
unfrequently attack the living flesh, when
their food becomes exhausted ; and in this wa,
if they gain access to wounds in large numbers,
they will not only greatly aggravate and enlarge
them, but in many cases, when neglected for a
short time, they have caused the death of men
and animals by actually eating away living tis-
sues. The females in this group of flies are
viviparous, the eggs being retained in capa-

Figure 27.— Larva or maggot of the Blue-bottle fly (Musca Ccesar Linn.), en-
larged. From Packard's Guide.

PARASITES OP ANIMALS. 81

cious spiral dilations of the oviducts, until hatched into small
larvae or maggots, when they are deposited by the mother, with
almost unerring instinct, upon or near decaying flesh. The
female flesh-fly {Sarcophaga carnaria Linn.), is said to de-
posit at least 20,000 of these young larvae. They are ready
to commence feeding at once, and grow with remarkable
rapidity, often becoming half an inch long in two or three
days. When mature, they crawl out of the flesh and change
to long-oval, brown pupae, in the earth or any other conven-
ient place, and the mature flies come forth in a few days.
By this rapid increase the progeny of a few pairs would in a
short time devour the carcass of a large animal. The blue-
bottle fly {Musca Ccesar Linn.), the meat-fly (Musca vomi-
toria Linn.), and others allied to them, are common and well
known species, having similar habits. The larvae of all these
are long, soft-bodied, footless maggots, smaller toward the
head, thicker and blunt behind. The larva of the blue-bottle
fly is represented in Figure 27. The eggs or larvae and
those of other similar flies are not rarely swallowed with
food by men and animals, and are capable of living, for a
time at least, in the stomach and intestine, sometimes giving
serious trouble. To keep them out of wounds or sores, the
old females should be kept away. If this cannot be done by
bandages, frequently washing the wounds with a weak solu-
tion of carbolic acid will be an effectual remedy and pre-
ventive.

PARASITES BELONGING TO THE HEMIPTERA.

The parasitic Hemiptera are all degraded, and mostly
wingless forms, belonging to three very different families :
the Cimicidce, including the bed-bug; Pediculidoe, including
the true lice ; and the Mallophagidce, including bird-lice, etc.

This family, as restricted by Westwood, includes only the
genus Cimex, or the bed-bug and its allies. These have a
smoothish, oval, flat body, with a broad metathorax ; a small
head ; a slender, three-jointed proboscis or beak, which reaches
as far as the front legs when folded down, and slender, four-

32 BOARD OF AGRICULTURE.

jointed antennae, the last joint not enlarged or clavate. They
seldom, if ever, have wings. In addition to the common bed-
bug, there are species infesting pigeons (<7. columbarim
Jenyns) ; swallows (C. hirundinis J.) ; and bats ((7. pipistrelli
J.). It is doubtful, however, whether all these be not identical
with the common species. At any rate, it appears that the
common bed-bug will attach itself to bats and various birds,
when opportunities occur.

The Bed-Bug, (Cimex lectularius Linn.). Figure 28.

This species has long been notorious. It was mentioned
by Pliny, Aristophanes, Aristotle, Dioscorides, and other an-
cient writers. Yet English writers have argued that it was
first carried to that country from America, and thence to
the continent of Europe. Moffitt mentions it, however, as
having been seen in England as early as 1503, though it does
not appear to have been common there until a century later.
Its early English name was " wall louse " ; the term " bug "
was applied to it much later, its original meaning having been
nearly synonymous with " bug-bear."

At the present day this insect is sufficiently common
throughout the civilized world, if not among the barbarians
also. Its form and general appearance are well shown in Fig-
ure 28, which represents it considerably larger than ordinary
specimens. Its size varies greatly, however, according to its
locality and the amount of blood it has been able to imbibe.
Its color, when young, is pale yellowish, the blood in the in-
testine showing through; as it grows older it becomes darker,
until, when full grown, it is reddish brown, the color being
darker when filled with blood. The eyes are small and bright
red ; the proboscis is much like that of the ordinary blood-
sucking Hemiptera, which prey on other insects ; the labium
forms a three-jointed sheath or tube, the middle joint being
broadest, the last one sharply pointed ; the labrum is broader
than the basal joint, which it overlaps. According to Dr.
Packard, the internal structure is as follows: " The mandibles
and maxilla3 arise near each other, in the middle of the head,
opposite the eyes, their bases slightly diverging. Thence they
converge to the mouth, over which they meet, and beyond are

PARASITES OP ANIMALS. 33

free, being hollow, thin bands of chitine, meeting like the
maxillas, or tongue, of butterflies, to form a hollow tube for suc-
tion. The mandibles each suddenly end in a curved, slender
filament, which is probably used as a tactile organ to explore
the best sites in the flesh of their victim for
Figure 28. ^ drawing blood. On the other hand, the
maxilla3, which are much narrower than the
mandibles, become rounded toward the end,
bristle-like, and tipped with numerous ex-
'ceedingly fine barbs, by which the bug
anchors itself in the flesh, while the blood is
pumped through the mandibles. The base
of the large, tubular labium, or beak, which ensheathes the
mandibles and maxilla?, is opposite the end of the clypeus, or
front edge of the upper side of the head, and at a distance
beyond the mouth equal to the breadth of the labium itself.
The labium, which is divided into three joints, becomes flat-
tened toward the tip, which is square, and ends in two thin
membranous lobes, probably endowed with a slight sense of
touch." At the same time that the blood is sucked up, some
poisonous secretion or saliva is introduced into the wound,
perhaps to render the blood more liquid. To some persons
these bites are extremely poisonous and cause large inflamed
swellings and violent itching, while in other persons no such
effects occur, and the bites are scarcely noticed.

These insects are inclined to be gregarious in their habits,
and are fond of herding together, a dozen or more in aplace,
whether in a crack, knot-hole, chink in the walls of houses, or
any snug corners about a bedstead. They are also fond of
returning constantly to the same hiding-place, morning after
morning, after their nocturnal raids, just as many birds re-
turn regularly to their roosts. On this account their retreats
become discolored by dark spots of excrement. When
much disturbed, or when food fails, they will disperse, how-
ever, and each one will migrate on its own account. In the
night they are quite lively and nimble, and run about with

Figure 28. — Bed-bug (Cimex leetularius Linn.), enlarged. The straight line
shows the ordinary length. From Packard's Guide.

5

34 BOARD OP AGRICULTURE.

great rapidity, and can then evidently see better than by day.
They are capable of making long journeys even during the day?
and may thus migrate from house to house. They are, how-
ever, not restricted to human dwellings or to human blood,
for they often take up their residences in poultry houses and
yards, at times completely swarming in such, places. They
will also attack dogs and cats, and may live about the places
where those animals sleep. They have even been found in
the woods under the bark of dead trees. The same species,
apparently, also attacks bats, and may thus enter houses. In
fact, there are a great many ways in which they may get into
the best of houses, besides the well known method of adhering
to clothing, etc. It is, therefore, no disgrace to any house-
keeper that a bug should now and then be detected in the
house ; but the disgrace consists in allowing them to remain
undisturbed until their numbers increase to a great extent, as
they will most surely do if neglected. Many kinds of Hem-
iptera, like the squash-bug, etc., have the power of forming a
peculiar odorous secretion, which, from the similarity of the
odor, probably consists in part of formate of amylic ether ;
but in the bed-bug this odor is combined with others that
are far more disagreeable.

The eggs are long-oval and white, and are laid in clusters
in the cracks, etc., about bedsteads and other places that they
frequent. The young hatch by forcing off one end of the egg-
shell like a lid. The young, when first hatched, are whitish
and translucent, and although having three legs and the gen-
eral features and habits of the old ones, they differ considerably
in form, being more louse-shaped. They have a broader and
more triangular head, and shorter and thicker antenna.
They cast their skins several times during growth, each time
looking a little more like the adult than before. It is said
that they require eleven weeks to -mature, but this probably
differs according to the temperature and food. They are,
however, lively and blood-thirsty from the first, and are well
able to look out for themselves. Their skill in finding a
sleeping person and reaching him is marvelous indeed.

In ordinary cases there is no great difficulty in eradicating

PARASITES OF ANIMA.LS 35

these insects completely, if a proper amount of care is be-
stowed in the way of keeping the house and beds clean and
neat. The principal trouble arises from neglect on the part
of housekeepers to examine the beds frequently, for, as al-
ready intimated, no bed is sure to escape their attentions for
any great length of time, especially in cities, where they may
at any time walk in from some neighbor's house for a friendly
visit or morning call.

When they are merely located in bedsteads, or bedding, there
is no better way than to make a careful and thorough examina-
tion of all cracks and corners, and when any are seen, a little
benzine poured upon them will kill them instantly, and the
benzine should be poured into all suspicious cracks, which
cannot otherwise be reached. Scalding hot water thoroughly
applied is also effectual, but is liable to injure the varnish of
furniture. One examination of a bed is seldom sufficient, for
eggs that have escaped observation, may subsequently hatch.
Therefore two or three searches, with benzine in hand, should
be made at intervals of a week or ten days. The use of cor-
rosive sublimate and similar poisons is unnecessary and
objectionable, for such preparations are not more dangerous
to the bugs than to the persons who occupy the beds, and are
less fatal, even when applied directly to the bugs, than ben-
zine. When the bugs have also taken up their residence in
the cracks and crevices in-the walls of old houses, it is much
more difficult to destroy them. If very bad, the house, when
empty, may receive a thorough fumigation with burning sul-
phur, which will generally prove very effectual. Hen-houses
and other out-buildings may be thoroughly drenched with a
mixture of crude petroleum and water, or with the solution
of carbolic acid.

Bed-bugs are extremely tenacious of life and have wonder-
ful powers of fasting. They have been kept hermetically
sealed in glass bottles for more than a year without any food,
and were still lively and had a good appetite.

PEDICULID^.

This family includes the ordinary lice of man and quadru^
peds, which are furnished with a sucking mouth. They are

36

BOARD OP AGRICULTURE.

Figure 29.

very low, degraded Hemiptera, destitute of wings. The head
is small, conical, and narrow ; the thorax is small and in-
distinctly separated into segments ; the
abdomen is large, flattish, rounded or
oval, with nine segments. The antenna
are very slender and five-jointed. The
eyes are simple and very minute. The
feet, or tarsi, have two joints, the
last joint forming a strong hook for
grasping the hairs firmly while crawling
and climbing among it. The mouth-
parts form a long and extremely slender
fleshy tube, which is retracted when not
in use, and is capable of being intro-
duced into the skin, for the purpose of
sucking blood. The structure of the
mouth is as follows, according to
Schiodte : u The peculiar attenuation of
the head in front of the antennae at once
suggests to the practised eye the exist-
ence of a mouth adapted for suction.
This mouth differs from that of Rhyn-
chota [Hemiptera, bed-bug, etc.] gen-
erally, in the circumstance that the
labium is capable of being retracted into
the upper part of the head, which there-
fore presents a little fold, which is ex-
tended when the labium is protruded.
In order to strengthen this part, a flat
band of chitine is placed on the under
surface, just as the shoemaker puts a

Figure 29.— Proboscis of body-louse (Pediculus corporis DeG6er), entirely pro-
truded and seen from above, magnified one hundred and sixty times ; aa, the
summit of the head, with four bristles on each side ; bb, the chitinous band, and
c, the hind part of the lower lip— such as they appear through the skin by strong
transmitted light; dd, the foremost protruding part of the lower lip (the haus-
tellum); ee, the hooks turned outwards ; /, the inner tube of suction, slightly
bent and twisted ; the two pairs of jaws are perceived on the outside as thin
lines ; a few blood globules are seen in the interior of the tube.— From American
Naturalist.

PARASITES OF ANIMALS. 37

small piece of gutta-percha into the back of an India-rubber
shoe ; as, however, the chitine is not very elastic, this band is
rather thinner in the middle, in order that it may bend and
fold a little when the skin is not extended by the lower lip.
The latter consists, as usual, of two hard lateral pieces, of
which the fore ends are united by a membrane so that they
form a tube, of which the interior covering is a continuation
of the elastic membrane in the top of the head ; inside its
orifice there are a number of small hooks, which assume
different positions according to the degree of protrusion ; if
this is at its highest point the orifice is turned inside out, like
a collar, whereby the small hooks are directed backward, so
that they can serve as barbs. These are the movements
which the animal executes after having first inserted the
labium through a sweat-pore. When the hooks have got a
firm hold, the first pair of setae (the real mandibles trans-
formed) are protruded ; these are, towards their points, united
by a membrane so as to form a closed tube, from which,
again, is exserted the second pair of setae, or maxillae, which
in the same manner are transformed into a tube ending in
four small lobes placed crosswise. It follows that when the
whole instrument is exserted. we perceive a long membranous
flexible tube hanging down from the labium, and along the
walls of this tube the setiform mandibles and maxillae in the
shape of long narrow bands of chitine. In this way the tube
of suction can be made longer or shorter as required, and
easily adjusted to the thickness of the skin in the particular
place where the animal is sucking, whereby access to the
capillary system is secured at any part of the body. It is
apparent, from the whole structure of the instrument, that it
is by no means calculated for being used as a sting, but is
rather to be compared to a delicate elastic probe, in the use of
which the terminal lobes probably serve as feelers. As soon
as the capillary system is reached, the blood will at once
ascend into the narrow tube, after which the current is con-
tinued with increasing rapidity by means of the pulsation of
the pumping ventricle and the powerful peristaltic movement
of the digestive tube."

38 BOARD OP AGRICULTURE.

The various species of these lice have similar habits, and all are
blood suckers, but each species inhabits only certain kinds of
animals, and some are restricted to particular parts of the
skin. Many animals have two or more species of these para-
sites. Five species have been described as parasitic upon man,
though but three are common.

When they become very abundant, as they soon will if the
animals upon which they once get well established be neg-
lected, they cause great irritation of the skin and nervous
system, and the itching that they produce causes the animals
to rub themselves against buildings, fences, etc., and thus the
hair is often worn off and the skin abraded. Such animals
generally soon become weak and emaciated, and are, there-
fore, more liable to be attacked by other diseases. •

There are various washes which, if properly applied, will
very rapidly destroy all species of lice, without much trouble.
The use of preparations of mercury and arsenic, and all similar
poisons, should be avoided, for they often poison the animals,
as well as the persons who use them, and thus the remedy
may be worse than the disease.

A strong solution of tobacco, made by boiling cheap tobacco
in water, is an effectual remedy, in common use. Snuff
rubbed into the hair is also used. Ordinary whale-oil, such as
was formerly used in lamps, poured upon the skin along the
back of an ox, cow, calf, or sheep, will diffuse itself over the
skin and kill the lice. Weak petroleum water, or carbolic
acid solution, or carbolic soap, may be used as a wash, or
small animals may be immersed in a bath, taking care to
keep the nose, mouth, and eyes out of it. But perhaps one of
the best and simplest, as well as safest, washes for this pur-
pose, as well as to destroy fleas, mites, itch-insects, mange-
acari, and all other external parasites of man and animals, is
a solution of sulphuret of potassium in water, — two to four
ounces to the gallon of cold water, varying the strength ac-
cording to the age and tenderness of the skin of the animal,
for the solution will contain some free potash, which, if too
strong, might irritate a delicate skin. There is otherwise no
danger from its use, though its odor, like sulphuretted hydro-

PARASITES OF ANIMALS. 39

gen, is disagreeable, and it should be used, therefore, where
there is plenty of ventilation. This is an exceedingly valua-
ble remedy, also, for the itch of man, as well as the " mange"
of animals. The sulphuret of potassium comes in the form
of grayish or greenish lumps, put up in tight bottles. It is
used in photography and can usually be bought at the princi-
pal drug stores.

An equally useful preparation, having the same properties,
may be easily made by taking fresh quick-lime, slacking it
gradually with water, and forming a milky solution by the
addition of more water, as in the preparation of white-wash.
Into this put as much flowers of sulphur as will dissolve by
boiling for some time. This will produce a deep yellow solu-
tion like that of the sulphuret of potassium in odor and
effects. It may be diluted if too strong. It contains sul-
phuret of calcium, upon which its usefulness depends. Sul-
phur may also be boiled in potash lye, to produce a similar
preparation, and to this, while boiling, tobacco is sometimes
added, but the sulphur is, no doubt, sufficient for all practical
purposes. But in no case can we be certain of destroying all
the eggs of these parasites by any wash whatever, that would
not be dangerous to the animal. Therefore the treatment
should be repeated two or three times, at intervals of ten or
twelve days, in order to destroy any young that may have
hatched in the meantime.

The Head-louse of man (Pediculus capitis DeGder). Fig. 30.
This is, probably, the best known species of the genus
Pediculus. It is still sufficiently common among persons who
Figure so. neglect personal cleanliness, though much less
so than it is said to have been formerly , when it
was thought no disgrace in some parts of the
old world, but was regarded as fashionable,
rather than otherwise. This insect is almost
exclusively confined to the human head. It
attaches its eggs firmly to the hair, near the
roots. These eggs are long-oval, with several
little conical prominences at the large end,

Figure 30. — Head-louse (Pediculus capitis DeGcer), greatly magnified.
From Packard's Guide.

40 BOARD OF AGRICULTURE.

which are open at the top, while the small end oears a cluster
of bristles. The habits and treatment are too well known to
need further description.

The Body-louse of Man (Pediculus corporis DeGeer).

Figure 31.

This species very closely resembles the last, but is usually
larger. It attaches itself especially to the clothing, and at-
tacks various parts of the body. It attaches its eggs chiefly
to the clothing which it frequents, especially Figure si.

along the seams, and when the clothing is sel-
dom changed, as often necessarily happens in
time of war, it increases rapidly and becomes
a great source of annoyance. Many unfortu-
nate soldiers, who were confined in the south-
ern prisons and prison-pens during the late
war, can testify to the abundance of this par-
asite under such circumstances. Nor were
the ordinary camps free from them, especially during active
campaigns.

The Crab-louse (Phthirius puUs Leach). Figure 32.

In the genus Phthirius the thorax is broad and not distinct
from the abdomen, which is flat and has eight segments, the
first one being composed of two united. Figure 32.

The first pair of legs are terminated by
slender tarsi, not changed to grasping
claws, but the claws of the other two
pairs are large and strong.

This species lives among the hairs of
the pubic regions of man, and also,
though much less commonly, upon the breast, arm-pits, in the
beard, eye-brows, and also upon the head. It sometimes also
clings to linen and clothing, and, not unfrequently, may be
found in the beds of those persons harboring them. They
may be destroyed by simple ointments and unguents, or by
the sulphuret washes described above.

Figure 31. — Body-louse (Pediculus corporis DeGe ), greatly magnified. From
Packard's Guide.

Figure 32. — Crab-louse (Phthirius pubis Leach), much enlarged. From Pack
ard's Guide.

PARASITES OF ANIMALS.

41

Figure 33.

The Cattle-louse (Hcematopinus vituli Denny). Figure 33-
In the genus Hcematopinus, which includes a large number
of species, the head is obtuse or truncated in front, the middle
segments of the abdomen well separated, and the posterior
legs much the longest. The eyes are very minute. They are
all small and some are minute species.

H. • vituli is brownish, with a pale
abdomen, the abdominal segments
bearing lateral chitinous pieces, in
which the spiracles are situated. The
head is elongated with a constriction
behind the antennse. It is about j1^
of an inch in length, or a little more.
It is parasitic both on cattle and horses,
and sometimes becomes very abun-
dant.

Another species (H. eurysternus
Denny), also infests both cattle and
horses. In this the head, thorax, and feet are horn-colored.
The thorax is very broad. The length is about TV of an
inch.

The Hog-louse (Hcematopinus suis Leach). Figure 34.
Figure 34. This species is brown, with a white

abdomen. The spiracles are placed in
blackish, horny plates along each
side of the abdomen. Length -J of an
inch.

H. stenopsis infests the goat. It is
a horn-colored species, with along oval
hairy abdomen.

If. asini Denny is parasitic on the
ass.

H. piliferus Denny lives upon the dog. It is uniformly
horn-colored. The body is slender and covered with pale
hairs. Length •£$ of an inch.

Figure 33. — Cattle-louse (Hcematopinus vituli Denny), much enlarged. From
American Naturalist.

Figure 34. — Hog-louse (H. suis Leach), much enlarged. From Cuvier.
6

42

BOARD OP AGRICULTURE.

MALLOPHAGA (Bird-lice).

These insects live both among the feathers of birds and hair
of mammals. They are peculiar in having distinct jaws (Figure
36), instead of a sucking tube. The body is flat, corneous,
and firm above. The head is horizontal and generally broad.
The antennae have three to five joints. The mandibles are
small and hook-like. The maxillary palpi, when present, are
four-jointed ; and the labial palpi two-jointed. The legs are
short and stout,, with one or two strong claws. There are sev-
eral hundreds of species already described, nearly every bird
having one or several peculiar species. They produce nearly
the same effects as the true lice, and may be destroyed by the
same remedies.

Figure 35.

a Figure 36.

The Turkey-louse (Goniodes stylifer Denny).

This is a large species, conspicuously marked with transverse
black bands. It is very common both on the domestic and
wild turkey, together with three or more other species, one of
which is much longer and nearly black. Some of the other
species parasitic on the turkey are Liotheum stramineum
Nitzsch, Philoplerus polytrapeziusNitzsch.

The Hen-lice (Liotheum pallidum Nitzsch, Philoplerus
variabilis N., P. heterographus N., P. dissimilis N., and P.

Figure 35. — Turkey-louse ( Goniodes stylifer Denny), much enlarged.
Figure 36. — Head of same, seen from below, more magnified ; a, mouth organs ;
b, antenna. Both from Cuvier.

PARASITES OF ANIMALS.

43

ho/og-aster N., Gf-oniocotes Burnettii Packard, Figure 37) are
common enemies of domestic fowls.

Figure 37.

Figure 38.

The Pigeon-lice (Liolheum giganteum Denny, Philopterus
bar/ulus Nitzsch, Nirmus clavicornis, Goniodes compar N.)
infest domestic pigeons.

Figure 39.

Figure 40.

The Goose-louse ( Trinotum squalidum Denny) is found with
other species on the goose.

The Duck-lice (Philopterus squalidus Nitzsch), Figure 38,
with other species, inhabit the common duck.

Figure 37. — Hen-louse (Goniocotes Burnettii Pack.). American Naturalist.
Figure 38. — Duck-louse (Philopterus squalidus N.) From Gervais.
Figure 39. — Cat-louse (Trichodectes subrostratwN.) From American Naturalist.
Figure 40. — Goat-louse (T. caprce Packard). From American Naturalist

44 BOARD OF AGRICULTURE.

The Peacock-lice (Philopterus faldcornis N., P. reclangula-
tus N.) are very common on the peacock.

The Cat-louse (Tricliodectes subrostratus Nitzsch), Figure
39, is one of the parasites of the house cat. This species is
whitish, with the head and thorax pale honey-yellow.

The Goat-louse ( Trichodectes caprce Packard, probably the
same as T. limbatus Gervais), Figure 40, lives with other
species upon the domestic goat. It is reddish yellow, trans-
versely Barred with reddish brown, the abdomen edged with
red.

SUB-CLASS, ARACHNIDA.

ACARINA (Mites).

These are characterized by their simple,' usually rounded or
oval bodies, in which there is no distinct separation into
thorax and abdomen. They have eight legs, which are gen-
erally short, but when young many of them are six-legged.
The species are numerous. Their habits are very
diverse ; many are parasitic upon man, various quadrupeds,
birds, reptiles, insects, etc., some externally and others in-
ternally. Species have even been found within the abdo-
minal cavity and skull. Other species live under the water,
and are parasitic on mollusca. Many attack plants and prove
very injurious. Others are carnivorous and prey on small
insects. Some, like the meal-mite, sugar-mite, cheese-mite,
fig-mite, and many others attack and greatly injure articles of
food. Many lead a solitary, wandering life, others occur
together in vast numbers at certain times.

DERMANYSSUS DugGS.

The insects of this genus are small, soft-bodied parasites,
which infest various birds, bats, insects, and some of them
are at times parasitic upon man.

The fifth joint of the palpi is smallest. The lip is sharp.
The mandibles of the male are forceps-like, with long hooks ;
those of the female ensiform. The anterior feet are the
longest. Young with six legs.

Dermanyssus gallinoe is found among the feathers of the
domestic fowl, and lives by sucking the blood.

PARASITES OP ANIMALS. 45

D. Grallopavonis infests the turkey. The body is marked
by peculiar, delicate, transverse strias, and with numerous
small circular impressions on the back.

D. avium torments small cage birds, like the canary. It
often takes refuge in cracks about the perches, which should
therefore be kept clean.

ARGAS Latreille.

This genus includes the famous Argas Persicus, which
infests old dwellings in Persia, especially at Mi ana, and is
said to be so poisonous that its bite produces convulsions and
speedy death ; or even its juices, if crushed upon the skin,
may produce the same results.

These are larger- than most of the mites, and somewhat
resemble the ticks. The body is broad-oval or roundish.
The upper side of the head so projects as to conceal the mouth
parts. The jaws are suctorial. The lower side of the body
is granulous, not scaly, and covered by a single piece.

Argas reflexus Latreille lives upon pigeons and sucks their
blood. It especially infests the young, upon which there are
sometimes great numbers. The body is marked with curious
tortuous grooves and pits. The color is yellowish, but when
filled with blood violaceous..

IXODES Latreille. (Ticks).

These are the largest of the Acariaris, and all are parasitic,
chiefly upon quadrupeds and reptiles, but sometimes on birds.
The body is broad-oval or round, and when not swollen with
blood is flatish, and the integument is firm and tough. Their
mandibles (Figure 43, b,) are covered with teeth and have ter-
minal hooks ; their maxilla are small, not reaching beyond the
beak, but bear a peculiar organ called the glossoid (Figure
43, a,) also covered with hook-like teeth. The legs are slender
and have two claws, and in the young have pads or suckers
(d). The young are six-legged (Figure 42). The ovarial
opening is near the mouth, between the first pair of legs.
These parasites, when young, cling in large clusters to the
tips of leaves and twigs of herbs and shrubs, with part of
their six slender legs extended. When brushed by a passing

46

BOARD OF AGRICULTURE.

animal, they instantly leave the plant and quickly disperse
over their host. They insert their glossoids and mandibles into
the skin, where they cling firmly by means of the numerous
hooks, and live by sucking the blood. The abdomen soon be-
comes very much swollen, and sometimes grows so large as to
resemble a tumor. They attack various animals and even man,
indiscriminately. In many parts of the Southern States the
" wood ticks " are extremely troublesome to persons who have
occasion to go into the forests, as well as to animals. The
eggs of Ixodes albipictus are laid in large masses, from the
first of May until the last of June. Early in July the eggs
hatch out simultaneously, " the shell opening like a clam."
The young when first hatched have six slender legs.

Figure 41. Figure 42.

tj

Figure 44. Figure 43.

The Cattle-tick (Ixodes bovis). Figure 41.
This is a flattened, leathery, reddish, seed-like species, with
an oblong-oval body. It sometimes grows to be nearly half
an inch long. It infests cattle, and is very troublesome in the
Western and Southern States, but is far less common in the
North. It also attacks the horse and many other quadrupeds,
as well as reptiles, including the rattle-snake.

Figure 41. — Cattle-tick (Ixodes bovis Riley), enlarged.

Figure 42 — Ixodes albiptctm Packard ; six-legged young, much enlarged ; d,
foot with sucker.

Figure 43. — Head of the same, more enlarged ; a, glossoid ; b, mandibles ; c
maxillary palpi.

Figure 44. — Adult of the same, gorged with blood, natural size. All from
Packard's Gu,ide.

PARASITES OP ANIMALS. 47

Ixodes albipidus Packard. Figures 42, 43,44.

This was originally found upon a tame moose by Mr. W.
G. Hays, but doubtless infests other animals.
Ixodes unipictus Packard.

This is about a quarter of an inch long and has an oval
form. Is is reddish brown, or mahogany-color, with a central
silvery spot upon the back. It often attacks men and vari-
ous animals. It has been found in New England, but is more
common southward.

In Europe, numerous species have been found.

Ixodes vicinus is very troublesome to dogs. It is of a brown-
ish violet color, crenulated posteriorly. It has five radiating
brown spots and some brown dots.

Ixodes reduvius infest sheep and dogs. It has a pale red or
yellowish color, and becomes more than a quarter of an inch
long. It must not be confounded with the ordinary " sheep-
tick" (see page 89).

Mites, ACARUS Linn.

This genus, which originally included all the mites, is now
restricted to those that are allied to the cheese-mite. The
mouth parts are prolonged into a rostrum or beak. There is
a constriction of the body between the second and third pair
of legs, dividing it somewhat into two parts.

The Cheese-mite (Acarus siro Linn.).
This species ordinarily lives in cheese and other articles of
food; but has sometimes been observed parasitic upon man, in
certain diseased conditions.

The Meal-mite (Acarus farince De Ge*er).

This species, found in meal and flour that has been in-
jured is sometimes accidentally swallowed while living.

Acarus dysmterice Linn, was found living in the excreta of
a person attacked by violent dysentery. It also sometimes oc-
curs in large numbers about wine and beer casks, and may
therefore be swallowed accidentally.

Glycipliagus hippopodos has been found in the ulcerated feet
of horses. A species of mite also occurs in the diseased
feet of sheep.

48 BOARD OP AGRICULTURE.

Mange-insect of the Horse {Psoroptes equi Gervais).

This insect is readily visible to the naked eye and swarms
on horses afflicted with the mange, which is a disease anala-
gous to the itch in man. It has a soft, depressed body, spiny
beneath at the base of the legs and on the thorax. One or
both £>f the two posterior pairs of feet bear suckers, and all
are more or less covered with long slender hairs.

Figure 45.

Fig. 46.

This insect may be destroyed by the same remedies used for
lice and for the human itch. The best remedy is probably the
solution of sulphuret of potassium, described on page 109.

The Itch-insect {Sar copies scabieiL&tY.'). Figure 47.
This is a very minute, whitish species, barely visible to the
naked eye, unless on a dark surface. It has been, in former
times, the subject of many lengthy discussions, in reference
to its causing the itch. It is, however, at the present time
fully ascertained to be the sole cause of the ordinary itch,
though other species of similar parasites may cause different
varieties of itch. The body is rounded and soft, with small
round pustules on the middle of the back, and with radiating
lines or ridges, the sides of the body and legs bearing long
bristle-like hairs. The mandibles are needle-like. The
female is largest and has the two pairs of hind legs but little
developed, ending a bristle ; in the male they are well devel-
oped and terminate in a slender sucker. These creatures, as
seen under the microscope, have something of the unwieldy

Figure 45. — Psoroptes equi Gervais, female ; ventral side, much enlarged.
Figure 46. — Head of the same, more magnified. Both from Cuvier.

PARASITES OF ANIMALS.

49

Figure 47.

appearance of a tortoise, and are ordinarily sluggish, yet they
are capable of leaping to a considerable distance. They bury
themselves in the human skin, especially in the more delicate
and less exposed parts, and excavate minute galleries for them-
selves, in a manner something like that
in which moles excavate galleries in
the soil. These galleries are at first
perpendicular, and then go off horizon-
tally to some distance. The females
lay their eggs in these galleries as
they progress.

These mining and boring operations
cause much irritation of the nerves of
the skin and induce an intolerable itch-
ing, and the inflammation that they
cause produces pustules, filled with a
watery exudation. The insects them-
selves are not found in the pustules but
in their minute galleries, off to one

side, the pustule generally marking the place where they en-
tered. The itch is contagious, simply because the insects,
especially in their young and more active state, pass from one
person to another, or are transmitted by clothing. They are
most active at night and, therefore, sleeping with an infested
person is pretty sure to be attended by the transfer of the
insects. The longer the parasites are neglected, the more
numerous they become. .The increase is, however, quite slow
at first, owing to the small number of eggs. There are
various remedies for this disease, but the different preparation
of sulphur are no doubt the best and safest. The solutions
of sulpha ret of potassium, described on page 109, is probably
the simplest and most efficacious preparation for this purpose.
Its use should be accompanied by a thorough change of gar-
ments and bedding, and it should be used by all the members
of an infected family simultaneously. It should be appliedat

Figure 47. — Itch-insect (Sarcoptes scabiei Latreille), female, upper side, much
enlarged. From Guerin.

7

09 BOARD OF AGRICULTURE.

least three times, at intervals of three or four days, to destroy
the young as fast as they hatch.

Species of Sarcoptes, closely allied to the itch-insect, have
been found on the domestic animals, causing diseases analo-
gous to the itch in man. Such diseases, caused by quite a
number of distinct parasites, are called " mange." They
have been observed on the cat, dog, camel,* and hog.

The genus Dermatodectes is closely allied to Sarcoples, and
the species likewise live on animals, burrowing in the skin.
D. bovis infests cattle, and D. ovis lives in the skin of sheep.
The genus Dermaleichus infests birds in a similar manner.

All these parasites should be treated like the itch-insect of
man. The sulphuret of potassium solution, applied with a
brush that has long bristles, like a white-wash brush, is
probably the best and simplest remedy.

The Face^mile (Demodex folliculorum Owen). Figure 48.

This singular but minute parasite lives in the diseased and
enlarged follicles in the skin of the human face, especially in
those about the nose and chin. The follicles, when thus dis-
eased, are enlarged and filled with a thickened
sebaceous matter, the orifice being usually ob- risure 48-
structed by a hardened, blackish substance. If
these be pressed, and the matter which is forced out
be carefully examined with a microscope, it will often
be found to contain numerous specimens of this minute
creature, in all stages of development. A drop of
oil or ether applied to the sebaceous matter, to
dissolve the fatty parts, will render them more
readily visible. The young ones have but six short
legs ; the adults have eight legs and a worm-like
body, as represented in Figure 48. It has been thought that
the " barber's itch" is caused by this parasite, but I do not
know that this has been fully established.

*S. dromedarii, of the camel, is sometimes communicated to man, causing a
form of itch worse than the ordinary, owing to its great size and numerous spines.

Figure 48. — Face-mite (Demodex folliculorum Owen, or Simonea folliculorum of
some authors), much enlarged. From Packard's Guide.

PARASITES OF ANIMALS. 51

The same species, or one very closely allied to it, occurs in
the skin of the dog and other domestic animals, producing
some forms of the " mange." These parasites will probably
be destroyed by the same remedies that are effective against
the itch-insect.

Library.

SECOND LECTURE

The Internal Parasites of Domestic Animals;

THEIR EFFECTS AND REMEDIES:

The parasites of man are so intimately connected with those
of his domesticated animals, that it is impossible to discuss
them separately. Indeed, many of the human parasites in-
habit also the hog, cattle, sheep, and the dog, in certain stages
of their development, and nearly all the most dangerous kinds
are derived, either directly or indirectly, from those animals.
While in return mankind furnish to them the eggs of several

52 BOARD OF AGRICULTURE.

of their worst parasites. Thus some of these creatures are
kept in existence solely by reason of the peculiar relations ex-
isting between man and his brute dependents. This is partic-
ularly the case in respect to the two most common tape-worms
of man, derived respectively from the flesh of cattle and hogs,
in which the young worms live. These two worms appear to
be capable of coming to maturity only in the human in-
testine.

Most of these internal parasites belong to the great class of
articulated animals known as Worms, constituting, however,
several distinct orders, which are often collectively called
Helminths. The orders of parasitic worms are much lower
in rank than those that include the independent kinds, like
the numerous species of free marine worms, or Annelids,
many of which have beautiful gills and locomotive organs, a
very complex circulation, red blood, and a well-organized head,
eyes, mouth, and intestine ; to such worms the common earth-
worms, or angler-worms, are also allied, although destitute of
gills. But the parasitic worms never have red blood nor
special organs for breathing, and rarely for locomotion ; most
have no distinct organs of sense, and many have no head and
no intestine. The reproductive system is, however, always
very highly developed, and most of them are exceedingly
prolific. This is essential to their existence, for it is often only
by mere chance that any of the eggs or young reach the
peculiar habitats in which alone they can grow to maturity.

The int<irnal parasites of animals have long been the sub-
ject of laborious and careful research by many of the ablest
naturalists and physiologists,* owing to the remarkable

*The following are some of the more important and useful of the recent gen-
eral works on parasitic worms :

Felix Dajardin, Histoire naturelle des Helminthes au vers intestinaux, 8vo,
with plates, Paris, 1845. (Suites a Buffon.)

C. M. Diesing, Systema Helminthum. Two volumes, 8vo. Vindobonae, 1850.

J. Leidy. A Flora and Fauna within living animals. Smithsonian contribu
tions, 1852.

C. Davaine, Traite" des Entozoaires et des mala-lies vermineuses de rhomme et
des animaux domestiques, 8vo, 930 pages, with 88 figures. Paris, 1860.

D. F. Weinland. An Essay on the tape-worms of man ; 8vo pamphlet, with
figures. Cambridge, Mass., 1858.

T. S. Cobbold. Entozoa ; an Introduction to the study of Helminthology, with

PARASITES OP ANIMALS. 53

peculiarities of their structure, habits, andmodes of reproduc-
tion, as well as to their great practical importance with refer-
ence to human health and property.

The total number of species hitherto described, from all
animals, is more than 2,000. Of these upwards of 100 species
are found in domestic animals and man.

The parasitic worms of man and domestic animals are nat-
urally divided into four principal orders, which are character-
ized by important anatomical and physiological peculiarities.
I. CESTODES. (Tape-worms).

This order includes the numerous kinds of tape-worms and
their young, the " measles," hydatids, and bladder-worms,
found in more or less abundance in all classes of vertebrate
animals, as well as in insects, mollusca, etc. These tape-
worms belong to three very distinct families and to numerous
genera. About 250 species have been hitherto described.

These worms in the sexually mature condition have a more
or less enlarged roundish, oval, angular, or lobedhead, desti-
tute of a mouth, but provided with two or four suckers, or
pits, and often with one or four proboscis-like organs, sur-
rounded by hooks, by means of which they fasten themselves
securely to the mucous membrane of the intestine of the
animal in which they live. There is no intestine or other di-
gestive system. The head is followed by a series of many
flattish joints or segments, those near the head being small
and short, while those that are more distant are larger and
usually oblong or squarish. These joints, as they mature, are
spontaneously detached and may enjoy a short independent
existence, and are then called proglottides. Each joint con-
tains distinct male and female reproductive organs, and
matures a vast number of eggs, which are generally liberated

reference more particularly to the internal parasites of man. Large 8vo, 480
pages, *with numerous figures and 21 plates. London, 1864.

J. L. W. Thudichum. On the Parasitic Diseases of Quadrupeds used for food.
In the Seventh Report of the medical officer of the Privy Council, p. 303. Lon-
don, 1865.

T. S. Cobbold. Tape-worms (Human Entozoa), their sources, nature, and treat-
ment; 12mo, 83 pages, with figures. London, 1866.

R. Leuckart, Die Menschlichen Parasiten, und die von ihnen herrahrenden
Krankhciten. Two volumes, 8vo, with numerous figures. Leipzig and Heidel-
berg, 1862 to 1868.

54 BOARD OP AGRICULTURE.

from the enclosing proglottid after the latter has been dis-
charged from the animal that nourishes the parent tape-worm.
The eggs usually escape by the bursting of the integument of
the proglottid, owing to their increase in size, as the embryos
develop within them. While attached to the tape-worm the
successive joints are connected -together by longitudinal tubes
or ducts that pass through the entire length of the worm-, gen-
erally one near each edge of the joints. These are connected
together by transverse tubes in each end of the successive
joints (Figure 54).

The reproductive organs occupy variously branched and
ramified cavities in the interior of the joints, communicating
by ducts with the external male and female organs, which are
placed side by side, either on the edge of each joint, as in
Tcenia, or in the middle of one side, as in BotTiriocephalus.
The remainder of the joint is composed of a firm, more or
less solid tissue.

All the species of this order undergo remarkable metamor-
phoses ; the larva living in one animal must be swallowed by
another before it can become mature.

II. TREMATODES. (Flukes).

This order includes a great number of more or less flattened
worms, of which the " fluke," frequently found in the liver of
sheep, causing the " rot," is an example (Figure 73).

The body is generally broad and more or less oval, some-
times elongated, but never divided into distinct joints. On
the lower side there is usually one or two prominent suckers,
and sometimes several. There is a small mouth on the lower
side, usually near one end, but no head. The mouth com-
municates with a small, dilated oasophagus or stomach, and
this with a more or less branched and subdivided, sometimes
arborescent, intestine, the branches ending in closed tubes or
blind-sacs. Another system of branched and often much sub-
divided tubes arises in the more or less solid tissues of the
body. These tubes are at first small, like rootlets, but grad-
ually uniting into larger and larger branches, finally empty
their contents into one or two main trunks, which open ex-
ternally by one, or sometimes two orifices, near the posterior
end of the body. This is called the water-vascular system,

PARASITES OF ANIMALS. 55

and is supposed to perform the office of excretory organs,
analogous to the kidneys and liver of vertebrate animals. In
the central region of the body there is a well developed repro-
ductive system, both male and female organs being generally
contained in the same individual worm ; but in some species
the sexes are separate. All the -rest of the body, around these
organs, is composed of a rather firm and solid tissue, the or-
gans not being contained in a distinct cavity.

The species constituting this order are very numerous, be-
longing to several distinct families and many genera. About
400 species have been described. They are found in all classes
of vertebrate animals, and are numerous in their larval states
in many invertebrates, especially in fresh-water snails. They
particularly abound in fishes, frogs, and aquatic birds. Nearly
all the species undergo very remarkable transformations, with
alternate generations, some of them passing different stages of
their lives free in water, and then in two or more distinct an-
imals, as parasites. So that the adult forms, found in the
higher animals, are generally derived from larvae swallowed
in small mollusks, like the river snails, and perhaps in insects.

III. ACANTHOCEPHALA. (Thorn-headed worms.)

This order includes elongated, more or less cylindrical
worms, usually with the body encircled by distinct transverse
ridges and wrinkles, and which have at the anterior end a
prominent, elongated or conical, retractile proboscis, covered
with numerous recurved hooks, by means of which they at-
tach themselves to the mucous membrane in the intestine of the
animals that they inhabit. The body contains a large cavity,
in which the reproductive organs are contained. The sexes are
distinct. The ovary, situated in the anterior part of the body,
sets free large roundish masses of cells from which the ova are
afterward developed, while these masses, or " cocoons," are
free in the abdominal cavity, each mass containing a large
number of eggs, often several hundred. In the male the two
testicles are attached to the lower closed end of the digestive
sac, and are connected by ducts with the intromittent organ,
which is a slender spiculum, enclosed in a sheath, situated at
the posterior end of the body.

56 BOARD OP AGRICULTURE.

4|

Many observers state that these worms have no mouth and
no digestive organs whatever, but obtain their nutriment by
absorbing the nutritive materials by which they are surrounded
in the intestine of their host directly into their own tissues,
after the manner of the tape-worms. M. Lespes* states, how-
ever, that Echinorhynchus clauceveps, found in the minnow, etc.,
has a complete alimentary system. The mouth is very small, in
form of a pore, opening at the end of the proboscis and raised
upon a small mobile papilla. This mouth communicates with
a short digestive cavity, in the form of a blind sac. He states
that he has seen the refuse of the food ejected from the mouth.

Upwards of 100 species of these worms have been described,
nearly all of which are referred to the genus Uchinorhynchus.

They are especially abundant in birds and fishes.

Those species in which the development has been studied,
have a kind of alternate generation, the young embryo be-
ing very different from the parent, and afterward developing
in its interior another form, which in turn becomes like the
grandparent. M. Lespes states that E. clavceceps produces
•" cocoons " containing 150 to 200 eggs. The embryos devel-
oped in the eggs are capable of moving while still in the shell,
and remain alive for a year. On feeding a snail with food
containing these eggs, they hatched in his intestine, and the
free embryos were quite lively and active, and furnished with
two pairs of hooks for boring purposes. They had consider-
able resemblance to the free embryos of tape-worms and no
doubt have similar habits, but they failed to undergo their
transformations in the snail.

Leuckart fed the eggs of E. proteus, found in the trout and
other fishes, to a small crustacean, Gammarus pulex. The eggs
hatched in a few days and the young embryos bored their way
through the intestine into the general cavity of the body, some
of them penetrating into the limbs. In the course of three
weeks they grew larger and the granular mass still in the inte-
rior of the body of these embryos developed into a distinct or-
ganism, which afterwards developed a proboscis, muscles, and
the other peculiar organs of an Echinorhynchus, becoming gradu-

*Journal de 1' Anatomic, 1864, p. 683 ; Gunther's Zoological Record, 1865, p. 747.

k PARASITES OF ANIMALS. 57

ally more and more like its grandparent. It finally fills up
the whole interior of the body of the enclosing embryo, sexual
organs appear, and then the outer skin of the latter is cast off*.
Thus the young Echinorhynchus. is formed, but in order to be-
come mature it must be swallowed, with its crustacean host,
by some fish. In the intestine of the fish it becomes sexually
mature in about a week.

The giant Ecliinorhynchus of the hog (^JE. gigas). Figure 74,
is the only species known to infest domestic quadrupeds.
IV. NEMATODES. (Round-worms).

This order includes a great number of worms, which occur
in all classes of animals, both vertebrates and invertebrates,
together with some that are not parasitic, but live in water,
moist earth, or decaying animal or vegetable matters. They
are much more highly erganized than those of the preceding
orders. The pin -worms of children, the common round-worms
of man and domestic animals, and the notorious Trichina spi
ralis are examples of this order. (See figures 76 to 83.)

These worms are almost without exception long, round, and
rather slender, varying in length from a tenth of an inch or
less to three feet, or even more, and usually tapering to one or
both ends. The external surface of the body Js generally
smooth and uniform, without suckers or other appendages. In
the interior of the body there is a continuous visceral cavity,
containing a distinct digestive system, the intestine generally
extending from one end of the body to the other, and well de-
veloped reproductive organs, the sexes being separated. The
mouth is usually at the smaller end of the body and is often
surrounded by papillae or other organs. Some of the species
are viviparous, like Trichina ; others produce eggs, like the com-
mon round-worms and pin-worms. There is great diversity
in their habits and modes of development. Some of them
pass through alternate generations and remarkable trans-
formations, living in some cases, like Trichina, in two different
animals in the larval and adult states, in other cases pass-
ing the young states in the water, as free worms, and after-
wards becoming parasitic, when swallowed by the proper ani-
mal, in which alone they develop their reproductive organs

'58 BOARD OF AGRICULTURE.

and become mature. Some species seem to have a much
more simple history during development. There are but few
species, however, of which the complete history is known.
The Trichina spiralis is, perhaps, better understood in all
stages of its life than any other species. Important discov-
eries remain to be made, without doubt, concerning other
species that infest our own bodies, as well as those of our
domestic animals ; At present the complete histories of the
two commonest human parasites, the round-worm and pin-
worm, are still unknown, although they have been most care-
fully investigated and experimented upon by many able nat-
uralists.

Of this order about 1,000 species have been already described,
but it is probable that a considerable number of these will event-
ually prove to be only the young of others. They particu-
larly abound in mammals, birds, and fishes, inhabiting the in-
testine, stomach, windpipe, lungs, kidneys, muscles, brain, and
various other parts of the body. Twelve species or more are
liable to infest human beings.

ACARINA.

In addition to the internal parasitic worms, there are certain
parasites which belong to other groups. Among these are
certain forms of acarina, or mites, some of which are, perhaps,
only accidentally parasitic, like the Acarus dysenteries mentioned
in our previous lecture. But the genus Pentastoma includes
species which are true parasites and have nearly the same
habits as some of the parasitic worms, which, indeed, they
closely resemble in general appearance. Formerly these par-
asites were regarded as worms by all authors, but they are
now generally referred to the Acarina, although they differ
greatly from the more typical forms. One of these species
is represented in Figure 84.

PROTOZOA.

Several genera and species of infusoria have been found liv-
ing in the human body, or in the excreta, especially of pa-
tients attacked with certain contagious diseases. The effects
of these parasites and their relations to diseases are not well
understood.

PARASITES OF ANIMALS. 59

Lists of the Parasites of Man and Domestic Animals.

The number of species of these internal parasites now
known is upwards of 100. Therefore it will be impossible, at
this time, to do more than enumerate the species, with their
principal modes of occurrence, and then describe more fully
some of the most important kinds, with their effects and rem-
edies, so far as space will admit. It is hoped that the lists
will serve as a key or index for those who wish to pursue the
subject further, in the more extensive works upon this subject.

INTERNAL PARASITES OF MAN.

CESTODES.

Iccnia solium Linnaeus. Intestine, young in hog ; common.
T. mediocancUala Kuch. Intestine, young in beef; common.
T. flauopunctata Weinland. Intestine ; one case only, in the

United States. '
T. lophosoma Cobbold. Intestine, larva unknown ; one

case.

T. elliptica Batsch. Intestine ; rare, common in cats.
T. nana Siebold. Intestine ; only observed in Egypt.
Bothriocephajus latus Bremser. Intestine, larva in fish (?) ;

Europe, rare in America.
B. cordatus Leuckart. Intestine ; common in Greenland.

In the larval state.

Tccnia solium Linn. In muscles, brain, eye, etc. ; not rare.

T. marginata Batsch. Abdominal viscera ; very rare.

T. acanthotrias Weinland. In muscles, mature worm un-
known ; observed once only, in Virginia.

T. echinococcus Siebold. Tumors in liver, brain, lungs, ab-
domen, muscles, etc., adult in dog ; common.

TREMATODES.

Billiarzia Jicematobia Cobbold. Inhabits the blood-vessels, es-
pecially the portal veins and those of the kidneys and blad-
der ; very common in Africa, producing a very serious disease.

Fasciola hepatica Linnaeus. Gall-bladder and ducts, and
sometimes beneath the skin ; common in sheep, rare in
man.

60 BOARD OP AGRICULTURE.

Distoma lanceolatum Mehlis. Gall-ducts ; rare.

D. crassum Busk. Duodenum ; one case.

D. heterophyes Siebold and Bilharz. Small intestine, in large

numbers ; two cases, in Egypt.
D. ophthalmobium Diesing, (perhaps young of D. lanceola-

tum). Eye, several together ; two cases.
Tetrastoma renale Delle Chiage. Kidney ; one case.
Hexanthyridium pinguicola Treutler. In an ovarian tumor ;

one case.
H. nenat wn Treutler, (probably young). Veins ; rare.

NEMATODES.

Trichina spiralis Owen. Adult in intestine, young in muscles ;
common.

Trichocephalus dispar Rudolphi. Small intestine.

Filaria trachealis Cobbold. Trachea and larynx ; one case.
' F. lentis Diesing, (larval form). Eye; very rare.

Dracunculus medinensis. Gmelin, (Guinea-worm). In the
connective tissue beneath the skin and among the muscles.
Yery common in Arabia, Guinea, Upper Egypt, and other
parts of tropical Asia and Africa ; also in some parts of the
West Indies.

D. oculi Diesing, (loa). Orbit of the eye, in the conjunctiva,
etc. Not uncommon in tropical Africa and America, chief-
ly in the African races.

Oxyuris vermicularis Brernser, (pin-worm). In the large in-
testine, chiefly in the rectum and near the anus, sometimes
in the genital passage ; very common, especially in chil-
dren.

Ascaris lumbricoides Linn., (round- worm). Intestine, some-
times ascending into the stomach, rarely passing into the
abdominal cavity by perforating the intestine ; very com-
mon.

A. mystax Rud. (round-worm of cats). Intestine ; rare in
man, common in the cat.

Eustrongylus gigas Diesing, (kidney-worm). Kidney ; rare
in man.

Strongylus bronchialis Cobbold. Bronchial tubes ; very rare.

PARASITES OP ANIMALS. 61

Dochmius duodenalis Leuckart. Small intestine ; Italy,
much more common in Egypt, causing very serious disease.

ACARINA.

Pentastoma dentimlatum Rud. (Probably the young of P.

tcenioides of the dog.) In cysts on the liver, etc. ; not very

rare.
P. comtrictum Siebold. Liver and lungs ; common in Egypt.

PROTOZOA.

Paramecium coli Malmstein. Colon, excreta.
Cercomonas intesiinalis Lambl. ((7. ^ommisDavaine). Intes-
tine ; from a cholera patient.
Variety B. From a typhoid fever patient.
C. urinarius Hassal. In urine.
C. saltans Ehrenberg.

Trichomonas vaginalis Donne". Vagina, in mucus.
PsorospermSj (perhaps the eggs of Distoma).

In addition to the preceding species of true parasites,
various kinds of insect larvae have been known to live for a
time in the human stomach and intestine, from which they
have been discharged either by vomiting or purging.

Among the most common larvae that may thus live in the
human body are those of the various species of meat-flies, blue-
bottle-flies, blow-flies, or flesh-flies (see page 101), and those
of the house-fly. Several species of the genus Homalomyia
have also been known to occur in this way, the eggs or larvae
having been swallowed with fruit, and more especially in de-
cayed fruit, in which they naturally live.* Such larvae often
cause considerable irritation of the intestine, and diarrhoea,
but as their life in the larval state is very short, they must
soon pass from the intestine or perish in it.

INTERNAL PARASITES OF THE DOG.

CESTODES.

Tcenia echinococcus Siebold. Intestine, many together ; larvae
in sheep, cattle, and man ; common.

*These insects are well described by Mr. B. D. Walsh in the American En-
tomologist, vol. II, page 137, 1870.

62 BOARD OP AGRICULTURE.

T. coenurus Kiich. Intestine, many together ; not rare.
Larvae in sheep.

T. marginata Batsch. Intestine, few or singly ; common.
Larvae in sheep and cattle.

T. serrata Goeze. Intestine ; common. Larvae in rabbits.

T. canis-lagopodis Rud. Intestine ; in Iceland common. Lar-
vae unknown. Perhaps same as T. Utter ata Batsch.

T. cucumerina Bloch. Intestine ; very common. Larvae un-
known.

T. solium Linn., (in cysticercus state). Muscles, brain, etc.

Bothriocephalus lalus Bremser. Intestine ; not common.

B. cordatus Leuckart. Intestine ; very common in Green-
land.

B. fuscus Krabbe. Intestine ; not rare in Iceland.
" " var. reticulalus Kr. " " "

"" " var. dubiusKr. " " "

Dibothrium serratum Diesing. Intestine ; very rare.

TREMATODES.

Holostoma alatum Nitzsch. Intestine ; less common than in
the fox.

NEMATODES.

Trichina spiralis Owen. Intestine (mature) ; larvae in

muscles.
Spiroptera sanguinolenta Rudolphi. (Esophagus, stomach, and

heart, larvae in blood ; very common in China.
Irichosoma plica Rudolphi. Bladder ; rare.
Trichocephalus depressiusculus Rud. Coecum ; not common.
Ascaris marginata Rud. Small intestine ; very common.
Pseudalius filum Duj.(?). Heart and pulmonary artery,

recorded by Collas ; originally from porpoise.
Eustrongylm gigas Diesing. Kidney ; rare.
Dochmius trigonocephalus Duj. Intestine, larvae in water ;

rare.

Filaria trispinulosa (larval form) . Eye.
F. sanguinis (larval form). In blood.
F. immitis Leidy. Heart.

PARASITES OP ANIMALS. 63

Dracunculus medinensis Cobbold. Sub-cutaneous tissues ; in
tropical- Asia, Africa, and America.

ACARINA.

Pentastoma tcenioides Rudolphi. Nostrils ; not rare. Larvae

in man and cattle.

That thousands of lambs and sheep are annually killed by
dogs that have a taste for mutton of their own procuring is
unfortunately too well known to most of the farmers in this
country, especially in those States where neither stringent
laws nor severe taxes have diminished the numbers of these
useless curs.

That the number of dogs in every part of the country is by
far too great, and even dangerously so, is generally admitted,
especially during the summer, when mad dogs and hydropho-
bia are the constant theme of conversation in our cities. That
the laws of every State ought to impose restrictions, or, at
least, very high taxes upon the owners of dogs is evident and
advocated by many legislators. Yet it is not, by any means,
generally known to what an alarming extent our flocks are in-
jured in health and depreciated in value by the parasites de-
rived directly from dogs. Still less is it known to what an
extent human lives and health are sacrificed on account of
these animals.

There are three principal and very important parasites of
sheep derived from tape-worms of dogs. These are : 1. The
" water-brain" of sheep, which is produced by the young or
larvas of a small tape-worm (Tcenia ccenurus) ; 2. The ech-
inococcus, or hydatid tumors of sheep, of cattle, and of man,
found Jn various organs, but most commonly in the liver,
brain, and kidneys, which are caused by the young of a very
small dog tape-worm (Tcenia echinococeus) ; 3. The diving
bladder-worm, or u water-bladder," often found in the abdo-
men of sheep, cattle, and pigs, frequently forming tumors as
large as a hen's-egg, or even a goose-egg, which is the young
of a larger tape-worm of the dog (Tcenia marginata). There
are, also, others of less importance obtained by sheep from
dogs, as indicated in the lists.

64 BOARD OF AGRICULTURE.

It is perfectly safe to say that at least twenty-five sheep are
killed by parasites derived from dogs, for every one killed by
the teeth of dogs ! It is also safe to say that more than fifty
persons die from the same parasites, for every one that dies of
hydrophobia ! And yet this work of destruction goes on
silently and almost unobserved, except by professional men
week after week and year after year. The loss of human life
every year more than counterbalances all the good that all the
dogs in the civilized world can possibly do. In Iceland it is
stated that one-sixth of all the deaths are caused by one of
the dog-parasites (EchinococcMs) . The same parasite occurs
also, not unfrequently, in all other parts of the world where
dogs are kept, and causes most horrible disease and death.
To this we may add the Pentastoma^ which man also derives
from dogs, and in all probability several other parasites, in-
ternal and external.

INTERNAL PARASITES OF THE CAT.

CESTODES.

Tcenia crassicollis Rud. Intestine, young in rats and mice.
T. elliptica Batscli. Small intestine ; common.
T. canis-lagopodis Rud. Intestine ; common in Iceland.
Dibothrium dedpiens Diesing. Intestine, also in leopard,
ounce, etc. Perhaps Bothriocephalus felis Creplin.

TREMATODES.

Amphistoma truncatum Rud.

Distoma lanceolatum Mehlis. Bile ducts ; rare.

NEMATODES.

Trichina spiralis Owen. Intestine, young in muscles.
Dochmius tubceformis Dujadin. Duodenum.
Ollulanus tricuspis Leuck. Intestine, and young in muscles.
Ascarismystax Rud. Small intestine ; common.

ACARINA.

Pentastoma denticulatum Rud. Cysts on liver, etc.

This list includes all those that I have found recorded from
the house cat, but doubtless many others may occur.

PARASITES OF ANIMALS.

INTERNAL PARASITES OF SHEEP.

65

CESTODES.

Tcenia expansa Rud. Mature, in small intestine.

Tcenia. (Undetermined species with hooks.) In cysticercus
state in muscles.

T. marginata Batsch. Young or cysticercus state in viscera,
adult in dog ; common.

T. coenurm Kuch. Young or encysted state in large tumors
in the brain, adult in dog ; common.

T. echinococctts Siebold. Young or hydatid condition in liv-
er, lungs, brain, and other organs, adult in dog ; common.

TREMATODES.

Fasciola Jiepatiea Linn. Liver and bile ducts.
Distoma lanceolatum Mehlis. Bile ducts.
Ampkistoma conicum Rud. First stomach.

NEMATODES.

Ascaris ovis Rudolphi. Intestine ; rare.
Trichocephalus ovis (affinisf). Large intestine ; common.
Sclerostoma hypostomum Dujadin. Intestine.
Strongylus contortus Rud. Small intestine.
S. filicollis R,ud.. Small intestine. Perhaps same^ as last.
S. filaria Rud. Trachea and bronchial tubes ; common ; also
in the goat.

ACARINA.

Pentastoma tcenioides Rud. Larynx, nostrils, etc.

The goat is infested by many of the parasites found in
sheep. Besides these, there are a few peculiar species;
among them are Tcenia caprce and Strongylus venulosus Ru-
dolphi, both found in the intestine.

INTERNAL PARASITES OF CATTLE.

CESTODES.

Tcenia expansa Rudolphi. Intestine, mature ; not common.
T. denticulata Rud. Intestine, mature ; rare.
T. mediocanellata Kiich. Young or cysticercus state in mus-
cles, adult in man ; common.
9

66 BOARD OF AGRICULTURE.

T. marginata Batsch. Young or cysticercus state in viscera,

adult in dog ; common.
T. echinococcus Siebold. Young or hydatid state in liver,

brain, and various other organs, adult in dog ; common.
T. coenurus Kiich. Young state in brain, adult in dog ; rare.

TREMATODES.

Fasciola Tiepatica Linn. Liver, gall-ducts, etc.; not rare.
Distoma lanceolatum Mehlis. Liver ; not uncommon.
Amphistoma conicum Rud. First stomach ; common.
A. crumeniferum Creplin. Stomach.
A. explanatum Creplin. Bile ducts.

NEMATODES.

Trichina spiralis Owen. Observed only in experimental an-
imals.

Trichoceplialus affinis Rud. Large intestine ; frequent.
Strongylus radialus Rud. Duodenum, colon, small intestine.
S micrurus Mehlis. Trachea and bronchial tubes.
Eustrongylus gigas Diesing. Kidney ; rare.
Filaria lachrymalis Gurlt. Lachrymal ducts, etc.
F.papillosa Rudolphi. Abdominal cavity, etc.; rare.

ACARTNA.

Pentastoma tcenioides Rud. Nasal cavaties, larynx, etc.
P. denticulatum Rud. (Young of preceding.) In cysts on
liver, etc.

INTERNAL PARASITES OF THE HORSE.

CESTODES.

Tcenia perfollata Goeze. Swell intestine, colon, ccecum ;

common, and sometimes in vast numbers.
T. plicata Rud. Stomach and small intestine ; common.
T. mamillana Mehlis. Large intestine ; common.
Tcenia, (species undetermined). Young state {cysticercus

fistularis) in peritoneum.

T. coenurus Kuch. Young or encysted state in brain ; rare.
T. echinococcus Siebold. Hydatid state in liver, etc.; not

common.

TEMATODES.

Fasciola hepatica Linn. Liver, gall-bladder, etc.

PARASITES OP ANIMALS. 67

NEMATODES.

Ascaris megalocephala Cloquet. Small intestine ; common.

Oxyuris curvula Rudolphi. Colon, coecum, rectum ; common.

Eustrongylus gigas Diesing. Kidney, etc.

Sclerostoma equinum Blainv. Duodenum, colon, coecum, pan-
creas, sometimes very numerous, and in enlargements of
the arteries; common.

S. tetraoanthum Diesing. Duodenum, ccecum, .colon.

Strongylus micrurus Mehlis. Trachea and bronchial tubes.

Filaria microstoma Schneider.

F. papillosa Rud. Abdomen, thorax, brain, eye, intestine.

F. lachrymal™ Gurlt. About the eyes, in lachrymal ducts, etc.

Spiroptera megastoma Rud. Tubercles in stomach.

Dracunculus medinensis Cobbold. (Guinea-worm). Subcu-
taneous tissues ; only in tropical parts of Africa, Asia, and
America.

ACARINA.

Pentastoma tamioides Rud. Nasal cavities, larynx, etc.

The mule and ass are subject to the same parasites as the
horse, but not to the same extent. The number of species
hitherto observed is less, and they are far less common.

INTERNAL PARASITES OF THE HOG.

CESTODES.

Tcenia solium Linn. In the larval or cysticurcus state in the

abdominal viscera.

T. marginata Kiich. Cysticercus state in the abdominal viscera.
T. echmococcus Siebold. Hydatid state in liver, etc.; not

common.

TREMATODES.

Fasciola hepatica Linn. Liver and bile ducts.
Distoma lanceolatum Mehlis. Bile ducts.

ACANTHOCEPHALA.

Echinorhynchus gigas Goeze. Small intestine ; common.

NEMATODES.

Trichina spiralis Owen. Mature in intestine, young in mus-
cles ; common.

68 BOARD OF AGRICULTURE.

Ascaris suilla Dujardin. Small intestine ; common.
Spiroptera strongs/Una Rud. Stomach.
Simondsia paradoxa Cobbold. Stomach, in cysts ; one case.
Trichocephalus crenatus Rud. Large intestine.
Strongylus dentatus Rud. Coecum, colon.
S. elongatus Dujardin. Bronchial tubes.
S. paradoxus Mehlis. Trachea and bronchial tubes.
EustrongyluB gigas Diesing. Kidneys, etc.
Sclerostoma pinguicola Verrill. In fat about kidneys and "spare-
ribs," in large numbers ; probably common.

ACARINA.

Pentastoma denticulatum Rud. Cysts on liver, etc.
INTERNAL PARASITES OF POULTRY.

CESTODES.

Tcenia infundibuliformis Goeze. Intestine of hens, ducks,

geese, etc.

T. proglotlina Davaine. Duodenum of hens ; common.
T. crassula Rud. Intestine of pigeons, hens, and geese.
T. malleus Goeze. Intestine of geese and ducks, etc.
T. lanceolata Goeze. Intestine of geese and ducks, etc.
T. setigera Froh. Intestine of geese ; common.
T. sinuosa Rud. Intestine of geese and ducks.
T.fasciata Rud. Intestine of geese ; common.

TREMATODES.

Monostoma mutabile Zeder. Sub-orbital cavities of geese, etc.

M. variabile. Geese.

M. triseriale. Geese. Perhaps same as the next.

M. verrucosum Zeder. Ducks, in coecum.

M. caryophyllinum Bremser. Ducks. Originally described

from fish.

Distoma ovatum Rud. Oviducts, etc., of geese and ducks.
D. linear e Zeder. Large intestine of hens.
D. dilitatum Miram. With last.
D. echinatum Zeder. Intestine of ducks and geese.
D. oxycephalum Rud. Same habits as last.

ACANTHOCEPHALA.

Echinorhynchus polymorplius Bremser. Intestine of ducks.

PARASITES OF ANIMALS. 69

NEMATODES.

Heterakis compressa Schneider. Intestine of chicken.

If. vesicularis Duj. Intestine of hens and turkeys.

H. dispar Duj. Intestine of geese.

Ascaris crassa Desl. Intestine of ducks.

A. inflexa Rud. Intestine of hens.

A.perspicillum Rud. Intestine of turkey.

A. maculosa Rud. Intestine of pigeon.

jSpirotera hamulosa. Gizzard of hens.

S. uncinata Rud. Tubercles in oesophagus of geese.

Syngamus trachealis Siebold. Windpipe, causing "gapes.''

Strongylus nodularis Rud. Gizzard and intestine of ducks

and geese.

In the preceding lists we have brought together most of the
parasites hitherto discovered in our more common domestic
animals. There can be no doubt but that many more will
hereafter be discovered. In the rabbit, Guinea-pig, parrots,
singing birds, and other animals often domesticated, many
additional species occur.

In the following pages only the more common and impor-
tant species will be described.

The Armed Tape-worm or Pork Tape-worm of Man (Tcenia
solium Linn.) ; and its young, the " measles" of pork and hu-
man flesh.

This is perhaps the best known of all the numerous kinds of
tape-worms. Its young or larvae are common in the muscles
and other organs of hogs, and not very rare in man. (See
Figures 49-51.) In the adult stale it is, so far as known, pe-
culiar to the human intestine, where it is unnecessarily com-
mon! It grows to a great length, frequently ten to fifteen
feet, or even more, and is then composed of upwards of 800
joints, those that are sexually mature commencing at about the
450th segment. The head is small, about the size of a pin-
head, roundish, with four prominent suckers on the sides, and
a conical, proboscis-like top, around which there are two cir-
cles of sharp hooks, 22 to 28 in each circle (Figure 53).
The neck portion is slender, crossed by fine lines, which are
wider apart as they recede from the head, finally forming dis-

70

BOARD OP AGRICULTURE.

tinct joints. These are at first very small and short, gradually
becoming broader and squarish, then oblong. The largest
are about a third of an inch in breadth and quite thin and flat
(Figure 52). The sexually mature joints or proglottides are
twice as long as broad, and contain the ovaries and a long
central egg cavity or uterus, with 7 to 12 lateral branches,
which are irregularly lobed and divided (Figure 54) ; and also
the male organ, or testicle, in the form of branched tubes,
communicating with a penis, which is situated on one edge
of the joint, in front of the female genital orifice, and has a
curved or sickle-shaped form. The genital openings are either
on the right or left edge indifferently, in the successive joints.

Figure 49. Figure 52.

The young or larval state produces the white spots known as

Figure 49. — Pork " measles" ; natural size; Hearth and Home, after Owen.

Figure 50. — Young tape worm from measles of pork; and Fig. 51, head of same,
more enlarged ; Hearth and Home, after Owen.

Figure 52. — Pork tape-worm (Tcenia solium), less than natural size ; Hearth and
Home, after Owen.

PARASITES OP ANIMALS.

71

/ measles " in pork (Figure 49)-. These are cavities or cysts
produced by inflammation, containing whitish fluid and enclos-
ing small, bladder-like, translucent, vesicles, filled with a watery
fluid, and which contain the proper head and neck of the young
worm coiled up spirally in the interior in an inverted position.
By gentle pressure the head and neck may be made to protrude
by inversion, like the finger of a glove, and will then present
the appearance shown in figure 50, the vesicle of fluid now
forming the flask-like caudal portion of the worm. The head
may now be seen to have four suckers and a central promi-
nence surrounded by two circles of hooks, as in the adult. In
this condition, enclosed in the cysts, they will remain living

Figure 53. Figure 54.

V

for a long time in the hog, even surviving the death of their
host for a considerable period. If one or more of these young
worms or measles be swallowed by a human being, the mus-
cular fibres and the cysts will be digested, and each young
worm thus liberated will evert its head, and losing its bladder-
like portion, will pass into the intestine. There it will fasten
itself to the inner membrane by its suckers and hooks, and
grow rapidly by absorbing the digested food by which it is
surrounded. New joints will be rapidly formed as the older
ones grow larger, until it becomes a mature tape-worm, with
joints ready to be cast off. There may be but one tape-worm in

Figure 53. Head of Tcenia solium, magnified. From Cob bold.
Figure 54. — A joint or proglottis of Tcenia solium, magnified ; a, branches of the
uterus ; &, external orifice ; c, male organ. From Cobbold.

72 BOARD OF AGRICULTURE.

the human intestine, or there may be several together, the
number depending only upon the number of living young-
swallowed.

It is, therefore, obvious that this tape-worm can be acquired
only by eating raw or under-done pork. In this country the
principal kinds of food serving as sources of this tape-worm
are raw smoked ham and raw sausages, but soldiers and others
are often obliged to eat their pork-rations uncooked, and thus
obtain the parasites. Our recent war was the means of greatly
increasing the numbers of this and other parasites, both in-
ternal and external.

Persons harboring the mature tape-worms become in their
turn the means of diffusing the race. Each mature joint cast
off contains several thousands of eggs, each of which encloses
an embryo, nearly ready to hatch, and as these joints are con-
tinually being discharged during the whole life of the worm,
which may be ten or twelve years, it is evident that one per-
son may thus be the means of diffusing many millions of eggs,
most of which will no doubt perish, but the chances are good
that some of them will find their way into the stomachs of
hogs, either with their food or in water.

The free joints or proglottides have an independent life for
a few days and are capable of moving and crawling about to
a considerable extent. In a short time, however, the myriads
of embryos in the interior so increase in size that the walls of
the proglottis burst open and thus liberate the eggs. The
eggs are globular and very small, their average diameter
being about ^4 of an inch ; the shell is comparatively
thick, being s^W of an inch. They are so small that they
may be blown about by the winds, carried on the feet of in-
sects, or may be suspended in unfiltered waters. They may,
therefore, also readily adhere to lettuce, celery, and other
garden plants, or to fallen fruit, especially when night-soil is
used as manure, and unless such food be carefully and
thoroughly washed, there is always more or less danger of
eating the eggs of this and other parasites. When these eggs
are swallowed, either by hogs or human beings, they hatch as
soon as acted upon by the gastric juice, and disclose their con-

PARASITES OP ANIMALS. 73

tained embryos, which are very different from both the old
worm and the measle-worm. They are provided with six
hooks or spines, placed in three pairs upon the head. By
means of these they quickly bore their way through the walls
of the intestine into the blood-vessels, and are thus carried to
all parts of the body. They finally lodge in various organs,
but especially in the muscles, liver, brain, eyes, lungs, and
heart. They then excavate galleries for themselves in these
situations, causing, if in large numbers, a great amount of
inflammation and disease, which in some cases proves fatal.
The inflammation soon causes cysts to be formed around the
intruders, by which they are enclosed and restricted in their
motions. Thus the " measles" in the muscles of hogs and
man are formed. After this the patient may recover, unless
these parasites have lodged in the brain or other vital organs, so
as to produce serious symptoms subsequently. In the human
subject more than 100 cases have been recorded in which
these parasites have taken up their abode in the brain, causing
epilepsy, insanity, and sometimes sudden death. In such
cases, which are probably more common than is generally im-
agined, there can be no relief. There have also been recorded
quite as many instances in which these cysticerci or larval tape-
worms have been situated within the ball of the eye, causing
a partial or total loss of sight, and sometimes great inflamma-
tion. Many of these have been successfully removed. In
other important organs they are liable to produce serious
trouble. But when in the subcutaneous, areolar, or inter-
muscular tissues, they may often be easily removed by the
surgeon. In hogs they are much more liable to produce these
results, because hogs are likely to swallow whole joints, or
even entire tape-worms, while human beings seldom swallow
more than a few dozens of eggs.

The effects and symptoms caused by the adult tape-worms
are discussed under the next species, together with the
remedies.

As means of prevention every one should avoid eating pork,
in any form, that has not been .thoroughly cooked. In this
way it is easy to avoid the mature tape-worm of this species.
10

74 BOARD OF AGRICULTURE.

To prevent measles in hogs they should not be allowed to have
access to human excrement, the reverse of which is too often
specially provided for by farmers. To avoid the same para-
sites in our own flesh we must take care to have all fruit and
other uncooked vegetable food well washed and our drinking
water pure.

The Beef Tape-worm of Man (Tcenia, mediocanellata Kuch.) ;
and its young, the " measles" of veal and beef.

This is a very large species, which was formerly generally
known as the unarmed variety of the human tape-worm. It
is known to occur among all beef-eating people, and is the
common species in Africa, Western Asia, and several European
countries, especially in Austria, Turkey, and certain parts of
Russia.

It has long been known that Jews, Mohammedans, and other
people who never eat pork, are nevertheless liable to be in-
fested by tape-worms. It was also observed, many years ago,
that infants fed upon dried beef — a custom much practised at
St. Petersburg — were liable to have the same parasites ; and
these facts were formerly brought forward as arguments
against the doctrine that the common tape-worm is derived
from eating the larval form contained in measly pork. BUG
it was soon discovered that nearly all the tape-worms obtained
from patients in Mohammedan countries, as well as in Austria,
and some other parts of Europe where pork is little used, were
destitute of the two circles of peculiar hooks around the cen-
tral, proboscis-like prominence of the head, as well as the
prominence itself, which are very conspicuous features in the
common tape-worm of pork-eating people. Owing to these
peculiarities, naturalists began to consider the two forms
either as different varieties or different species. The source
of the unarmed tape-worm remained uncertain, however, until
direct experiments were undertaken by Leuckart, Mosler, and
others to settle this question. Thus it was discovered that
when the joints or eggs of the unarmed tape-worm ( Tcenia
mediocanellata) were given to calves, the eggs hatched in the
stomach, and the young embryos worked their way, by means

PARASITES OP ANIMALS. 75

of their six boring hooks, through the intestine into the cir-
culation and, lodging in the muscles, caused serious disease
or death, if in too large numbers, and after a time became
enclosed in little capsules, producing, in fact, " measly" veal
or beef, as shown in Figure 55, which represents part of a
muscle of the hind leg from a calf that had been fed by Drs.
Cobbold and Simonds upon the eggs of this tape-worm, and
killed three months afterward. The flesh of this calf was
estimated to contain over eight thousand measles, and yet,
although at first it had been seriously ill from the effects of
the parasites, it was at the time when slaughtered perfectly

Figure 55. Figure 56.

healthy and fat. The measles of veal or beef are much
smaller than those of pork, and if they existed only in
moderate numbers, would scarcely be detected either by the
butchers or consumers. They are seldom larger than a small
pea. One of these u measles," when examined with the
microscope, is found to consist of an outer oval cyst or mem-
branous sac, enclosing loosely in its cavity a more delicate
vesicle filled with fluid and containing the inverted head of
the young tape-worm, as represented in Figure 56. The head
has four well-marked suckers, but has no central proboscis
and no circle of hooks — differing therefore from the pork-
measle, or cysticercus, in just the same way that the heads of
the mature tape-worms differ from each other. Thus it was
definitely settled that the unarmed or bookless tape-worm of

Figure 55. — Measles in veal,"reduced. Hearth and Home, after Cobbold.
Figure 56. — One of the measles magnified. Hearth and Home, after Cobbold*

76

BOARD OP AGRICULTURE.

man ( Tcenia mediocanellata) is obtained by eating the young,
in the shape of "measles," in raw or slightly cooked beef and

Figure 57. Figure 58.

Figure 59.

veal. And thus the presence of tape-worms in infants fed on
dried beef, as well as in Jews and others not guilty of eating

Figure 57. — Tcenia mediocanellata, natural size. Hearth and Home, after
Leuckart.

Figure 58. — Head of beef tape- worm, magnified. Hearth and Home, after
Leuckart.

Figure 59. — A joint of the beef tape-worm, showing the ovaries, enlarged. Hearth
arid Home, after Leuckart.

PARASITES OP ANIMALS. 77

pork, is fully explained. Since these facts have been ascer-
tained, search has been made for " measles" in beef from
animals not experimented upon, and they have been found in
several instances.

When such beef is swallowed by man, without cooking, the
young tape-worms are liberated from their capsules or cysts
by the process of digestion ; the head becomes protruded, and,
passing into the intestine, it fastens upon the lining mem-
brane by its suckers. There it rapidly grows larger, new
joints are developed, and the body grows longer and longer,
the form of the joints changing as they grow, until those that
are most mature become square, and finally oblong, as shown
in Figure 57, which represents a beef tape-worm, of natural
size, in several sections, the intermediate joints being omitted.
When full grown, which requires three or four months, one of
these tape-worms may contain over 800 joints, of which 860
to 400 of the last ones will be sexually mature, each one con-
taining 5000 or more eggs. This species is much larger than
the pork tape-worm (T. solium}, as well as longer, its length
being sometimes twenty feet, and its greatest breadth half an
inch, while the joints are thicker and stouter, or have a plump
look, instead of being thin and flat, as in the other. The
head, as already intimated, is quite different in the two species
— that of the beef-worm being larger and flat, or even concave,
at the end, with four large suckers on the sides, as shown,
greatly magnified, in Figure 58. The joints themselves are
very different internally, the egg-masses or uteri being very
numerous, and crowded together in a more parallel manner
(Figure 59) in this than in the pork tape-worm, in which
they are fewer and more aborescently branched. The mature
joints, filled with eggs, are cast off, as in other tape-worms,
and leaving the intestine, have an independent existence for
a few days, when they burst by the enlargement of the embryos
in the eggs. The eggs are thus scattered about in manure, in
water, in the drainage of cess-pools and sewers, by the winds,
and by insects. It is not strange, therefore, that cattle should
occasionally swallow such eggs with their food and drink,
especially if we reflect that one man, harboring only one of

78 BOARD OF AGRICULTURE.

these worms, may thus scatter about, during a single year,
more than a thousand joints, and if each of these contains but
5000 eggs, he would thus diffuse 5,000,000 eggs, each con-
taining an active embryo, ready to leave its shell the moment
that it enters the stomach of a calf, cow, or ox. Young ani-
mals seem to be more liable to be infected by them than old
ones. Fortunately these young worms retain their vitality
for but one year when enclosed in the flesh, and after* that
die and, withering away, leave only a very small yellowish
spot, containing calcareous particles. The adult worm, if
left undisturbed, will live in a person ten or twelve years,
constantly dropping its joints. Among the Burates, or Cos-
sacks of ihe Baikal region, this species is very abundant.
Their habits of eating chiefly the raw or slightly cooked flesh
of cattle, sheep, camels, horses, and goats, while they devour
the liver, kidneys, and fat quite raw, would lead us to expect
that this and other parasites might abound in their bodies,
which proves to be the case. According to Dr. Kaschin in 130
post mortem examinations only two bodies were found with
out this tape-worm, and among 500 hospital patients every
one had it. Sometimes as many as fifteen specimens were
found in one person.

It has been supposed until within a short time that the
beef tape-worm (Tcenia, mediocanellata) was very rare in
Great Britain and the United States, where the pork tape-
worm was thought to be the only one that was at all common
in man. Dr. Cobbold has shown, however, in his late works
on parasitic worms, that the beef tape-worm is really quite as
common in England as the pork tape worm, the wealthier
classes generally harboring the former, and the poorer people
the latter. I am convinced that, even if not so common as
the pork tape-worm, the beef tape-worm is by no means so
rare in America as is generally supposed. The Museum oi
Yale College possesses one large specimen, raised by a citizen
of New Haven, and many other museums in the United States
no doubt contain them, labelled, however, " Tceniq solium." In
fact, probably not one physician in a thousand, in the country
at large, possesses the knowledge of the subject requisite for

PARASITES OF ANIMALS. 79

distinguishing the two species and, therefore, both are con-
founded together as " the common tape-worm."

In this country persons generally obtain this parasite by
eating dried beef and Bologna sausages uncooked. In the lat-
ter, there may be not only the young of this tape-worm, but
also those of the pork tape-worm and Trichina, since there is
also an admixture of pork. It is therefore evident that it is
unsafe for the individual, and even a wrong to the community
for persons to indulge in eating raw meats of any kind, for
we find that pork, beef, and mutton may each contain the
young of different tape-worms and other parasites, and per-
sons who harbor these worms in their own bodies become, in
one sense, a nuisance, since they thus serve as the propaga-
tors and disseminators of parasites. And although one or
two of these tape-worms may not cause any serious trouble in
the bowels of one man, in another they may produce very
grave consequences, and still more so, if, as often happens,
several live together in one person.

Symptoms.

The symptoms and treatment are the same for both species
of human tape-worms, but the species now under considera-
tion is said to be more easily destroyed than T. solium, per-
haps because it does not have so secure an anchorage as the
latter has, with its hooks well imbedded in the membranes.

The symptoms vary greatly, according to the temperament
and other peculiarities of the person affected. Sometimes it
causes little or no marked disturbance of the health, though
causing perhaps more or less weakness, lassitude, and sense of
weariness, often accompanied by restlessness, nervous irritabil-
ity, and headache, which are nearly always attributed to other
causes. In more severe cases, these symptoms become much
increased, the headache especially, which is often accompa-
nied by giddiness. " The sight and hearing may be affected ;
noises in the head, itchings at the nose and anus, obscure
pains about the body and limbs, loss of appetite, -and other
dyspeptic symptoms, show themselves in greater or less de-
gree in different cases. One of the most common symptoms,
however, which I have noticed, is the tendency to faintness.
This is sometimes so marked as to create much alarm, and a

80 BOARD OF AGRICULTURE.

person uninformed as to the true cause of the disorder might
be led to treat the symptom as arising from a totally different
source. In female patients the nervous symptoms display
features more or less peculiar to the sex. The restlessness
and anxiety are excessive, and at times accompanied by cho-
rea and fits of hysteria. In the worst cases, in both sexes,
the cerebral disturbance may show itself in convulsions and
epileptiform seizures. I regret to have to add that in not a
few instances even mania itself has been entirely attributable
to the presence of tape-worms in the intestinal canal." Such
are the usual symptoms, according to Dr. Cobbold. Many un-
usual and remarkable cases are on record. In one instance,
mania of eight years duration was completely cured by the
removal of the parasite. In another, hysteria was caused by
eighteen tape-worms in one patient. Many cases of insanity,
due to this cause, arc also on record. The best and perhaps
only sure evidence of tape-worms is the passage of the joints
from the intestine.

Remedies.

The remedies for tape-worms are numerous and, if fresh
and pure drugs be used, there are several that appear to be
perfectly reliable in most cases. These remedies should, how-
ever, be administered with proper precautions. Therefore, pa-
tients afflicted in this way should immediately place them-
selves under the care of a reliable and competent physician.

The remedies chiefly used are the oil or root of male-fern,
kousso, kamala, oil of turpentine, panna, pumpkin-seeds, and
pomegranate-root bark. These are generally administered
while the patient fasts. The pumpkin-seeds are perhaps the
most domestic remedy, as well as one of the best, and safest in
the hands of inexperienced persons. The fresh seeds may be
bruised or pounded in a mortar, and mixed with water into a
paste, of which the patient may eat freely, morning and even-
ing, at the same time fasting, or eating sparingly soups or similar
food. The root of the male-fern (Aspidium filix mas) is gen-
erally regarded as the most certain remedy, if fresh and pure.
The dose for an adult is ten to fifteen grammes of the powder,
morning and evening, followed by a purgative. The etherial

PARASITES OP ANIMALS. 81

extract is generally more effectual, however. The patient
should have a sparing diet of soup, etc., for twelve or fifteen
hours before taking the medicine, and the second dose should
be followed, after an hour or two, by a purgative like castor-
oil. These remedies are mentioned here not to encourage
self-treatment, but for the benefit of those who may not be
within reach of a reliable physician.

The margined Tape-worm of the Dog (Tcenia marginata
Batsch) ; and its young, the " diving bladder-worm " of
Sheep and Cattle.

The young of this parasite are very frequently found in the
abdominal cavity of sheep, either attached to various parts of
the viscera, especially the liver and mesentery, or else nearly
or quite free among the organs, so that when the sheep are
opened, the bladder-like sacs fall out, of their own accord.
These are usually known to butchers as " water-bladders."
When attached to the organs, these bladders or sacs are usu-
ally enclosed in a cyst or membrane, formed by the inflamma-
tory action that they cause. The sac is soft and whitish, en-
closing a watery fluid, and varies in size from that of a pig-
eon's egg, or less, to that of a child's head ; but it is rather un-
common to find them larger than a hen's egg. In form they
are often globular, but more frequently pear-shaped, as repre-
sented in Figure 60. If one of these bladders, while still en-
closed in its cyst, be placed in a plate of warm water and care-
fully examined in a good light, there may be dimly seen in the
interior, near the upper end, the outlines of the head and neck,
which are turned inward, as usual in most young tape-worms ;
but what is singular in this case, the head and neck alternately
rise and sink in the fluid of the interior, with remarkable reg-
ularity. From this peculiarity it lias received the name of
" diving blacbder-worm." This motion is produced by a pe-
culiar arrangement of muscular fibres in the interior, which
are attached to the neck. At the top of the little knob on the
upper end of the bladder there is a small slit, from which, by
gentle pressure, the neck may be gradually forced out, so as
to project externally, and finally the head also appears. In
11

82 BOARD OP AGRICULTURE.

this condition the creature has a flask-shaped form. The neck
tapers gradually from the bladder to the head, and is divided
transversely into a series of many short joints. The head is
but little enlarged, bearing four suckers, as usual, and in the

Figure 60.

Figure 61.

center has a proboscis, surrounded by two rows of hooks, con-
taining from sixteen to twenty-four pairs. Sometimes there
are found in large bladders of this kind a few secondary blad-
ders attached to the inside of the large one, produced by a
process of budding, somewhat as in the water-brain, or coenu-
rus. This parasite, as thus characterized, was formerly sup-
posed to be a distinct and peculiar species, and received the
name of " Cysticercus tenuicollis" or slender necked bladder-
worm. Recent investigation and experiments have, however,
proved it to be only the young or larval condition of one of the
common tape-worms of the dog (Tcenia marginata). Blad-
der-worms of the same kind are found, though less commonly, in
cattle and horses, as well as in pigs, monkeys, and many other
animals, and very rarely in man. Owing to the large size to

Figure 60. Diving bladder-worm, from a sheep ; natural size. Hearth and
Home, after Thudichum.

Figure 61. Head of Ttenia marginata, enlarged. Hearth and Home, after
Thudichum.

PARASITES OF ANIMALS. 83

which this parasite grows, it is always liable to produce se-
rious disease, or even death; but the symptoms that it causes
and the danger will depend very much upon the situation of the
tumors. In some districts it is extremely common. According
to Dr. Thudichum, it occurs in nearly every sheep slaughtered
in London ; and the dogs that feed upon the offal of slaughter-
houses nearly always have the mature tape-worms in abun-
dance.

When a dog swallows one of these bladders, either free or
in its cyst, the bladder portion is digested, and the head be-
comes protruded ; on reaching the intestine, it fastens itself to
the membrane by means of its suckers and hooks. In this
situation, it rapidly develops new joints, and in the course of
three or four months becomes a mature tape-worm, about
three feet in length, and begins to discharge its ripe joints
filled with eggs. A dozen or more of these tape-worms may
exist together in the intestine of one dog. In general appear-
ance, this tape-worm (Tcenia marginata) resembles the pork
tape-worm of man (Tcenia solium), but never grows so large,
and its neck portion is much thicker, compared with the size
of the head as shown in Figure 61.

The first hundred joints are very short ; the mature joints are
squarish, the posterior end of one somewhat overlapping the
anterior end of the next. These joints contain a very much
branched and subdivided female organ, with an oviduct ter-
minating on one edge in a bell-shaped orifice ; and an arbor-
escently branched male organ or spermary, with small, round
dilations connected with the small branches. Dogs harbor-
ing these tape-worms scatter the mature joints and thousands
of eggs everywhere over the fields, and in the water of
streams and ponds. The sheep and cattle swallow the eggs,
either with their food or water or both. The eggs are hatched
in the stomach of the sheep, and liberate minute worms,
which are armed with three pairs of hooks for boring their
way through the tissues, like the embryos of other tape-worms.
By this means, these embryos force their way through the
lining membrane of the intestine into the blood-vessels, and
are carried to various parts of the body. Many lodge in the

84 BOARD OF AGRICULTURE.

lungs, heart, and other organs, and cause for a time great irri-
tation and inflammation of these and other parts by their move-
ments in forcing and boring passages for themselves in the
tissues ; but they all eventually perish, while still small, in
such localities, and those that get into the liver and abdomi-
nal viscera are the only ones that survive and develop to their
full size, becoming the water-bladders, or " Cysticercus tenu-
icollis" first described.

The complete history of this, like the other tape-worms,
previously described, has been ascertained beyond doubt by
direct experiment. In this case the water-bladders have been
given to dogs, and at the proper time the dogs have been killed,
when the mature tape-worms have always been found corres-
ponding in number to the number of water-bladders eaten,
and in size to the length of time. And then the eggs or joints
of the tape-worms have been given to lambs ; and although
such lambs generally die in the course of five or six days,
when they swallow large numbers, yet even in that short time
the young worms have been found in vast numbers already
distributed in the system ; but when only a few eggs are em-
ployed, they do not cause immediate death. And in this way
Prof. Leuckart has studied their complete development. This
tape-worm, in its mature state, does not inhabit the human
body. Dr. Moller even swallowed several of the living blad-
der-worms without any result.

When these young worms have once got into the system of
a sheep, there is no remedy. In this case, prevention is our
only hope ; and to this end the same means should be used as
against the Tcenia coenurus and T. ec/iinococcus, to be de-
scribed farther on. Especial care should always be taken to
destroy the water-bladders and all other parasites observed in
slaughtering animals, as well as those removed from living
animals by medicines or surgical operations ; for in many cases
the eggs are capable of retaining their vitality for many weeks
or months. They should never be thrown aside as harmless,
or even buried, but should be destroyed by scalding hot water
or fire. Much may be done, also, in diminishing the numbers
of this and other parasites by frequently doctoring those dogs

PARASITES OF ANIMALS.

85

that are worth keeping, or are necessary, in order to expel
their parasitic worms, of which there are generally many
kinds. There are numerous drugs that are efficacious for this
purpose, some of which are mentioned under the beef tape-
worm (page 191). But the principal difficiiltyis this — those
who keep the most dogs, the worst dogs, and the dogs most
likely to harbor parasites in abundance, are the very persons
who are least likely to adopt such measures, either not know-
ing or not caring for the consequences.

Tcenia coenurus Kuch.,0/£/*e Dog ; audits young, the "water-

brain" of Sheep.

In the substance of the brain of sheep there is often found
a soft tumor, often as large as a pigeon's egg, and sometimes
larger than a hen's egg, which is filled with a watery fluid.
Such tumors would go on increasing in size indefinitely, until

Figure 62.

death ensues. But even long before the result becomes fatal,
the health is seriously impaired. The brain is often found
much diseased, and in part quite disorganized — a state of
things which in man would produce incurable insanity. In
sheep, it causes " staggers," " gid," "vertigo," or " sturdy,"
and other cerebral derangements. This disease is, in most

Figure 62. — Coenurus or water-brain of sheep. Natural size. Hearth and
Home, after Thudichum.

86

BOARD OF AGRICULTURE.

cases, incurable, and such diseased sheep are too often sent
to the market. Fortunately, man cannot be infected with
this parasite.

When one of these tumors is removed with care, it will be
found to consist of a thin, white, translucent cyst or sac,
roundish, oval, or irregular in shape. On one side may be

Figure 63.

Figure 64.

seen clusters of little white spots (Figure 62). If the spots
be examined with a lens, each one will be found to consist of
the minute head and neck of a young tape-worm, projecting
from the surface, and provided with four suckers and a -circle of

Figure 65.

hooks, as usual in young tape-worms in this stage of their
growth (Figure 63). Or else the heads will be found to be
withdrawn into the sac, each in its own capsule, and then
the spots are made by small depressions or pits, with a slit-
like opening at the bottom. If the interior of the sac-mem-
brane be examined with a microscope, each pit will be found

Figure 63. — Portion of the outer membrane, with the heads of Ccenurus. En-
larged four diameters. From Davaine.

Figure 64. — Inner surface of the membrane of the cyst, with inverted heads,
magnified. Hearth and Home, after Thudichum.

Figure 65. — Brain of shesp in which the young embryos of C.cenurus have ex-
cavated galleries. Davaine, after Van Benedeu.

PARASITES OF ANIMALS. 87

to correspond to one of the withdrawn and inverted worms,
as represented in Figure 64.

Each little worm has a head with a circle of hooks in the
middle, surrounded by four suckers, just as in the measle-
worm of pork. In this case, each little worm with a head is
the larva of one of the dog tape-worms (Tcenia caenurus),
hut in this the young worms have the power of propagating
themselves by a kind of budding, in a manner similar to that
by which the coral-animals bud from each other and so
build great colonies. Thus it is that one of these little
worms, lodged in the brain, by budding produces hundreds of
others like itself, all connected together by the membrane of
the sac ; and thus the tumor constantly grows larger, instead
of always remaining small, as does the measle-worm.

Effects.

Now, if a dog gnaws a skull containing such a tumor, and
swallows the whole cyst, or any part of the membrane that
has heads on it, the heads will be liberated from the mem-
brane, and each one will fasten to the lining of the dog's
intestine by means of its suckers and hooks. There they will
rapidly grow larger and larger ; new joints will be formed for
the body, and in the course of three months each one will become
a small tape-worm, with many joints, and each of the larger
joints will have both male and female organs, and will be
capable of propagating the race by itself. The female organs
of each joint contain thousands of eggs, which are discharged
when mature, and passing from the intestine of the dog in
large numbers, they will be scattered about freely over the
pastures and fields wherever the dogs go. If a lamb or sheep
accidentally swallows some of the eggs with grass or in water,
the eggs will hatch in the stomach into minute worms. These
force their way, by means of their six little hooks, through
the lining of the intestine into the blood-vessels, and are thus
carried to different parts of the system ; but usually only
those that lodge in the brain live, and there excavate galleries
(Figure 65) and grow, and bud, thus forming the " water-
brain," and finally kill the sheep. Ccenurus cysts have been
observed, however, beneath the skin of sheep, in the cellular
tissue. Similar cysts have, also, been found in the liver

88 BOARD OF AGRICULTURE.

of rabbits, and in squirrels, and other animals, so that dogs
may perhaps obtain the same tape-worms by eating rabbits, and
then give the "water-brain" in turn to lambs. But the.
coenurus-like cysts of rabbits, etc., may prove to be a distinct
species, which does not produce the same dog tape-worm, as
several writers suppose. Young lambs are more liable to be
infected by this parasite than sheep, the liability decreasing
with age. This parasite is by no means uncommon, and is
always abundant in proportion to the number of dogs in any
country. Thus, in Iceland, where both dogs and sheep are
kept in large numbers, Dr. Krabbe found this tape-worm in
eighteen per cent, of the dogs, while the two other tape-worms
dangerous to sheep were found even in much greater num-
bers. "Giddy" sheep are, of course, very abundant in that
unfortunate country. In this country the disease is far more
common than most persons suppose.

That this disease is caused in the manner described above,
has been repeatedly proved by direct experiments made by a
number of naturalists. The following by Dr. Kiichenmeister,
was one of the earliest : " On the 6th of January, 1854, at 8
o'clock in the evening, and on the 7th of January, at 11 o'clock
in the forenoon, I gave some mature proglottides (joints) of the
Tcenia coenurus of the dog to six lambs of from six to nine
months old, taken from three different flocks, which were not
subject to vertigo. On the 20th of January the animals exhibit-
ed the first symptoms of vertigo. They were then successive-
ly killed, and presented the following phenomena on exami-
nation.

On the seventeenth day after the introduction, from twenty
to thirty vesicles (Coenuri) inhabited the surface of the brain ;
the substance of the brain was hollowed into galleries as though
a Sarcoptes had been formingits passages (see Figure 65) ; the
vesicles were still free and without envelopes, and of the size
of a grain of millet.

On the twenty-fifth day the vesicles were larger. On the
twenty-sixth day they were of the size of a lentil ; the envel-
opes began to be formed, and the first traces of heads appear-
ed. On the thirtieth day, the heads, under the form of tuber-

PARASITES OF ANIMALS. 89

cles, were visible to the naked eye. On the thirty-eighth day,
the eminences appeared more distinctly on the surface, and
the heads exhibited signs of their suckers and hooks.
Toward the forty-fifth day the Coenuri were of the size of a
bean, and the cavities in which the heads are lodged were
formed." Encysted vesicles, containing strayed and aborted
worms, were also found in the heart, the diaphragm, and the
oesophagus. Some of the " water-brains" obtained in this ex-
periment were given to a dog early in March, and in due time
a good crop of the mature tape-worm (Taznia coenurus) was
obtained by killing the dog, which was done May 24th. These
were immersed in white of eggs, in which some of them were
kept alive, by changing it daily, for eight days, and sent to
several other naturalists residing in other parts of Europe, at
Louvain, Copenhagen, and Giessen. Prof. Von Beneden re-
ceived his at Louvain, May 27th, and tried the following ex-
periments : " On the day of their arrival, at 9 o'clock A. M.,
half a proglottis was given to each of two young sheep, about
two months old, and in the afternoon each of them took an
entire proglottis. On the 3d of June, one of them, marked
No. 1, swallowed another proglottis. The first symptoms of
vertigo made their appearance on the*13th of June ; on the
morning of the 15th, I was told that the one marked No. 2
was dying. Its head was burning hot, its eyes red, its legs
bent under its body ; it beat with its head against the railings,
and turned it constantly in one direction. It was then killed.
The upper and lower surfaces of the two hemispheres of the
brain presented irregular grooves which might be taken for
the deserted tubes of certain annelids (Figure 65) ; these have
been already mentioned by M. Kiichenmeister. There were
about a dozen of them. At the end of these tubes there were
the same number of Coenuri , almost all lodged in the cortical
substance of the brain. Some of them were removed with the
membranes of the brain. They were of nearly the same size,
about three or four millimetres in diameter. These Coenuri
as yet only consisted of a simple milk-white vesicle filled with
fluid. The heads were not yet to be seen. * *

The second sheep (No 1), was killed on the
12

90 BOARD OF AGRICULTURE.

29th of June. It presented nearly the same symptoms as th e
former. For the last few days of its existence the right fore-
leg was always bent, and in walking it could not support it- 1
self upon its hoofs. In removing the brain from the cranium,
a Ooenurus of the size of a small nut fell upon the dissecting
table. Two other Ccenuri, of the same size, were found in
the right hemisphere, one above, the other behind ; and in
separating the hemispheres of the cerebellum, I found two
others touching the quadrigeminal tubercles. The left lobe
of the cerebellum also contained one. Eight were found in
all. These Ooenuri were nearly all of the same size, except
two or three, which were scarcely larger than a cherry-stone.
Through the walls of the larger ones the naked eye could dis-
tinguish some little whitish flakes, the indications of so many
heads (scolices). The smaller ones had no appearance of
heads, nor of the place where they were to rise. The Coenuri
were enclosed in a membrane of recent formation, produced
by the inflammation of the neighboring surfaces."

Similar experiments, with the same results, were tried by
Eschricht at Copenhagen, and Leuckart at Giessen, to whom
tape-worms from the same dog were sent. Three sheep were
fed by Dr. Esckricht. Of these one was not affected, but the
other two became ill on the 15th and 16th days and died four
days afterward with the symptoms already described, and in
their brains the same kind of young Coenuri were found.

In these experimental cases, where large numbers of eggs
are given, the symptoms come on violently and death takes
place at an early stage in the development of the worms, but
under ordinary circumstances only a few eggs are swallowed
and then the sheep may live long enough to allow the cysts to
become much larger, with more numerous heads. The num-
ber of the heads is often 300 or more on a large cyst, and each
head is capable of forming a complete tape-worm, with many
joints. Allowing 500 sexual joints to each tape-worm, and
each joint to contain 5000 eggs, there might result, as the pro-
geny of one egg in a single generation, 150,000 joints, con-
taining 750,000,000 eggs !

Remedies. — The only remedy for sheep with this parasite at

PARASITES OP ANIMALS. 91

work in the brain, would be trepanning, and that can seldom
be effectual, unless the cysts be small and favorably situated,
which is not often the case. As with most internal parasites,
instead of remedies, we must seek means of prevention. It is
very apparent that, in this case, prevention simply demands
the absence of dogs that harbor the tape-worms, from all
places where the sheep feed or drink. Prevention on the
part of dogs can be secured by not allowing them to feed on
the offal of slaughter-houses, and especially the heads of sheep.
The mature tape-worms can be expelled from dogs by the or-
dinary remedies for other tape- worms, some of which are men-
tioned under Tcenia mediocanellata.

Perhaps the most effectual of these remedies is oil or spir-
its of turpentine mixed with castor oil.

Tcenia echinococcus Siebold, of the Dog ; and its young, the
hydatid tumors of Man, Sheep, and Cattle.

This is by far the most important and dangerous of all ces-
tode worms. In the mature state it lives in the intestine of
dogs and wolves in great numbers, as a very small tape-worm,
about an eighth of an inch long, with only three sexual joints
or proglottides (Figure 70). In its larval state it forms com-
pound cysts and tumors in a great variety of animals.

Not imfrequently there may be found imbedded in the sub-
stance of the liver and lungs of sheep, watery tumors of con-
siderable size, sometimes becoming several inches in diameter
and causing serious disease, and even the death of the ani-
mal. Similar tumors occur, though less frequently, in the
brain, kidneys, ovaries, among the muscles, and in various
other situations in sheep. They occur also in pigs, horses, and
cattle, though less commonly than in sheep, but unlike the Ccen-
urus, or " water-brain," these tumors are not confined to the
lower animals. They are also found in the human body, and
give rise to incurable and most horrible diseases, to which per-
sons of ail classes are liable, 110 matter how wealthy or refined.
That large numbers of human beings of all ages and condi-
tions die annually from diseases caused by this parasite is es-
tablished beyond a doubt. And although such diseases are

92 BOARD OP AGRICULTURE.

most common among the poorer classes of society, and espec-
ially among those who associate most familiarly with dogs,

Figure 66.

Figure 67.

they are by no means confined to them. Many men of great
eminence and talent have likewise perished from the same
cause. And, unfortunately, society is so constituted that no
one can be certain of escaping so long as the parasites that
produce the eggs exist in the dogs of every country. It is
estimated that 500 persons die annually by this parasite in
Great Britain.

These tumors, in their simplest form, or when young, con-
tain a roundish cyst or membranous sac, enclosing a watery
fluid, as shown in Figure 66, which represents of natural size
a parasite of this kind from the human kidney. More fre-
quently the cysts become compound by a process of budding,
either upon the outside or inside, or both without and within
the membrane of the original cyst, so that its size goes on in-
creasing indefinitely, sometimes becoming as large as a child's
head, and often completely permeating and destroying the
liver, lungs, or other organs. Thus the danger becomes con-
stantly greater and greater by reason of the pressure upon
and destruction of the adjacent organs. When the budding
is external, it results in a cluster of secondary cysts, often a
dozen or more, and sometimes hundreds, all more or less con-
nected together (Figure 67). And each of the external second-
ary or daughter cysts, may increase and multiply itself in the
same way, thus, at times, producing many hundreds of other
tertiary cysts or " grand-daughter cysts." By internal budding,

Figure 66— rHydatid or echinococcus cyst, natural size. Hearth and Home,
after Thudichum.

Figure 67. — Secondary cysts from a tumor in the liver, natural size. From
Cobbold.

PARASITES OF ANIMALS. 93

secondary or daughter cysts are formed inside the primary
ones, and then others inside the secondary ones, within which
the heads of the future tape-worms are formed by a peculiar
budding process. If the inner membrane of one of the small
cysts be examined when quite fresh with a good microscope,
there will be seen attached to it by means of slender stalks,
numbers of small oval or rounded heads, looking something
like fruit on a miniature plant, as shown in Figure 68, which
shows a few of these heads attached to the inner mem-
brane of a cyst from an echinococcus tumor of a sheep. The
heads may also bud forth from the outer as well as the inner
surface of the cysts, or brood-capsules, as they are called. And
these heads, either external or internal, may become changed
by an enlargement of their bladder-like portion into new
brood-capsules or cysts, and by budding produce other heads
in their interior, as shown in Figure 69. The heads are found
attached to the inner membrane of the primary cyst, together
with secondary cysts or brood-capsules ; they occur in the same
way in the interior of the secondary cysts, sometimes associ-
ated with tertiary cysts, or grand-daughter vesicles; and also
on the interior of the tertiary cysts. They sometimes appear
even on the exterior surface of the secondary and tertiary
vesicles. In all these situations they are similar in appear-
ance and structure, and all are equally capable of developing
into tape-worms in the intestine of a dog. Many of the
smaller secondary and tertiary brood-capsules or cysts are not
more than T^ of an inch in diamter, and then generally coil-
tain only three or four heads.

Each of the oval heads is a hollow sac, which contains the
real head of the young tape-worm turned in like the finger of
a glove, just as the heads are turned inward in the ccenurus
and in the measles of pork, or the young of any other tape-
worm. Often the head is turned outward, as is seen in one
case in Figure 68, which shows well the four suckers around
the head and the proboscis in the middle with its circle
of hooks. These same organs can be seen indistinctly even
when in their inverted position, as in the other he.ads shown
in Figure 68, owing to the partial transparency of the mem-

94 BOARD" OP AGRICULTURE.

branes. As long as these cysts remain in a living animal,
new heads are constantly formed, by their peculiar methods
of budding, and when new cysts are formed either within or
outside of the older ones, they develop on their inner mem-
branes other heads in the same way, so that if the sheep or
other animal lives long enough to develop a large tumor, it will
finally contain many thousands of these minute tape-worm
heads. In examining one of these tumors taken from a dead
animal, most of the heads and also the internal secondary cysts
are usually found floating freely in the watery fluid in great
numbers, giving it a turbid appearance, and on standing they
settle to the bottom as a granular sediment. This is
due to changes after the death of the parasite, though some
of the secondary cysts may be free during life.

Development.

Now, if a dog eats the liver, lungs, kidney, or other parts
containing such tumors, and swallows either the cysts or the
detached heads, these will lose the enclosing membrane, stems,
and other parts that are no longer useful, the heads with their
suckers and hooks will be protruded, and, passing into the
dog's intestine, each one will fasten itself by means of the
hooks and suckers to the soft membrane lining the intestine.
In this situation they remain and soon develop a small body,
having only three separable sexual joints, as shown in Figure
70, which represents the mature tape- worm {Tcenia echinococ-
cus) greatly magnified. This tape-worm never becomes long,
with hundreds of joints, as do the pork and beef tape-worms of
man. It is only about an eighth of an inch long when ma-
ture. The last joint, which is much the largest, contains both
male and female organs, and is perhaps capable of self-impreg-
nation ; it is therefore a complete hermaphrodite. After this
has matured and discharged its eggs, the two next in turn de-
velop their sexual organs and take its place. In Figure 70
the male organ may be seen projecting from one side, and the
ovaries, containing many eggs, occupy the bulk of the
joint. The eggs pass out through a duct that opens by
the side of the male organ, and each egg is fertilized
before being discharged. Thousands of these little tape-
worms, derived from one large cyst, often live together in

PARASITES OF ANIMALS.

95

the intestinefof one dog, so that they make up by numbers
what they lack in size. Such a dog is constantly discharging
and scattering thousands or millions of the extremely mi-
nute eggs of this tape-worm wherever he goeskJ^Tf^JBJR

/%§**' -^

Fiirare 68.

JLibrary

They are scattered among the grass in fields and pas-
tures ; they get into the water of brooks and springs ; they
are liable to adhere to fruit that has fallen, or to lettuce
and other garden vegetables.

Dr. Cobbold has calculated the number of progeny that
might proceed from one egg during a single generative cycle.
Allowing 500 secondary cysts to be formed and 10,000
heads or scolices to be developed by each hydatid cyst of
average size, these might produce 5,000,000 tape-worms,
each of which having three joints that become free, would
give 15,000,000 joints or proglottides, and if each of these
contains 10,000 eggs, the whole number of eggs in one gen-
eration, would be 150,000,000,000!

Figure 68. — Echinococcus heads attached to inside of brood-capsule, greatly
magnified. Hearth and Home, after Thudichum.
Figure 69. — A head or scolex, becoming a brood-capsule. From Leuckart.

96 BOARD OF AGRICULTURE.

Effects and Remedies.

These eggs are well protected by a shell, but when taken
into the human stomach, or into the stomach of sheep, cattle,
or pigs, they are acted upon by the gastric-juice and then im-
mediately hatch, The embryo is a very minute worm, very
different from the parent, and provided with six little hooks,
by means of which it digs its way through the lining of the
intestine into the blood-vessels, and entering the circulation
they are carried to the various organs of the body, where they
develop into the peculiar cysts first described, and thus cause
disease and death. When lodged in the brain, they are most
dangerous, soon causing insanity and death by their rapid
growth and consequent pressure. In the lungs they are also
very dangerous and often fatal ; in the liver they cause severe
disease, often terminating fatally ; and in other organs the
effects differ according to the nature of the organ. When
the lodgment is among the muscles, or near the exterior of
the body, the tumors may be removed by a surgical operation,
or even by simple puncture, they maybe destroyed. The dis-
charge of the contents is fatal to the life of the hydatid
opened, but there may be many others adjacent that will not
be affected. Injections of iodine, etc., after opening, are un-
necessary. When in the internal organs there is generally
no remedy, though by chance the cyst may of itself burst, as
sometimes happens, when, if the discharge takes place through
some natural channel, recovery is possible, but such cases are
of very rare occurrence. In the majority of cases the true
nature of the disease is not suspected until a post mortem
examination reveals it, or until the tumors burst or are
opened, when a microscopic examination of the matters dis-
charged gives reliable evidence ; but many of these hydatid
tumors are no doubt observed and treated by physicians, who
do not even suspect what their real character may be, because
they have neither suitable instruments nor sufficient knowl-
edge to make the requisite examinations. Chemical tests
may be applied to the liquid discharged, it is said, with satis-
factory results. The properties of the fluid are described as
follows: "If the sac be not inflamed, it is limpid, has a
specific gravity of 1007 or 1009, and contains no albumen,

PARASITES OF ANIMALS.

97

but throws down a copious precipitate with a solution of
nitrate of silver, owing to its strong impregnation with com-
mon salt. These characters apply to no other fluid in the
Figure 70. body, whether healthy or morbid." — Dr.
Murchison. In some cases hydatid tumors
situated in the liver and other internal organs
have been opened from the exterior, with suc-
cess, by skillful surgeons, but these operations
are always dangerous and often immediately
fatal. The escape of the fluid, with the
minute cysts and heads contained in it, into
the abdominal cavity, will give rise to other
tumors, and thus increase the disease, even if
death does not immediately result.

This is. eminently a case where " an ounce
of prevention is worth a pound of cure." The
means of prevention are simple, though not
easy of application in all cases. The iirst and
most important rule is to diminish the num-
ber of dogs to the utmost possible extent, and
then to keep them at the minimum number ;
second, avoid as much as possible the prox-
imity of dogs and sheep ; third, avoid feeding
dogs with uncooked livers or other offal of
sheep containing these parasites, or never give
them such raw food without careful exami-
nation ; fourth, avoid too much familiarity
with dogs, and especially between children
and dogs ; fifth,, be careful not to eat lettuce,
fallen fruit, or other raw food that has not
been thoroughly washed, both on account of
this and other parasites j sixth, avoid by all
means possible the use of impure water, or water liable to
be contaminated by eggs of parasites and excreta of animals,
both for household purposes and to supply sheep, cattle, and
horses, for such water is not only liable to contain echino-

Figure 70. — Mature Tcenia echinococcus, much enlarged. Hearth and Home,
after Leuckart.

13

98 BOARD OF AGRICULTURE.

coccus eggs, but those of several other tape-worms, round-
worms, and many other parasites, and is of itself unhealthy
and often the prolific cause of disease. If water from a good
well, or a well protected spring, cannot be had, the water
should be carefully filtered, and by preference through char-
coal. Most of the water consumed in our cities, both from
wells and the water-works, is wholly unfit to drink without
filtering. In cities with loose sandy soils the well-water is
the worst possible.

Finally, dog-kennels and other places much frequented by
dogs, should be frequently cleaned and the litter burned,
while frequent sprinklings with strong petroleum water or a
solution of carbolic acid in water should be used to destroy
the eggs that may have escaped from the intestine. By these
precautions the numbers of this and several other dog-parasites
might be much diminished. Dogs might also receive a
thorough course of medical treatment, once in three months
to expel all their intestinal worms, with great advantage, and
this might, with propriety, be made obligatory by law. In
this case the dogs should be confined while treated and all
excreta should be burned.

The frequency of this parasite is in direct proportion to the
extent to which the precautions are neglected in different
countries. In Iceland, the conditions for its rapid increase
and perpetuation have been favorable, and in that unfortunate
country, Dr. Krabbe states that there are at all times about
eighteen hundred patients suffering with severe forms of this
parasitic disease — a number equal to about one-fortieth of all
the inhabitants. In some districts, the proportion is said to
be one in every seven, and scarcely a family can be found
without two or more cases ! It is also stated that one-sixth
of all the deaths are due to diseases caused by this parasite !
The number both of dogs and sheep in Iceland is very large,
and the dogs mingle with the natives and live with them in
their rude dwellings, and are used in bringing the sheep to-
gether, so that abundant opportunities occur for propagating
the parasite. According to Dr. Krabbe, there is one dog for
every three to five inhabitants in Iceland, while in Great

PARASITES OF ANIMALS. 99

Britain, with a high tax on dogs, there is only one to fifty.
Doctor Krabbe found the echinococcus tape-worms in twenty-
eight out of one hundred Icelandic dogs examined, while in
Denmark he found them in less than one per cent, of the
three hundred and seventeen dogs examined for this purpose.

Tape-worm of the Horse ( Tcenia perfoliata Goeze).

This is a small species, seldom becoming more than three
inches long and a third of an inch broad. The head is rather
square, with four prominent suckers, but without a proboscis
and hooks. There is no distinct neck, the first joints behind

Figure 71. Figure 72.

the head being broad, but short. There are about 45 joints
in full-grown specimens. The reproductive organs open on
one edge of the joints, the first 22 segments having both male
and female organs, the rest only female.

It occurs quite frequently, in considerable numbers, in the
coecum and colon of the horse, and more rarely in the small
intestine. The development and the source from which
horses derive them are unknown. The larvae may, perhaps,
live in insects accidentally swallowed with grass. It does not
appear to produce any serious disease, unless in great num-
bers, and may be expelled by the same medicines used against
the human tape-worms.

A still smaller species, T. mamillana Mehlis, only about
half an inch long, and also without a distinct neck, but with
wedge-shaped joints, lives in the large intestine of the horse.
A much larger species than either of these (T. plicata Rud.)
lives in the small intestine and sometimes in the stomach of
the horse. It grows to the length of three feet or more, and
has a remarkably large head, with four suckers, but no hooks

Figure 71. — Young Tcenia perfoliata, natural size. From Cuvier.
Figure 72. — Head of T . perfoliata, magnified. From Cuvier.

100 BOARD OF AGRICULTURE.

or proboscis. The neck is short and thick, transversely
plicated, and the reproductive organs are in a single series on
one edge. If in considerable numbers, this species may pro-
duce serious symptoms, such as loss of flesh, tight skin, loss
of strength and spirit, and general debility.

The Sheep Tape-worm ( Tcenia expansa Rudolphi) .

This species, which is found both in sheep and cattle, grows
to the length of eight or ten feet, varying in breadth from a
quarter of an inch to upward of an inch, in large specimens.
The head is very small with four suckers directed forward,
and close together. The neck is scarcely distinct, or very
short. The posterior border of the joints are uneven, divided
up into rounded lobes and notches, or wavy. The reproduc-
tive organs are double, opening on each edge of every joint.
Its young stage is unknown, and consequently the source
from which the sheep obtain it. It does not appear to be very
common in this country, judging from the few cases recorded.
In Germany it is very common in sheep. It does, without
doubt, produce effects in sheep similar to those caused by the
tape-worms in man.

Tcenia cucwnerina Bloch, of the Dog.

This species is very common in the small intestine of the
dog. It grows to the length of ten or fifteen inches up to
nearly ten feet, with a width of one-twelfth to one-eighth of
an inch. The head is somewhat rhomboidal, with four sucke rs
and a central proboscis, which is surrounded by three circles
of claw-shaped hooks, the whole number being about 48.
The mature joints are elliptical, or shaped somewhat like the
seed of a melon or cuciimber. From this peculiarity it takes
its name. There are two genital orifices to each joint, one
in the middle of each edge. The eggs are much fewer in
each joint than in most other tape-worms. Its development
is unknown. It has been supposed that the larvae live in flies
or other insects.

When in large numbers in a dog, it occasions more or less
severe symptoms, especially if associated, as it usually is,
with several other species of tape-worms and round-worms.
It can be expelled by the same remedies mentioned under
some of the previous species.

PARASITES OF ANIMALS. 101

Tcenia elliptica Batsch is a similar species living in the cat,
and by some is thought to be the same.

Several tape-worms of the dog have already been de
scribed (Tasnia echinococcus, T. coenurus, T. marginata),
but there is another that is equally common in some districts.

Tcenia serrata Goeze closely resembles T. ccenurus and T.
marginata. The larva? live among tho viscera of rabbits and
hares, producing small round cysts, and the dogs get this tape-
worm by eating rabbits or the refuse thrown aside in dressing
them. The young state or larva was formerly named Cysti-
cercus pisiformis, in allusion to the pea-shaped cysts.

The Broad Tape-worm of Man (Bothriocephalus latus
Bremser) .

The genus Bothriocephalus differs greatly from the true
tape- worms (Tcenia) in many anatomical characters, but has
a similar form of body, divided into many flat joints. The
head has no suckers, but is long-oval in shape, with a long
and deep, groove on each side. It has no proboscis and no
hooks. The reproductive organs open at the middle of the
side of each joint, instead of the edge.

There are numerous species living in fishes and quite a
number in birds. The present species grows to an enormous
size — probably larger than any other known tape-worm. It
grows to the length of 25 or 30 feet, and according to some
authors to 50 or 60 feet. It is sometimes an inch wide. The
joints seldom break off, either singly or in chains, but the
eggs are discharged by the bursting of the joints while still
attached within the body of the infested person. The male
and female organs oprn separately, the male organ being a
little in advance of the female orifice. The female uterine
organ forms a sort of rosette, with eight or ten lobes, around
the external orifice.

Its fertility is remarkable, even for a tape-worm. Prof.
Eschricht found in one specimen 10,000 joints ; allowing each
of these to contain only a thousand eggs, this worm would
have produced 10,000,000 young. The full history of this
parasite is not yet known. The eggs, however, will hatch in
water, producing curious embryos, which are provided with
vibrating cilia by means of which they swim around for a

102

BOARD OF AGRICULTURE.

few days. The external skin, with the cilia, is then cast off,
liberating a very different looking embryo or larva, which is
provided with six boring hooks, similar to those of the em-
bryos of ordinary tape-worms. Their subsequent history has
not been ascertained, but it is probable that they enter some
fish (most likely trout and salmon) and become encysted
among the muscles, and that persons who eat imperfectly
cooked or raw dried fish get the parasite in that way.

It is remarkable that this species is not known to be indig-
enous in any but European countries, and even in Europe it
is peculiar to certain districts. It is particularly common in
certain parts of Switzerland. In Geneva it is said that about
one-fourth of all the inhabitants are afflicted with this worm.
It occurs also in some parts of Russia, Poland, and Prussia.
In America it has only been observed in emigrants from
Europe, and in persons who have traveled in the European
countries where it naturally occurs. It causes similar symp-
toms and is removed by the same remedies as the common
tape -worms.

TREMATODE WORMS.

The Liver-fluke of Sheep and Cattle (Fasciolahepatica Linn.).
This common and notorious parasite has a very flat body,
different on the two sides, and more or less oval in form, the
anterior end suddenly narrowing to a sort of neck, which
tapers off to the mouth end, where it is either rounded or
pointed. The posterior end of the body is Figure 78.
somewhat tapering, but blunt. Ordinary speci-
mens are about three-quarters of an inch long
and half an inch wide, but large ones become
an inch and a quarter long and three-quarters
broad. While living they often curl up the ends
of the body, toward the lower side. The color
is pale brownish or greenish yellow, sometimes
with a faint rosy tint. At the anterior end of
the body there is a small, cup-shaped sucker, at
the bottom of which the mouth is situated
(Figure 73, a) ; near the origin of the neck-
like portion, on the middle line of the lower side, there is

PARASITES OF ANIMALS. 103

another larger sucker (6), with no opening at its bottom ;
just in advance of this there are situated, side by side, the
male and female genital orifices (c). The external male
organ is long, slender, and when protruded is curved in a
spiral. It can be retracted into a small cavity.

Anatomy.

The reproductive system is very largely developed and com-
plicated. The male organs, or testicles, consist of large
clusters of vermiform, convoluted, yellowish tubes, situated
in the middle region of the body, and filling up about one-
half of the whole interior. The female organs, for they are
hermaphrodites, are also largely developed and complicated.
The lateral and hinder parts of the body are filled with in-
numerable, very small, yolk-sacks, which communicate, by a
complicated system of branched ducts, with a heart-shaped
ovary, and this in turn has a short duct leading to the uterus-
like organ, which consists of a convoluted, wide tube, forming
a sort of rosette behind and around the ventral sucker. The
uterine tubes show through the skin and are brownish yellow,
owing to the numerous minute eggs with which they are filled.
These eggs are discharged, one by one, from the small ex-
ternal orifice as fast as they become mature. The mouth
communicates with a small dilated oesophagus, and this gives
rise to two large intestinal tubes, which diverge in advance of
the genital orifice and extend backward, along each side, to
near the posterior end, sending off numerous lateral branches,
which again subdivide into many short divergent branchlets,
as shown in Figure 73, d. The branches of these digestive
tubes are all closed at the ends, and they communicate with
the exterior only through the mouth. In life these tubes are
all filled with food, consisting chiefly of bile, with some blood-
corpuscles, etc. Another system of numerous, arborescently
branched tubes is found nearer the dorsal surface, and as they
show through the skin, on that side, they may be examined

Figure 73. — Fasciola hepatica, natural size, seen from below ; a, mouth and
oral sucker ; b, ventral sucker ; c, genital orifice ; d, branches of intestine. From
Cuvier.

104 BOARD OF AGRICULTURE.

with an ordinary lens. These tubes commence in fine, rootlet-
like branches, with rounded and closed ends, but the small
branches constantly unite into larger trunks, which in turn
all unite into one main trunk, running along the middle line
of the body, and this terminates in an external orifice at the
posterior end. The use of this system of tubes is to remove
the waste materials from the body. It may therefore take
the place both of the kidneys and liver of the higher animals.
There is 110 blood circulation and no true blood in these
animals.

Development.

The fluke is a very prolific creature. Prof. Leuckart esti-
mates that the ovaries may at any one time contain 45,000
eggs. The number of broods that they produce is not known.
The eggs that are discharged pass out of the intestine of the
sheep, or other animal in which they live, with the excre-
ment. Those that get into water or moist places hatch after
several weeks, producing minute conical embryos, which are
covered with vibrating cilia or lashes, by means of which
they swim freely about in the water. In this state the em-
bryo is YJJTJ- of an inch long and -§$•$ of an inch broad at the
larger end. The cilia are T^ of an inch long.

In a few days the external skin, with the cilia, is cast off,
and after that the embryos are obliged to creep about, instead
of swimming. Its farther development has not been traced,
but it probably has a history similar to that of other species
of flukes of which the entire history is known. Therefore it
is supposed that the young embryos, above described, attach
themselves to the bodies or enter the tissues of the fresh-
water spiral snails, such as Limncea and Physa. In this
situation the form probably changes, and they become the so-
called " nurses," and then a brood of larvae of another form
is developed in their interior, by a process of internal budding.
These larvae are provided with a tail and have a form some-
what resembling minute tad-poles. In this state they are
known as cercarice. They are finally discharged from the
body of the " nurses," and escaping from the snails, may
again swim actively about in the water, by means of

PARASITES OP ANIMALS. 105

their tails, but eventually they, in all probability, again enter
the bodies of other small snails, and losing their tails, become
encysted ih Mttle capsules. Finally these snails, with their
parasites, are swallowed by sheep and cattle, while adhering
to the herbage growing on moist land or near the water,
or when adhering to water-cresses they might be swallowed
by mankind. In the stomach and intestine of these higher
animals they are again liberated from their cysts. They then
gain access to the liver, where they rapidly develop their
sexual organs and become mature. Eventually, after they
have matured and perhaps discharged a large part of their
eggs, they themselves, or at least a part of them, enter the
intestine and are discharged, while still living, in company
with innumerable eggs. The eggs that they still contain may
be laid after they reach the earth or water. These eggs are
exceedingly minute and may be diffused in various ways, as
by rains, winds, insects, and the feet of animals, and getting
into water, or moist situations, they are ready to hatch and
commence another series of transformations.

The history of most of the flukes, which have hitherto been
fully investigated, agrees in the main with that above given,
and there can be little doubt but that this will prove to be the
case with the common fluke, when its full history shall have
been ascertained. At any rate it is certain that the eggs can
hatch only in water, or in moist places. Therefore it is evi-
dent that sheep and cattle will be much more liable to the
disease when kept in low wet pastures, than in dryer and
more elevated situations ; and also that wet seasons will be
favorable for the parasites and dry ones unfavorable. These
conclusions have been fully sustained by the experience of
sheep-owners in all countries.

Modes of Occurrence.

The liver-fluke is one of the few internal parasites that is
capable of living in several very different animals. It is most
common in sheep ; less so in cattle, goats, horses, and the
ass ; and quite rare in man. It has also been found in the
hog, elephant, camel, beaver, squirrels, rabbit, hare, deer,
and antelopes of several kinds, and in the great kangaroo.
14

106 BOARD OF AGRICULTURE.

It is chiefly found in the gall-bladder and bile ducts, but
occurs also in the intestine, and sometimes in blood vessels.
In the human subject it has, in some instances, been found in
tumors beneath the skin. In these cases it is supposed that
the larvae entered from the exterior by boring through the
skin.

Effects.

The injurious effect of this parasite is best known in the
case of sheep. In these animals it produces the fatal disease
generally known as " rot,"* " water-rot," or " fluke-rot." In
severe cases of this disease there are always large numbers of
flukes in the bile-ducts- and gall-bladder, — often several dozens
and sometimes several hundreds, or even a thousand in some
fatal cases. A few may exist in a sheep without causing any
marked disease ; in proportion to the number, the symptoms
become more marked and the disease more fatal. In some
wet seasons, and in certain districts, these parasites have
destroyed immense numbers of sheep. Thus in 1830-1 it is
estimated that between one and two million sheep died of
this disease in Great Britain. If the number was but 1,500,-
000, it would represent a loss equal to about $20,000,000. In
a single year, in England, individual farmers have lost from
300 to 800 sheep in the same way. In France, during the
year 1812, according to Davaine, 300,000 sheep died by the
same cause in the vicinity of Aries, and 90,000 at Nimes
and Montpellier. In Germany, Holland, and most other
European countries similar disastrous outbreaks of the dis-
ease have occurred every few years, while during the most
favorable years the aggregate annual loss is far greater than
is generally supposed. In this country there are no reliable
statistics by which the losses from this cause can be estimated.
Yet there can be no doubt but that it amounts in reality to a
large sum annually. Even those sLeep that have the disease
in a milder form and are sent to the market before they be-
come too sick to be moved, lose very much in value, and are

*This must not be confounded with an entirely different disease, known as
" foot-rot."

PARASITES OF ANIMALS. 107

really unfit for -food, though it is to be feared that farmers, as
well as butchers, are not always over scrupulous in such cases.

Symptoms.

In severe cases any one at all familiar with sheep can
readily detect the disease even by the general looks of the
animal. They also show a peculiar weakness in the loins
when the hand is pressed along the back over that region.
In very bad cases the back becomes hollow and the belly
hangs down, while the sheep become more and more
emaciated and weak, dull, and dejected, with a feeble gait.
The skin loses its natural color and becomes dry, while the
wool is also harsh and dry, and conies off easily.

The skin on the inner parts of the thigh, especially where it
is naked, becomes dry or scaly early in the progress of the dis-
ease. The eye affords very certain evidence, even at an early
stage, so that even shepherd boys are able to select from a
flock those that are diseased, by this symptom alone. If the
lids be turned back and the membrane at the corner of the eye
be pushed away, the conjunctiva and other parts will present
an unnatural watery appearance, the vessels being swollen
and filled with pale or yellowish colored blood, When the
disease is farther advanced the blood-vessels lose their color
and are scarcely distinguishable, though a few of them may
be swollen and filled with dark, unhealthy looking blood.

Remedies.

It can be safely stated that when these parasites have once
entered the liver in considerable numbers there is no known
specific remedy. All that can be done is to keep up the
general health and strength of the animal until nature effects
a cure, or until the parasites complete the natural course of
their lives and voluntarily leave the sheep. To this end the
afflicted animals should be removed to a dry pasture or good
shelter, and be liberally fed with a variety of nutritious and
palatable food, while they should be freely supplied with salt.

This is another of those instances where prevention is far
easier and better than cure. From what we already know of
the history of the parasite it is evident that sheep will be

108 BOARD OF AGRICULTURE.

little liable to get it if pastured on uplands, or other dry
places, and supplied with pure spring water, by preference
from a trough or other similar arrangement. On the other
hand, sheep pastured on meadows, or swampy lands, or in
places where they have access to the marshy banks of streams,
ponds, and swamps, will be far more liable to get this and
several other parasites.

An exception should, however, be made in the case of salt
marshes and meadows, for sheep pastured in such places sel-
dom get the disease. This is probably owing to the fact that
the fresh water snails, that harbor the young flukes, cannot
live in salt or brackish water.

Smaller Liver-fluke (Distoma lanceolatum Mehlis).

This species is also found in the bile-duct and gall-bladder
of sheep and cattle, and occasionally in man. It is sometimes
associated with the common fluke. It is much smaller, the
length being about one-third of an inch and the breadth an
eighth. It has a smooth, flat, lance-shaped body, broadest
behind the middle, narrowing to each end, the mouth-end
being most pointed. There are two suckers, as in the com-
mon fluke, the one at the front end having the mouth at the
bottom.

The anatomy is quite different, for in this, as in all other
true Distomas, the digestive tube only forks once, each branch
remaining a simple, closed tube, running down on each side
of the middle region of the body. The testicles are two
large, roundish, but somewhat lobed organs, just below and
near the ventral sucker. The uterine tube has numerous
branches arranged on each side of a main central trunk, in the
hinder part of the body. The ovaries are comparatively
small and situated on each side of the middle region of the
body.

Development.

The eggs hatch in water, after several weeks, producing
very small, nearly round embryos, which have the vibrating
cilia only on the head end, which is a little smaller than the
other end. They are not such lively swimmers as the em-

PARASITES OF ANIMALS. 109

bryos of the common fluke. They are about ¥^ to -^ of an
inch long, and ^-^^ of an inch broad. The head end is pro-
vided with a dagger-like boring spine, which can be alternate-
ly thrust out and withdrawn. It is supposed that these em-
bryos become parasitic in fresh-water snails, for a time, and
undergo transformations like those described under the pre-
ceding species. Their effects and remedies are the same as
for the common fluke, though owing to their small size they
would be less injurious, unless in much greater numbers.

The Stomach-flukes of Cattle (AmpTiistoma conicum Rud. and
A. crumeniferum Creplin).

The flukes belonging to the genus Amphistoma, which in-
cludes, besides the two indicated, A. explanatum from the
bile-ducts of cattle and A. truncatum from the cat, have a
small, rather thick, and somewhat conical body, the mouth-
sucker being at the small end. The large end is rounded and
bears the other sucker, which is always much larger, near the
posterior end. The stomach and reproductive organs are
nearly like those of Distoma. The eggs also produce ciliated
embryos in the water, and they are supposed to go through
similar transformations. I do not know that either of them
have been observed in sufficient numbers to produce serious
diseases in cattle.

ACANTHOCEPHALA.

(Thorn-headed worms. )
Echinorhynchm gig as Goeze. Figures 74, 75.
This, which is the only representative of the order hitherto
found in our domestic mammals, is quite frequent in the intes-
tine of hogs. It may at once be known by the peculiar pro-
boscis, which bears several circles of small but sharp hooks,
which are arranged alternately, in quincunx, mostly toward
the end of the proboscis (Figure 75). These worms have a
long roundish body, tapering to the posterior end. The skin
is generally crossed by numerous transverse wrinkles, but is
sometimes smoothish. The color is whitish or a little bluish.
The males grow to the length of three or four inches, with a

110

BOARD OF AGRICULTURE.

diameter of one-eighth to one-fifth of an inch. The females
may become six inches, or even a foot in length, and some-
times one-quarter of an inch in diameter, though generally

Figure 74.

smaller. The female is very prolific, producing an immense
number of somewhat oblong-oval eggs.

The history of its development and transformations has
not yet been made out. There can be little or no doubt,
however, that the young worms are parasitic in some other
animals, — most likely in insects, worms, or snails, — and that
the hogs get them by devouring the embryos included in
some such small animals.

Effects and Symptoms.

This is the commonest and most injurious intestinal worm
found in swine. These parasites live in the small intestine,
and more rarely in the large intestine. They usually adhere
to the lining, or mucus membrane, by means Figure 75.
of the hooks on the proboscis, which is thrust
into the substance of the membrane. Not
unfrequently they perforate the walls of the
intestine and stray into other parts of the
viscera, producing serious disease. Some-
times the intestine of a hog is found per-
forated by so many of these holes that it can-
not be used in the manufacture of sausages !

In severe cases, hogs afflicted with this parasite are weak
in the loins, and have the membranes in the corners of the
eyes swollen, watery, and lighter colored than usual. The
excrement is hardened and highly colored, and the animal
often keeps up a continual squealing and grunting, especially
in the morning. Such hogs are generally cross and morose,

Figure 74. — Echinorkynchus gigas, natural size. From Cuvier.
Figure 75. — Head of E. gigas, enlarged showing the reticulated vessels in the
skin. From Curier.

PARASITES OF ANIMALS. Ill

biting and snarling at its companions, but is usually too weak
to defend himself, if attacked in return, and is easily thrown
down. Finally the weakness increases until the poor crea-
ture is unable to walk about, or to stand. This parasite will
probably yield to the same remedies used for tape-worms, or
those employed against the common round-worms of man (As-
caris lumbricoides) , to which, therefore, the reader should refer.

NEMATODES.

(Round-worms and Thre ad-worms J)
The Flesh-worm (Trichina spiralis Owen). Figure 76.
This most important and most dangerous of all human para-
sites, is a very minute round worm, which in the larval state
lives in the muscles of man, swine, dogs, cats, rats, mice,
rabbits, Guinea-pigs, and many other animals, and in the ma-
ture state inhabits the intestines of the same animals. The
body is slender, smooth, and round. The intestine is com-
posed of a series of small, bead-like swellings, separated by
constrictions. The male is much smaller than the female,
when mature measuring only TV of an inch ; its body is filiform,
pointed at the head, enlarged at the opposite end, generally
somewhat bent or curved upon itself ; the head is very small
and pointed, unarmed, but with a minute central mouth ; the
posterior end of the body is furnished with a bilobed ap-
pendage, the anal opening being between the lobes ; the penis
is a single spiculum, cleft above so as to have a V-shaped out-
line. The female is stouter than the male and longer, meas-
uring about -J- of an inch, when mature ; the posterior end is
bluntly rounded ; the genital orifice is at about a fifth of the
length from the anterior end of the body. They are viviparous
and the uterus occupies most of the body, in the form of along
and wide tube, in which the embryos are closely packed. The
eggs are T^7o of an inch long. The young Trichinae, like young
tape-worms, occur imbedded in the muscles of the hog and
various other animals, and man. But unlike the young tape-
worms or " measles," the young Trichince are so small as to be
quite invisible to the eye, and millions of them may ex-
ist in the flesh of a pig without producing any unusual appear-
ance in the meat sufficient to attract the attention even of an

112

BOARD OF AGRICULTURE.

expert, unless examined with a powerful microscope. This is
one reason why deaths so frequently occur from eating pork
filled with this parasite. When recently introduced into pork
or human flesh, the little worms are free and coiled up among
the muscular fibres, but after four or five weeks they become
enclosed in minute, whitish, elongated, oval or roundish cysts
or capsules, due to the irritation and inflammation that they
cause by feeding and moving (Fig. 76). After a year or more
these cysts become calcified by a deposit of carbonate of lime
in the membrane, and at this time are visible to the
eye as minute specks, about the size of hemp-seed, scattered
through the muscles. When enclosed in the cyst, the worms
become dormant, and though they may live for years, and
even some weeks after the death of their host, they can do no
further harm unless swallowed by man or some animal. Each
cyst contains a little slender worm about one twenty-fifth or
one thirtieth of an inch long, and one seven hundredth thick,
coiled up in two or three

turns. The cysts average Ei£ure 76>

about one eightieth of an
inch long and a hundred
and thirtieth thick.

If pork or other flesh
containing these worms,
either free or enclosed in
cysts, be eaten by man,
they become liberated in
the stomach, and, en-
tering the intestine at-
tach themselves to its soft
lining, and there, sur-
rounded with abundant
food, they grow very rap-
idly and become mature,
with fully developed sex-
ual organs, in two days.

Figure 76. — A small piece of human muscle containing encysted young of
Trichina spircdis Owen, enlarged forty-five diameters. From Hearth and Home,
after Leuckart.

PARASITES OF ANIMALS. 113

The females are larger and more numerous than the males,
and become about one-eighth of an inch long when full grown.
They pair as soon as mature, and the males soon die ;
but the females begin to give birth to living young in five
or six days from the time when they enter the stomach,
and they live long enough to produce a brood of from five hun-
dred to one thousand young worms each. As one ounce of pork
sometimes contains a quarter of a million or more of the worms,
it is not surprising that the millions of adult worms and their
offspring, sometimes resulting from a single meal of raw
pork, should, by their presence, produce great irritation and
inflammation of the intestine and violent diarrhoea and vomit-
ing, which are often the first symptoms in severe cases. But
the young worms, almost as soon as born, begin to eat or
force their way through the membranes of ' the intestine into
the minute blood-vessels and other organs, thus vastly in-
creasing the irritation. Entering the circulation they
are carried by the blood to the heart, thence to the lungs,
and then become diffused through the whole system. Accord-
ing to other observers, the young worms force their way di-
rectly through the intestine and all other intervening organs,
until they finally reach a suitable habitation in the voluntary
muscles. It is, however, difficult to understand how they can
become so evenly and generally distributed through the whole
muscular system as they often are, if this be their only mode
of diffusing themselves. It is, therefore, not improbable that
they migrate by both these methods, part entering the circu-
lation and part going directly through the tissues, while in
either case, if they find themselves in an unfavorable locality,
they have the power of changing their position while still in
the free state. According to Dr. Leuckart, they travel by the
way of the intermuscular connective tissues, and are found
most abundantly in the groups of muscles nearest the abdomi-
nal cavity, especially in those that are smallest and have the
most connective tissue.

Effects.

Large numbers often lodge in the heart, lungs, and various
other organs, producing great irritation and various danger-
15

114 BOARD OP AGRICULTURE.

ous symptoms, but the majority finally reach and remain in
the voluntary muscles, where they live and thrive for some
weeks, making for themselves passages, and even entering and
destroying the fibres themselves. All these operations cause,
of course, an immense amount of inflammation and irritation,
if, as often happens, millions of these flesh-worms are at work
at the same time in all parts of the system ; and it is no won-
der that many violent symptoms and high fever result, or that
there should be intense soreness and pain or paralysis of the
muscles, and dropsical swellings. Death in severe cases may
occur at any time from the fifth to the fiftieth day. The du-
ration of the disease, like its severity, is in direct proportion to
the number of living Trichinae swallowed, and varies from two
weeks to three or four months. Even in many comparatively
mild cases, the sutfering is intense and the recovery slow and
tedious, while many secondary diseases, like pneumonia,etc.,are
liable to ensue. When all the worms have become lodged in
the muscles and enclosed in cysts, the direct symptoms cease,
and, if the strength of the patient has been kept up, recovery
is probable. Some persons, especially females, are much more
severely affected than others, by the same number of the para-
sites.

Persons in robust health may be able to survive the attack
of half a million or more of these flesh-worms and recover,
but there is a limit to all human endurance, and the numbers
often contained in the muscles of animals or persons who
have been killed by them, are almost incredible. In a cat fed
with trichinous flesh by Leuckart, they were so numerous that
he estimated that one ounce of the flesh contained at least
325,000 worms. Microscopic preparations, not much larger
than a pin's head, often contain from ten to forty worms, and
one bit of muscle, weighing about one-fifth of a grain, from a
child that died on the seventy-ninth day, contained fifty-
eight. Allowing only one hundred worms to a grain of mus-
cle, a man weighing 150 pounds might contain over forty
millions of the parasites, and the length of the muscular
fibres actively inflamed by such a number, if placed in a line,
would amount to more than 120 miles.

PARASITES OF ANIMALS. 115

In some very severe cases the numbers contained in human
bodies have been estimated, by reliable authorities, as
high as forty and sixty millions.

The cysts containing Trichince were first observed in human
muscles in 1822, but the worms from similar cysts were first
named and described by Owen, in 1835, but were only regarded
as anatomical curiosities of no practical importance, until 1860,
when Zenker proved that they are capable of producing the
severe and often fatal disease now well known under the name
of Trichiniasis, but which had been previously (as it often is
still) confounded with typhoid fever, inflammatory rheuma-
tism or rheumatic fever, poisoning, and various other
diseases.

Symptoms and treatment of the disease.

The disease caused by this parasite has three more or less
distinct phases :

First. While the mature worms and young remain in the
intestine, and while passing through its walls. In this stage
the symptoms are derangement and inflammation of the in-
testine, often resulting in severe diarrhoea, nausea and vomit-
ing, swelling and pain, and sometimes peritonitis, due to the
perforations of the intestinal walls. These symptoms ensue
in two or three days after swallowing the trichinous flesh, and
may last a fortnight or more. Animals experimented upon often
die in this stage. Purgatives and anthelmintics are used in
this stage to expel the mature and pregnant females, but after
three or four weeks have passed this will be useless. Castor-
oil and calomel have been used with success for this purpose.

Second. While the young worms are migrating and work-
ing in the muscles, a variety of symptoms are developed,
varying in different persons, and depending, also, upon the
number of worms. This stage commences in ten to fourteen
days, and generally lasts four or five weeks. The principal
symptoms are lassitude and swelling of the muscles, with
soreness, or intolerable pains, resembling rheumatic pains but
not affecting the joints ; profuse sweating sometimes occurs ;
the pulse is very rapid, but the heat of the body is usually

116 BOARD OF AGRICULTURE .

low, often never exceeding 102° Fahr. ; the face frequently
becomes suddenly and greatly swollen, and sometimes the
whole body is affected in the same way. In certain cases, a
peculiar congestion of the eyes has been observed. In general,
many of the symptoms in this stage resemble those of typhoid
fever.

In very severe cases the patient is unable to use the mus-
cles or move the limbs without the most intense agony, and
filially is obliged to lie passively, flat upon the back, with the
arms and legs somewhat bent, in the position that gives the
least pain ; and later the limbs are rigidly stretched out, some-
what apart, the body stiff, and the muscular system in a state
of more or less complete paralysis. Children generally lie
on the side, with the body bent and the legs drawn up. The
jaws are sometimes closed as in lock-jaw. The breathing is
difficult, shallow, and rapid. The lungs are often affected,
and frequently, also, the heart ; and many secondary diseases
are liable to ensue.

The most that can be done in this stage of the disease by
the physician relates to the relief of special symptoms and
secondary diseases, and sustaining the strength of the system
until nature may in time effect a cure. Most experimental
animals die in this stage, and human patients, also, frequently
perish even during the early part of this period.

Third. In case the patient survives the two first stages, the
inflammation gradually ceases, breathing becomes more
natural, and recovery generally commences, but in very severe
cases the muscles and other organs have been so much in-
jured as not to perform their proper functions, and general de-
bility often results, ending in a kind of consumption that finally
proves fatal. In many cases of recovery, lameness lasts for
several months. In many cases, however, the final recovery
is complete and may be followed by robust health, although
tens of thousands of living worms may be still enclosed in
the capsules in the muscles.

From this it is obvious that a hog may be fat and appear in
every respect healthy, and yet his flesh may contain such im-
mense numbers of the parasites as to be capable of killing a

PARASITES OF ANIMALS. 117

hundred or more persons, should they eat it raw or but slightly

cooked.

Oases of Trichiniasis.

Since 1860 thousands of cases have been observed and hun-
dreds of deaths are known to have occurred, especially in
Germany, where the custom of eating various forms of raw
or imperfectly cooked pork is much more common than in
this country. At Hettstadt, in 1863, the flesh of one pig in-
fected one hundred and thirty-five persons, of whom twenty
died. Several other similar " epidemics" have also occurred
in the same country. In the United States, many sad cases
have also been recorded, as the following in stances will show:

At Marion, Iowa, May, 1866, Mr. Bemis and eight mem-
bers of his family ate rare -done and raw ham, and were im-
mediately taken sick. Up to June 3d, three had died, and
others were considered critical. A post-mortem examination
showed about two hundred thousand worms to a cubic inch of
muscle in one of those who died.

AtDubuque, Iowa, according to Dr. Asa Horr, two families
were attacked. In one five persons died ; in the other, five
or six. Through him we also learn of a case where the
mother of a family ate of the interior, rare-done part of a
ham and took the disease, while those who ate the outside
escaped.

At Springfield, Mass., February, 1867, Mr. Ransley Hall
and family ate of raw ham, and all seven were attacked in
various degrees, according to the amount eaten. A daughter,
aged seventeen, died, and the father had a long and very
dangerous illness.

At Albany, N. Y., January, 1869, two boys ate of raw ham
and were infected ; the rest of the family ate of the same
ham, when cooked, and escaped.

At Rome, Oneida County, N. Y., December, 1868, Mr.
John Wilbrecht and family, nine persons in all, ate raw
smoked and dried sausages. All were dangerously sick, and
four adults, the father, son, and two daughters died before
January 15th. Their sausages and salt pork were examined
and found to be full of Trichina, as were also the muscles of
those who died.

118 BOARD OF AGRICULTURE.

In New York City, January, 1869, eight cases occurred in
a boarding-house in Carlisle Street, from eating sausages.
Two of the victims died in the New York Hospital, and others
were dangerously sick. It is a significant fact that the physi-
cians in two hospitals mistook these cases at first for typhoid
fever, and only discovered the mistake after one death had
occurred.

In Bridgeport, Conn., January 30th, 1870, raw smoked
ham was eaten by five persons. Of these Mrs. Koch died of
acute Trichiiiiasis, February 15th ; Mrs. Winter died February
16th ; Mr. Winter died March 1st ; a daughter of Mrs. Koch,
aged two and a half years, died March 7th. Mr. Strasburg
was for a long time very dangerously ill, and was left in a very
feeble condition. Another person who ate some of the same
ham fried, escaped entirely. Mr. Winter thought himself not
seriously ill when his wife died. Some portions of his pec-
toral muscles, which I have had an opportunity to examine,
were filled with Trichincs, not yet encysted. There were
perhaps 100,000 to the cubic inch.

Prevention.

Experiments have fully shown that nothing less than the
most thorough cooking, so prolonged as to destroy all redness
of the juices even in the interior of the meat, is capable of
destroying these parasites and rendering pork a safe article
of food. Cases, some of them fatal, have occurred from eat-
ing ordinary fried sausages, roast pork, and pork that had
boiled two hours. But the majority of severe and fatal cases
have happened from eating smoked ham, raw or partly cooked,
and various kinds of smoked and dried sausages, which are
often eaten raw, or but slightly cooked.

Therefore, if people will eat pork at all, they should make
it a fixed rule never to eat it unless thoroughly cooked, if
they would avoid one of the most painful and dangerous dis-
eases known.

There appears to be no certain way of preventing the
disease in hogs, for it is probable that in most cases they get
it by eating rats or mice, which are often full of Trichince,
but it is quite probable that they may often be infected by

PARASITES OF ANIMALS. 119

eating slaughter-house offal. It is possible, also, to infect
hogs and other animals by means of the mature female
Trichince that have been discharged from the intestines of
men or animals, before all the young worms contained in their
uteri have been born. Therefore hogs may obtain this, as
well as the Iarva3 of the tape-worm of man and many other
parasites, by being kept in places where they have access to
manure, as is too often the case. Cats, rats, mice, rabbits,
Guinea-pigs, young dogs, and various other animals may be
infected, but adult dogs, like old hogs, are not nearly so likely
to become infected as the young. Although lambs, calves,
and horses may be infected by forcing them to eat trichinous
meat, it is probable that they seldom or never become infected
naturally.

Trichocephalus dispar Rudolphi. Figure 77.
This is a small round-worm, living in the human intestine,
and remarkable for its long, very slender, filiform neck, which
Figure 77. *s about two-thirds of the entire length. The
male grows to the length of one inch and a
half, and the female to two inches. The sur-
face of the body appears smooth to the naked
eye, but when magnified, a longitudinal band of
minute, wart-like papillae is seen on one side.
The male has the posterior end of the body
spirally curved, with a single spicule, which is
emitted from the extremity of the body, and is
enclosed in. a short, tubular sheath, that is cov-
ered with minute recurved spinules. The female
has the posterior end of the body nearly straight
and bluntly pointed (Figure 77). The genital
orifice is situated at the origin of the neck. The eggs are
elliptical, with a small projection at each end, and are -&G to
?fa of an inch long. They are discharged from the human in-
testine before the contained embryos are fully developed. If
kept in water for six months or more they hatch, liberat-
ing a minute embryo 3^ of an inch long, which tapers
from behind toward the head.

Figure 7 '7. —Trichocephalus dispar,' a, female, natural size ; b, posterior end, en-
larged. From Guerin.

120 BOARD OF AGRICULTURE.

It is therefore probable that they are taken into the
human system in impure water. In some regions it is very
common. Davaine estimates that one-half of the inhabitants
of Paris entertain this parasite. Its effects are not well made
out, but it does not seem to cause, ordinarily, any marked in-
convenience. It lives in the coecum and small intestine.
TricJiocephalus affinis Rud.

This species lives in the coecum of cattle, sheep, deer, and
antelopes. It closely resembles the preceding, but the reck
part is still longer and more slender. The posterior end of
the male is curved in a close, conical spiral, and the spicule,
like its sheath, is much longer, being equal to about a third of
the length of the body. The genital orifice,of the female is
situated at the summit of a prominent, hour-glass shaped
papilla, which is obliquely truncated at the summit and
covered with minute spinules, like those of the spicule-sheath
in the male. The eggs are similar to those of the preceding
species and, without doubt, develop in the same way. It is
not known to cause any serious disease.

Spiroptera strongylina Rud., from the Hog. Figure 78.

The genus Spiroptera includes numerous species of small,
whitish or reddish, slender, round worms, which taper some-
what toward the anterior end, or toward both Figure 78.
ends. The head is small, and either naked, or
with small papillae. The male has the posterior
end curved in a spiral, with membranous expan-
sions, and with two unequal intromittent
spicules. In the female the posterior end of the
body is nearly straight and conical, and the
ovary is either simple or double, with the genital
orifice situated at one side of the body.

The 8. strongylina has a smooth, tapering body, with a
simple head and mouth. The male spicules are very long,
relatively to the entire length of the body. The male grows
to the length of half an inch or more. The female to more
than three-fourths of an inch. It lives in the stomach of the
hog, but ordinarily does not produce any serious disease.

Figure 78. — Spiroptera str any y Una ; a, male, natural size; b, spicnles and pos-
terior end of the body, enlarged. From Guerin,

PARASITES OF ANIMALS. 121

Spiroptera megastoma Rudolphi, of the Horse.
This is a small species, which has a more cylindrical body,
tapering a little toward each end. The head is separated by
a slight constriction and bears four lobes. The mouth is
large. The male becomes rather more than a quarter of an
inch long, and the female nearly half an inch. It lives in
the stomach and oesophagus of the horse and produces
tubercles, or hard tumors, of considerable size, most frequent-
ly situated near the pylorus. These contain many cavities,
connected together and filled with purulent matter, in which
there are numerous specimens of the parasite. The tumors
are sometimes one and a half inches in diameter, and there
are at times several in the same stomach.

Spiroptera sanguinolenta Rudolphi, of the Dog.
This is a larger, reddish species, which produces similar
tumors in the oesophagus and stomach of the dog. This
species usually grows to the length of one and a half to three
inches, but it has been found ten inches long, living in the
cavities of the ventricles of the heart of dogs at Shanghai,
China, where it appears to be very common. Its complete
history is unknown, and therefore little can be said about the
special means of prevention, or cure. It often produces death.

Pin-worm of the Horse (Oxyuris curvula Rudolphi).
Figure 79.

This is a small, whitish worm, quite commonly found in
the coecum and colon of the horse and ass. The female is
about one inch and a half to two inches long, when mature.
The male is far more rare and but one-third to two-thirds of
an inch long. The body is fusiform, tapering to a slender
tail, thicker in front, with the anterior end more or less
pointed. The mouth is situated at the end, and usually has
the form of a small, round pore, but is provided with three or
four small retractile papillae, which can be protruded. The
buccal cavity contains a peculiar apparatus of folds and tooth-
like processes ; the oesophagus is long and muscular, round
externally, but with a three-cornered cavity ; it is separated
from the round, gizzard-like stomach by a constriction, and
16

122 BOARD OP AGRICULTURE.

then a second constriction separates the stomach or gizzard
from another somewhat enlarged cavity, which tapers grad
ually into the slender intestine. The anal orifice is near the
posterior end of the body, and in the male also gives exit to
the intromittent organ, which is a single, sharp, grooved
ticuluna^ with a very small accessory one. The female

•*^

orifice is situated near the anterior third of the body. This,
like the other species of Oxyuris^ produces eggs having firm
shells. These probably hatch in water, and the embryos may
thus be swallowed in drinking. The intestines of these para-
"sites are generally filled with vegetable matters derived from
the food of the animals in which they live, and the structure
of the digestive organ seems to be adapted to vegetable food.
For this reason it is probable that they ordinarily cause little
or no inconvenience to the horses that they inhabit.

The Pin-worm of Man (Oxyuris vermicularis Bremser).

This is a much smaller species than the preceding, but is
similar inform. It is very common, often in great numbers, in
children, and occurs also in adults, especially in aged and
debilitated persons, and inhabits chiefly the lower part of the
rectum and the vicinity of the anus.

The male is about one-eighth of an inch long, with the tail
curved in a spiral form, terminating in a very short point.
The female is about four-tenths of an inch long and one-
fiftieth in diameter, with the posterior part of the body taper-
ing to a very slender tail.

The digestive system and structure of the mouth is similar
to that of the preceding species. But the head sometimes
shows inflated lateral lobes.

Reproduction.

This species is very prolific ; each female produces thou-

Eigure 79. — Oxyuris curvula, female, twice natural size. From Guerin.

PARASITES OF ANIMALS. 123

sands of eggs, in which the embryos are considerably de-
veloped before they are laid. The embryos enclosed within
the eggs are shaped somewhat like tad-poles, the slender tail
being bent up against the lower side of the body, which faces
the flattened side of the egg. The body is broad and well
fills the egg. The full history of the development of the eggs
is not yet known. It is probable, however, that a portion of
the eggs imbedded in the mucus membrane of the intestine
hatch in that situation, remaining thus in the same person.
But it is also probable that the eggs that are discharged will
hatch in water, and that persons become infested by swallow-
ing the embryos with their food and drink.

Symptoms.

The most marked symptom of these parasites is an intoler-
able itching in and about the anal orifice, which is generally
worst in the evening or during the night, when the worms are
migrating or changing their localities. This is usually accom-
panied by sensations of heat and inflammation. Not unfre-
quently, by irritation of the adjacent nerves, they cause
similar sensations in the genital and urinary organs, which
sometimes become very distressing. They sometimes even
migrate into the genital passages of female children, causing
great irritation and very serious symptoms. By the irritation
of the sexual organs, in both sexes, various unfortunate sec-
ondary diseases and bad habits not unfrequently result,
especially if they occur at the period of early puberty. Other
symptoms caused by the irritation of the nervous system, are
restlessness, general nervousness, involuntary twitchings,
itching of the nose, chorea, convulsions, and sometimes
epileptiform seizures.

Remedies.

The various medicines ordinarily used as anthelmintics, or
vermifuges, will often bring away large numbers of these
worms. Of these the etherial extract of male fern is probably
the best, but santonine and panna have been used with good
results. Ordinarily they can be treated more easily and
effectively by means of injections of cold, or nearly cold,

124 BOARD OP AGRICULTURE.

water, to which may be added a small amount of salt, oil of
anise-seed, or assafoetida. Sometimes decoctions of quassia,
worm-wood, or southern-wood {Artemisia abrotanum) are
used for this purpose, with good results. To these a portion
of olive-oil may be added. But any remedy that may be em-
ployed must be repeated as often as once every three or four
days for at least three weeks, in order to destroy the young
ones as fast as they develop. An application of mercurial
ointment to the parts about the anus is recommended to pre-
vent the migrations of the parasites and the uncomfortable
itching sensations that they thus produce.

The common Hound-worm of Man (Ascaris lumbricoides

Linn.).

This species is well known as a parasite of the human in-
testine, especially in children, though often found in persons
of all ages. The round-worm of cattle is generally regarded
as the same species.

These worms are round and smooth, tapering to both ends,
with a tough, elastic skin. The mouth is situated at the more
pointed end, and is provided with three prominent papillae, or
fleshy lobes. The male grows to the length of six inches,
and has the posterior end curved and provided with two
slender spicules. The female is much larger, sometimes be-
coming twelve or fourteen inches long and one-fourth of an
inch in diameter ; the female genital orifice is in advance of
the middle of the body.

Development.

The females produce great numbers of minute eggs, which
are provided with thick, rough .shells. The eggs are dis-
charged and pass from the human intestine before the
development of the embryos commences. If kept
in water the embryos go on developing slowly and
gradually, the whole process requiring from six months
to nearly a year. The fully developed embryos are
round and slender, about T£o of an inch long, with
an obtuse head and an acute tail. They have not been ob-
served to quit the eggs of their own accord, but may live for
at least a year within the egg-shell, after they attain their full

PARASITES OP ANIMALS^ 125

size. It is probable that such eggs, containing embryos,
when swallowed in the water that we drink, will be hatched
in our stomachs by the action of the gastric juice, and that
the young worms thus reach their destined abode. It is
possible, however, that under the proper circumstances the
eggs will hatch in the water, and that the free swimming em-
bryos may be swallpwed in the same way. This part of their
history still remains uncertain.

Symptoms.

The presence of one or two of these parasites in the human
intestine does not ordinarily cause any marked effects or
noticeable symptoms. But when they occur in persons of
delicate health, and when in great numbers, as sometimes
happens, they may cause great disturbance of the natural
functions of the digestive system, and induce various serious
consequences. Cases have occurred in which from 100 to
500 of these worms have passed from one child. They live
chiefly in the small intestine, but sometimes enter the stomach
and may even be expelled by vomiting. In some instances
they have been known to perforate the walls of the intestine
and enter the abdominal cavity, and thus even to get into the
other organs, including the lungs, pleura, gall-bladder, etc.
In such cases death often results.

Their presence in the stomach and intestine causes colic
and shooting pains, often accompanied by nausea, vomiting,
dyspepsia, itching of the nose, and diarrhoea. Owing to the
irritation of the nervous system they may cause restlessness,
convulsive twitchings, especially during sleep, and various
mental disturbances. In some cases, serious convulsions,
epilepsy, and insanity have been caused by them, and have
been cured at once by expulsion of the worms.

Remedies.

The most reliable remedy appears to be santonine, but this
is a powerful preparation, and must be used with caution.
For children the dose is one to three grains, in the form of
powder, which does best if taken in castor- oil or. honey,
though it may be sprinkled over a piece of bread and butter.

126 BOARD OF AGRICULTURE.

For an adult the dose is four or five grains, twice a day, on
every second day, for a week, the quantity to be diminished if
the medicine causes ill effects, such as spasms, tenesmus, etc.
It often causes temporary perversion of vision, things appear-
ing of unnatural colors, etc., but this effect soon passes away.

The root of male fern (see page 191), given in powder, in
connection with purgative medicines, is also recommended.

As means of prevention, the use of impure water should be
avoided. And if water from streams and ponds must be
used for drinking, as in most large cities, it should be
thoroughly filtered through powdered charcoal.

The Round-worm of the Horse (Ascaris megalocephala
Cloquet) .

This species inhabits the intestine of the horse, ass, and
mule, and is quite common. It closely resembles the preced-
ing species in form and general appearance, but grows to a
larger size, the male becoming ten inches long, and the female
twelve inches or more. The mouth is surrounded by three
large, rounded, very prominent lobes or papilla. In the male
the tail is provided with wing-like folds along the sides ; in
the female it is conical, terminating in a point, the female
genital opening being situated in the anterior fourth of the
body.

This species likewise produces vast numbers of eggs, which
develop embryos externally to the body, in water. Dr. Cob-
bold states that he has reared free, active embryos from these
eggs by keeping them five months in water. The horses,
most probably, swallow these embryos in the water that they
drink.

These parasites, when numerous, will no doubt produce
effects analogous to those caused in the human body by the
preceding species, and the remedies will be similar.

The Round-worm of the Cat (Ascaris mystaxRndolphi).

Although very common in the cat, this parasite is of inter-
est chiefly on account of its occasional occurrence in the
human intestine.

It may be easily distinguished by the presence of peculiar

PARASITES OF ANIMALS. 127

wing-like membranous expansions on each side of the head
or anterior end of the body. The male grows to the length
of two and one-half inches ; the female sometimes becomes
four inches long and one-twelfth in diameter.

This worm probably propagates its kind in a manner similar
to that of the two preceding species, and no doubt gains ad-
mittance to the human intestine, as well as to that of the cat,
by the medium of impure water and unclean vegetable food.

Its effects and remedies are the same as those of the com-
mon round-worm.

The Round-worm of the Hog (Ascaris suilla Dujardin).

This very closely resembles the Ascarislumbricoides of man,
and probably has nearly the same habits. It differs chiefly in
the structure of the reproductive organs. The male spicules
are not so sharp, and the tubes of the uterus are much longer.
The eggs are smaller. It appears to be less common than
the Echinorhynchus gigas in the intestine of hogs, and prob-
ably produces less injurious effects.

STEONGYLUS.

The genus Strongylus includes slender, filiform worms,
mostly of small size, and often reddish in color. Several of
them live in the windpipe and bronchial tubes of various
animals, including sheep, deer, cattle, pigs, etc., and when
numerous may occasion the death of the animals that they
infest, by suffocation.

The body generally tapers toward the head, and sometimes
in both directions. The mouth is small, situated at the end
of the small head, which is either simple or with lateral ex-
pansions. It is sometimes surrounded by small papilla, but is
often simple, and either round or triangular, but not enclosed
by a hard or chitinous organ, as in Sclerostoma, etc. The
oasophagus is enlarged, club-shaped, and muscular.

The male has the posterior end of the body provided with
an expanded, often lobed pouch, or bursa, for adhering to the
female during copulation. The spicule is slender and filiform,
enclosed in a sheath. In the female the posterior end is

128 BOARD OF AGRICULTURE.

conical or pointed, and the genital orifice is placed in advance
of the middle of the body, or more rarely toward the pos-
terior end.

The Strongylus of Sheep {Strongylus filaria Rud.).
Figure 80.

The present species is whitish, very long and slender. Th
head is obtuse and without appendages, the mouth surrounded
by three small papillae. The caudal pouch of Figure so.
the male is entire, with ten rays (Figure 80).
The male is about two and a half inches long,
and the female three and a half, though gener-
ally not more than two or three inches long, the
interior of the body of the female is mostly oc-
cupied by two long convoluted uterine tubes,
containing eggs in which the embryos are in all
stages of development. These open at an
orifice situated at about one-third of the length
of the body from the head.

Habits.

This species lives in the lungs, air-passages,
and bronchial tubes of sheep and other rumi-
nants. They often occur, singly or several to-
gether, in cavities in the substance of the lungs,
producing great inflammation and destruction
of the tissue, which often results in the death of
great numbers of lambs, and greatly injures the
health of old sheep, even if it does not actually
kill them. In this way many thousands of
lambs are annually lost in certain districts in
England. In this country we have far less in-
formation concerning the extent of its ravages,
but have no reason to suppose that it is less
common than in Europe, in localities that are favorable for its
development. Sheep infested by this parasite continually
cough up the eggs and embryos of the worms, and either dis-
charge them directly from the nose or mouth, or swallow them

Figure 80. — Strongylus filar ia, male, enlarged. From Thudichura.

PARASITES OF ANIMALS. 129

and thus pass them with the faeces. In either case they will
often adhere to grass *nd other herbage, and may thus be
swallowed by other sheep or lambs, fed in the same pastures,
and pass directly into the windpipe, or else do so when the
cud is raised for mastication. Therefore lambs should never
be put into fields or pastures where diseased animals have
been kept, but such infected lands should be tilled, or at least
left at rest for several months. As soon as an animal gives
any indication of the presence of the parasites by the
peculiar cough, it should be separated from the rest of the
flock for treatment ; or else immediately killed and the para-
sites should be effectively destroyed, and not thrown on the
ground as harmless, for all these worms are remarkably
tenacious of life, and often may even be dried up completely
for months, and then revive when moistened.

Remedies.

When these parasites are once lodged in numbers in the
substance of the lungs, there is probably no reliable remedy
whatever. When merely in the windpipe and bronchial tubes,
expectorant medicines that will produce a copious secretion
of mucus may be useful. It might be possible to remove
them by a surgical operation, opening the windpipe from 'the
exterior, but this would require surgical skill and would not
pay, perhaps, except as a last resort for valuable animals.

The Strongylus of Cattle and Horses (Strongylus micrurus

Mehlis).

This species closely resembles the preceding. The male
grows to the length of about one inch and a half ; and the
female to three inches or a little more. The body is very
slender with a simple, blunt head. The bursa of the male
has five rays. The female genital orifice is near the middle
of the body. It is said to be viviparous.

The habits of this species are nearly the same as those of
the last, except that this inhabits the air-passages of cattle,
horses, asses, and mules, instead of sheep. It is much more
liable, like the former, to infest young animals than adults.
Calves less than a year old are particularly liable to be in-
17

130 BOARD OF AGRICULTURE.

vaded, and those that are once attacked seldom or never re-
cover. The same remarks, concerning the means of preven-
tion, made under the preceding species, will apply equally to
this. If neglected, these parasites increase with great
rapidity, and thus the disease that they cause appears like an
epidemic, in certain localities destroying hundreds or thou-
sands of animals, while adjacent farms may be entirely free
from it.

The Strongylus of the Hog (Strongylus parodoxus Mehlis).

This is a slender, whitish or brownish worm, with a small,
simple head. The mouth has three small papillae. The
oesophagus is long and muscular. The anus is situated some-
what in advance of the posterior end of the body at the sum-
mit of a small papilla. The male becomes half an inch or
more in length, and has the caudal bursa bilobed, each lobe
with five rays, the lateral ones divided. The female grows to
the length of about an inch and a half, but is usually about
an inch long ; the tail is terminated by a point, turned to one
side ; the genital opening is near the posterior end and a little
prominent. This species is viAdparous. It inhabits the wind-
pipe, bronchial tubes, and lungs of swine. Its history and
the effects it produces are nearly the same as those of the
Strongylus filar ia.

The Strongylus of the Intestine of the Hog (Strongylus
dentatus Rud.).

This is a slender filiform species, about half an inch long,
which lives in the small intestine, coecum, and colon of hogs.
The head is obtuse and surrounded by six acute papillae. The
oesophagus is short and thick, muscular. In the male the
tail is truncated and provided with an oblique bursa, formed
of a single piece, strengthened by three subdivided rays ;
there are two slender spicules. The tail of the female is
elongated and slender, ending in a fine point ; the genital
opening is near the posterior end.

The effects of this species and its history are little known.

PARASITES OF ANIMALS. 131

The Strongylus of the Intestine of Sheep ( Strongylus contortus

Rud.).

This is a filiform species, tapering to both ends, but more
slender toward the head, which is provided with two semi-
elliptical, wing-like appendages ; the mouth with three small
papillse. The male is about three-fourths of an inch long,
with a bilobed bursa, each lobe with about eight rays : the
sheath of the male spicule is very long. The female sometimes
becomes four inches long.

It is not uncommon in the small intestine of sheep, but its
history is very imperfectly known. When abundant it may,
without doubt, cause serious trouble.

Strongylus filicollis Rudolphi .

This species also inhabits the small intestine of sheep. The
body is very slender and whitish or reddish. The head has
two, very small, lateral, wing-like appendages. The male
bursa is bilobed, each lobe with six rays. It is from a third
to four-fifths of an inch long.

Strongylus radiatus Rudolphi.

This worm lives in the small intestine and colon of cattle
and several other ruminants. The head is simple ; the mouth
naked. The male is about half an inch long, with a bilobed
caudal bursa, the lobes many rayed. The female is about
three-quarters of an inch long ; the genital opening is near
the tail.

Its complete history is unknown.

The Kidney-worm (Euslrongylus gig as Diesing). Figure 81.

This is the largest of all the Nematode worms, the females
sometimes becoming three feet long and half an inch in
diameter, though usually much less. The body is smooth,
cylindrical, tapering somewhat to each end, and more or less
deeply tinged with red. The head is simple, obtuse. The
mouth is terminal and surrounded by six rounded, chitinous
papillse. The male becomes ten to twelve inches long and
one-fourth of an inch in diameter ; the caudal bursa is cup-
shaped, circular and entire, without rays ; the male spicule or

132

BOARD OP AGRICULTURE.

penis is very slender. The female has a nearly straight,
obtuse tail ; the anus is triangular, near the end ; the genital
orifice is anterior, near the mouth ; the ovaries and oviducts
are simple, but long and convoluted. The intestine is large
and blackish, with thin walls, and quite simple, running
directly from one end of the body to the other, and is attached
to the sides of the body, along its whole length, by fibres.

Habits.

This formidable parasite lives in the kidneys of man and
various animals. It has been found in the dog, horse, cattle,
hog, wolf, \veasles, mink, otter, seal, glutton, raccoon, and coati.
In this country it has been found quite frequently in the kid-
Figure si.

neys of the mink. It has been found very rarely in the blad-
der, in the abdominal cavity, and, it is said, in the heart. In
man it is very rare. When lodged in the kidney it gradually,
but completely, destroys the substance of the organ, which
becomes filled with purulent and bloody matter, upon which
the worm feeds, while the walls often become hardened with
calcareous deposits. The effects and symptoms are the same
as in other acute diseases or abscesses in one of the kidneys.
The only positive evidence of the presence of the worm would
be the discovery of the eggs in the urine. It is probable that
no remedy can be applied when the parasite is once lodged in
the kidney.

The history of this worm is not fully known. According
to Leuckart, a slender worm found coiled up in cysts in
the muscles and peritoneum of fishes is the young or larva of
some species of Eustrongylus. The larval form referred to

Figure 81. — Eustrongylus gigas, male, less than natural size; a, spiculum and
bursa ; 6, anus of female, enlarged. From Guerin.

PARASITES OF ANIMALS. 133

is the Filaria cystica Rudolplii, originally found in a Brazilian
fish (^SymbrancTius lalicaudus). It is, therefore, probable that
the eggs or young embryos of E. gigas are swallowed by
fishes, and in their bodies develop into the larval form and be-
come encysted, and if then swallowed by some mammal,
migrate into its kidneys to become sexually mature. The
frequency of these parasites in those animals that feed chiefly
on fish, such as the otter, mink, and seal, renders this view
very probable.

The Crape-worm of Chickens, etc., (Syngamus trachealis

Siebold). Figure 82.

This parasite lives in the windpipe and bronchial tubes of
chickens, turkeys, pheasants, partridges, crows, wood-peckers,
and many other birds. In young chickens and turkeys it
Figure 82. often proves very destructive, by filling up

the air passages, and thus quickly killing
whole flocks. In some parts of this
country at least three-quarters of all the
young chickens and turkeys are some-
times destroyed by this parasite. The
\l \\ 1! /S worms are reddish in color and have a
I \KwJl H smo°th skin, but spiral depressions run
I rm around the body, giving it a twisted

I iH 1 appearance. The reproductive organs

show through the skin, as slender,
whitish, convoluted tubes. The males
and females are almost invariably found united firmly to-
gether, as shown in the figures, the integument of the male
soon becoming organically united to that of the female, so
that the copulation is permanent or for life. The females are
very much larger than the males, becoming about three-
quarters of an inch in length, and one:sixteenth of an inch
in diameter. The anterior end, in both sexes, suddenly ex-
pands into a trumpet-shaped, concave disk, in the middle of
which the mouth is situated, surrounded by six small chitinous
lobes ; the posterior portion of the body of the female is more

Figure 82. — Syngamus trachealis Siebold ; a, male and female united, natural
size ; 6, anterior part of female, enlarged ; c, male, enlarged. From Cobbold.

134 BOARD OP AGRICULTURE.

or less bent and folded, and suddenly narrows at the end,
terminating in a small point. The genital orifice is near the
anterior fourth of the body, where the caudal bursa of the
male is attached and conceals it. The male is only one-eighth
or one-seventh of an inch long and very slender ; the caudal
bursa is simple, sucker-like, with an entire margin, strength-
ened by about ten rays ; the penis consists of two very small,
cylindrical spicules, about 225 of an inch long. The eggs are
oval, about 250 of an inch long. The embryos develop while
the eggs are still in the oviducts and uterine tubes, and the
eggs or young probably escape by a rupture of the integument
of the body of the female.

The history of the young worms, after they are expelled
from the windpipes of the birds, is not yet known, however.
Possibly they may enter the bodies of insects to pass their
larval state, but it is more probable that they bury themselves
in the surface of the soil or other moist places, and are thus
picked up directly by the birds and gain admittance to the
windpipe by their own active motions.

Symptoms.

The disease commonly known as " the gapes " is caused
solely by the presence of numbers of these worms in the wind-
pipe, which thus becomes so filled up as to render respiration
difficult, and if in considerable numbers, by their growth the
obstruction becomes complete, and death results from suffoca-
tion. Young chickens, thus attacked, seldom recover without
special treatment for the removal of the worms. Chickens
only three or four days old often show symptoms of the dis-
ease by opening wide their mouth and gasping for breath, and
attempting to swallow. They also frequently sneeze. As the
disease grows worse these symptoms become more marked;
they continually gasp and struggle for breath, grow weak and
dispirited, and finally 'droop and die. In fatal cases, one or
two dozen of these worms are often found in the windpipe,
completely filling it up.

Remedies.

The worms may be removed by a feather from which the
web has been stripped, except a small portion near the tip.

PARASITES OP ANIMALS. 135

This may be moistened with oil, salt-water, or a weak solution
of carbolic acid, and' introduced into the windpipe, when if it
be twisted round once or twice and removed, it will usually
bring away several of the worms. The operation should be
repeated at intervals until all the worms are destroyed. All
worms removed in this or any other way should be carefully
destroyed, preferably by fire, for the embryos are extremely
tenacious of life, and if left upon the ground are likely to
spread the disease. For the same reason, those birds that are
infected should be separated from the healthy ones, and poultry
should never be allowed to run in the same yards or grounds,
or be kept in the same houses where infected ones have previ-
ously been kept, unless the premises- have first been thor-
oughly sprinkled with a strong solution of carbolic acid or
petroleum-water, to destroy those old worms or the eggs and
embryos that may have been discharged from the sick ones.
The vessels from which they feed should be frequently and
thoroughly cleansed, and they should be supplied with pure
water, frequently renewed.

In extreme cases, the worms may be safely removed by a
surgical operation ; but this requires some skill. This is done
by first carefully securing the bird, or still better by adminis-
tering a few drops of chloroform, placed upon cotton and
held to the nostrils. The skin of the neck is then to be di-
vided with a very sharp knife, and the windpipe opened by a
longitudinal slit about a quarter of an inch long. The worms
may then be removed by a pair of small forceps or other suit-
able instrument. , The incision in the skin may be closed by
one or two stitches, and the wound will generally heal in a
few days. By this operation an almost instantaneous cure
may be effected, even when the disease has progressed nearly
to the point of suffocation ; but in unskilful hands it is not
likely to be so successful as the remedies already described.

The Sclerostoma of the Horse (Sclerostoma equinum Dujardin,
or S. armatum Davaine). Figure 83.

This is a small, slender, cylindrical worm, reddish or brown-
ish in color, which lives in the intestines, and in peculiar
enlargements of the arteries of horses, asses, and mules. The

136 BOARD OP AGRICULTURE.

head is round, nearly globular, supported by a cliitinous bulb
or capsule, truncated at the end, where the large, round
mouth is situated. The mouth is surrounded by one to sev-
eral circles of fine denticles, or converging hooks. The oesc-
phagus is muscular and thick, club-shaped, separated from
the intestine by a strong constriction.

The male is an inch or an inch and a quarter long, with a
large, membranous, caudal bursa, divided into two lateral
lobes, which are strengthened by numerous rays ; there arc
two long and slender spicules. The female grows to the length
of one and a half to two inches, with a long, tapering, caudal
portion, the anus not terminal ; the ovaries long and con-
voluted around the intestines, and showing through the integu-
ments ; the uterine tubes are double and contain great num-
bers of eggs, in which embryos are developed.

Habits.

This parasite is very common in the horse, generally living
attached by the hooks of its head to the lining membrane of
the intestine, particularly in the coecum and colon, but some-
times in the small intestine and duodenum, and even in the
pancreas. At the points where it adheres it Figure 83.
causes small, dark-colored, raised spots. They
sometimes occur in vast numbers in the large
intestine, completely covering the surface ;
the number sometimes amounting, it is said,
to a million or more. Ordinarily, however,
these parasites, when lodged in the intestines,
do not appear to produce any marked dis-
ease or notable symptoms, although when in
great numbers, there can be no doubt but
that they must cause some inflammation and
pain. More serious results, sometimes prov-
ing fatal, happen when the worms enter the
blood-vessels. They produce large aneurisms or dilations of
the arteries, chiefly in the anterior mesenteric artery, but

Figure 83. — Sclerostoma equinum, female, natural size ; and anterior portion en-
larged ; a, mouth ; b, circle of hooks ; c, oesophagus ; d, intestine ; e, reproductive
organs. From Cuvier.

PARASITES OP ANIMALS. 137

also in the arteries of the colon, coecum, small intestine, and
liver, as well as in the posterior mesenteric and renal arteries,
and others adjacent to the intestine. These tumors are gen-
erally fusiform, and as large as a man's finger ; but they are
sometimes globular, and may become as large as a man's
head. The middle membrane of the artery in these dilations
becomes enormously thickened, sometimes being twelve times
as thick as in the healthy artery. In old tumors various hard
or calcareous deposits often take place in the thickened walls
or in the inner membrane ; and in such cases, the walls being
weakened, are liable to be ruptured by some unusual exertion
of the animal, when death results almost instantly. In the
interior of the aneurism there is generally a deposit of fibrin,
firmly adherent to the inner surface. In this and in the dif-
ferent layers of the walls the worms are found, — sometimes
only a few, but frequently large numbers. This disease is
very prevalent among old horses. In France, as many as
ninety-six out of one hundred have been found affected with
the disease.

I am not aware that any remedies have ever proved useful.
Generally it would be impossible to detect the disease during
life, unless the tumors became very large.

Sclerostoma pinguicola Yerrill.

On two occasions I have received specimens of a rather
large parasitic worm, which lives in the fat of hogs. In the
first case, five specimens were obtained, at New Haven, by
Dr. M. C. White, from the fatty portion of a spare-rib ; in the
second instance, at Middletown, Conn., Dr. N. Cressy found
large numbers of the worms in the fat about the kidneys of a
young Suffolk pig, brought from New Jersey. Un-
fortunately, none of these specimens are in so good a state
.of preservation as to enable me to determine with certainty
all the points of their structure. Those which I owe to the
kindness of Dr. White, had been mounted in glycerine as
microscopic objects and pressed out flat, before they came
into my possession, and the tissues were thus injured and
the organs deranged. Those from Dr. Cressy, were both
pressed flat and dried. Yet by careful masceration, and
with much labor, I believe that most of the important char-
18

138

BOARD OF AGRICULTURE.

acters have been made out. The body is rather robust, es-
pecially in the female, and tapers to both ends ; the color is
yellowish white, and the integument is seen to be finely
striated transversely, when considerably magnified. The
head is smaller than the body, truncated at Figure 83 a.
the end ; the mouth is terminal, roundish, or
somewhat angular, surrounded by the thick-
ened rim of the chitinous capsule, or pharynx.
This chitinous ring rises at intervals into four
to six denticles, or very small teeth, which
correspond to thickened longitudinal, chitin-
ous bands, that strengthen the pharynx, and
give a slightly angular form to the mouth.
The pharynx itself is small, short, and rather
squarish, when seen in profile, and has three
or four small, conical teeth at the bottom.
The oesophagus is thick, club-shaped, and very muscular.

The male is 1.12 of an inch long, and about .05 of
an inch in diameter ; the tail ends in a small blunt lobe,
united with two small, entire, membranous expansions,
one on each side, forming a small bursa, which is
strengthened by several short rays, the exact number of
which could not be determined in my specimens ; there
are two long, slender spicules. The females are 1.25
to two inches in length, and, as flattened between glass,
they are .10 to .13 of an inch in breadth. The posterior
end suddenly and obliquely narrows to a small conical
point, which is turned to one side. The anal opening is close
to the end, and the genital orifice appears to be adjacent to
it. The oviducts are long, voluminous, much convoluted,
and unite in a large and capacious uterus, which fills most
of the cavity of the body near the posterior end. The uterus
and oviducts are both filled, in the larger specimens, with im-
mense numbers of small oval eggs.

It is probable that this parasite is by no means uncommon.

Pentastoma tcenioides Rudolphi. Figure 84.
This parasite is not a true worm, but is now generally re-
Figure 83 a. — Sclerostoma pinguicola ; a, male, natural size ; b, posterior end, en-
larged; c, female, natural si/e; d, head, enlarged. Original.

PARASITES OF ANIMALS.

139

garded as belonging to the Acarians, with the true mites. In
the adult state it inhabits the nostrils and frontal sinuses of
dogs and wolves, and more rarely, of horses and sheep. The
larvse, formerly described under the name of Pentastoma den-
ticulatum, lives in, cysts on the outside, or in the outer por-
tion, of the liver of sheep, deer, antelopes, . peccary, porcu-
pine, Guinea-pig, rabbit, hare, rat, and cat ; and some-
times invades the human body in the same way. It has also
been found free in the visceral cavity of the body.

In the mature state (Figure 84) the body is long, lance-
shaped, tapering behind, flattened below, and divided into
about ninety segments by transverse lines. The segments
next to the head bear two pairs of small, but strong and
Figure 84. sharp, retractile claws, which represent the true
legs of ordinary mites. The mouth is broad-
oval, and provided with a hard chitinous lip.
The segments behind the head are perforated
by small openings, regarded by many as
spiracles, or breathing pores. The adult is
smooth, but the larvae are covered with many
rows of small, sharp spines. The male is
only .07 to .08 of an inch in length, but
the female becomes three or four inches long,
and half an inch wide. The female genital
opening is in the tail, that of the male, in the
middle of the front part of the abdomen. They
are oviparous, and the young undergo a com-
plete and remarkable metamorphosis.
The adults live in the nasal cavities of dogs, and
produce an irritation of the delicate membranes, which
causes a flow of mucus, often accompanied by sneez-
ing. The eggs discharged with the mucus .may ad-
here to vegetables or fruit, or get into drinking-
water, and in these ways gain admittance to the stomach of
man, or other animals. In the stomach they hatch into mi-
nute embryos, furnished with a boring apparatus and two pairs
of double claws. They bore their way through the intestines
and lodge in the liver or other parts, and soon become dor-

140 BOARD OF AGRICULTURE.

mant and enclosed in cysts, in which they pass a sort of
pupa state. During this period of their life, the skin is cast
several times, and the appearance changes at each moult, un-
til they attain the next period of their life, when they
again become active ; this is the state described as Petastoma
denticlatum. These larvae are long-oval, broadest anterior-
ly, and covered with numerous rows of transverse tooth-like
spinules. They have two pairs of sharp, curved claws, which
are situated near the mouth and placed obliquely, diverging
from the median line of the body, and directed downward.
Each claw has a sort of hood or capsule, into which it can be
retracted. If dogs feed on the liver or other viscera of animals
containing these larvae, they come in contact with, and man-
age to enter the nose, working their way up by means of the
motions of the body, aided by their spines and claws. In
this situation they gradually become mature.

In the human body the larval form is quite frequent, es-
pecially in some parts of Europe ; but there is little known
concerning the effects that it produces. When in small num-
bers, it probably causes very little disturbance, but if in large
numbers, in the liver and lungs, it would no doubt produce
serious disease, as does another species (P. constrictuin) ,
which is very common in Egypt, living in the same way en-
cysted in the liver and lungs. The latter, when in consider-
able numbers, frequently proves fatal.

As a means of prevention, dogs that show symptoms of
the parasites in the nose, should be treated to a solution of
carbolic acid, thrown up the nostrils by a small syringe.
Feeding dogs with the offal of slaughter houses, or with un-
cooked livers, etc., should be avoided, both on account of this
and the other dangerous parasites that they get in this way,
(see Tcenia echinococcm, p. 202, T. marginata, p. 192, T.
ccenurus, p. 196, and Trichina spiralis, p. 222). Too much
familiarity, especially of children, with dogs is always liable
to result in the transfer of these and other parasites to the
human body.

ERRATA.

In making up the author's copies, and repaging, several errors have been intro-
duced, which the reader should correct : —
Page 3 third line of foot notes, for Corydalus cornutas, read Corydalis cornutus.

" 6, line 19, for orceps, read forceps.

" 8, " 31, for pair, read pairs.

"12, " 13, for labium, read labrum.

" 13, figure 18 is inverted.

" 4*7, " 17.. for page 89, read page 16.

" 48, " 10, for page 109, read page 38.

" 49, " 31, for page 109, read page 38.

'' 60, " 10, for nemarum, read venarum.

" 61, " 23, for page 101, read page 30.

" 85, " 5, for page 191, read page 80.

" 100, " 34. It should be stated that Dr. Cobbold, in 1860, fed dogs with a
small cysticercus, from the liver of rabbits, but distinct from
" G. pisiformis" and obtained specimens of Tcenia cucwnerina,
which he thought were developed from them.

" 110, " 30, for " such hogs are," read such a hog is.

"126, <l 6, for page 191, read page 80.

"140, lines 32 and 33, for page 202, read 91; for 192, read 81; for 196, read
85; for 222, read 111.

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