PART VIII (RUMINANTIA).

In the matter of parasites this order of mammalian animals stands second

in importance. An entire volume of the dimensions of the present would

barely do justice to the subject. Although in the article “Ruminantia”

in ‘Todd’s Cyclopædia,’ and in my popular treatise on the mammalia, I

have described the oxen (_Bovidæ_) and sheep (_Ægosceridæ_) as separate

families, I shall here speak of their entozoa together; and, at the

same time, I shall introduce occasional reference to the helminths

of the antelopes and gnoos (_Antilopidæ_), also of the giraffes

(_Camelopardidæ_), the deer tribe (_Cervidæ_), the camels, and the

llamas (_Camelidæ_). The parasites of the last family, however, will

necessarily stand somewhat apart.

Almost all ruminants harbor the liver fluke (_Fasciola hepatica_).

This worm has been found in every variety of the common ox and zebu

(_Bos taurus_, var. _Indicus_), in the sheep, goat, and argali (_Ovis

aries_, _Capra hircus_, and _G. argali_), in the antelopes and gazelle

(_A. dorcas_), in red-deer, roe, and fallow (_Cercus elaphus_, _C.

capreolus_, and _C. dama_), and in the two-humped camel (_Camelus

bactrianus_). A closely-allied but much larger species of fluke (_F.

gigantea_) infests the giraffe (_Camelopardalis_). All these animals are

more or less liable to suffer from the “rot” which is produced by these

flukes. Into the history of the affection the space at my command does

not permit me to enter, but as regards the development of the common

fluke I believe the following conclusions to be tolerably well founded.

I had long entertained the opinion that our common _Planorbis_ plays

the rôle of intermediate bearer, and this view has at length received

confirmation.

1. The liver fluke, in its sexually-mature state (_Fasc. hepatica_),

gives rise to the disease commonly called _rot_; this affection being

also locally termed _coathe_ (Dorsetshire, Devon), _iles_ (Cornwall),

and _bane_ (Somersetshire). In France it is known as the _Cachexie

aqueuse_, and more popularly as _pourriture_. In Germany the epidemic

disease is called _egelseuche_, and in a more limited sense either _die

Fäule_ or _die Leberkrankheit_.

[Illustration: FIG. 61.--_Fasciola hepatica._ Enlarged. After Blanchard.]

2. The _rot_ is especially prevalent during the spring of the year, at

which time the fluke itself and innumerable multitudes of the free eggs

are constantly escaping from the alimentary canal of the bearer. The

germs are thus ordinarily transferred to open pasture-grounds along with

the fæces of the bearer.

3. As it has been shown by dissections that the liver of a single sheep

may harbor several hundred flukes, and as, also, a single adult fluke is

capable of throwing off several thousand eggs, it is certain that any

rot-affected flock is capable of distributing millions of fluke germs.

4. Such flukes as have escaped the host per anum do not exhibit active

powers of locomotion. Their slight contractile movements, however, serve

the purpose of concealing them in the grass, and probably aid in the

further expulsion of eggs, which pass from the oviduct in single file.

5. After the death of the escaped flukes the further dispersion of the

eggs is facilitated by the subsequent decomposition of the parent worm,

and also by its disintegration, partly occasioned by the attacks of

insects. It has been calculated that the uterus of a full-grown fluke

may contain upwards of forty thousand eggs.

6. By the agency of winds, rains, insects, the feet of cattle, dogs,

rabbits, and other animals, as well as by man himself, the freed ova are

dispersed and carried to considerable distances; and thus it is that a

considerable proportion of them ultimately find their way into ponds,

ditches, canals, pools of all kinds, lakes, and running streams.

7. At the time of their expulsion the eggs exhibit a finely segmented

condition of the yolk. The egg-contents continue to develop whilst

outside the parent’s body, the granular matrix finally becoming

transformed into a ciliated embryo, which when set free follows the

habit of infusorial animalcules in general by swimming rapidly in the

water. The escape of the embryo is effected at the anterior pole of the

egg-shell, which is furnished with a lid that opens in consequence of

the action of prolonged immersion, aided by the vigorous movements of

the contained embryo.

8. The ciliated, free-swimming embryo, at the time of its birth,

exhibits the figure of an inverted cone, its anterior extremity, which

is broad and somewhat flattened, supporting a central proboscis-like

papilla. A small pigment spot placed dorsally, and having the form of a

cross, is supposed to be a rudimentary organ of vision. After the lapse

of a few days the cilia fall off, the embryo then assuming the character

of creeping larvæ (planulæ).

9. Notwithstanding its abridged locomotive powers the non-ciliated larvæ

sooner or later gain access to the body of an intermediary bearer,

within or upon whose tissues it becomes transformed into a kind of sac

or _sporocyst_. In this condition the larva is capable of developing,

agamogenetically, other larvæ in its interior. The sporocysts are highly

organised, forming _rediæ_. According to Willemoes-Suhm, the redia of

_Fasciola hepatica_ lives on the body of _Planorbis marginata_. This

organised nurse, which is about a line in length, is the _Cercaria

cystophora_ of Wagener. The progeny of this redia consists of armed

Cercariæ, which after a time quit the nurse to pass an independent

existence in the water.

10. In the cases of some species of fluke there is reason to believe

that before the _Cercariæ_ gain access to their final or definitive host

they re-enter the bodies of the mollusks. This they accomplish by means

of a boring apparatus, and having previously cast off their tails they

encyst themselves beneath the surface of the skin. In this new situation

they develop into the so-called _pupa_, which is at length passively

transferred with the fodder, or drink, to the digestive organs of the

host. In the case of _Fasc. hepatica_, as probably obtains also with

many other flukes, I think there can be no doubt that the Cercariæ pass

directly into the bodies of ruminating animals. The circumstance that

flukes of this species have been found beneath the human skin shows how

considerable are the boring powers of the armed Cercariæ.

In regard to the possibilities of fluke development, that will be best

understood by glancing at the constitution of the zoological individual.

The sum total of the products of a single germ may be tabulated as

follows:--

Zoological individual (_Fasciola hepatica_).

_a._ Ovum in all stages, } First “biotome.”

_b._ Ciliated free-swimming embryo, }

_c._ Nurse, germ-sac, sporocyst (_redia_), } Second “biotome.”

_d._ Active, migrating, tailed larva (_cercaria_), }

_e._ Encysted, resting larva (_pupa_), } Third “biotome.”

_f._ Sexually-mature fluke (_fasciola_). }

This is a fair representation of the life-phases of the fluke.

The life-phases are rarely less numerous or complicated than here

indicated, but Pagenstecher’s researches tend to prove that under

certain climatal conditions the number of larval forms may vary

considerably. In other words, the fluke individual does not comprise

any definite number of “zoöids,” although the kinds of zoöids are

limited. I recognise three “biotomes.” The first includes only one

temporary, independent life-phase, this is the ciliated animalcule,

which I call a “protozoöid.” The second “biotome” may comprise only a

solitary simple sporocyst or germ-sac (deuterozoöid), but an almost

indefinite multiplication of new and independent germ-sacs, as well as

other more highly organised “nurse formations,” may also be developed

from the primary sporocyst (secondary and tertiary “deuterozoöid”). The

third “biotome” embraces a large but variable number of “tritozoöids”

(_cercariæ_), an equal number, whatever that may be, of “tetartozoöids”

(pupæ), and, therefore, also, a similar number of “pemptozoöids”

(flukes).

Practically, other curious results arise out of the foregoing

considerations. For example, a single sheep may harbor 1000 flukes. Each

fluke will develop 10,000 to 40,000 eggs. Each egg may give rise to 370

zoöids. It thus appears that, if all the conditions were favorable,

a single fluke might originate between three and four millions of

individualised life-forms, whilst the solitary sheep itself would,

under the same circumstances, be the means of causing the production of

at least 3,000,000,000 fluke zoöids! Happily, no such results as this

can possibly occur in nature, since interfering agencies reduce the

favorable conditions. However, the balance of parasitic forms from all

sources is usually sufficient to destroy thousands of sheep annually.

The virulence of rot-epizoöty is entirely due to the presence of

conditions favoring the development of fluke larvæ.

As regards the injurious action of this parasite on animals, it is well

known that in particular years, in England alone, hundreds, and even

thousands, of sheep have been destroyed in a single season. A writer in

the ‘Edinburgh Veterinary Review’ for 1861 states that in the season of

1830-31 the estimated deaths of sheep from _rot_ was between one and two

millions. This would, of course, represent a money loss of something

like four million pounds sterling. As affording additional striking

instances of the disastrous effects of rot, I may cite the statements of

Davaine. Thus:--“In the neighbourhood of Arles alone, during the year

1812, no less than 300,000 sheep perished, and at Nimes and Montpellier

90,000. In the inner departments, during the epidemic of the years

1853-54, many cattle-breeders lost a fourth, a third, and even three

fourths of their flocks.” In like manner our English authority, Prof.

Simonds, furnished a variety of painful cases. Thus, on the estate of

Mr Cramp, of the Isle of Thanet, the _rot epidemic_ of 1824 “swept away

£3000 worth of his sheep in less than three months, compelling him to

give up his farm.” Scores of cases are on record where our English

farmers have individually lost three, four, five, six, seven, and even

eight hundred sheep in a single season; and many agriculturists have

thus become completely ruined.

Remarkable periodic outbreaks of this disease are recorded by Simonds

as occurring in England in the successive years of 1809, ’16, ’24, ’30,

’53, and ’60; whilst, for France, Davaine mentions 1809, ’12, ’16, ’17,

’20, ’29, ’30, ’53, and ’54, as the most remarkable years. It would

be interesting to know how far these outbreaks tally with the similar

outbreaks which have occurred in Holland, Germany, and other European

districts. The disease was prevalent during four separate years in

France and England at one and the same time. This, indeed, is no more

than we would naturally expect, considering that the extent of the

development of the larval forms must, in a great measure, be dependent

upon atmospheric conditions. A warm and moist season would alike prove

beneficial to the development of the larvæ and their intermediate

molluscan hosts. Their numbers would also multiply enormously; for, as

already remarked, the degree of non-sexual production of trematode larvæ

within their sporocysts is materially affected by climatic changes. On

the other hand, a fine, dry, open season will tend to check the growth

and wanderings of the larvæ, and thus render the flocks comparatively

secure.

Considerations like these sufficiently explain many of the crude

theories which were early propagated concerning the causes of this

disease, and in particular, the very generally prevalent notion that

water, and water alone, was the true source of the disease. Intelligent

cattle-breeders and agriculturists have all along observed that the

_rot_ was particularly virulent after long-continued wet weather, and

more especially so when there had been a succession of wet seasons. They

have likewise noticed that flocks grazing in low pastures and marshy

districts were much more liable to invasion than sheep which pastured

on higher and drier grounds, but noteworthy exceptions occurred in the

case of flocks feeding in the salt-water marshes of our eastern shores.

The latter circumstance appears to have suggested the common practice

of mixing salt with the food of sheep and cattle, both as a preventive

and curative agent; and there can be little doubt that this remedy

has always been attended with more or less satisfactory results. The

intelligible explanation of the good effected by this mode of treatment

we shall find to be intimately associated with a correct understanding

of the genetic relations of the entozoon, for it is certain that

the larvæ of _Fasciola hepatica_ exist in the bodies of fresh-water

snails. As already hinted from Willemoes-Suhm’s observations, it is not

improbable that the larvæ are confined to gasteropod mollusks belonging

to the genus Planorbis.

The symptoms produced by _rot_ are very striking. When the disease has

far advanced it is easy to know a rotten sheep, not only by its very

look, but still more convincingly, as I have myself tested, by slightly

pressing the hand over the region of the loins. In this region the

diseased animal is particularly weak, and the pressure thus applied

instantly causes it to wince. At the same time the hand feels a peculiar

sensation very unlike that communicated by the spine of a sound animal.

In bad cases the back becomes hollow, and there is a corresponding

pendulous condition of the abdomen. The spinal columns ultimately stick

out prominently, forming the so-called “razor-back.” As Professor

Simonds has well observed, in an earlier stage of the disease, “an

examination of the eye will readily assist in determining the nature of

the malady. If the lids are everted it will be found that the vessels

of the conjunctiva are turgid with pale or yellowish colored blood, the

whole part presenting a peculiar moist or watery appearance. Later on,

the same vessels become blanched and scarcely recognisable.” The skin

also becomes harsh and dry, losing its natural tint, and the wool is at

length rendered brittle, either becoming very easily detached or falling

off spontaneously.

The first thing noticeable in dissecting a rotten sheep is the wasted

and watery condition of all the tissues. There is a total absence of

that firm, fresh, carneous look which so distinctively characterises

the flesh in a state of health. Not only is the rigidity and firm

consistency of the muscles altogether wanting, but these structures

have lost that deep reddish color which normally exists. When the

abdominal cavity is opened a more or less abundant, clear, limpid, or

yellowish fluid will make its escape, and the entire visceral contents

will, at the same time, display a remarkably blanched aspect. These

pathological changes are also shared by the important organ especially

affected, namely, the liver. This gland has lost its general plumpness,

smoothness, and rich, reddish-brown color, and has become irregularly

knotted and uneven both at the surface and the margins, its coloring

being either a dirty chocolate brown, more or less strongly pronounced

at different parts, or it has a peculiar yellowish tint, which in places

is very pale and conspicuous. To the feel it is hard and brawny, and

when incised by the scalpel, yields a tough and, in places, a very

gritty sensation. On opening the gall-ducts a dark, thick, grumous,

biliary secretion oozes slowly out, together with several distomes,

which, if not dead, slowly curve upon themselves, and roll up like a

slip of heated parchment. On further slitting open the biliary passages,

they are found distended irregularly at various points, and in certain

situations many flukes are massed together, having caused the ducts

to form large sacs, in which the parasites are snugly ensconced. The

walls of the ducts are also much thickened in places, and hardened by a

deposit of coarse calcareous grains on their inner surface. Mr Simonds

says, that the “coats of the _ductus hepaticus_, as also of the _ductus

communis choledicus_, are not unfrequently so thick as to be upwards of

ten times their normal substance, and, likewise, so hard as to approach

the nature of cartilage.” Respecting their numbers, the greatest

variation exists. The presence of a few flukes in the liver is totally

insufficient to cause death; consequently, when a sheep dies from rot,

or is killed at a time when the disease has seriously impoverished the

animal, then we are sure to find the organ occupied by many dozen,

many score, or even several hundred flukes. Thus from a single liver

Bidloo obtained 800, Leuwenhoeck about 900, and Dupuy upwards of 1000

specimens. Even the occurrence of large numbers only destroys the

animal by slow degrees, and, possibly, without producing much physical

suffering, excepting, perhaps, in the later stages. Associated with

the above-described appearances, one also not unfrequently finds a

few flukes in the intestinal canal, whilst a still more interesting

pathological feature is seen in the fact that the bile contained in the

liver ducts is loaded with flukes’ eggs. In some cases there cannot be

less than tens or even hundreds of thousands. Not a few may also be

found in the intestinal canal and in the excrement about to be voided.

Occasionally dead specimens become surrounded by inspissated bile, and

gritty particles deposited in the liver ducts, thus forming the nuclei

of gall-stones. Mr Simonds mentions a remarkable instance, “where the

concretion was as large as an ordinary hen’s egg, and when broken up was

found to contain about a dozen dead flukes. It was lying in a pouch-like

cavity of one of the biliary ducts.”

In respect of treatment we all know that “prevention is better than

cure.” Moisture being essential to the growth and development of the

fluke-larvæ, it is clear that sheep cannot be infected so long as they

remain on high and dry grounds, and even in low pastures they can

scarcely take the disease so long as they are folded, and fed on hay,

turnips, and fodder procured from drier situations. When once the malady

has become fairly developed, internal remedies are of little avail, at

least, in view of producing a thorough cure. Palliative treatment may

undoubtedly do good, especially in cases where the disease is not very

strongly pronounced. The most important thing is the transference of the

rot-affected animals to dry ground and good shelter, supplying them, at

the same time, with a liberal quantity of manger food, such as beans,

peas, and other leguminous seeds. The fodder, of whatever kind, should

be frequently changed, and many other hygienic measures adopted, all

tending to promote the appetite and general health of the animal. An

admixture of salines is a matter of essential importance, especially in

cases where the disease is not far advanced. The beneficial effect of

salt is one of those few points on which nearly all parties are agreed,

and its preservative influence in the case of sheep fed upon salt-water

marsh-land has been previously explained. In regard, however, to the

legion of remedies which have from time to time been proposed, all I

need here say is, that most of them when fairly tested have been found

to fail ignominiously. Every year we hear of the adoption, often with

enthusiasm, of new so-called specifics, or of ancient medicines whose

employment had long fallen into disuse. Thus, for example, in the April

number of the ‘Journal des Vétérinaires du Midi’ for 1860, we find

M. Raynaud strongly recommending soot, in doses of from one to three

spoonfuls, to be followed up by the administration of a grain of lupin

for tonic purposes. In like manner, we received from France wonderful

accounts of the medicinal virtues of a certain fœtid oleaginous

compound, the value of which was put to a fair test by our distinguished

veterinarian, Professor Simonds. Having with infinite care and trouble

undertaken a series of experiments with the remedy in question, Mr

Simonds writes in the ‘Scottish Farmer and Horticulturist’ to the effect

that, as a result of his inquiries, he fears “we must conclude that this

supposed cure of _rot_ in sheep has proved quite ineffective for good.”

The last new “cure” announced is by Mr Robert Fletcher (‘Journ. Nat.

Agric. Soc. of Victoria,’ Dec., 1878).

The examination of rotten sheep is not altogether free from danger.

Professor Simonds tells us that in August, 1854, “a person of

intemperate habits, following the occupation of a country butcher,

was employed in skinning and dressing a number of rotten sheep on

the premises of a farmer in the county of Norfolk. The sheep were

necessarily opened when _warm_, and while he was so engaged he

complained greatly of the sickening smell. The same evening he was

attacked with choleraic disease, and two days afterwards was a corpse.”

This case is highly instructive and, when taken in connection with the

well-known fact that animals affected with the disease putrefy very

rapidly, clearly points to the necessity of removing slaughter-houses

far away from densely populated localities.

Notwithstanding the above statement, there is little or no danger to be

apprehended from the consumption of the flesh of rot-affected animals.

On this vexed question we have the strong testimony of the late Dr

Rowe, of Australia, who, after leaving the medical profession, became a

large and successful stockowner, and devoted himself especially to this

question. Dr Rowe, writing from the Goulburn district, said:--“The mere

presence of flukes in the viscera of an animal is no proof that it is

unfit for human food. For inspectors of slaughter-houses to adopt such

a test of wholesome food would be the greatest mistake. It would afford

no protection to the public against unhealthy food, would increase the

price of animals, and be ruinous to our farmers and graziers. If the

consumption of flukey beef and mutton were prejudicial to the health of

man, there would be very few people alive in this part of the colony;

for, to my certain knowledge, they have had no other animal food to live

upon for the last twenty-five years, yet for physical ability I believe

they may be favorably compared with the inhabitants of any other part of

Australia.” Speaking of his own experiences, Dr Rowe avers that he found

the common liver fluke in sheep, cattle, goats, opossums, kangaroos,

geese, ducks, and other creatures, but he had never encountered it in

men, dogs, or pigs. On the whole I think we may agree with Dr Rowe, in

regarding the consumption of the flesh of rot-affected animals as free

from danger provided only the meat, be well or even moderately well

cooked. It must be borne in mind, however, that an essential objection

to its consumption lies in the fact that the watery and otherwise

chemically deteriorated flesh is comparatively innutritious. It must

also be noted that the meat-supply from fluke-affected animals, as

usually sold in the markets, is chiefly derived from animals which have

only entered the early stage of the disorder, that is, long before the

watery and wasted condition of the muscles has fairly set in.

Respecting the other trematodes I have to observe that _Distoma

lanceolatum_ not only infests the liver ducts of cattle and sheep,

but also the deer tribe. Its larvæ are likewise supposed to reside

in _Planorbis marginatus_. Still more common and widespread amongst

ruminants is the _Amphistoma conicum_, occupying the paunch. It has

been found in the ox, sheep, musk-ox, elk, roe, fallow, red-deer,

goat, and dorcas-antelope; also in _Cerrus campestris_, _C. nambi_, _C.

rufus_, and _C. simplicicornis_. Prof. Garrod has also recently shown

me examples from the sambu deer of India (_C. Aristotelis_). Diesing’s

_A. lunatum_, infesting _Cerrus dichotomus_, is inadmissible. Two other

species of Amphistome (_A. explanatum_, _A. crumeniferum_) are said to

infest the zebu; and I have described another (_A. tuberculatum_) from

the intestines of Indian cattle. An aberrant amphistomatoid entozoon

(_Gyrocotyle rugosa_) has been found in a Cape antelope (_A. pygarga_).

Of more interest, however, is the circumstance that Dr Sonsino has

discovered a species of Bilharzia (_B. bovis_) in Egyptian cattle and

in sheep. The eggs of this species are distinctive, being fusiform and

narrowed towards either pole.

Comparatively few tapeworms are found in ruminants. Cattle are infested

by _Tænia expansa_ and _T. denticulata_, the former of these two species

being also more or less prevalent in sheep, antelopes, and deer. Other

alleged species (_Tænia fimbriata_ and _T. capræ_) appear to me more

than doubtful. Unquestionably the common _Tænia expansa_ is capable of

giving rise to severe epizoöty among lambs. The privately communicated

evidence of Professors Brown and Axe, and published evidence supplied

by Messrs Cox and Robertson on this head, are conclusive. Mr George

Rugg has also (in a letter to Prof. Simonds, dated Dec. 4th, 1878)

communicated the particulars of an outbreak in which “large numbers of

lambs perished rapidly” from tapeworms in the intestines, the parasites

varying from one to five or six feet in length. This tapeworm (_T.

expansa_) is also very prevalent in Germany. Ruminants, however, both at

home and abroad, suffer much more severely from bladder-worms. Of these,

_Echinococcus veterinorum_, _Cysticercus tenuicollis_, and _Cœnurus

cerebralis_, are not only shared alike by all varieties of cattle,

sheep, and goats, but they also infest the deer tribe, antelopes, the

giraffe, and even camels. In 1859 I obtained the slender-necked hydatid

from a spring-bok (Gazella). Besides these larval cestodes, cattle

are very liable to harbor measles (_Cysticercus bovis_), whilst sheep

also entertain an armed Cysticercus (_C. ovis_). I cannot again dwell

at any length upon the source of these immature helminths, but I may

remark upon the extreme frequency of measles in Indian cattle. This is

explained by the careless habits of the people. They not only consume

veal and beef in an imperfectly cooked state, but when suffering from

tapeworm no precautions are taken to prevent cattle from having access

to the expelled proglottides of _Tænia mediocanellata_. The subject has

already been dealt with in the first part of this work, and also in my

‘Manual,’ quoted in the bibliography. The mutton measle is described

under the heading of _Tænia tenella_. In like manner I must refer

to the ‘Manual’ for a detailed account of the gid hydatid (_Cœnurus

cerebralis_). How many kinds of Cœnuri exist it is impossible to say,

but I am of opinion that the various polycephalous bladder-worms found

by Rose, Baillet, and Alston in rabbits, by myself in a lemur and in

a squirrel, and by Engelmeyer in the liver of a cat, are referable to

tapeworms specifically distinct from the _Tænia cœnurus_ of the dog.

It was in 1833 that Mr C. B. Rose, formerly of Swaffham, Norfolk,

discovered an undoubted example of polycephalous hydatid in the rabbit,

the parasite in question bearing a very close resemblance to _Cœnurus

cerebralis_. As the accuracy of Rose’s determination respecting the

characters of the hydatid has been called in question, I again invite

attention to the original description as recorded in the ‘London

Medical Gazette’ for November 9th, 1833. At page 206, vol. xiii, of

that periodical, after describing the common _Cœnurus cerebralis_ of

the sheep, Rose writes:--“This (_i.e._ _C. cerebralis_) is the only

species of Cœnurus noticed by authors, but I have met with another. It

infests the rabbit, and I have found it situated between the muscles

of the loins. It is also met with in the neck and back. This hydatid

grows rapidly, and multiplies prodigiously, and being seated near the

surface it soon projects, and sometimes forms a tumour of considerable

magnitude. When the warrener meets with a rabbit thus affected, he

punctures the tumour, squeezes out the fluid, and sends the animal to

market with its brethren. I possess a specimen of this species in a

pregnant state. The earliest visible state of gestation is a minute

spot, more transparent than the surrounding coats of the parent; this

enlarges till it projects from the parietes of the maternal vesicle. It

continues to enlarge until it becomes a perfect hydatid, attached by a

slender peduncle only; even whilst small, other young are seen sprouting

from it, and so on in a series of three or four. My specimen exhibits

them in every stage of growth, from a minute point to a vesicle the

size of a hen’s egg. As I can see no difference in structure between

this hydatid and the last-mentioned (_i.e._ _Cœnurus cerebralis_), I

am unwilling to consider it a different species, for surely a varying

locality ought not to constitute a specific character.”

The observations of Rose did not escape the well-known Dutch

author, Numan. In a foot-note to his memoir, entitled “Over

den veelkop-blaasworm der Hersenen,” he makes the following

observations:--“Rose observes that he has found Cœnurus in bladdery

rabbits (blaaszieke konijnen) in the skin, and in the cellular tissues

of the trunk and extremities. The veterinary surgeon, Engelmeyer, of

Burgau, says he has also found the _Cœnurus_ (Veelkop) in the liver

of a cat (‘Thierärztliche Wochenschrift van 1850,’ s. 192). These

observations differ thus far from those of other writers, according to

whom the Cœnurus is only found in the brain and spinal marrow. However,

it is not impossible in particular cases that some parasites may have

strayed from their ordinary dwelling-places.” Numan seems to have been

not a little puzzled to account for these discrepancies, and he was

altogether undecided regarding the mode of propagation of Cœnuri and

Cysticerci. This will be gathered from the following passage, which I

quote in the original:

“Ik moet het onbeslist laten, of de grondbeginsels, waaruit de wormen

uit de blaas ontspruiten, als wezenlijke of als zoogenaamde kiemen

(_gemmæ_) zijn te houden, waaromtrent de gevoelens der voornamste

Natuuronderzoekers, die zich met de nasporing der blaaswormen hebben

onledig gehouden, nog uiteenloopen. Gulliver, door Rose (a. p. pag. 231)

aangehaald, houdt ze voor eijeren, in den _Cysticercus tenuicollis_, en

Goodsir, mede aldaar genoemd, spreckt ook van _ova_ bij den _Cœnurus

cerebralis_; doch de laatstgenoemde en Busk houden ze voor _gemmæ_.

Hier wordt voots gewezen op Owen en de meeste onderzoekers van den

tegenwoordigen tijd, die het daarvoor houden, dat alle hydatiden zich

alleen door _gemmæ_ reproduceren. Rose merkt voorts aan, dat, hetzij

men de geboorte dezer ingewandswormen toekenne aan eijeren of kiemen

(_gemmæ_), dit om het even is, wat hunne verspreiding (_dissemination_)

betreft, daar zij ingesloten zijn, waardoor de wijze, hoe zij naar

buiten komen en verspried worden, tot dusver een gesloten boek is.”

The idea of Numan that these are strayed forms of _Cœnurus cerebralis_

is not convincing. It must not be forgotten, however, as Leuckart and

Numan have both reminded us, that Eichler discovered an hydatid about

the size of a goose egg in the subcutaneous tissue of a sheep. This

bladder-worm supported nearly two thousand heads. In regard to true

hydatids or acephalocysts in ruminants, on which subject I have already

dwelt at much length, I may again observe that the Hunterian Museum

contains some remarkable examples. In 1854 I obtained Cysticerci from a

giraffe, and I have reason to believe that similar bladder-worms infest

antelopes and deer.

The nematodes of the ruminants are both numerous in, and destructive to,

their bearers, those infesting the lungs being productive of a parasitic

bronchitis termed husk or hoose. In cattle the lung-worm (_Strongylus

micrurus_) is particularly fatal to calves, whilst _S. filaria_ attacks

sheep, and especially lambs. A larger but less common lung strongyle

(_S. rufescens_) is sometimes found associated with the latter. In

1875 I conducted experiments with the view of finding the intermediate

hosts of _S. micrurus_, and I arrived at the conclusion that the larvæ

of this parasite are passively transferred to the digestive organs

of earth-worms. The growth and metamorphoses which I witnessed in

strongyloid larvæ taken from earth-worms (into which I had previously

introduced embryos) were remarkably rapid, and accompanied by ecdysis.

The facts were as follows. About the middle of October, 1875, I received

from Messrs Farrow, of Durham, a fresh and characteristic specimen of

diseased lungs, in which the bronchi were swarming with Filariæ.

In reference to the case itself, Mr George Farrow afterwards informed

me by letter that the calf was one of a herd of seven, whose ages

respectively varied from four to six months. At the time of his writing

(October 20th) the remaining six animals were progressing favorably

towards recovery--a result which Mr Farrow attributes to the employment

of inhalations of turpentine and savin, combined with the internal

administration of tonics. In regard to this plan of treatment, and in

reference to the source of infection, he adds:--“I should have preferred

trying the inhalations of chlorine gas, but as the patients were so

very young and in poor condition, I deemed it advisable to try a milder

course of treatment.

“The history of the case is brief. The cattle are on a very dry and

well-drained farm, but during the summer there was a great scarcity of

water, and they were supplied from a stagnant pool which eventually

became dry. This, in my opinion, is where the disease originated.”

Mr George Farrow’s opinion is probably correct, being in harmony with

the most recent results of scientific research as made known more

particularly by Leuckart. But the facts thus conveyed do not explain

the whole truth; or, rather, they convey it only in a very incomplete

manner. Professor Leuckart’s experiments were made with several

species such as _Strongylus armatus_ of the horse, _S. rufescens_, _S.

hypostomus_, and _S. filaria_ of the sheep, and _S. commutatus_ of the

hare. Still, as regards the strongyles, partial as the results have thus

far appeared, there cannot be a doubt that his successes with several

allied nematode species form a key by which we may yet unlock and expose

to view the entire life-history of that specially obnoxious form under

consideration, namely, _Strongylus micrurus_. To summarise the whole

matter in a few words, Leuckart supposes that all these strongyloids

require a change of hosts before they can take up their final abode

in the sexually-mature state. This he infers especially because their

respective embryos display characters very similar to those exhibited by

_Olulanus_. He believes that either small mollusks or insects and their

larvæ play the _rôle_ of intermediary bearer. His experiments with the

embryos of _Strongylus filaria_ prove that these larvæ can be kept alive

for several weeks in moist earth, and that whilst so conditioned they

undergo a first change of skin within a period varying from eight to

fourteen days. Experiments on sheep, made with these moulting larvæ, led

only to negative results. Unless the following facts be accepted, the

scientific position remains pretty much where Leuckart left it.

On the 22nd of October, 1875, at 1 p.m., I placed the entire

egg-contents of the uterus of a _Strongylus micrurus_ on a glass slide

hollowed out in the centre. Probably something like ten thousand ova

were thus brought under observation, yet only three were noticed as

freed from their shells, probably as the result of accidental rupture.

Two of these displayed lively movements. In round numbers the ova gave

a measurement of 1/300 of an inch in length by 1/750 of an inch in

breadth, whilst the free embryos measured about 1/90 of an inch long,

and less than 1/1000 of an inch in thickness. The integument of the

embryo displayed neither markings of any kind nor any double contour.

The contents of the worm were granular throughout, these granules being

crowded in the centre of the body, but scarcely visible towards the head

and tail, where for a considerable space (fully 1/300″) the worm was

perfectly transparent. No trace of any sexual organs or their outlets

was visible. An examination of numerous eggs and free embryos obtained

from near the primary bronchial bifurcations (of Mr Farrow’s specimen)

yielded the same microscopic results, the only thing worthy of remark

being that the embryos from the mucus seemed much more lively than those

which, as I supposed, had accidentally escaped their shells.

At 1.30 p.m. I placed some free embryos in two watch-glasses, one

containing water and the other saliva, and placed them before the fire.

Being called away professionally I found on my return at 3 p.m. that

evaporation to dryness had occurred in the interval. All my attempts to

resuscitate the embryos by moisture proved unavailing, a result which,

though negative, proves how little capable these embryonic creatures are

of enduring desiccation. If these facts be confirmed, their practical

significance is not without value in relation to the choice of dry

pasturage grounds for the rearing of young cattle. I may add that whilst

half an hour’s immersion of the dried embryos failed to restore any sign

of life, the previous warmth and moisture had caused many more embryos

to escape their shells during the time they were placed before the fire.

At 4 p.m. I passed some very rich mould through muslin. Some of this

finely sifted earth I placed in a watch-glass, adding a little water to

moisten it, and also numerous eggs and free embryos. In a wine-glass and

also in a small jar I placed some coarse earth with water added to make

thin mud, and to both of these I added, not only eggs and embryos, but

also portions of the reproductive organs of the adult female worms.

On the 23rd of October, at 2 p.m., I examined the contents of these

vessels. All the embryos in the vessels containing the coarse earth were

dead, but several were found alive in the watch-glass containing the

fine moist mould. Structurally these latter had undergone no perceptible

change beyond a somewhat closer aggregation of the somatic granules.

Although the embryos in the coarse wet mud had perished, the eggs

with unhatched embryos appeared to have retained their vitality. Of

this fact, indeed, I subsequently obtained abundant proof; and I

also satisfied myself that the death of the embryos had not resulted

either from the coarseness of the earth or from excessive moisture,

but from the presence of numerous shreds of the uterine tubes which I

had somewhat carelessly added to the vessels. Previous experiments,

conducted many years back, had indeed taught me that few if any

nematoid larvæ can resist the fatal action of putrid matter, however

slight the putrescence.

Having removed the offending shreds, I next placed a quantity of living

ova together in the earthenware jar, and allowed the earth-contents to

become much drier by evaporation before the fire. I also left others in

a watch-glass, which was placed under a bell-jar enclosing several ferns.

On the 25th of October I removed particles of the moist earth,

altogether weighing about two grains, and, on submitting them to

microscopic examination, had the satisfaction to observe about a dozen

living embryos, some of which exhibited very lively movements. There

was not the slightest indication of putridity; nevertheless, I noticed

several shreds of the adult worms whose presence had been accidentally

overlooked, and, curiously enough, all the embryos subsequently removed

from the immediate neighbourhood of these decomposing shreds of tissue

were almost motionless and apparently in a moribund condition. On

examining the contents of the watch-glass placed under the fern shade,

I noticed several points of interest. First of all the earth contained

strongyle embryos, such as I had seen before. Secondly, the surface

of the mould was being traversed by three or four briskly-moving

_Thysanuridæ_, hunting about with all that restless activity which Sir

John Lubbock has so well described. Thirdly, in marked contrast to the

behaviour of these I noticed several slow-moving _Acaridæ_, apparently

also employed in searching for food. And lastly, while thus engaged, the

surface of the mould in the centre of the deep watch-glass was suddenly

upheaved, by which I was at once made aware of the presence of another

most welcome and unexpected intruder. In short, an earth-worm had crept

from the dry mould in which the ferns were growing, and had taken up its

temporary abode in the soft moist experimental-earth contained in the

watch-glass. When contracted, this _Lumbricus terrestris_ was barely

an inch in length. On placing it under the half-inch objective glass,

I noticed a single embryonic strongyle adhering to the skin, but not

firmly, and evidently only in an accidental way, so to speak. It was

clear to me that it possessed neither the intention nor the power to

penetrate the chitinous integument of the earth-worm.

Having in the next place removed the _Lumbricus_ with a pair of forceps,

and having washed it under a current of water, I snipped off the

lower end of the body, and allowed some of the intestinal contents to

escape on a clean glass slide for separate microscopic examination.

Immediately, to my satisfaction, I found that the fæcal contents

displayed a large quantity of my strongyle ova, enclosing still living

embryos, and in addition several free embryos presenting characters

which declared that they were from the same source. Clearly they had

been ingested by the earth-worm along with its ordinary food. One or

two of the embryos were conspicuously larger than their fellows, but

the structural changes they had undergone were not so marked as to

lead me for a single moment to associate them with any of the various

sexually-mature worms which have been described as normally infesting

the earth-worm. I had no doubt whatever that such slight structural

changes as were now discernible had resulted from growth and development

consequent upon this accidental admission into the body of the

intermediate bearer which might or might not prove to be its legitimate

territory. It will be seen that subsequent observations tended to

affirm the truth of this view. I made a careful examination of one of

these larvæ, whose active movements were such as to render the process

exceedingly tedious. The earth-worm itself (or rather its unequal

halves) was placed in a fresh watch-glass containing ordinary mould. The

larvæ or embryos obtained from the earth-worm now measured about 1/80 of

an inch in length, their heads exhibiting a short and simple chitinous

buccal tube, whilst their tails were somewhat more pointed and bent

upward. The somatic granules were more crowded, rendering the position

of the intestinal tract more marked, though, as yet, the differentiation

gave no indication of the formation of a distinct intestinal wall. There

was no perceptible increase of thickness of the body of the embryos.

The results thus far naturally encouraged me to procure some fresh

earth-worms for experimental purposes.

On the 26th of October I found that the halves of the earth-worm were

alive, and I left them undisturbed in rather dry mould, freshly added.

To a watch-glass containing newly sifted earth and embryos I added a

fresh garden-worm, which was rather sluggish from the cold; and in

the original jar I placed another smaller and very active earth-worm

obtained the same morning. Finding the soil in the jar congenial,

this _lumbricus_ soon buried itself. Another and larger earth-worm

subsequently added refused to follow this example. It was therefore

removed from the jar. Believing the fine and artificially prepared

soil to be still much too moist, I caused further evaporation; and I

afterwards found that the thicker the mud the more suitable it proved as

a residence for embryonic nematodes and earth-worms alike.

On the 27th I found the small earth-worms in the jar burrowing freely

and throwing up fæcal casts. From one of my watch-glasses the worm

had escaped, its place being occupied in the meantime by an actively

crawling _Julus_. I put a second _Julus_, obtained from the mould in the

fern jar, to form a companion (in view of other experiments), and I also

added a fresh earth-worm, covering all by another inverted watch-glass,

which I thought would prevent their escape.

In the next place I examined the halves of my original experimental

earth-worm. They were scarcely capable of motion, but retained a certain

amount of vitality. The tail was the more active half, and unfortunately

it was soon afterwards lost. Carefully washing the superior half, and

transferring its contents to a glass slide, I immediately detected

under the microscope a large number of embryos. They were in a state of

marked activity, the largest having increased to about 1/50″ of an inch

in length, whilst their structure had become correspondingly advanced.

Here, again, there was no room for doubt as to their source, especially

as they individually displayed different degrees of organisation, all

answering to one and the same embryonal type. I now observed a distinct

œsophagus, the rest of the intestinal tract being still more conspicuous

than heretofore, though, as yet, no true cells marked the limitation of

the stomach and chylous intestine.

After an hour’s immersion in cold water some of the larvæ became much

less active, whilst others were motionless, so that I feared all were

about to perish. In the hope of keeping a few of them alive I now added

to the slide some finely sifted grains of mould, placing the slide under

a small bell jar which protected some of my ferns. The remains of the

moribund earth-worm were also covered with mould.

Other larvæ, derived from the earth-worm, were placed on the moist pinnæ

of a living fern-frond which supported small drops of water, for by

this process I hoped in some measure to imitate the dew which naturally

condenses on the grass and fodder of our low-lying fields. At 3.15 p.m.

of the same day (27th) I also examined a fresh worm pellet from the jar,

and found it to contain living strongyle embryos, which as heretofore

had not exhibited the slightest advance either in respect of size or

structure.

At noon on the 28th I again sought for the larger larvæ, first of all on

the slide covered with fine earth, and afterwards within the remains of

the upper half of the original earth-worm. On the slide I could detect

none, but within the intestine of the worm there were still two living

larvæ left, whose characters corresponded precisely with the largest

that I had previously obtained from the same source only the day before.

They had undergone, however, no further change in structure, and their

measurements remained precisely the same.

At 12.30 p.m. I snipped off two or three of the terminal fern-fronds

on which I had placed a few advanced larvæ. On examination under the

half-inch objective I immediately detected one of the larvæ cruising

about most actively. On adding a drop of water it soon rushed across

the field of the microscope, its movements being thoroughly eel-like.

The size of this larvæ had so much increased that it was now visible to

the naked eye, measuring, indeed, as much as 1/30 of an inch from head

to tail. Moreover, its organisation had advanced in a marked degree.

Thus, the digestive organs were better defined, and on one side of them

there appeared a regularly arranged congeries of cellules, forming the

commencement of the reproductive organs. As yet, however, I could not

pronounce as to the sex.

At 1.45 p.m. I again examined a few grains of earth from the jar, when

I at once noticed five or six active embryos whose structure failed

to show the slightest advance upon that originally described. It was

evident that the jar contained thousands of them; and since no ova were

found, it became probable that all their embryonic contents had escaped

to swell the number of free larvæ, leaving their very delicate envelopes

to perish. I think I had hit upon the most suitable degree of moisture

favorable to this result.

In the next place I sought for the earth-worm that had been placed

in the infested soil between two watch-glasses. It had escaped. This

obliged me to transfer the mould to a rather wide-mouthed and open

phial, in which four more fresh lumbrici were placed. I feared the

closing of the bottle would be detrimental.

Later in the day I selected an earth-worm which had not been exposed

to strongyle infection, but which was in a moribund condition. In the

intestine there were several free nematoids and also several psorosperms

of the genus _Monocystis_, so well illustrated by E. Ray Lankester. As

to the nematoids, which were filariform, they neither corresponded in

size nor structure with my strongyle embryos.

At 1 p.m. on the 29th I renewed my examination of the larva removed

from the fern-pinnule. It showed a further stage of growth, the male

character of the reproductive organs having become apparent. The now

tolerably well-formed vas deferens had pushed the chylous intestine on

one side, whilst a series of caudal rays, five on either side, supported

two narrow membranous wings, which represented the lateral lobes of the

hood of the adult strongyle.

At 1.30 p.m. I submitted the intestinal contents of four fresh

earth-worms removed from my garden to microscopic examination, but no

nematoids were found in any one of them.

About 2 p.m. I removed another large and active strongyle larva that had

been reared on another fern-pinnule. It was of the same size as that

previously described, but was in the act of changing its skin. It was

then put aside along with the other worm under the glass shade.

At 3 p.m. I intended to have examined one or more of the earth-worms

placed in the open-mouthed phial, but all had escaped and buried

themselves in the fern-mould out of reach.

At noon on the 30th I renewed my examination of the two large larvæ

whose developmental changes I had been instrumental in producing from

the time of their escape from the egg-coverings. I saw no reason to

doubt that the sequence of changes thus far noticed referred to the

species of parasite under consideration. Both larvæ were active, but the

moulting one had now completed its ecdysis. Its sexual distinctiveness

had become yet more pronounced by the formation of two rather short

and stout spicules, the point of the tail displaying a very minute

awl-shaped projection. The lateral membranes had not visibly increased

in size. One of these larvæ, the first under observation, now perished

from the injuries sustained during inspection.

Again, and later in the day, I sought to clear up any doubts that might

still suggest themselves respecting the source of these larvæ, by once

more submitting the intestinal contents of two fresh and uninfected

earth-worms to careful scrutiny. In the first worm no parasite could be

found, and in the second only one minute nematoid; its organisation,

which was sexually incomplete, neither corresponded with my strongyle

embryos, nor, so far as I could judge, with Goeze’s _Ascaris minutissima

microscopica_ (the _Anguillula lumbrici_ of Diesing and others), nor

with Dujardin’s _Dicelis filaria_. It was a very long and narrow

creature, but I lost it whilst attempting to secure an accurate

measurement. I should say it was about 1/50th of an inch in length, and

not more than 1/1500th in breadth. I made a rough outline sketch of it.

In view of further observations I now placed five more earth-worms in

the jar containing strongyle embryos, and I also placed six others in

the phial which contained coarser mould, and only a comparatively small

number of the original strongyle embryos. The phial was closed with

a cork and half buried in the fern-mould of one of my larger Wardian

fern-pans. Before this transfer was made I again took an opportunity

of ascertaining by microscopic evidence that the embryos lodged in the

coarse and fine mould had none of them made the slightest advance in

organisation. The worms placed in the jar immediately proceeded to bury

themselves.

At noon on the 1st of November I sought to get further results from the

only large free larva which now remained to me (for the fern-pinnules

on which the larvæ were originally placed had dried up and no third

specimen could be discovered). Structurally the larva presented no

advance. It therefore appeared to me necessary to place it under new

conditions in view of exciting further progress towards sexual maturity

and adult growth. To transfer it to the bronchus of a living calf would,

of course, have been the crucial experiment, but the hopelessness of

getting any satisfactory result from this solitary transfer deterred me

from the attempt. On a larger scale, with many larvæ, a positive issue

would of course prove decisive. Accordingly, the only thing I could

do, in partial imitation of nature, was to try and induce some further

changes by placing the larva in human saliva, kept warm artificially. As

a first step I immersed the creature in a little of the secretion added

to the glass slide, when it immediately displayed very lively movements,

such as could only be fitly described as frantic. This encouraged me

to replace the slide under one of the fern shades without applying any

additional heat. I then left it.

At 12.30 p.m. I selected three of the eleven worms lodged in the

infested earth, namely, two from the jar and one from the closed phial,

and made a microscopic examination of their respective intestinal

contents. In one of the worms from the jar I found several embryos

clearly referable to my strongyles, their structure showing scarcely

any advance upon that exhibited by the embryos in the mould itself.

The weather was now excessively cold and the larvæ were motionless;

nevertheless, the application of warmth showed that they were by no

means dead. The fæcal matter obtained from the worm that had lived in

the phial displayed an immense number of infusoriæ (_Bacteria_) which

rushed about rapidly over the field of the microscope. No other signs of

life were detected.

On the 2nd of November I found my solitary strongyle larva alive, but

its movements, though active, were by no means so active as on the

previous day. No fresh structural changes had occurred.

At noon on the 3rd the larva at first lay almost motionless in the

now thick and ropy saliva; nevertheless, on applying a thin glass

cover its movements became tolerably vigorous. During its quiescent

state I succeeded in getting a good view of the caudal rays and other

imperfectly developed organs, of which I retain figures.

Having now satisfied myself that other new conditions were necessary to

enable the larva to arrive at sexual maturity, I sought to transfer it

to a glass tube filled with fresh saliva. This transfer was a matter

of difficulty. After passing the thick ropy saliva into the tube, I

examined the slide and found that the larva was gone. I concluded it was

in the tube, which, in order to keep the contents warm, I subsequently

carried about concealed in my under-clothing during the day and placed

in my bed during the night. This increase of temperature, however,

caused decomposition of the saliva; so when next day I diligently sought

for my experimental nematode it was nowhere to be found. Thus terminated

my observations on the first set of embryos, which had enjoyed their

temporary sojourn in the intestinal tract of the earth-worm, and which

had certainly afterwards undergone a series of marked structural and

morphological changes, accompanied with ecdysis.

The weather had now been for several days exceedingly cold, but on the

4th a favorable change set in, which led me to hope that I might be

able to verify the facts above recorded. Accordingly, as a new point of

departure, I re-examined the fine mould, and at once found my embryos

in a high state of activity. The mould, however, appearing too moist

for the earth-worms, I permitted further evaporation before closing

the jar with a glass cover. Four days subsequently I examined the

intestinal contents of two of the earth-worms. In one of these, an inch

in length, no parasite of any kind could be detected; but in the other,

which was beyond three inches in length, there were numerous _Opalinæ_

besides several strongyle embryos, the latter presenting characters not

visibly in advance of those still living in the mould. All of them were

motionless, as if they had not got over the shock produced by previous

cold. Moreover, the weather had again become cold, and thus, when I

again inspected my experimental embryos living in the jar, I also found

them motionless, so different from their behaviour on the 4th. However,

since a further result with the earth-worm embryos appeared possible, I

placed some of the fæcal matter, already ascertained to contain a few

of them, on the fronds of a thoroughly moist and dew-covered _Asplenium

bulbiferum_. This plant was in a fern-pan which had the advantage of

considerable fire-warmth during the day. When, however, on the 15th

of November, I examined the fæcal earth removed from several of the

pinnules, I failed to find any of the embryos. Possibly they had

wandered, for the entire frond was covered with dew-drops, which was not

the case with the fern that I had previously experimented on with such

satisfactory results. At all events, whether they had wandered or had

perished, their apparent absence in no way affects my previous record;

and the more so since only a few had been observed in the fæcal matter.

The smallness of the number found in the earth-worm was also readily

accounted for. Thus, when at 1.30 p.m. on the 15th I made a diligent

search for embryos in several grains of the fine mould, not a single

young strongyle could be detected. Possibly the frost of the previous

night had killed them. The earth-worms were still alive and in good

condition.

In conclusion, I may observe that every experimenter with helminths

is well aware how unfavorable the winter season is for this kind of

research. If a repetition of this inquiry in the spring or summer should

confirm these results, it will prove a clear and substantial addition

to our knowledge of the development of the strongyles. Meanwhile, I

think that the data above given render it highly probable that the

larvæ of the hoose-producing strongyle (_S. micrurus_) are passively

transferred to the bodies of setigerous annelids, which are thus

called upon to act as intermediate hosts. If this be so, it is further

certain that important structural changes with ecdysis follow after

their escape from the earth-worms or other annelids, moisture, dew, or

water being essential to the penultimate stage of growth. Final passive

transference, either with fresh fodder from swampy grounds, or, it may

be, from pond water, ultimately enables them to acquire their definite

sexual form, size, and other adult characteristics.

According to Mégnin it is not the _Strongylus filaria_, but a hitherto

unknown and totally distinct species (_Strongylus minutissimus_)

which occasions pneumonia in Algerian sheep. In England the parasitic

bronchitis affecting sheep is generally called the “lamb disease.”

This is unfortunate, because many other parasites prove destructive to

lambs. One of the most injurious species is _Strongylus contortus_,

infesting the true stomach, whilst _S. hypostomus_, occupying the

small intestines, is almost equally obnoxious to the ovine bearer. By

Leuckart and others this last-named worm is retained in Dujardin’s genus

_Dochmius_, in which genus another species occurs (_D. cernuus_). This

worm is quite distinct, but not readily distinguishable by the naked eye

alone. It occasionally occupies the upper part of the colon, as well as

the lower end of the small intestine. A rarer intestinal worm in lambs

is the _Strongylus filicollis_. Several other strongyles infest the ox

(_S. radiatus_, _S. inflatus_, _S. gigas_), goat (_S. venulosus_), and

stag (_S. ventricosus_).

As showing the extraordinary prevalence and destructiveness of entozoa

in certain countries, I will adduce an instance in which my opinion

was requested and given some five years since. My informant stated the

case somewhat in the following manner:--On a farm in New South Wales,

and lying about 200 miles to the north-west of Sydney, on the Trafalgar

tributary of the Macquarie river, out of a flock of about 8000 sheep no

less than 1200 have perished. In many instances post-mortem examinations

were made, _worms_ appearing in all cases to be the cause of death.

There were four kinds of parasites present. The most numerous were

red and white, “marked like a barber’s pole.” These occurred chiefly

in the fourth stomach and commencement of the duodenum, but some were

found throughout the entire length of the small intestine. A second

set comprised small black worms, resembling needles, scattered only

in the lumen of the intestines. The third set were tapeworms, each

being several fathoms in length. The fourth set was made up of white

threadworms, individually measuring two inches in length. These occupied

the bronchial tubes, and were characterised by my informant as “the

most deadly of all.” Without the aid of specimens I at once recognised

these brief diagnostic characters as severally referring to _Strongylus

contortus_, _Dochmius hypostomus_, _Tænia expansa_, and _Strongylus

filaria_.

What the inquirer desired at my hands was “full information respecting

the general principles to be carried out in view of the prevention of

this parasitic disease, regard being had to the difficulty of finding

any food but pasture, to the number of animals to be treated, and to

the not unfavorable circumstance that the run is divided by fencing

to a great extent.” I was also requested to explain the best modes of

treatment, being at the same time informed that turpentine drenchings

had already been employed with only “partially effective” results. I

was also expected to give numerous and varied formulæ, to be tried in

succession, supposing the first should fail. Of course, it should have

been known that I neither prescribe medicines nor accept fees in respect

of animal patients; but, as in this instance my opinion was permitted

to assume the form of a “written scientific report,” I was pleased to

have an opportunity of commenting freely and fully on the significance

of the facts submitted. My advice took the form of a long report, which

might here be usefully given _in extenso_ were it not somewhat of the

nature of a private and privileged communication. I have no doubt that

the stockowner would be pleased that I should utilise his remarkable

“case” for the benefit of agriculturists and others; but it is for him

to publish the “opinion” as it stands, should he think fit to do so.

Practical men, on reading the few foregoing particulars, will perceive

that one of the principal obstacles to success in cases of this kind

lies in the circumstance that artificial food can only be procured with

difficulty. Where the source of the disease is associated with the

pasture-supply, any treatment, however effectual for a time, can only be

followed by partially satisfactory results.

The destructive powers of any one of the above-mentioned parasites being

sufficient to produce a fatal lamb-disease, it is clear that when two

or more of these particular species attack their victim in considerable

numbers, the ovine-bearer has little chance of recovery. The intestinal

strongyles, by means of their oral armature, behaving as veritable

leeches, will, if not expelled in good time, produce a rapidly fatal

anæmia, precisely in the same way as the human _Anchylostomum_ of the

tropics.

The worst of dealing with this sheep-parasite is that it will not

succumb to ordinary doses of salines like the stomach strongyle;

moreover, the little leech-like wounds will probably bleed after the

parasites have been compelled to abandon their hold. Prevention is

better than cure. Accordingly, I sought to explain the origin of these

creatures, and in what possible ways the germs of the various species

could be destroyed, or at least limited in numbers.

As to the drugs and inhalations to be employed, it would be difficult to

advise any more effective than those commonly in vogue, the great thing

being to effect changes of pasture and ground, to look to the purity

of the water-supply, and to supply the best kinds of nourishment after

active treatment. The diseased animals should, from the very first, be

separated from their companions, because the amount of germ distribution

is thereby greatly lessened. They should be at once drenched or treated

by inhalation (as the parasitic nature of the attack requires), and the

enclosure in which the animals have been temporarily housed should be

thoroughly scoured with boiling-hot water impregnated with salt.

The nomenclature of the parasitic diseases of animals is excessively

vague. Thus, _apropos_ to the case above recorded, I may mention that

an American veterinary practitioner appeared to be much shocked that

I should have had the temerity to speak of four distinct kinds of

lamb-disease. It is in this way that practical men often commit serious

mistakes by rolling together disorders that are totally distinct. If

it were true that epizoöty in lambs is exclusively due to _Strongylus

filaria_, then professionals might aptly speak of the parasitic

bronchitis of young sheep as lamb-disease; but we now know that several

other helminths prove terribly fatal to lambs, occasioning death in

totally different ways. In one set of cases the animals are asphyxiated;

in another set they become fatally anæmic; and in a third set they

perish from the severity of nervous reflex irritations. Lastly, it may

be remarked that, in view of the successful management of the parasitic

disorders of animals, the veterinary practitioner must necessarily be

guided by the same general principles as the physician. For myself, I

may say that I have hitherto designedly withheld many practical hints

which a long experience with human patients suggested, not wishing to

appear to dictate to those who are constantly seeing animals. However,

since (contrary to my own wishes) it has happened that both professional

men and agriculturists have not only invited me to give opinions, but

have, at various times, asked me to prescribe, it seems there can have

been no impropriety in publishing my views on this subject. Certainly I

have had no professional motives to serve.

Of the few non-strongyloid nematodes, one of the commonest is

_Trichocephalus affinis_. I have obtained this worm from the giraffe,

and the parasite may be said to infest all ruminating animals, not

excluding even the camels and llamas. As before remarked, the whipworm

has been known to produce severe symptoms in man, and it occasions

“scour” in the sheep. The eyes of cattle are occasionally infested by

_Filaria lacrymalis_ and _F. papillosa_. The last named is the common

eye-worm of the horse. On Feb. 27th, 1875, Dr Edward L. Moss, of H.M.S.

“Alert,” brought me three examples of a nematode which I referred to

_Filaria terebra_. Dr Moss obtained these parasites in 1874, during the

time that he had charge of the Naval Hospital at Esquimalt, Vancouver’s

Island. They occupied the abdominal cavity of the black-tailed deer

(_Cervus columbianus_). The worms were mostly found lying amongst the

coils of the small intestine. They were not attached to the peritoneal

membrane. Dr Moss had shot seventeen deer in all, the males and females

being in about equal proportion; nevertheless, not one of the bucks

showed any trace of the presence of these entozoa. This absence of

parasites in the male deer is noteworthy. Hitherto the worm appears to

have been observed in the red deer (_C. elaphus_), and by Natterer in

three species of American roe (_C. rufus_, _C. simplicicornis_, and

_C. nambi_). Two of the worms measured each about 2-1/3″ in length,

the third exceeding 3″. They displayed in profile two prominent oral

papillæ. Probably there were four of these processes, such as Dujardin

described in his _Filaria cervina_, which, according to Diesing, is a

synonym. They all possessed spirally twisted tails.

Amongst the arachnidan parasites of ruminants having entozoal habits are

_Pentastoma denticulatum_ and _P. constrictum_. The former larval worm

is excessively common in cattle, sheep, deer, and antelopes. According

to Rhind, the adult worm (_P. tænioides_) also infests the sheep. The

_P. constrictum_ has hitherto only been found in the giraffe. On the

10th February, 1859, I obtained numerous examples (_P. denticulatum_)

from a bubale (_Antilope bubalis_) which died at the Zoological

Society’s Gardens. The greater number occupied the surface of the lungs

and intestines; some few, however, were enclosed in cysts beneath the

pleura. In the spring of 1860 I also procured several specimens from the

abdomen of a cape guevi (_Cephalopus pygmæus_).

The ectozoa of ruminants have received much attention, but I can

merely indicate the known forms. Following Mégnin’s classification

we have three well-marked varieties of the acarine genus _Sarcoptes_

(_S. scabiei_, var. _ovis_, var. _capræ_, and var. _cameli_), two

varieties of _Psoroptes_ (_P. longirostris_, var. _bovis_ and _ovis_),

and _Chorioptes spathiferus_. This last is the true mange mite of the

ox (or _Symbiotes bovis_ of Gerlach). A variety of the follicle mite

infests the sheep (_Demodex folliculorum_, var. _ovis_). Numerous

species of tick (_Ixodidæ_) have been more or less fully described.

Of these we have the Carapartos of the Portuguese (_Ixodes bovis_),

attacking cattle; the _I. reduvius_, attacking sheep; the _I. plumbeus_,

said to attack lambs; the _I. albipictus_ and _I. unipictus_, found

on the moose-deer. Probably this species also attacks cattle. A

most horrible arachnidan is found on camels. I allude to _Galeodes

araneoides_ belonging to the _Solpugidæ_. This parasite will bite

severely any person who attempts to dislodge it from the bearer.

Turning to the insects, we find ruminants liable to be annoyed alike

by flies (_Diptera_), fleas (_Aphaniptera_), and lice (_Hemiptera_).

Various species of four different families of flies are apt to prove

troublesome. Of the _Œstridæ_, attacking the ox, we have _Hypoderma

bovis_, whose larvæ form tumours or warbles on the back; also _H.

lineata_, _Dermatobia noxialis_, and _Cephenomyia bovis_ (mihi). The

larvæ of the latter reside at the root of the tongue and adjacent parts.

In the sheep we have _Œstrus ovis_, _Œ. purpureus_, and _Hypoderma

lineata_. Various species also attack goats and antelopes. Dr Kirk

presented me with specimens of Œstrus from the frontal sinuses of a

harte-beest or caama, and they have also been obtained from the sassabe,

the saiga or colus, from the gnoo, and from the brindled gnoo, kokoon

or gorgon. Mr Charles Danford presented me with several bots from an

ibex. One or more species of _Hypoderma_ have likewise been removed from

the gazelle and other antelopes. The deer tribe are much attacked by

bots. In the red deer we have _Hyp. actæon_ and _H. diana_, a species

also infesting the elk. The throat-grubs are _Ceph. rufibarbis_ and

_Pharyngomyia picta_; another species, also occurring in the fallow

deer, _Ceph. ulrichii_, infests the elk, and _C. stimulator_ the roe,

the last-named deer being also infested by _Hyp. diana_. A throat-fly

infests the reindeer, which is also frequently attacked by _Hyp.

tarandi_. Specimens of the latter worm have been obtained by Dr Murie

at the Zoological Gardens. The Hunterian Museum also contains these and

other species of bots, presented by myself in Mr Andrew Murray’s name.

A subcutaneous bot has been found in the musk-deer. A throat-bot (_C.

maculata_) infests the dromedary.

In regard to the so-called free dipterous parasites and other noxious

insects that attack ruminants, their name is legion. One of the worst

is the tsetse (_Glossina morsitans_), immortalised by Livingstone.

Of the _Muscidæ_ we have the ox-fly (_Musca bovina_), the sheep-fly

(_M. cæsar_), and the executioner (_M. carnifex_). Of the _Tabanidæ_

we have _T. bovinus_ and _T. autumnalis_, _Chrysops cæcutiens_, and

the allied _Asilus crabroniformis_ (_Asilidæ_). Amongst the specially

noxious insects must also be placed _Stomoxys calcitrans_ and _Rhagio

columbaschensis_. This fly proves fearfully destructive to cattle in

Hungary and Servia. Lastly, I can only further mention the common

_Melophagus ovinus_. This is nothing more than a gigantic louse, which

from long use agriculturists and veterinarians persist in calling

the sheep-tick. It belongs to the _Hippoboscidæ_, the members of

which family only attack quadrupeds and birds. As regards the lice

(_Anoplura_), I have to mention _Hæmatopinus vituli_ of the calf,

_H. eurysternus_ of cattle, and _H. stenopsis_ of the goat; also

_Trichodectes scalaris_, _T. sphærocephalus_, and _T. capræ_. These

infest the ox, sheep, and goat, respectively.

For some account of the protozoal parasites (_Psorospermiæ_, &c.)

infesting the flesh of ruminants I must refer the reader to Book I,

Section IV, Part VI of this treatise.

BIBLIOGRAPHY (No. 49).--(Anonymous), “On the Hydatid in the Brain of

Sheep,” from ‘Journ. de Méd. Vét.,’ in ‘Veterinarian,’ vol. xxviii, p.

461, 1855.--(_Idem_), “Note on the ‘Rot in Sheep,’” ‘Veterinarian,’

vol. xxxvi, p. 100, 1863.--(_Idem_), “On the Hydatid, or Tumour of the

Brain (of Sheep),” under sig. of “Ben Ledi,” in ‘Veterinarian,’ vol.

xii, p. 467, 1839.--(_Idem_), “Note on Rot in Sheep, Cattle, and Hares,”

from the ‘Bristol Mirror and Scotsman,’ in ‘Veterinarian,’ vol. xxxvi,

pp. 156-7, 1863.--(_Idem_), “Tapeworm Epizoöty in Nottinghamshire,”

‘Brit. Med. Journ.,’ 1858.--(_Idem_), “Prevalence of Rot in Sheep,” from

‘Carlisle Journ.,’ in ‘Edin. Vet. Rev.,’ 1863.--_Baillet_, “Filariæ in

the Eye of an Ox,” from ‘Journ. des Vét. du Midi,’ in ‘Veterinarian,’

vol. xxxi, p. 703, 1858.--_Barnett, J._, “Hydatids in the Liver of a

Cow,” &c., ‘Veterinarian,’ 1865, p. 236.--_Beale, L. S._, “On Entozoa

(?) in the Muscles of Animals destroyed by the Cattle Plague,” ‘Med.

Times and Gaz.,’ Jan. 20, 1866, p. 57; see also “Annotation,” ‘Lancet,’

Jan. 13, 1866, p. 45, and ‘The Microscope in Medicine,’ 4th edit.,

1878.--_Beneden_ (see Van Beneden).--_Böllinger, O._, “_Echinococcus

multilocularis_ in der Leber des Rindes,” ‘Deutsch. Zeitschr. f. Thier

med.,’ ii, 1876, s. 109.--_Brauer_ (see Bibl. No. 50).--_Bugnion, E._,

“Sur la pneumonie vermineuse des animaux domestiques,” ‘Compt. Rend. de

la réunion de la Soc. Helvet.,’ Andermatt, 1875.--_Chaignaud_, “Worms

in the Eyes of Oxen (with remarks by Desmarets),” from the French,

in ‘Veterinarian,’ vol. i, p. 77, 1828.--_Cobbold_, “Descr. of a new

Trematode from the Giraffe,” ‘Rep. of Glasgow Meeting of Brit. Assoc.,’

1854, and in ‘Edin. New. Philosoph. Journ.,’ 1855.--_Idem_, “On Flukes,”

‘Intellectual Observer,’ Feb., 1862.--_Idem_, “The common Liver Entozoon

of Cattle,” _ibid._, March, 1862.--_Idem_, “The Whipworm of Ruminants,”

_ibid._, Dec., 1863.--_Idem_, “Parasite-larvæ,” _ibid._, March,

1863.--_Idem_, “On the Measles of Cattle and Sheep” (see various papers

quoted in Book I, Bibl. No. 13).--_Idem_, “On the Cattle-Plague Bodies

(spurious Entozoa),” see Bibl. No. 41.--_Idem_, “On the Fluke Parasites

of our Food-producing Ruminants,” Lect. iv of the Cantor series, pub.

in ‘Journ. Soc. Arts,’ 1871.--_Idem_, “Remarks (&c.) in ref. to the

Management of Sheep suffering from Nematoid Worms,” ‘Veterinarian,’

Oct., 1876.--_Idem_, “Record of preliminary Experiments with the Eggs

and Embryos of the Husk-producing Strongyle of the Calf,” _ibid._, Dec.,

1875.--_Idem_, in ‘Entozoa,’ pp. 145-183; also in ‘Manual,’ and in the

chap. on “Parasitic Diseases” contributed to ‘Williams’ Principles

of Vet. Med.’--_Idem_, “Remarks on Prof. Perroncito’s Researches,”

‘Veterinarian,’ Dec., 1877.--_Idem_, ‘Amphistomes of the Ox,’ see

Bibl. No. 51.--_Cooper, J._, “Three Cases of Cœnurus in Calves,”

‘Veterinarian,’ 1865, p. 357.--_Copeman, A._, “Hydatids in the Brain

of Lambs,” ‘Vet. Record,’ vol. iii, p. 337, 1847.--_Cox, W._, “Tænia

in Lambs,” ‘Veterinarian,’ vol. xxviii, p. 446, 1855.--_Creplin_, fig.

of _Amphist. crumeniferum_, in ‘Wiegmann’s Archiv,’ 1847, tab. ii, s.

30.--_Crisp, E._, “On the ‘Lamb-disease,’ of which Parasites in the

Lungs are generally the Cause or Consequence,” repr. from ‘Journ. of

Bath and West of England Soc.,’ in July to October Nos. of ‘Edin. Vet.

Rev.,’ 1863.--_Idem_, “Note on _Str. filaria_,” ‘Proc. Zool. Soc.,’

1856.--_Danford_ (see Cobbold, Bibl. No. 52).--_De Reck_, “On the

Draconcule (_Strong. filaria aut veinulosus?_) of Lambs,” from ‘Ann.

de Logelin,’ in ‘Veterinarian,’ vol. v, p. 521, 1832.--_Dupleune_,

“Hydatids in the Brain of an Heifer,” from ‘Mém. de la Soc. Vét. du

Calvados,’ in ‘Veterinarian,’ vol. ix, p. 115, 1836.--_Dupuy_, “An

Hydatid in the Lumbar portion of the Spinal Marrow of a Lamb, aged

eighteen months,” from ‘Journ. Théorique et Prat.,’ in ‘Veterinarian,’

vol. iv, p. 285, 1831.--_Engelmeyer_, ‘Thierärztliche Wochenschrift,’

1850, p. 191.--_Findeisen_, “Ech. in der Lunge,” ‘Repert. f.

Thierheilkund,’ 1875, s. 48.--_Fry, J._, “Worms in the Trachea (of

cattle),” ‘The Hippiatrist,’ vol. iii, p. 5, 1830.--_Furstenberg_, “On

_Pent. tænioides_ of the Sheep,” ‘Edin. Vet. Rev.,’ 1863.--_Gamgee, J._,

“On Parasitic Diseases,” extr. from his ‘Rep. to the Privy Council,’

‘Edin. Vet. Rev.,’ Dec., 1863.--_Idem_, “On Cattle Diseases (including

those produced by Entozoa),” from letters in the ‘Times’ of Oct.

22, Nov. 10 and 13, &c.; in ‘Edin. Vet. Rev.,’ Dec., 1863.--_Idem_,

“On Diseased Meat (especially in relation to Trichina),” ‘Pop. Sci.

Rev.,’ Jan., 1864.--_Idem_, “On Sturdy in Sheep (with figs. from Van

Beneden, Leuckart, and Cobbold),” ‘Edin. Vet. Rev.,’ vol. i, p. 440,

1859.--_Idem_, “Gleanings from the Researches of Eschricht, Haubner, A.

Thomson, &c., respecting the Origin and Development of the Entozoa,”

‘Veterinarian,’ 1855.--_Giacomini_ (see Bibl. No. 13).--_Gulliver_,

“On the Structure of the Entozoa belonging to the genus Cysticercus,”

‘Med.-Chir. Trans.,’ ‘Lond. Med. Gaz.,’ and ‘Lancet,’ 1840-41.--_Idem_,

“Notes on the Ova of _Dist. hepaticum_, and on certain Corpuscles

obtained from the genus Cysticercus,” ‘Proc. Zool. Soc.,’ March, 1840,

and in ‘Ann. Nat. Hist.,’ vol. vi, 1841; also ‘Month. Journ. Med.

Sci.,’ vol. ii, 1842, and ‘Micros. Journ. and Struct. Rec.,’ p. 95,

1842.--_Hewlett_ (see Bibl. No. 13).--_Holmes, J._, “Filaria in the

Bronchi of a Calf,” ‘Vet. Rec.,’ vol. i, p. 125, 1845.--_Hunter, J._,

“Ileum of a Ruminant containing Acephalocyst Hydatids;” see description

of preparation No. 863 in the ‘Catalogue of Mus. Roy. Coll. Surg.

Lond.’ (“Pathology,” vol. ii, p. 201), 1847.--_Idem_, “Hydatid in the

Humerus of an Ox” (_ibid._, prep. No. 864).--_Idem_, “On Hydatids of

the Sheep,” in supp. to his paper on ‘Human Hydatids,’ in ‘Trans. of

Soc. for the Improvement, &c.,’ vol. i, 1793, p. 34.--_Huxley_, “On

the Anatomy and Development of Echinococcus (from a Zebra),” ‘Proc.

Zool. Soc.,’ and ‘Ann. Nat. Hist.,’ 1852.--_Karkeek, W. F._, “Notes

on the _Rot_ (or _iles_ of the Cornish graziers),” ‘Veterinarian,’

vol. iv, p. 573, 1831.--_King, E._, “On the Propagation of Rot (by

means of the eggs of _Fasc. hepatica_) in Sheep,” ‘Veterinarian,’ vol.

ix, p. 95, 1836.--_Krabbe_, “Husdyrenes Indvoldsorme,” ‘Tidsskrift

for Vet.’ (See also my notice of the memoir in ‘Lond. Med. Rec.’ for

1872; repr. in ‘Veterinarian,’ May, 1873.)--_Küchenmeister_ (see Bibl.

No. 13).--_Leaver, T._, “Cases of the Husk (from worms) in Cattle,”

‘Veterinarian,’ vol. ii, p. 355, 1829.--_Lepper_, “Hydatids in the

Kidney of a Lamb (with remarks by Prof. Varnell),” ‘Veterinarian,’

vol. xxxvi, p. 524, 1863.--_Lewis_ (see Bibl. No. 13).--_Lord, J._,

“On some of the Parasites principally affecting Ruminants,” ‘Trans.

Vet. Med. Assoc.,’ 1842-43.--_Masse_ (see Bibl. No. 13).--_Mayer,

T._, “On Hoose in Cattle (from Filaria),” ‘Veterinarian,’ vol. xiii,

p. 227, 1840.--_M’Call, J._, “On Sturdy in Sheep,” _ibid._, vol.

xxx, p. 267, 1857.--_Mégnin, P._, “Le _Str. minutissimus_,” ‘Bullet.

de la Soc. Centrale Vét.,’ in ‘Rec. de Méd. Vét.,’ July, 1878, and

in ‘Ann. de Méd. Vét.,’ Oct., 1878, p. 563.--_Moorcroft_, “Brain

Hydatids,” ‘Med. Facts and Observ.,’ 1792.--_Morton, W. J. T._, “On

the Entozoa affecting Domesticated Animals, and particularly on _Fasc.

hepatica_ or Liver Fluke in Sheep,” ‘Veterinarian,’ vol. xii, p. 735,

1839.--_Mosler_ (see Bibl. No. 13).--_Murie, J._, “On the occurrence of

_Œstrus tarandi_ in a Reindeer in the Zoological Society’s Gardens,”

‘P. Z. S.,’ 1866, with woodcuts.--_Idem_, “On a Leech (Trocheta) found

in the Viscera of a Molluscan Deer (_Cervus moluccensis_, _Müller_),”

_ibid._, 1865.--_Numan_, “Over den Veelkop-blaasworm der Hersenen” (this

beautifully illustrated memoir, in the ‘Trans. of the Dutch Soc. of

Sciences,’ supplies an elaborate bibliography of continental writings

on _Cœnurus cerebralis_--T. S. C.), ‘Œrste Kl. Verh.,’ 3e Reeks, 2e

Deel, p. 225 _et seq._--_Oliver_ (see Bibl. No. 13).--_Padley, G._, ‘On

Entozoa from a Sheep;’ see Sandie.--_Parsons_, “On Diarrhœa in Lambs

(with bronchial worms),” ‘Veterinarian,’ 1855, p. 685.--_Patellani_,

“Sturdy in Cattle,” from ‘München Jahresbericht,’ in ‘Veterinarian,’

vol. xxx, p. 81, 1857.--_Pellizzari_ (see Bibl. No. 13).--_Perroncito_

(see Bibl. No. 13).--_Pourquier_ (see Bibl. No. 13).--_Ralph, T. S._,

“On the Parasitic Nature of Pleuro-pneumonia,” &c., two papers in

‘Austr. Med. Journ.,’ 1865.--_Ranke_, “Pulmonary Entozoic Disease of

Sheep,” ‘Path. Soc. Trans.,’ 1858; see also ‘Veterinarian,’ vol. xxx, p.

708, 1857.--_Raynaud_, “A Word on the Cachexia, or Rot in Ruminants,”

trans. from the ‘Journ. des Vét.,’ by W. Ernes, in ‘Veterinarian,’

vol. xxxiii, p. 488, 1859.--_Read, R._, “Destruction of Strongylus and

Filaria in the Bronchial Passages of Calves, through nasal inhalation

of ether, chloroform, oil of turpentine, or rectified oil of amber,”

‘Veterinarian,’ vol. xxi, p. 604, 1848.--_Reck_ (see De Reck).--_Reed,

R._, “Congenital Hydatids in a Lamb,” ‘Veterinarian,’ vol. viii, p.

551, 1835.--_Rhind_, “Description of a species of Worm (Pentastoma)

found in the Frontal Sinus of a Sheep,” ‘Farrier and Naturalist,’ vol.

iii, p. 277, 1830, and ‘Lancet,’ 1829.--_Robertson_, “Remarks on Tænia

in Lambs,” ‘Rep. of Scottish Med. Vet. Soc.,’ in ‘Veterinarian,’ 1875,

p. 80.--_Rochard_ (see Bibl. No. 13).--_Rose, C. B._, “On Cœnurus and

Acephalocysts,” ‘Lond. Med. Gaz.,’ vol. xxiv, p. 525, 1844.--_Idem_,

“On the Anat. and Physiol. of the _Cysticercus tenuicollis_,” ‘Roy.

Med.-Chir. Soc. Trans.,’ and ‘Lancet,’ 1848.--_Idem_, “On the Vesicular

Entozoa, and particularly Hydatids,” ‘Lond. Med. Gaz.,’ vol. xiii, p.

204, 1833-34.--_Sandie_ (with _Padley_), “On Entozoa in the Lungs of

a Sheep,” ‘Ann. Nat. Hist.,’ 1849.--_Schwarzmeier_, “Die Trepanation

des Rindes bei Cœnurus,” ‘Wochenschr. f. Thierheilk.,’ 1875, s.

295.--_Shenton_, “Worms from the Stomach of a Cow,” ‘Veterinarian,’

1844, p. 487.--_Siedamagrotzky_, “Hydatids in the Liver of a Cow,”

‘Bericht üb. das Veterinawesen im Kön. Sachsen,’ 1875, s. 29.--_Simonds,

J. B._, “Death of Sheep from Worms in the Stomach (abomasum), being

remarks on Mr. Haywood’s case,” ‘Veterinarian,’ vol. xxxiv, p. 525,

1861.--_Idem_, ‘The Rot in Sheep, its nature, cause, treatment,

and prevention,’ London, 1862.--_Idem_, “On Filariæ in the Bronchi

of Calves,” ‘Trans. Vet. Med. Assoc.,’ 1843, p. 517.--_Idem_, “On

Strongylus in the Bladder and Intestines,” _ibid._, 1843.--_Idem_,

“On Hydatids of the Liver of a Sheep (Mr Scruby’s case),” _ibid._, p.

331.--_Idem_, “On Disease of the Mesenteric Artery from Strongyli within

the Vessel,” ‘Path. Soc. Trans.,’ 1854.--_Idem_, “Lecture on the Nature

and Causes of the Disease known as Rot in Sheep,” vol. xxxiv, p. 274,

1861.--_Spence, G. W._, “On Œstrus of the Ox,” ‘Edin. Med. Journ.,’

1858, and ‘Edin. Vet. Rev.,’ vol. i, p. 400.--_St Cyr_ (see Bibl. No.

13).--_Stoddart, J._, “Case of Hydatids in the Liver (of a Cow),”

‘Veterinarian,’ vol. xi, p. 637, 1838.--_Sutton_ (Lecture), ‘Gardiner’s

Chronicle,’ June 29, 1872.--_Sylvester, F. R._, “Cases of Parasites

infesting the Brains and Intestines of Lambs,” ‘Vet. Rec.,’ vol. ii, p.

40, 1846.--_Thudichum_ (see Bibl. No. 13).--_Idem_, “Echinococci from

the Sheep’s Lungs,” ‘Rep. Med. Soc. Lond.,’ in ‘Assoc. Med. Journ.,’

1856, p. 195.--_Tommasi_ (see Bibl. No. 13).--_Van Beneden_, “On the

Development of Cœnurus,” from ‘Comp. Rend.,’ in ‘Ann. Nat. Hist.,’ vol.

xiv, 1854.--_Watson, K. W._, “Experiment for the Cure of the _gidd_

(Cœnurus) in a Sheep,” ‘Lond. Med. Repos.,’ 1815.--_Willemoes-Suhm_, in

‘Sieb. and Köll. Zeitschr.,’ Bd. xxv, s. 176.--_Wilson, E._, “On the

Anatomy of _Trichocephalus affinis_,” ‘Vet. Rec.,’ 1846.--_Wymann_,

“Note on Filaria in the Bronchi of a Sheep,” see Anon. on “Entozoa and

Parasites,” in ‘Amer. Journ. Sci.,’ vol. xxxix, p. 183, 1840.--_Youatt_,

“On Hydatids in the Sheep (symptoms, prevention, treatment, &c.),”

‘Veterinarian,’ vol. ii, p. 519, 1834.--_Idem_, “On the peculiar

Bronchitis in young Cattle, accompanied by Worms in the Bronchial

Passages,” part of lecture, in ‘Lancet,’ 1832.--_Idem_, “Hydatids in

the Brain of a St Domingo Goat,” ‘Veterinarian,’ vol. ix, p. 443,

1836.--_Idem_, “Bronchitis from Worms (in Cattle),” _ibid._, vol. vi,

p. 177, 1833.--_Idem_, “Hydatids in the Brain (in Cattle),” _ibid._,

vol. vii.--_Yvart_, “Brain Hydatids,” _ibid._, 1828, p. 19.--_Zahn_,

“Lungenwürmer beim Reh,” ‘Œsterr. Vierteljahrschr. f. w. Vet.,’ 1875,

s. 125.--_Zurn_ (see Bibl. No. 13).--For further references to the

literature of Hydatids in Animals, see Bibliography No. 20, _o_, in the

first half of this work.