A Treatise on Sheep Part 10

[29] To enable the reader more easily to understand Mr d.i.c.k's views of this disease, I have added a drawing of the foot of the sheep, which it may be well to consult before entering on the subject.

_Fig. 4. Plate._ I. Section of a toe:--_c.c._ Crust of the hoof; _s._ Sole; _g.g._ Gland which secretes the hoof.

(153.) _Causes of Foot-rot._ "What do we gain," says Mr d.i.c.k, "by enticing the sheep from his native and natural haunts to the richer pasturage of our meadows or lawns? There the animal enjoys a more luxuriant repast; it fattens to a larger size, and will, in this respect, repay the increased allowance which has been made to it. But instead of moving about in small troops, with the alacrity of the wild kinds, the sheep are seen in flocks of thousands, moving slowly over their pastures, and gorging themselves to an extent which cuts short the thread of life, by the advancement of various diseases. Instead of wandering from the summit of one peak to another, in quest of a scanty subsistence, or instead of being compelled to descend from the summits of the mountain in the morning, and ascend again in the evening, they are compelled, in many cases, to remain within a few yards of a particular spot for weeks together, and there engorge themselves to satiety.

"But what, it may be asked, has this to do with the foot-rot? More, I am inclined to think, than is generally imagined. The hoofs of the sheep being intended to receive a degree of friction from hard surfaces, are not acted upon when the animal is placed under such circ.u.mstances; and the necessary consequence is an overgrowth of the hoof. The crust,--the part naturally intended to support the weight of the animal, and to endure the greatest share of fatigue,--is here allowed to grow out of all due bounds, because the softness of the pasturages, upon which it now moves, presents little, if any, of that rough friction to which the feet of the animal is naturally intended to be exposed. The crust, therefore, grows unrestrained, until it either laps over the sole, like the loose sole of an old shoe, and serves to retain and acc.u.mulate earth and filth, or is broken off in detached parts, in some cases exposing the quick, or opening new pores, into which the particles of earth or sand force their way, until reaching the quick, an inflammation is set up, which, in its progress, alters or destroys the whole foot."

"The finest and richest old pastures and lawns are particularly liable to this disease; soft, marshy, and luxuriant meadows are equally so; and it is also found in light, soft or sandy districts. In the first of these it is perhaps most prevalent in a moist season, and in the latter in a dry one; in short, it exists to a greater or less extent in every situation which has a tendency to increase the growth of the hoofs without wearing them away, and more especially where they are kept soft by moisture. It is so prevalent in fine lawns and pleasure grounds, that they are, in many instances, reduced in value to a mere trifle as a pasture for sheep; they are said to be _infected_ with this disease, and having once become so, the vicissitudes of _seven_ seasons are scarcely sufficient to destroy the contagion! A luxuriant herbage, on soft pastures, is equally subject to it; and, in both cases, the disease is increased in a wet season.

"The reason why, in these situations, sheep are so liable to the disease, is quite obvious. They are generally brought from lands where their range of pasturage was greater than in these situations. In their former state, from the exercise which the animal took, and the nature of the grounds on which it pastured, the hoof was worn down as it grew; but, under the state in question, the hoofs not only continue to grow, but, where the land is moist, that growth is greatly increased; and the animal does not tread upon hard ground, nor has it exercise to wear them down. Now, in the case of man himself, when the nails of his fingers or toes exceed the proper length, they break, or give him such uneasiness as to induce him to pare them. And the same takes place with the hoof of sheep. But there is this difference in the case of the latter, that when their hoof once breaks, as the animal has not the power of paring it, the part thus broken must continue a wound. Some parts grow out of their natural and proper proportions; the crust of the hoof (_c.c._) grows too long; and the overgrown parts either break off in irregular rents and unnatural forms, or, by over-shooting the sole (_s._), allow small particles of sand or earth to enter into the pores of the hoof. These particles reach the quick, and set up an inflammation, which is followed by the destructive effects which are too well known to require description.

"Similar effects are produced on soft, wet grounds. The feet, in such a situation, are not only not subject to a proper degree of friction to wear down the hoofs, but the growth of the hoofs is materially increased by the soft and moist state in which they are kept. And this state renders the feet the more liable to the disease, as it opens up the pores of the horn, and allows the earth or sand to penetrate, and wound the quick, in the manner I have already stated. On soft sandy ground, of a dry nature, the same circ.u.mstances may occur. The soft sand gives way by the weight of the animal, and the crust of the hoof is not worn down. The sand penetrates between the sole and the crust, as has been already explained, and produces inflammation. The disease, however, is not so common on sand as in the other situations to which I have alluded, the sand seldom being found in such a loose state."

Another variety of foot-rot is produced by the friction of long gra.s.s between the hoofs, but is mostly confined to hill sheep, when first pastured on lowland districts. These animals, from having been accustomed to collect their food on extensive ranges of bare pasture, are more exposed than heavy breeds to this frequent exciting cause of the complaint. The rubbing of the gra.s.s frets the skin in the cleft of the hoof, the gland in that situation swells, becomes enlarged, and suppurates, and in no long time the animal is compelled to rest upon its knees.[30] This complaint is, however, more readily remedied than the former, and does not cause nearly so much suffering to the sheep.

[30] _Fig. 5. Plate._ I. Gives a view of the inner surface of the toe of a sheep, with the interdigital gland laid open.

_g._ The gland.

_d._ The duct of the gland, opening upon the anterior surface of the leg.

When the interdigital gland is much enlarged, it becomes necessary to cut it out. This ought to be a last resource, as the part appears to be of too much importance to be easily dispensed with.

(154.) _Treatment and Prevention of Foot-rot._ As foot-rot, in nine cases out of ten, is an attempt on the part of nature to get rid of a portion of the hoof, which ought, in the proper course of things, to have been worn away as fast as it appeared, the prevention and treatment of the first stage of the complaint will naturally suggest themselves. "As this disease," says Mr d.i.c.k, at the conclusion of the aforementioned paper, "arises in consequence of the hoofs not being exposed to sufficient friction to wear them down, or keep them in their proper state, or where their natural growth is increased by the nature and moisture of the ground, the hoofs of all the flock should be regularly rasped or pared at short intervals, say from eight days to a fortnight, according to the rapidity with which a particular pasture produces the disease. In certain situations, they might be made to travel upon a hard surface, similar to natural sheep tracts, or be folded in a place purposely prepared, upon which they could move about and wear their hoofs. For that purpose, they should be placed in it every day."

When foot-rot has fairly commenced, pare the hoof from the affected part, and trim away any ragged portions, wash the foot with soap and water, and place the animal in a situation where as few irritating things as possible will be in the way of the tender surface, and give a purgative. If not properly attended to, the suppuration soon terminates in mortification. Cleanliness in every stage and variety of foot-rot, is of the first importance. Many corrosive preparations are recommended for the cure of this disease, but I have decided objections to one and all of them. When the foot is clean, endeavour, by frequent applications of soap and water, to keep and treat the ulcers as directed in paragraph 110.

(155.) _Inflammation produced by Insects in the Air Pa.s.sages._ Much annoyance is caused to the sheep by the presence of animals in the air pa.s.sages. The _OEstrus ovis_ deposits its eggs on the margin of the nostril in autumn; these are soon hatched, and the larvae immediately find their way up the interior of the nose, till they arrive at the frontal sinus, a cavity situated between the layers of the frontal bone, and of considerable size in the sheep. Here they remain till the following spring, when they quit their hold, become winged insects, and enter upon the career of torment so ably gone through by their predecessors.

The _Pentastoma_, an animal supposed at one time only to exist in the frontal sinus and lungs, and on the surface of the liver, of the dog, wolf, and horse, as well as in some reptiles, has been discovered by an able naturalist, my friend Mr Rhind of Edinburgh, in the frontal sinus of the sheep. It spends its whole existence there, and is distinguished from other entozoa by having the mouth between two pores on each side, through which a spicular process comes out. Figure 3, Plate VII. is taken from a drawing kindly furnished by Mr Rhind.

(156.) _Removal of Insects from the Nostril._ The _OEstrus ovis_ occasions much distress to the sheep at the moment of depositing its eggs within the nostril. The animal on feeling the movements of the fly, rubs its nose against the ground, or, carrying it low, darts off at a rapid pace, vainly endeavouring to escape from its tormentor.

During this period, a thin limpid fluid distils from the nostrils, leading a careless observer to confound the symptoms with those which accompany Coryza. In general the irritation is now terminated, as, while in the larvae state, the insects are incapable of offensive measures. If they are cl.u.s.tered in considerable numbers in the frontal sinuses, they will doubtless lead to great suffering, parallel to what is recorded to have followed the nestling of insects in the same situation in the human being; and it is, therefore, advisable, when the cause of st.u.r.dy (paragraph 169) is in any way doubtful, first to apply those substances to the nostril, which are calculated to destroy both these larvae and the _pentastoma_, should they happen to be there.

Tobacco smoke is the only available remedy, and a very good one, being easily brought in contact with the worms, and, when properly administered, certain in its effects. One person secures the sheep holding the head in a convenient position, while another, having half filled a pipe with tobacco, and kindled it in the usual manner, places one or two folds of a handkerchief over the opening of the bowl, then pa.s.ses the tube a good way up the nostril, applies his mouth to the covered bowl, and blows vigorously through the napkin. When this has continued for a few seconds, the pipe is withdrawn, and the operation repeated on the other nostril.

The round hair-worm (_strongylus filaria_) has been found in great numbers in the trachea and bronchii of calves by Camper, and of the sheep by Daubeuton. It has also been found in the reed and duodenum of the latter animal by Rudolphi. Two other species of the genus _Strongle_, the _S. contortus_ and _S. filicollis_, have been detected in the sheep, the former in the belly, the latter in the small intestines. They all appear to originate only in such sheep as are exposed to the sapping influence of low damp situations, combined with stinted diet. Those occuring in the air tubes give rise to irritation, and a consequent hara.s.sing cough, which is only to be arrested by removing the sheep to a dry airy locality, and a nutritious pasture.

Unless portions of the worms are thrown up during coughing, they cannot be p.r.o.nounced with confidence to exist, as the symptoms which they produce are very similar to those which accompany the two following diseases.

(157.) _Coryza._ During the winter months, this affection is of very frequent occurence among sheep; but health is only in a few instances seriously affected. It is brought on by the exposure of the animal to intense cold, or to sudden chills, after it has been heated. In slight cases, the only annoyance to which the sheep is subjected, is from matter acc.u.mulating in the nostril, and plugging up the orifice, so that the poor creature is compelled to raise its head every three or four minutes, and labour hard for breath.[31] When the inflammation extends further down the air tubes, the symptoms a.s.sume a severer type, and death soon occurs, in general from suffocation. If the inflammation of the bronchial tubes becomes chronic, that is to say, if it goes on in a mild form for a length of time, pulmonary consumption (rot) will in all probability succeed, and destroy the sheep in a more lingering manner.

[31] The sheep is more inconvenienced by Coryza than other animals, owing to the naturally small calibre of the nostrils, the inferior turbinated bone being of large dimensions, and occupying the greater part of the nasal cavity. It is from this peculiar formation of the nose, that sheep are so very easily blown, when made to exert themselves in running.

(158.) _Treatment of Coryza._ Should this disease prevail in a lenient form among your sheep, removal to a sheltered field, and a dose of purgative medicine, are all that is required. If, however, the feverish symptoms are severe, besides giving a purgative, bleed at the outset of the disease, and administer ten grains of the following fever powder, dissolved in a tea-cupful of warm water:--

Take of powdered Digitalis (Foxglove) half a drachm.

Tartarized Antimony fifteen grains Nitre two drachms.

Rub them well together, and divide the mixture into fifteen parts or powders. Half an hour after the powder is swallowed, give the sheep a basin of warm gruel, and repeat the powder at the end of six hours, if the symptoms are not considerably abated. When the sheep is recovering, keep it on juicy food, and do not expose it to inclement weather, as it will be very liable to another and more severe attack. Those sheep which are subject to cough on slight changes of temperature, should always be picked out, fattened for the market, and disposed of at the earliest opportunity, as they will, in all probability, sooner or later, fall victims to the following disease.

(159.) _Rot._ Every animal, from the serpent up to man, that is to say, every animal possessed of lungs, is liable to _rot_. The inelegance of the term might be overlooked, provided a precise meaning were attached to it. Every one, however, seems to place some peculiar signification, and to hang some favourite theory, upon it, so that little wonder need be expressed either at the varying tenor of the treatment, or at the unsatisfactory conclusions which have been drawn regarding it. The word "_rot_," when employed in speaking of man, implies what, in popular language, is called "_consumption_," and is applied to that disease only when it affects the lungs. Thus the fork-grinders of Sheffield, who, from the nature of their employment, are much exposed to the exciting causes of consumption, and who, at an early age, fall victims to it, are said, by the people of that town, to die of rot. The term, however, so far as it has yet been used in relation to the sheep, has figured as the representative of a host of diseases, and, in becoming standard from frequent usage, has only rendered confusion worse confounded. "_Rot_," says the late Professor Coventry, in his _Introductory Discourses_, "is a word which has been employed to express a variety of disorders affecting this animal, with no small confusion and detriment. Indeed, in few instances has senseless indiscrimination done more mischief; for means inapt and injurious have been had recourse to, where skilful and timely interference would have had the happiest effects. Sheep are sometimes said to have the rot, when they labour under _phthisis pulmonalis_ (consumption of the lungs), which they do but rarely; or under disorders of the liver, as _hepat.i.tis chronica_, and that state of the same organ produced, or attended by the _fasciolae hepaticae_ (fluke worms), _hydatides_, &c., which affections of the liver are not unfrequent. But the most common rot is still another and very distinct disorder, resembling, in many points, and probably the very same in its nature with, _s...o...b..tus_ (scurvy) in the human species, or that _miseranda lues_, that direful ruin of the general health and const.i.tution, which silently supervenes from deficient or depraved aliment; and from which, as numerous observations testify, every flock, every sufferer, may be recovered by simple means seasonably used; but against which, in its advanced stage, all remedies prove of no avail. Perhaps, as the last symptoms of debility are very similar, and are most taken notice of by ordinary observers, the different kinds of rot might conveniently enough pa.s.s under the names of pulmonic, hepatic, and general rot."

Setting aside, for the moment, the inaccuracy of part of the above observations, I shall only remark, that, though Dr Coventry, in thus calling attention to the conflicting state of opinions on the subject, has accomplished much in reconciling discrepancies, he has still left something to be done in simplifying the matter; while he has, at the same time, rendered that something difficult of execution, from his own high authority being a.s.sociated with the blunder. The only way, therefore, to remedy the thing, is to quit for the present the views of that learned gentleman, while I endeavour to give a plain account of the disease, its causes, and effects.

(160.) _Symptoms of Rot._ The first thing which indicates the presence of the disease, is the unwillingness of the affected animal to move about. It lags behind the flock, ascends a slope with difficulty, and has a listless, heavy, pithless appearance. Cough varying in frequency and violence, but extremely hara.s.sing, is present at every period of the disease, and is always increased on the slightest exertion.[32] At first this is accompanied by expectoration of the mucus of the air tubes; but in no long time purulent matter, indicative of more extensive inroads on the const.i.tution, begins to be coughed up, and goes on increasing in quant.i.ty and becoming worse in quality till the termination of the disease. The wool becomes fine, white, thin, and brittle in the pile, and is easily brought away in ma.s.ses by the slightest pull. The appet.i.te is, throughout the disease, voracious, and though all the bad symptoms may be present, still the animal keeps up an appearance of plumpness. This, however, is hollow and deceitful, and the rapid loss of flesh which immediately succeeds, shows with what insidious certainty the malady has been progressing. Owing to the falling off in flesh and in fat, the neck appears to have acquired additional length, and the eyes to have sunk within the head. Sooner or later the skin beneath the neck becomes distended with serous fluid, and from this the disease has acquired the name of _Poke_. The word, however, is far from applicable, as it might, with equal propriety, stand for any other disease attended with dropsical acc.u.mulations.

Violent purging soon terminates the disease, death being generally preceded by the evacuation of a quant.i.ty of blackish matter.

[32] It is quite possible that a sheep may die of true pulmonary consumption and yet have scarcely any cough.

(161.) _Appearances on Dissection._ The first thing which strikes a person on viewing the carca.s.s of a sheep which has died of rot, is its leanness. In conducting the examination, the fell appears of a bluish white, the muscles are pale and wasted, and fat hardly to be met with.

Where it once existed, a tough yellow substance alone remains, which is so dest.i.tute of all pretentions to the name of suet, that it cannot, even when thrown upon a fire, be made to blaze. Dropsical acc.u.mulations are found in the legs, chest, neck, and belly. On opening the chest, the lungs are often seen adhering at intervals to the lining membrane of the ribs, and have always a shrunk, diminutive appearance. These adhesions are frequently seen where there are no tubercles, and are in that case simply the result of exposure to cold; but where they are coincident with tubercles, they may be ascribed either to the animal having been exposed to cold, or to the inflammatory action set up by the tubercles themselves. The lungs are always the princ.i.p.al, and I may also, from my own experience, add, the primary seat of the affection.

When examined in the early stage of rot, they have a hard lumpy feel, especially at the upper part or lobe, and at this time a great number of irregular yellowish white, patchy-looking bodies (_Plate_ VI. _fig.

2._), will be seen s.h.i.+ning through the membrane, _pleura_, which surrounds the organ. These _tubercles_, as the hard white bodies are called, vary in size from that of a mustard seed to that of a pea. They are sprinkled through all parts of the lung, and will in every dissection, be found in a variety of stages, from the firm condition in which they were deposited, to the softened state which denotes their speedy expectoration. Each tubercle, however small, usually holds a particle of calcareous matter in its centre. The lungs, in the advanced stage of rot, will be full of cells or caverns, owing to the destruction of its texture by suppuration in those parts where tubercles existed. The cells or sacs are of all sizes, from that of a bean to that of a goose egg; but if the animal has been taken care of during the progress of the complaint, and lingered long, the abscesses will be so numerous, and so closely situated, as to give the remains of the lung the appearance of a large bag. Extreme cases of this nature are, however, rare; as the sheep, in general, either falls before the knife, or is killed from exposure to cold long ere the disease has reached its farthest limit. These sacs contain purulent matter, of all shades and odours, and identical with that which the animal coughed up.

Tubercles, and all their concomitants as above detailed, are also met with in the liver, though not so frequently as in the lungs. They constantly occur in the _clyars_ (mesenteric or lacteal glands) which on this account are much above their usual size, and are occasionally found in other parts; but I need not proceed in their description, as sufficient has been said about them to enable the unprofessional reader to understand their relation to the complaints.

Fluke worms and hydatids are almost constant attendants on rot, and seemingly most important ones, especially the former, which have, I may say, kept a great bulk of the learned and unlearned for many years in a perpetual bustle, and have so effectually hoodwinked writers on this subject, as to prevent them seeing the truly important points in the disease. For this reason, I hold them worthy of particular description; as it is only by becoming acquainted with their history and habits that we can form correct ideas either of their mode of origin or of their supposed ability to cause rot.

(162.) _The Liver Fluke_ (_fasciola hepatica_ or _distoma hepatic.u.m_, _Fig. 6._ _Plate_ I.) derives its name from the resemblance it bears to the plaice or flounder, though its shape has been more aptly compared to that of a melon seed. It is flat and oval, of a brownish-yellow colour, and varies in size from that of a pin-head to one inch in length, and half an inch in breadth. Each worm is bis.e.xual or hermaphrodite, on which account they multiply with great rapidity. The generic name--_distoma_--signifies having two pores, _a.b. Fig. 6, Plate_ I., and is for this reason applied to it. The nipple-like body at the extremity _a._ contains the orifice of the pore or opening leading to the female division of the generative apparatus, situated between _a._ and _b._ In this cavity are formed the eggs, which are at intervals protruded, to be hatched when floating in the sheep's bile.

The male organ is situated in front of the ventral pore. The anterior opening _b._ is equivalent to a mouth, and leads inwards and backwards, communicating with the intestinal ca.n.a.ls _c._, which are easily made out in the recent animal, from their containing dark bile, and which, as in other creatures low in the scale of being, serve the double purpose of a digestive and circulatory apparatus; that is to say, the stomach first prepares a fluid which is equivalent to blood, and then distributes it throughout the body.[33]

[33] The examination of fluke worms is much facilitated by placing several of various sizes flat upon a slip of gla.s.s, and allowing them to dry in this position. On holding the gla.s.s between a bright light and a lens, and looking through the latter, the distribution of the vessels, and the position and form of the eggs, are beautifully displayed.

Flukes are never found in the _arteries_ of the liver, as has been erroneously stated by some writers, their abode being limited to the gall bladder and its ducts. In these they are often present in such numbers as to cause great distention of the sac and tubes, and in some instances the irritation produced by them leads to the thickening of the walls of the gall bladder, and to a deposition of calcareous matter between its coats; frequently also to complete obliteration of portions of the ducts. Hence the crackling sound sometimes perceived when handling the liver of a rotten sheep.

(163.) _The Hydatid or Blob_ (_Cysticercus tumicollis_, _Fig. 1._ _Plate_ VII.) so frequently found in sheep, is in form one of the simplest of the entozoa (literally dwellers within), being little more than a bag containing a quant.i.ty of fluid. As relates to outline, this hydatid bears no small resemblance to a Florence flask. It is said to have a head, _h._--a neck, _n._--a body, _b._-- and a posterior or caudal vesicle, _c.v._ Its claims to the t.i.tle of an animal have been much disputed, but as it has been seen to move spontaneously, and as the contained fluid is always essentially different from that by which the hydatid is surrounded, the question may be looked upon as set at rest.[34]

[34] The property of acting on organized matter, so as to convert it into substances similar to those which const.i.tute the agent, is characteristic of a vital power.

The method of their reproduction is in unison with their structure, simple in the extreme. Nothing, however, very precise is known about the process. The vesicle which acts as heart and stomach serves also as the reproductive cavity, but how or by what means it is fecundated would be difficult to determine. The young hydatids are found adhering to the inner surface of the parent cavity. When they have attained maturity, the parent dies and shrivels, and the young ones begin to eliminate their nourishment from the juices of the quadruped which they infest.

These entozoa are found in general on the surface of the intestines, between them and their outer membrane (_peritoneum_), and on the exterior of the lungs and liver. They are always included in a cyst, to the inner surface of which they adhere by means of two hook-shaped processes projecting from the head. These cysts are always on the surface of the different viscera of the sheep, and in this way may be distinguished from another sacular animal, or rather supposed animal, termed acephalocyst or headless bag, which is sometimes found in cl.u.s.ters in the substance of the lungs, liver, &c. and is often confounded with the true hydatid.

(164.) _Causes of Rot._ If any one had been asked, thirty years ago, the cause or rather causes of the appearances which pa.s.s under the name of rot, he could not have enumerated them even in a day, for at that time each symptom was a disease, and as such was reckoned worthy of a separate and proximate cause. Nor could any person have had the courage to promulgate a common-sense opinion on the subject; for simple views regarding the diseases of domestic animals were then either not deemed worthy of a moment's notice, or, if considered, were swept at once, by the strong current of prejudice, into the foul ocean of predetermined disapproval. Opinions in cattle medicine were at that time valued according to the prolixity of their detail; and the more improbable the dependence of the effects upon the cause a.s.signed, so much more was its discoverer lauded, and in like proportion was the chimerical fabric he had raised admired. Times are, however, now happily changed; that potent oculist, the march of intellect, has cleared the film from the public eye, and no one need, at present, be afraid to state the unaspiring fact, that _tubercles_ are the sole and proximate cause of the disease called rot.

The observations of the late Dr Coventry, already quoted, would lead us to suppose that tubercles are of rare occurrence in the lungs of sheep, but in refutation of this a.s.sertion, I need only request the reader to take a ramble through a butcher-market, and he will perceive, even on cursory inspection, the fallacy of this conclusion. What the state of the liver is which is attended with flukes and hydatids, he has left us to make out. Chronic hepat.i.tis, which accompanies tubercles in the liver, goes for nothing as a disease of sheep, and therefore does not require a notice; besides, it is not rot, and is quite incompetent of itself to cause it. As for the scurvy of which he speaks, he evidently means the disease now generally known by the name of _Pining_, but which, as it has no connexion with rot, and has only become prevalent within the last sixteen years, could not be very well known to him.

The following questions will naturally occur to many of my readers.

What gives rise to these tubercles? what are the predisposing causes which lead to their formation? and, when formed, how do these apparently unirritating bodies produce effects so baneful? Queries like these, however, cannot shortly be replied to, leading, as they do, to discussions which embrace many curious theories; but as the negative mode of teaching is often of avail where the positive or more direct would fail to bring conviction, I shall, before proceeding to allude to what the causes are, endeavour to state what they are not.

_Imaginary Causes of Rot._ The liver-fluke has long been looked upon as the origin of rot, and this opinion has now become so deeply rooted, and taken so fast a hold of the public mind, that if I were to contradict it by plain a.s.sertion, I should only be striving to buffet singly a tide of opposition. The best way, therefore, will be to examine a few of the theories supposed to be confirmatory of the notion that fluke worms are the beginning of the mischief, and then see whether their supporters have managed to make good the point.

I. The fluke is supposed to get into the liver of the sheep by being swallowed, and this, according to our theorists, may be brought about in some of the following ways:--

1. The eggs may be floating in the air, and thus accidentally reach their destination. This is the view taken by the celebrated Clater; but if he had been, in this instance, a man of experiment, rather than of idle conjecture, he would have found, as any one readily may, that the eggs of the fluke worm sink in water, and, consequently, that they cannot float in air.[35]

[35] To obtain the eggs of the fluke worm for examination, hold a saucer under the gall bladder, make an opening in it with scissors, and the bile containing the eggs will flow into the dish. Pick out any fluke worms that may be in the fluid, then dilute it with about twelve times its bulk of water, agitate for a few minutes, and filter. The eggs will be found in the corner of the filtering paper.