* /. arm v of Division Range Shelf BIOLOGY LIBRARY G 18? (> ^ .V.tfi/ > >3pS \ / BIOLOGY IRA G x [From the Kcport S^j^X^ftW^ of Agriculture for 1870.] The External Parasites of Domestic Animals, THEIR EFFECTS AND REMEDIES.* BY A. E. YERBILL. The external parasites of our domestic animals nearly all belong to the great class of animals which we call Insects, but the internal parasites are, with few exceptions, representatives of the class of Worms. The division of the subjects of these lectures is, therefore, both convenient and natural. The class of Insects includes a far greater number of spe- cies than any other class of animals, the number actually amounting to several hundred thousands, each country having a vast number peculiar to itself. They are also exceedingly diverse in habits, as well as in form and structure. In order to show the affinities of the insect-parasites and their position among other insects, it will be necessary to give a brief sketch of the whole class, with a few remarks on the more important peculiarities of their anatomy. All insects, like the other articulated animals (worms and Crustacea), have a body composed of a series of segments or rings, placed one behind the other, and together forming a sort of irregular tube, which incloses in one cavity all the in- * In the preparation of the reports of these lectures on the parasites of domes- tic animals, we are greatly indebted to Dr. A. S. Packard for the use of many cuts of insects from his excellent "Guide to the Study of Insects" and the "American Naturalist," published at Salem, Mass.; and to Donald G. Mitchell, Esq., editor of the "Hearth and Home," published by Pettingill, Bates & Co., New York, for the use of several excellent cuts of parasitic worms, prepared to illus- trate a series of articles on parasites of man and domestic animals by the writer. Without this assistance the lectures could have been illustrated only imperfectly. In addition to these we have added, so far as the available funds would admit, fig- ures of the more important parasitic insects and worms, copied from Cuvier, Gue- rin, Clark, Leuckart, Cobbold, and others. A. E. Verrill. Fig. 2. z BOARD OF AGRICULTURE. ternal organs. The nervous system consists of a double nerve-centre or ganglion in the upper part of the head, connected with another below by nerves that pass around the gullet on each side, so as to enclose it as in a ring, and this lower double ganglion is connected by a double nervous cord with a series of similar ganglions or nerve-masses, which are arranged along the lower side of the body, below the intestine, each ganglion sending off small nerves to the adja- cent organs (figure 2). The rings of the body are thickened in certain parts, and in the head and middle region of the body are more or less consolidated. They thus form a somewhat firm external skeleton, composed of a peculiar substance, called chitin. When the rings are movable this outer covering, where it connects the rings to- gether, is thinner and flexible, and often folded inward so as to form peculiar joints. The legs, jaws, and other external organs, are merely hollow out- foldings of the outer covering, and contain, like the body, the muscles that move the various parts, while their cavities com- municate freely with that of the body, and thus receive their supply of blood, nerves, etc. Each joint of the legs and other appendages is also formed by a thinner portion of the outer covering, which is folded in upon itself in various ways. The wings, when present, are also outfoldings of the integu- For description of Figures see next page. Fig. 1. PARASITES OP ANIMALS. Fig. 3. ment, which appear at first in the form of little sacks containing fluid, but finally ex- pand into broad membranes and the sides of the sack unite so as to appear like a simple membrane, supported by little branching, hollow rods, or tubes, which communicate with the cavity of the body, and also form the joints of the wings. The legs and jaws originate from the lower part of the sides of each ring that bears such appendages, so that there must be as many rings or segments in any part of the body as there are pairs of such organs, but Fig. 4. FIGURE 1. " Hundred-legs," ( Scolo^ocryptops sexspinosa Say), natural size; color deep orange, with yellow feet. From Packard's Guide. FIGURE 2. Nervous system of Corydalus cornutas, a large neuropterous insect; a and b, ganglions of the head; c, the three ganglions of the thorax, which send nerves to the three pairs of legs ; d, d, the eight double ganglions of the abdomen. From Packard's Guide, after Leidy. FIGURE 3. Portion of one of the tracheae or breathing tubes, prepared so as to show the spiral fibre a, a part of which has been unwound; c, a secondary branch. From Packard's Guide. FIGURE 4. Transverse section of the thorax of a bee; a, one of the nervous ganglions ; 6, breathing pore or spiracle, opening into the tracheae, which branch in the interior, and send small tubes into the legs and wings; c, the dorsal vessel or pulsating organ, which circulates the blood; d, the intestine. From Packard's Guide. 4 BOARD OF AGRICULTURE. the wings originate from the upper part of the same rings that bear legs below (fig. 4). Most insects breathe air by means of a complicated system of finely branched air tubes, having a sort of spiral spring to keep them open (fig. 3), which are con- nected with valvular openings, called spiracles, along each side of the body. Some species of spiders have respiratory cavities that somewhat resemble lungs, and contain numerous thin membranes, arranged like the leaves of a book. These are, however, connected with openings in the lower side of the body, and may be regarded as a peculiar modification of the air tubes or tracheae found in other insects. In many flying insects the air tubes expand in certain parts into large hollow vesicles, which give greater lightness to their bodies. In all insects we can distinguish three regions of the body: the head, composed of several rings closely united together, and bearing the organs of the mouth and senses as many pairs as there are rings ; the thorax, composed of either three or four rings, which bear as many pairs of legs, and sometimes one or two pairs of wings above ; the abdomen, composed of numerous rings, which are not consolidated, and generally bear only the external reproductive organs ; but in the spiders they bear the spinnerets, in many Iarva3 several pairs of fleshy legs, in centipeds, etc., numerous legs, (figures 1 and 6), and in some insects long, slender, feeler-like organs (figure 5). Insects are naturally divided into three great groups or sub-classes,* founded on important differences in their internal anatomy and the arrangement of their external parts. I. HEXAPOD INSECTS. The highest sub-class contains the Hexapod or six-legged insects, including all the flying insects, and many that are destitute of wings. In these the head, thorax, and abdomen, are distinctly separated as three regions of the body. * According to some writers these divisions are called orders. FIGURE 5. "Furniture-bug," or Shiner, (Lepisma), natural size. A smooth, shining, neuropterous insect, covered with minute silvery scales, but destitute of wings. It lives in houses among books, papers, clothing, or in furniture, etc., eating them in various ways ; it is very fond of the paste of books, and will often loosen wall-paper. PARASITES OP ANIMALS. 5 The head appears to be composed of seven rings, and there are three pairs of mouth organs. They all breathe by means of air tubes or tracheae. II. ARACHNIDS. The next sub-division, called AracJtmda, includes the spi- ders, scorpions, " daddy-long-legs," or harvest men, mites, etc. In these the head is generally more or less united to, or sunken in, the thorax, as in the spiders, which have the abdomen very distinct; or the abdomen may be closely united to the thorax, Fig. 6. as in the mites (figure 48). When mature they have eight legs. The head bears but few organs. There are no antennas. The eyes are simple, but often numerous. Many breathe by tracheae, but some spiders by lung-like organs, and others by both combined. III. MYRIAPODS. The lowest sub-elass, called Myriapoda, includes the centipeds, "thousand-legs," etc., (figures 1 and 6.) These have the rings of the thorax and abdomen all very similar, and the rings of the ab- domen in some become very numerous, sometimes amounting to several hundred. Each ring usually bears a pair of legs, aiid contains a nerve ganglion. The head is similar to that of the six-legged insects, and bears antennae, and sometimes com- pound eyes. They breathe by air tubes or tracheae. This last sub-class contains no parasites, but in both the others there are numerous examples. Yet in those they are confined to particular orders and families. Among the Arachnids we find parasites only in the lowest order, which includes the mites, the true ticks, the itch-insect, etc., but among the Hexapod insects we find that the parasites belong mostly to two of the seven orders into which they are naturally divided. The seven orders of six-legged insects are based on many anatomical differences, but they are characterized, also, by FIGURE 6. Lithobius Americanus Newport, natural size; color yellowish brown. From Packard's Guide. 6 BOARD OP AGRICULTURE. differences in their transformations, and peculiarities in their habits. The most obvious distinctions are found in the structure of the organs composing the mouth, and in the wings, when these exist. Their names are derived from the character of their wings. The orders are as follows : I. Hymenoptera, (membrane-winged). This order includes the bees, wasps, ichneumon-flies, saw-flies (figures 7, 7 a), etc. Fig. 7 a. Fig. 7. They have four small but strong membranous wings, the front pair largest. The body is compact, the head large, and the three regions of the body very distinct. The head (figure 8) usually has three simple eyes Fig. 8. in front, forming a triangle ; a pair of slender antenna3 or feelers, and a pair of very large compound eyes ; connected with the mouth we find a pair of powerful, often toothed, mandibles or jaws; a pair of orceps-like maxillce, bearing near the base a jointed palpus or small feeler ; and finally the labium or lower-lip, which bears a pair of palpi or feelers, and the. ligula or tongue, which is long and highly developed and covered with hairs in the bees. They have, therefore, all the parts of the mouth symmetri- FIGURE 7. The Pear-slug or Saw-fly (Selandria cerasi Peck), enlarged. Color black, with white spots on four anterior legs and feet. FIGURE 7a. Larvae of the same on leaf of pear, natural size ; and a, enlarged. It is covered with sticky slime. Both from Packard's Guide. FIGURE 8. Head of wild Bee (Anthophora), much enlarged ; a, compound PARASITES OP ANIMALS. cally developed. The jaws are used for biting and cutting the materials used in constructing their nests ; the maxillae are used in manipulating and arranging ; the tongue is used for lapping up honey and other liquid food. The Iarva3 are gen- erally soft, footless, and white, but those of the saw flies re- semble caterpillars, and have numerous abdominal legs. II. Diptera (two-winged). Insects belonging to this order have but one pair of wings. The three regions of the body are very distinct. The common house-fly, meat-flies, mos- quito, Hessian-fly, wheat-midge, onion-fly (figure 9), bot-fly, Fig. 9. horse-fly, and the fleas are examples. The mouth organs- corres- pond in number with those of the Hymen- optera, but the mandi- bles and maxillce are usually formed like long sharp lancets, as in the horse-fly (fig. 10), or have the shape of slender and sharp piercing organs, as in the mosquito. The labium and tongue together generally form a long proboscis, often with the tongue curiously bilobed and expanded at the end as in the horse-fly and house-fly. The sharp mandibles and maxillaB are used to penetrate the skin of animals, or the bark of plants, and rind of fruits, and the fleshy tongue is used to suck up the blood or other liquid food. The larvae eyes ; b, clypeus ; c, the three simple eyes or ocelli ; d, the antennae ; e, labrum or upper lip ;.f, mandibles ; h, maxillary palpi, borne upon the base -of the maxillae i, which are slender and hairy ; j, labial palpi ; k, ligula or tongue ; /, palpifer ; m, paraglossae or lateral lobes of the ligula. From Packard's Guide, after New - port. FIGURE 9. Onion-fly (Anthomyia ceparum), considerably enlarged, with larvae, a and 6. From Packard's Guide. FIGURE 10. Head of Green-head fly or Horse-fly (Tabanus lineola Fabr.), much enlarged ; a, antennae ; m, mandibles ; mx, maxillae ; mp, the large, two-jointed maxillary palpi ; /, the ligula or tongue ; lb, the labrum. From Packard's Guide. Fig. 10. 8 BOARD OF AGRICULTURE. are usually soft, white, and footless, and generally pass under the name of maggots. In this order we find many parasites, of which the fleas, sheep-tick, bat-ticks, horse-tick, forest-flies, bot-flies, etc., are examples. This order contains some bene- ficial and very many injurious insects. III. Lepidoptera (scaly wings). This order includes the butterflies, moths, millers, army worm (figure 11), canker- worms, cut-worms, silk-worms, etc. The wings are four in number, usually broad, and covered with minute scales, looking somewhat like beautiful feath- ers under the microscope, but appear- ing like fine dust to the naked eye. The mandibles are nearly abortive, but the maxilla3 are usually very long, slen- der, and hollowed out on the inside, so that when fitted to- gether they form a long hollow tube or proboscis, through which they suck up their liquid food. The proboscis can be rolled up beneath the head when not in use. The larvae mostly feed upon plants, and are generally known as cater- pillars. They are often bright colored, sometimes hairy, and usually have, in addition to three pair of small true legs, two or more pairs of fleshy legs under the abdomen. Most of the insects of this order are injurious to vegetation. IV. Coleoptera (shield-wings). Insects of this order are known as beetles, weevils, etc. The front wings are thick- ened and stiff, not used in flight, but serve to protect the hinder wings, which are larger and thin, and can be folded up and tucked away under them. The mandibles and maxilla are both used as jaws for biting and chewing. The larvae have usually three pair of legs, and many are well known as grubs and borers in wood. The apple-tree borer (figure 12), is an example. This great order includes many beneficial carnivorous insects, as well as many that are injurious to vegetation. Y. Hemiptera (half-wings). This order embraces those FIGURE 11. Southern Army-worm (Leucania) imago; and larva, a, natural size. From Packard's Guide, after Glover. PARASITES OF ANIMALS. 9 insects properly called bugs, such as the squash-bug (figure 13), strawberry-bug, bed-bug, and also the cicada or "seven- Fig. 12. teen-year locust," the plant-lice, bark-lice, cuckoo-spits, the true lice, bird-lice, etc. In this order we find, therefore, the greatest number of external parasites. The wings, when present, are often crossed upon the back, and the front wings are often thickened toward the base, but in other cases, as in the cicada and plant-lice, the wings are transparent and not crossed. The mouth organs form a sharp hollow proboscis, for piercing the bark of plants or skin of animals, in order to suck up the blood or sap. When not in use the proboscis can be folded down upon the breast, by means of three joints. The mandibles and maxillae are four, long, slender, very sharp, piercing organs, often barbed near the points. These are enclosed in the jointed proboscis, as in a sheath, but can be thrust out through the opening in the end. The proboscis is formed mostly by the lower lip or labium, but the opening in the upper side is covered by the shorter upper lip. The larvae of many Hemiptera resemble the adults from the first, except that they lack wings ; the pupae are also active and have the same habits. They therefore undergo less remark- able transformations than those of the preceding orders. Many of these insects are beneficial by destroying other in- sects, but most are injurious to vegetation by sucking sap. FIGURE 12. Apple-tree Borer (Saperda Candida Fabr.), natural size. Color light brown with two white stripes ; the lower figure represents the larvas. From-, Packard's Guide. FIGURE 13. Squash-bug ( Coreus tristis DeGeer.), natural size. Color dart brown. From Packard's Guide. 2 10 BOARD OF AGRICULTURE. VI. Orfhoptera (straight-wings). This order includes the grasshoppers, true locusts, katydid, crickets, cockroaches, etc. Fig. u. The front wings are generally long and straight, somewhat thickened, and in the male often have some sort of musical ap- paratus, as in crickets, katydids, etc. The hind wings are broad, fan shaped, and can be folded up like a fan beneath the front wings, which when folded gen- erally lie lengthwise of the body, forming a sort of roof. The mandibles and maxillae are chewing organs. The larva& have nearly the same form as the adults, but lack wings ; they have similar habits; the pupae are also active. Most of these insects, except the Mantis, are injurious to vegetation by eat- ing the leaves. VII. Neuroptera (nerve-winged). The dragon-flies, lace- winged flies (Figure 15), May Kg. is. flies, Lepisma (Figure 3), and white ants, belong to this order. The wings, when present, are thin, membranous, and subdivided by very numerous rods or nervures into small spaces, which are often squarish. The mandibles and maxilla are chewing organs. The abdomen is generally long. The larvae are of many forms, often aquatic, generally carnivorous and predacious in habits, and usually undergo a complete metamorphosis ; the pupae are mostly inactive. Most insects of this order, excepting the Figure 14. Katydid ( Cyrtophyllum concavum Say), male, natural szie. Color bright green. From Packard's Guide. Figure 15. The Lace-wing Fly (Chrysopa oculata Say), natural size, with the eggs attached to the tips of slender pedicels. Body light green. This insect lays its eggs among plant-lice (Aphis), which the larvae, when hatched, destroy. From Packard's Guide. PARASITES OP ANIMALS. 11 white ants and Lepisma, are beneficial by destroying noxious insects. To those who desire more information upon the struc- ture, habits, and classification of insects generally, we would especially recommend Packard's Guide to the Study of In- sects, Salem, Mass., 1869, and Harris' Treatise on Insects Injurious to Vegetation (illustrated edition), Boston, 1862. PARASITES BELONGING TO THE DIPTERA. The Fleas. PULICI D^B. It is somewhat singular that parasites are almost always degraded species of the orders and families to which they belong. This is very evident in the case of parasitic insects, for they are mostly destitute of wings, and are imperfectly organized in other respects when contrasted with their self- supporting allies. The fleas furnish us with examples of degraded diptera, and the sheep-tick is even more degraded than the fleas. Of fleas there are several species that attack man and domestic animals ; but the species do not appear to be so strictly limited to particular animals as are the lice and some other parasites ; for the common dog-flea and cat-flea will attack man without hesitation, and in New England ap- pear to be far more troublesome to the human race than is the species commonly regarded as the real human flea (Pulex irritans), which so far as I have observed, is comparatively rare, though in some localities it may be sufficiently common, as it is in parts of Europe. In the genus Pulex, which includes the common species of fleas, the body is compressed and the integument is very firm, so that they are well adapted for gliding among hairs or feathers, and are not liable to be injured by any ordinary pressure. The wings are represented only by two pairs of short, stiff scales, which have little or no power of motion. The posterior legs are large and powerful, enabling them to leap with remarkable agility. The head is small ; the eyes 12 BOARD OP AGRICULTURE. are simple, in some species very minute ; the antennae are curi- ously constructed with three broad, flat, singularly lobed joints, and are, in nearly all species, closely folded away out of sight, in a socket or cavity behind the eyes ; though in the males of the mouse-flea and pigeon-flea they are exposed and carried erect. The mouth organs are peculiarly con- structed and well adapted for piercing the skin and sucking the blood. The maxillae (Figure 16, a), are a pair of broad, flat, thin, somewhat lance-shaped organs, bearing at base the long, four-jointed feelers or palpi (5). The mandibles (#) are slender, flattened, sharp, piercing organs, finely serrated along their sides, like a minute saw. The Figure IG. labium (tT) is a round, slender, piercing organ, forming the central lancet. The lower lip and labial palpi (f the two posterior pairs of feet bear suckers, and all are more or less covered with long slender hairs. Figure 45. Fig. 46. This insect may be destroyed by the same remedies used for lice and for the human itch. The best remedy is probably the solution of sulphuret of potassium, described on page 109. The Itch-insect {Sar copies scabieiL&tY.'). Figure 47. This is a very minute, whitish species, barely visible to the naked eye, unless on a dark surface. It has been, in former times, the subject of many lengthy discussions, in reference to its causing the itch. It is, however, at the present time fully ascertained to be the sole cause of the ordinary itch, though other species of similar parasites may cause different varieties of itch. The body is rounded and soft, with small round pustules on the middle of the back, and with radiating lines or ridges, the sides of the body and legs bearing long bristle-like hairs. The mandibles are needle-like. The female is largest and has the two pairs of hind legs but little developed, ending a bristle ; in the male they are well devel- oped and terminate in a slender sucker. These creatures, as seen under the microscope, have something of the unwieldy Figure 45. Psoroptes equi Gervais, female ; ventral side, much enlarged. Figure 46. Head of the same, more magnified. Both from Cuvier. PARASITES OF ANIMALS. 49 Figure 47. appearance of a tortoise, and are ordinarily sluggish, yet they are capable of leaping to a considerable distance. They bury themselves in the human skin, especially in the more delicate and less exposed parts, and excavate minute galleries for them- selves, in a manner something like that in which moles excavate galleries in the soil. These galleries are at first perpendicular, and then go off horizon- tally to some distance. The females lay their eggs in these galleries as they progress. These mining and boring operations cause much irritation of the nerves of the skin and induce an intolerable itch- ing, and the inflammation that they cause produces pustules, filled with a watery exudation. The insects them- selves are not found in the pustules but in their minute galleries, off to one side, the pustule generally marking the place where they en- tered. The itch is contagious, simply because the insects, especially in their young and more active state, pass from one person to another, or are transmitted by clothing. They are most active at night and, therefore, sleeping with an infested person is pretty sure to be attended by the transfer of the insects. The longer the parasites are neglected, the more numerous they become. .The increase is, however, quite slow at first, owing to the small number of eggs. There are various remedies for this disease, but the different preparation of sulphur are no doubt the best and safest. The solutions of sulpha ret of potassium, described on page 109, is probably the simplest and most efficacious preparation for this purpose. Its use should be accompanied by a thorough change of gar- ments and bedding, and it should be used by all the members of an infected family simultaneously. It should be appliedat Figure 47. Itch-insect (Sarcoptes scabiei Latreille), female, upper side, much enlarged. From Guerin. 7 09 BOARD OF AGRICULTURE. least three times, at intervals of three or four days, to destroy the young as fast as they hatch. Species of Sarcoptes, closely allied to the itch-insect, have been found on the domestic animals, causing diseases analo- gous to the itch in man. Such diseases, caused by quite a number of distinct parasites, are called " mange." They have been observed on the cat, dog, camel,* and hog. The genus Dermatodectes is closely allied to Sarcoples, and the species likewise live on animals, burrowing in the skin. D. bovis infests cattle, and D. ovis lives in the skin of sheep. The genus Dermaleichus infests birds in a similar manner. All these parasites should be treated like the itch-insect of man. The sulphuret of potassium solution, applied with a brush that has long bristles, like a white-wash brush, is probably the best and simplest remedy. The Face^mile (Demodex folliculorum Owen). Figure 48. This singular but minute parasite lives in the diseased and enlarged follicles in the skin of the human face, especially in those about the nose and chin. The follicles, when thus dis- eased, are enlarged and filled with a thickened sebaceous matter, the orifice being usually ob- ri s ure 48 - structed by a hardened, blackish substance. If these be pressed, and the matter which is forced out be carefully examined with a microscope, it will often be found to contain numerous specimens of this minute creature, in all stages of development. A drop of oil or ether applied to the sebaceous matter, to dissolve the fatty parts, will render them more readily visible. The young ones have but six short legs ; the adults have eight legs and a worm-like body, as represented in Figure 48. It has been thought that the " barber's itch" is caused by this parasite, but I do not know that this has been fully established. *S. dromedarii, of the camel, is sometimes communicated to man, causing a form of itch worse than the ordinary, owing to its great size and numerous spines. Figure 48. Face-mite (Demodex folliculorum Owen, or Simonea folliculorum of some authors), much enlarged. From Packard's Guide. PARASITES OF ANIMALS. 51 The same species, or one very closely allied to it, occurs in the skin of the dog and other domestic animals, producing some forms of the " mange." These parasites will probably be destroyed by the same remedies that are effective against the itch-insect. Library. SECOND LECTURE The Internal Parasites of Domestic Animals; THEIR EFFECTS AND REMEDIES: The parasites of man are so intimately connected with those of his domesticated animals, that it is impossible to discuss them separately. Indeed, many of the human parasites in- habit also the hog, cattle, sheep, and the dog, in certain stages of their development, and nearly all the most dangerous kinds are derived, either directly or indirectly, from those animals. While in return mankind furnish to them the eggs of several 52 BOARD OF AGRICULTURE. of their worst parasites. Thus some of these creatures are kept in existence solely by reason of the peculiar relations ex- isting between man and his brute dependents. This is partic- ularly the case in respect to the two most common tape-worms of man, derived respectively from the flesh of cattle and hogs, in which the young worms live. These two worms appear to be capable of coming to maturity only in the human in- testine. Most of these internal parasites belong to the great class of articulated animals known as Worms, constituting, however, several distinct orders, which are often collectively called Helminths. The orders of parasitic worms are much lower in rank than those that include the independent kinds, like the numerous species of free marine worms, or Annelids, many of which have beautiful gills and locomotive organs, a very complex circulation, red blood, and a well-organized head, eyes, mouth, and intestine ; to such worms the common earth- worms, or angler-worms, are also allied, although destitute of gills. But the parasitic worms never have red blood nor special organs for breathing, and rarely for locomotion ; most have no distinct organs of sense, and many have no head and no intestine. The reproductive system is, however, always very highly developed, and most of them are exceedingly prolific. This is essential to their existence, for it is often only by mere chance that any of the eggs or young reach the peculiar habitats in which alone they can grow to maturity. The int about one eightieth of an inch long and a hundred and thirtieth thick. If pork or other flesh containing these worms, either free or enclosed in cysts, be eaten by man, they become liberated in the stomach, and, en- tering the intestine at- tach themselves to its soft lining, and there, sur- rounded with abundant food, they grow very rap- idly and become mature, with fully developed sex- ual organs, in two days. Figure 76. A small piece of human muscle containing encysted young of Trichina spircdis Owen, enlarged forty-five diameters. From Hearth and Home, after Leuckart. PARASITES OF ANIMALS. 113 The females are larger and more numerous than the males, and become about one-eighth of an inch long when full grown. They pair as soon as mature, and the males soon die ; but the females begin to give birth to living young in five or six days from the time when they enter the stomach, and they live long enough to produce a brood of from five hun- dred to one thousand young worms each. As one ounce of pork sometimes contains a quarter of a million or more of the worms, it is not surprising that the millions of adult worms and their offspring, sometimes resulting from a single meal of raw pork, should, by their presence, produce great irritation and inflammation of the intestine and violent diarrhoea and vomit- ing, which are often the first symptoms in severe cases. But the young worms, almost as soon as born, begin to eat or force their way through the membranes of ' the intestine into the minute blood-vessels and other organs, thus vastly in- creasing the irritation. Entering the circulation they are carried by the blood to the heart, thence to the lungs, and then become diffused through the whole system. Accord- ing to other observers, the young worms force their way di- rectly through the intestine and all other intervening organs, until they finally reach a suitable habitation in the voluntary muscles. It is, however, difficult to understand how they can become so evenly and generally distributed through the whole muscular system as they often are, if this be their only mode of diffusing themselves. It is, therefore, not improbable that they migrate by both these methods, part entering the circu- lation and part going directly through the tissues, while in either case, if they find themselves in an unfavorable locality, they have the power of changing their position while still in the free state. According to Dr. Leuckart, they travel by the way of the intermuscular connective tissues, and are found most abundantly in the groups of muscles nearest the abdomi- nal cavity, especially in those that are smallest and have the most connective tissue. Effects. Large numbers often lodge in the heart, lungs, and various other organs, producing great irritation and various danger- 15 114 BOARD OP AGRICULTURE. ous symptoms, but the majority finally reach and remain in the voluntary muscles, where they live and thrive for some weeks, making for themselves passages, and even entering and destroying the fibres themselves. All these operations cause, of course, an immense amount of inflammation and irritation, if, as often happens, millions of these flesh-worms are at work at the same time in all parts of the system ; and it is no won- der that many violent symptoms and high fever result, or that there should be intense soreness and pain or paralysis of the muscles, and dropsical swellings. Death in severe cases may occur at any time from the fifth to the fiftieth day. The du- ration of the disease, like its severity, is in direct proportion to the number of living Trichinae swallowed, and varies from two weeks to three or four months. Even in many comparatively mild cases, the sutfering is intense and the recovery slow and tedious, while many secondary diseases, like pneumonia,etc.,are liable to ensue. When all the worms have become lodged in the muscles and enclosed in cysts, the direct symptoms cease, and, if the strength of the patient has been kept up, recovery is probable. Some persons, especially females, are much more severely affected than others, by the same number of the para- sites. Persons in robust health may be able to survive the attack of half a million or more of these flesh-worms and recover, but there is a limit to all human endurance, and the numbers often contained in the muscles of animals or persons who have been killed by them, are almost incredible. In a cat fed with trichinous flesh by Leuckart, they were so numerous that he estimated that one ounce of the flesh contained at least 325,000 worms. Microscopic preparations, not much larger than a pin's head, often contain from ten to forty worms, and one bit of muscle, weighing about one-fifth of a grain, from a child that died on the seventy-ninth day, contained fifty- eight. Allowing only one hundred worms to a grain of mus- cle, a man weighing 150 pounds might contain over forty millions of the parasites, and the length of the muscular fibres actively inflamed by such a number, if placed in a line, would amount to more than 120 miles. PARASITES OF ANIMALS. 115 In some very severe cases the numbers contained in human bodies have been estimated, by reliable authorities, as high as forty and sixty millions. The cysts containing Trichince were first observed in human muscles in 1822, but the worms from similar cysts were first named and described by Owen, in 1835, but were only regarded as anatomical curiosities of no practical importance, until 1860, when Zenker proved that they are capable of producing the severe and often fatal disease now well known under the name of Trichiniasis, but which had been previously (as it often is still) confounded with typhoid fever, inflammatory rheuma- tism or rheumatic fever, poisoning, and various other diseases. Symptoms and treatment of the disease. The disease caused by this parasite has three more or less distinct phases : First. While the mature worms and young remain in the intestine, and while passing through its walls. In this stage the symptoms are derangement and inflammation of the in- testine, often resulting in severe diarrhoea, nausea and vomit- ing, swelling and pain, and sometimes peritonitis, due to the perforations of the intestinal walls. These symptoms ensue in two or three days after swallowing the trichinous flesh, and may last a fortnight or more. Animals experimented upon often die in this stage. Purgatives and anthelmintics are used in this stage to expel the mature and pregnant females, but after three or four weeks have passed this will be useless. Castor- oil and calomel have been used with success for this purpose. Second. While the young worms are migrating and work- ing in the muscles, a variety of symptoms are developed, varying in different persons, and depending, also, upon the number of worms. This stage commences in ten to fourteen days, and generally lasts four or five weeks. The principal symptoms are lassitude and swelling of the muscles, with soreness, or intolerable pains, resembling rheumatic pains but not affecting the joints ; profuse sweating sometimes occurs ; the pulse is very rapid, but the heat of the body is usually 116 BOARD OF AGRICULTURE . low, often never exceeding 102 Fahr. ; the face frequently becomes suddenly and greatly swollen, and sometimes the whole body is affected in the same way. In certain cases, a peculiar congestion of the eyes has been observed. In general, many of the symptoms in this stage resemble those of typhoid fever. In very severe cases the patient is unable to use the mus- cles or move the limbs without the most intense agony, and filially is obliged to lie passively, flat upon the back, with the arms and legs somewhat bent, in the position that gives the least pain ; and later the limbs are rigidly stretched out, some- what apart, the body stiff, and the muscular system in a state of more or less complete paralysis. Children generally lie on the side, with the body bent and the legs drawn up. The jaws are sometimes closed as in lock-jaw. The breathing is difficult, shallow, and rapid. The lungs are often affected, and frequently, also, the heart ; and many secondary diseases are liable to ensue. The most that can be done in this stage of the disease by the physician relates to the relief of special symptoms and secondary diseases, and sustaining the strength of the system until nature may in time effect a cure. Most experimental animals die in this stage, and human patients, also, frequently perish even during the early part of this period. Third. In case the patient survives the two first stages, the inflammation gradually ceases, breathing becomes more natural, and recovery generally commences, but in very severe cases the muscles and other organs have been so much in- jured as not to perform their proper functions, and general de- bility often results, ending in a kind of consumption that finally proves fatal. In many cases of recovery, lameness lasts for several months. In many cases, however, the final recovery is complete and may be followed by robust health, although tens of thousands of living worms may be still enclosed in the capsules in the muscles. From this it is obvious that a hog may be fat and appear in every respect healthy, and yet his flesh may contain such im- mense numbers of the parasites as to be capable of killing a PARASITES OF ANIMALS. 117 hundred or more persons, should they eat it raw or but slightly cooked. Oases of Trichiniasis. Since 1860 thousands of cases have been observed and hun- dreds of deaths are known to have occurred, especially in Germany, where the custom of eating various forms of raw or imperfectly cooked pork is much more common than in this country. At Hettstadt, in 1863, the flesh of one pig in- fected one hundred and thirty-five persons, of whom twenty died. Several other similar " epidemics" have also occurred in the same country. In the United States, many sad cases have also been recorded, as the following in stances will show: At Marion, Iowa, May, 1866, Mr. Bemis and eight mem- bers of his family ate rare -done and raw ham, and were im- mediately taken sick. Up to June 3d, three had died, and others were considered critical. A post-mortem examination showed about two hundred thousand worms to a cubic inch of muscle in one of those who died. AtDubuque, Iowa, according to Dr. Asa Horr, two families were attacked. In one five persons died ; in the other, five or six. Through him we also learn of a case where the mother of a family ate of the interior, rare-done part of a ham and took the disease, while those who ate the outside escaped. At Springfield, Mass., February, 1867, Mr. Ransley Hall and family ate of raw ham, and all seven were attacked in various degrees, according to the amount eaten. A daughter, aged seventeen, died, and the father had a long and very dangerous illness. At Albany, N. Y., January, 1869, two boys ate of raw ham and were infected ; the rest of the family ate of the same ham, when cooked, and escaped. At Rome, Oneida County, N. Y., December, 1868, Mr. John Wilbrecht and family, nine persons in all, ate raw smoked and dried sausages. All were dangerously sick, and four adults, the father, son, and two daughters died before January 15th. Their sausages and salt pork were examined and found to be full of Trichina, as were also the muscles of those who died. 118 BOARD OF AGRICULTURE. In New York City, January, 1869, eight cases occurred in a boarding-house in Carlisle Street, from eating sausages. Two of the victims died in the New York Hospital, and others were dangerously sick. It is a significant fact that the physi- cians in two hospitals mistook these cases at first for typhoid fever, and only discovered the mistake after one death had occurred. In Bridgeport, Conn., January 30th, 1870, raw smoked ham was eaten by five persons. Of these Mrs. Koch died of acute Trichiiiiasis, February 15th ; Mrs. Winter died February 16th ; Mr. Winter died March 1st ; a daughter of Mrs. Koch, aged two and a half years, died March 7th. Mr. Strasburg was for a long time very dangerously ill, and was left in a very feeble condition. Another person who ate some of the same ham fried, escaped entirely. Mr. Winter thought himself not seriously ill when his wife died. Some portions of his pec- toral muscles, which I have had an opportunity to examine, were filled with Trichincs, not yet encysted. There were perhaps 100,000 to the cubic inch. Prevention. Experiments have fully shown that nothing less than the most thorough cooking, so prolonged as to destroy all redness of the juices even in the interior of the meat, is capable of destroying these parasites and rendering pork a safe article of food. Cases, some of them fatal, have occurred from eat- ing ordinary fried sausages, roast pork, and pork that had boiled two hours. But the majority of severe and fatal cases have happened from eating smoked ham, raw or partly cooked, and various kinds of smoked and dried sausages, which are often eaten raw, or but slightly cooked. Therefore, if people will eat pork at all, they should make it a fixed rule never to eat it unless thoroughly cooked, if they would avoid one of the most painful and dangerous dis- eases known. There appears to be no certain way of preventing the disease in hogs, for it is probable that in most cases they get it by eating rats or mice, which are often full of Trichince, but it is quite probable that they may often be infected by PARASITES OF ANIMALS. 119 eating slaughter-house offal. It is possible, also, to infect hogs and other animals by means of the mature female Trichince that have been discharged from the intestines of men or animals, before all the young worms contained in their uteri have been born. Therefore hogs may obtain this, as well as the Iarva3 of the tape-worm of man and many other parasites, by being kept in places where they have access to manure, as is too often the case. Cats, rats, mice, rabbits, Guinea-pigs, young dogs, and various other animals may be infected, but adult dogs, like old hogs, are not nearly so likely to become infected as the young. Although lambs, calves, and horses may be infected by forcing them to eat trichinous meat, it is probable that they seldom or never become infected naturally. Trichocephalus dispar Rudolphi. Figure 77. This is a small round-worm, living in the human intestine, and remarkable for its long, very slender, filiform neck, which Figure 77. * s about two-thirds of the entire length. The male grows to the length of one inch and a half, and the female to two inches. The sur- face of the body appears smooth to the naked eye, but when magnified, a longitudinal band of minute, wart-like papillae is seen on one side. The male has the posterior end of the body spirally curved, with a single spicule, which is emitted from the extremity of the body, and is enclosed in. a short, tubular sheath, that is cov- ered with minute recurved spinules. The female has the posterior end of the body nearly straight and bluntly pointed (Figure 77). The genital orifice is situated at the origin of the neck. The eggs are elliptical, with a small projection at each end, and are -&G to ?fa of an inch long. They are discharged from the human in- testine before the contained embryos are fully developed. If kept in water for six months or more they hatch, liberat- ing a minute embryo 3^ of an inch long, which tapers from behind toward the head. Figure 7 '7. Trichocephalus dispar,' a, female, natural size ; b, posterior end, en- larged. From Guerin. 120 BOARD OF AGRICULTURE. It is therefore probable that they are taken into the human system in impure water. In some regions it is very common. Davaine estimates that one-half of the inhabitants of Paris entertain this parasite. Its effects are not well made out, but it does not seem to cause, ordinarily, any marked in- convenience. It lives in the coecum and small intestine. TricJiocephalus affinis Rud. This species lives in the coecum of cattle, sheep, deer, and antelopes. It closely resembles the preceding, but the reck part is still longer and more slender. The posterior end of the male is curved in a close, conical spiral, and the spicule, like its sheath, is much longer, being equal to about a third of the length of the body. The genital orifice,of the female is situated at the summit of a prominent, hour-glass shaped papilla, which is obliquely truncated at the summit and covered with minute spinules, like those of the spicule-sheath in the male. The eggs are similar to those of the preceding species and, without doubt, develop in the same way. It is not known to cause any serious disease. Spiroptera strongylina Rud., from the Hog. Figure 78. The genus Spiroptera includes numerous species of small, whitish or reddish, slender, round worms, which taper some- what toward the anterior end, or toward both Figure 78. ends. The head is small, and either naked, or with small papillae. The male has the posterior end curved in a spiral, with membranous expan- sions, and with two unequal intromittent spicules. In the female the posterior end of the body is nearly straight and conical, and the ovary is either simple or double, with the genital orifice situated at one side of the body. The 8. strongylina has a smooth, tapering body, with a simple head and mouth. The male spicules are very long, relatively to the entire length of the body. The male grows to the length of half an inch or more. The female to more than three-fourths of an inch. It lives in the stomach of the hog, but ordinarily does not produce any serious disease. Figure 78. Spiroptera str any y Una ; a, male, natural size; b, spicnles and pos- terior end of the body, enlarged. From Guerin, PARASITES OF ANIMALS. 121 Spiroptera megastoma Rudolphi, of the Horse. This is a small species, which has a more cylindrical body, tapering a little toward each end. The head is separated by a slight constriction and bears four lobes. The mouth is large. The male becomes rather more than a quarter of an inch long, and the female nearly half an inch. It lives in the stomach and oesophagus of the horse and produces tubercles, or hard tumors, of considerable size, most frequent- ly situated near the pylorus. These contain many cavities, connected together and filled with purulent matter, in which there are numerous specimens of the parasite. The tumors are sometimes one and a half inches in diameter, and there are at times several in the same stomach. Spiroptera sanguinolenta Rudolphi, of the Dog. This is a larger, reddish species, which produces similar tumors in the oesophagus and stomach of the dog. This species usually grows to the length of one and a half to three inches, but it has been found ten inches long, living in the cavities of the ventricles of the heart of dogs at Shanghai, China, where it appears to be very common. Its complete history is unknown, and therefore little can be said about the special means of prevention, or cure. It often produces death. Pin-worm of the Horse (Oxyuris curvula Rudolphi). Figure 79. This is a small, whitish worm, quite commonly found in the coecum and colon of the horse and ass. The female is about one inch and a half to two inches long, when mature. The male is far more rare and but one-third to two-thirds of an inch long. The body is fusiform, tapering to a slender tail, thicker in front, with the anterior end more or less pointed. The mouth is situated at the end, and usually has the form of a small, round pore, but is provided with three or four small retractile papillae, which can be protruded. The buccal cavity contains a peculiar apparatus of folds and tooth- like processes ; the oesophagus is long and muscular, round externally, but with a three-cornered cavity ; it is separated from the round, gizzard-like stomach by a constriction, and 16 122 BOARD OP AGRICULTURE. then a second constriction separates the stomach or gizzard from another somewhat enlarged cavity, which tapers grad ually into the slender intestine. The anal orifice is near the posterior end of the body, and in the male also gives exit to the intromittent organ, which is a single, sharp, grooved ticuluna^ with a very small accessory one. The female *^ orifice is situated near the anterior third of the body. This, like the other species of Oxyuris^ produces eggs having firm shells. These probably hatch in water, and the embryos may thus be swallowed in drinking. The intestines of these para- "sites are generally filled with vegetable matters derived from the food of the animals in which they live, and the structure of the digestive organ seems to be adapted to vegetable food. For this reason it is probable that they ordinarily cause little or no inconvenience to the horses that they inhabit. The Pin-worm of Man (Oxyuris vermicularis Bremser). This is a much smaller species than the preceding, but is similar inform. It is very common, often in great numbers, in children, and occurs also in adults, especially in aged and debilitated persons, and inhabits chiefly the lower part of the rectum and the vicinity of the anus. The male is about one-eighth of an inch long, with the tail curved in a spiral form, terminating in a very short point. The female is about four-tenths of an inch long and one- fiftieth in diameter, with the posterior part of the body taper- ing to a very slender tail. The digestive system and structure of the mouth is similar to that of the preceding species. But the head sometimes shows inflated lateral lobes. Reproduction. This species is very prolific ; each female produces thou- Eigure 79. Oxyuris curvula, female, twice natural size. From Guerin. PARASITES OF ANIMALS. 123 sands of eggs, in which the embryos are considerably de- veloped before they are laid. The embryos enclosed within the eggs are shaped somewhat like tad-poles, the slender tail being bent up against the lower side of the body, which faces the flattened side of the egg. The body is broad and well fills the egg. The full history of the development of the eggs is not yet known. It is probable, however, that a portion of the eggs imbedded in the mucus membrane of the intestine hatch in that situation, remaining thus in the same person. But it is also probable that the eggs that are discharged will hatch in water, and that persons become infested by swallow- ing the embryos with their food and drink. Symptoms. The most marked symptom of these parasites is an intoler- able itching in and about the anal orifice, which is generally worst in the evening or during the night, when the worms are migrating or changing their localities. This is usually accom- panied by sensations of heat and inflammation. Not unfre- quently, by irritation of the adjacent nerves, they cause similar sensations in the genital and urinary organs, which sometimes become very distressing. They sometimes even migrate into the genital passages of female children, causing great irritation and very serious symptoms. By the irritation of the sexual organs, in both sexes, various unfortunate sec- ondary diseases and bad habits not unfrequently result, especially if they occur at the period of early puberty. Other symptoms caused by the irritation of the nervous system, are restlessness, general nervousness, involuntary twitchings, itching of the nose, chorea, convulsions, and sometimes epileptiform seizures. Remedies. The various medicines ordinarily used as anthelmintics, or vermifuges, will often bring away large numbers of these worms. Of these the etherial extract of male fern is probably the best, but santonine and panna have been used with good results. Ordinarily they can be treated more easily and effectively by means of injections of cold, or nearly cold, 124 BOARD OP AGRICULTURE. water, to which may be added a small amount of salt, oil of anise-seed, or assafoetida. Sometimes decoctions of quassia, worm-wood, or southern-wood {Artemisia abrotanum) are used for this purpose, with good results. To these a portion of olive-oil may be added. But any remedy that may be em- ployed must be repeated as often as once every three or four days for at least three weeks, in order to destroy the young ones as fast as they develop. An application of mercurial ointment to the parts about the anus is recommended to pre- vent the migrations of the parasites and the uncomfortable itching sensations that they thus produce. The common Hound-worm of Man (Ascaris lumbricoides Linn.). This species is well known as a parasite of the human in- testine, especially in children, though often found in persons of all ages. The round-worm of cattle is generally regarded as the same species. These worms are round and smooth, tapering to both ends, with a tough, elastic skin. The mouth is situated at the more pointed end, and is provided with three prominent papillae, or fleshy lobes. The male grows to the length of six inches, and has the posterior end curved and provided with two slender spicules. The female is much larger, sometimes be- coming twelve or fourteen inches long and one-fourth of an inch in diameter ; the female genital orifice is in advance of the middle of the body. Development. The females produce great numbers of minute eggs, which are provided with thick, rough .shells. The eggs are dis- charged and pass from the human intestine before the development of the embryos commences. If kept in water the embryos go on developing slowly and gradually, the whole process requiring from six months to nearly a year. The fully developed embryos are round and slender, about T o of an inch long, with an obtuse head and an acute tail. They have not been ob- served to quit the eggs of their own accord, but may live for at least a year within the egg-shell, after they attain their full PARASITES OP ANIMALS^ 125 size. It is probable that such eggs, containing embryos, when swallowed in the water that we drink, will be hatched in our stomachs by the action of the gastric juice, and that the young worms thus reach their destined abode. It is possible, however, that under the proper circumstances the eggs will hatch in the water, and that the free swimming em- bryos may be swallpwed in the same way. This part of their history still remains uncertain. Symptoms. The presence of one or two of these parasites in the human intestine does not ordinarily cause any marked effects or noticeable symptoms. But when they occur in persons of delicate health, and when in great numbers, as sometimes happens, they may cause great disturbance of the natural functions of the digestive system, and induce various serious consequences. Cases have occurred in which from 100 to 500 of these worms have passed from one child. They live chiefly in the small intestine, but sometimes enter the stomach and may even be expelled by vomiting. In some instances they have been known to perforate the walls of the intestine and enter the abdominal cavity, and thus even to get into the other organs, including the lungs, pleura, gall-bladder, etc. In such cases death often results. Their presence in the stomach and intestine causes colic and shooting pains, often accompanied by nausea, vomiting, dyspepsia, itching of the nose, and diarrhoea. Owing to the irritation of the nervous system they may cause restlessness, convulsive twitchings, especially during sleep, and various mental disturbances. In some cases, serious convulsions, epilepsy, and insanity have been caused by them, and have been cured at once by expulsion of the worms. Remedies. The most reliable remedy appears to be santonine, but this is a powerful preparation, and must be used with caution. For children the dose is one to three grains, in the form of powder, which does best if taken in castor- oil or. honey, though it may be sprinkled over a piece of bread and butter. 126 BOARD OF AGRICULTURE. For an adult the dose is four or five grains, twice a day, on every second day, for a week, the quantity to be diminished if the medicine causes ill effects, such as spasms, tenesmus, etc. It often causes temporary perversion of vision, things appear- ing of unnatural colors, etc., but this effect soon passes away. The root of male fern (see page 191), given in powder, in connection with purgative medicines, is also recommended. As means of prevention, the use of impure water should be avoided. And if water from streams and ponds must be used for drinking, as in most large cities, it should be thoroughly filtered through powdered charcoal. The Round-worm of the Horse (Ascaris megalocephala Cloquet) . This species inhabits the intestine of the horse, ass, and mule, and is quite common. It closely resembles the preced- ing species in form and general appearance, but grows to a larger size, the male becoming ten inches long, and the female twelve inches or more. The mouth is surrounded by three large, rounded, very prominent lobes or papilla. In the male the tail is provided with wing-like folds along the sides ; in the female it is conical, terminating in a point, the female genital opening being situated in the anterior fourth of the body. This species likewise produces vast numbers of eggs, which develop embryos externally to the body, in water. Dr. Cob- bold states that he has reared free, active embryos from these eggs by keeping them five months in water. The horses, most probably, swallow these embryos in the water that they drink. These parasites, when numerous, will no doubt produce effects analogous to those caused in the human body by the preceding species, and the remedies will be similar. The Round-worm of the Cat (Ascaris mystaxRndolphi). Although very common in the cat, this parasite is of inter- est chiefly on account of its occasional occurrence in the human intestine. It may be easily distinguished by the presence of peculiar PARASITES OF ANIMALS. 127 wing-like membranous expansions on each side of the head or anterior end of the body. The male grows to the length of two and one-half inches ; the female sometimes becomes four inches long and one-twelfth in diameter. This worm probably propagates its kind in a manner similar to that of the two preceding species, and no doubt gains ad- mittance to the human intestine, as well as to that of the cat, by the medium of impure water and unclean vegetable food. Its effects and remedies are the same as those of the com- mon round-worm. The Round-worm of the Hog (Ascaris suilla Dujardin). This very closely resembles the Ascarislumbricoides of man, and probably has nearly the same habits. It differs chiefly in the structure of the reproductive organs. The male spicules are not so sharp, and the tubes of the uterus are much longer. The eggs are smaller. It appears to be less common than the Echinorhynchus gigas in the intestine of hogs, and prob- ably produces less injurious effects. STEONGYLUS. The genus Strongylus includes slender, filiform worms, mostly of small size, and often reddish in color. Several of them live in the windpipe and bronchial tubes of various animals, including sheep, deer, cattle, pigs, etc., and when numerous may occasion the death of the animals that they infest, by suffocation. The body generally tapers toward the head, and sometimes in both directions. The mouth is small, situated at the end of the small head, which is either simple or with lateral ex- pansions. It is sometimes surrounded by small papilla, but is often simple, and either round or triangular, but not enclosed by a hard or chitinous organ, as in Sclerostoma, etc. The oasophagus is enlarged, club-shaped, and muscular. The male has the posterior end of the body provided with an expanded, often lobed pouch, or bursa, for adhering to the female during copulation. The spicule is slender and filiform, enclosed in a sheath. In the female the posterior end is 128 BOARD OF AGRICULTURE. conical or pointed, and the genital orifice is placed in advance of the middle of the body, or more rarely toward the pos- terior end. The Strongylus of Sheep {Strongylus filaria Rud.). Figure 80. The present species is whitish, very long and slender. Th head is obtuse and without appendages, the mouth surrounded by three small papillae. The caudal pouch of Figure so. the male is entire, with ten rays (Figure 80). The male is about two and a half inches long, and the female three and a half, though gener- ally not more than two or three inches long, the interior of the body of the female is mostly oc- cupied by two long convoluted uterine tubes, containing eggs in which the embryos are in all stages of development. These open at an orifice situated at about one-third of the length of the body from the head. Habits. This species lives in the lungs, air-passages, and bronchial tubes of sheep and other rumi- nants. They often occur, singly or several to- gether, in cavities in the substance of the lungs, producing great inflammation and destruction of the tissue, which often results in the death of great numbers of lambs, and greatly injures the health of old sheep, even if it does not actually kill them. In this way many thousands of lambs are annually lost in certain districts in England. In this country we have far less in- formation concerning the extent of its ravages, but have no reason to suppose that it is less common than in Europe, in localities that are favorable for its development. Sheep infested by this parasite continually cough up the eggs and embryos of the worms, and either dis- charge them directly from the nose or mouth, or swallow them Figure 80. Strongylus filar ia, male, enlarged. From Thudichura. PARASITES OF ANIMALS. 129 and thus pass them with the faeces. In either case they will often adhere to grass *nd other herbage, and may thus be swallowed by other sheep or lambs, fed in the same pastures, and pass directly into the windpipe, or else do so when the cud is raised for mastication. Therefore lambs should never be put into fields or pastures where diseased animals have been kept, but such infected lands should be tilled, or at least left at rest for several months. As soon as an animal gives any indication of the presence of the parasites by the peculiar cough, it should be separated from the rest of the flock for treatment ; or else immediately killed and the para- sites should be effectively destroyed, and not thrown on the ground as harmless, for all these worms are remarkably tenacious of life, and often may even be dried up completely for months, and then revive when moistened. Remedies. When these parasites are once lodged in numbers in the substance of the lungs, there is probably no reliable remedy whatever. When merely in the windpipe and bronchial tubes, expectorant medicines that will produce a copious secretion of mucus may be useful. It might be possible to remove them by a surgical operation, opening the windpipe from 'the exterior, but this would require surgical skill and would not pay, perhaps, except as a last resort for valuable animals. The Strongylus of Cattle and Horses (Strongylus micrurus Mehlis). This species closely resembles the preceding. The male grows to the length of about one inch and a half ; and the female to three inches or a little more. The body is very slender with a simple, blunt head. The bursa of the male has five rays. The female genital orifice is near the middle of the body. It is said to be viviparous. The habits of this species are nearly the same as those of the last, except that this inhabits the air-passages of cattle, horses, asses, and mules, instead of sheep. It is much more liable, like the former, to infest young animals than adults. Calves less than a year old are particularly liable to be in- 17 130 BOARD OF AGRICULTURE. vaded, and those that are once attacked seldom or never re- cover. The same remarks, concerning the means of preven- tion, made under the preceding species, will apply equally to this. If neglected, these parasites increase with great rapidity, and thus the disease that they cause appears like an epidemic, in certain localities destroying hundreds or thou- sands of animals, while adjacent farms may be entirely free from it. The Strongylus of the Hog (Strongylus parodoxus Mehlis). This is a slender, whitish or brownish worm, with a small, simple head. The mouth has three small papillae. The oesophagus is long and muscular. The anus is situated some- what in advance of the posterior end of the body at the sum- mit of a small papilla. The male becomes half an inch or more in length, and has the caudal bursa bilobed, each lobe with five rays, the lateral ones divided. The female grows to the length of about an inch and a half, but is usually about an inch long ; the tail is terminated by a point, turned to one side ; the genital opening is near the posterior end and a little prominent. This species is viAdparous. It inhabits the wind- pipe, bronchial tubes, and lungs of swine. Its history and the effects it produces are nearly the same as those of the Strongylus filar ia. The Strongylus of the Intestine of the Hog (Strongylus dentatus Rud.). This is a slender filiform species, about half an inch long, which lives in the small intestine, coecum, and colon of hogs. The head is obtuse and surrounded by six acute papillae. The oesophagus is short and thick, muscular. In the male the tail is truncated and provided with an oblique bursa, formed of a single piece, strengthened by three subdivided rays ; there are two slender spicules. The tail of the female is elongated and slender, ending in a fine point ; the genital opening is near the posterior end. The effects of this species and its history are little known. PARASITES OF ANIMALS. 131 The Strongylus of the Intestine of Sheep ( Strongylus contortus Rud.). This is a filiform species, tapering to both ends, but more slender toward the head, which is provided with two semi- elliptical, wing-like appendages ; the mouth with three small papillse. The male is about three-fourths of an inch long, with a bilobed bursa, each lobe with about eight rays : the sheath of the male spicule is very long. The female sometimes becomes four inches long. It is not uncommon in the small intestine of sheep, but its history is very imperfectly known. When abundant it may, without doubt, cause serious trouble. Strongylus filicollis Rudolphi . This species also inhabits the small intestine of sheep. The body is very slender and whitish or reddish. The head has two, very small, lateral, wing-like appendages. The male bursa is bilobed, each lobe with six rays. It is from a third to four-fifths of an inch long. Strongylus radiatus Rudolphi. This worm lives in the small intestine and colon of cattle and several other ruminants. The head is simple ; the mouth naked. The male is about half an inch long, with a bilobed caudal bursa, the lobes many rayed. The female is about three-quarters of an inch long ; the genital opening is near the tail. Its complete history is unknown. The Kidney-worm (Euslrongylus gig as Diesing). Figure 81. This is the largest of all the Nematode worms, the females sometimes becoming three feet long and half an inch in diameter, though usually much less. The body is smooth, cylindrical, tapering somewhat to each end, and more or less deeply tinged with red. The head is simple, obtuse. The mouth is terminal and surrounded by six rounded, chitinous papillse. The male becomes ten to twelve inches long and one-fourth of an inch in diameter ; the caudal bursa is cup- shaped, circular and entire, without rays ; the male spicule or 132 BOARD OP AGRICULTURE. penis is very slender. The female has a nearly straight, obtuse tail ; the anus is triangular, near the end ; the genital orifice is anterior, near the mouth ; the ovaries and oviducts are simple, but long and convoluted. The intestine is large and blackish, with thin walls, and quite simple, running directly from one end of the body to the other, and is attached to the sides of the body, along its whole length, by fibres. Habits. This formidable parasite lives in the kidneys of man and various animals. It has been found in the dog, horse, cattle, hog, wolf, \veasles, mink, otter, seal, glutton, raccoon, and coati. In this country it has been found quite frequently in the kid- Figure si. neys of the mink. It has been found very rarely in the blad- der, in the abdominal cavity, and, it is said, in the heart. In man it is very rare. When lodged in the kidney it gradually, but completely, destroys the substance of the organ, which becomes filled with purulent and bloody matter, upon which the worm feeds, while the walls often become hardened with calcareous deposits. The effects and symptoms are the same as in other acute diseases or abscesses in one of the kidneys. The only positive evidence of the presence of the worm would be the discovery of the eggs in the urine. It is probable that no remedy can be applied when the parasite is once lodged in the kidney. The history of this worm is not fully known. According to Leuckart, a slender worm found coiled up in cysts in the muscles and peritoneum of fishes is the young or larva of some species of Eustrongylus. The larval form referred to Figure 81. Eustrongylus gigas, male, less than natural size; a, spiculum and bursa ; 6, anus of female, enlarged. From Guerin. PARASITES OF ANIMALS. 133 is the Filaria cystica Rudolplii, originally found in a Brazilian fish (^SymbrancTius lalicaudus). It is, therefore, probable that the eggs or young embryos of E. gigas are swallowed by fishes, and in their bodies develop into the larval form and be- come encysted, and if then swallowed by some mammal, migrate into its kidneys to become sexually mature. The frequency of these parasites in those animals that feed chiefly on fish, such as the otter, mink, and seal, renders this view very probable. The Crape-worm of Chickens, etc., (Syngamus trachealis Siebold). Figure 82. This parasite lives in the windpipe and bronchial tubes of chickens, turkeys, pheasants, partridges, crows, wood-peckers, and many other birds. In young chickens and turkeys it Figure 82. often proves very destructive, by filling up the air passages, and thus quickly killing whole flocks. In some parts of this country at least three-quarters of all the young chickens and turkeys are some- times destroyed by this parasite. The \l \\ 1! / S worms are reddish in color and have a I \KwJl H smo th skin, but spiral depressions run I rm around the body, giving it a twisted I iH 1 appearance. The reproductive organs show through the skin, as slender, whitish, convoluted tubes. The males and females are almost invariably found united firmly to- gether, as shown in the figures, the integument of the male soon becoming organically united to that of the female, so that the copulation is permanent or for life. The females are very much larger than the males, becoming about three- quarters of an inch in length, and one : sixteenth of an inch in diameter. The anterior end, in both sexes, suddenly ex- pands into a trumpet-shaped, concave disk, in the middle of which the mouth is situated, surrounded by six small chitinous lobes ; the posterior portion of the body of the female is more Figure 82. Syngamus trachealis Siebold ; a, male and female united, natural size ; 6, anterior part of female, enlarged ; c, male, enlarged. From Cobbold. 134 BOARD OP AGRICULTURE. or less bent and folded, and suddenly narrows at the end, terminating in a small point. The genital orifice is near the anterior fourth of the body, where the caudal bursa of the male is attached and conceals it. The male is only one-eighth or one-seventh of an inch long and very slender ; the caudal bursa is simple, sucker-like, with an entire margin, strength- ened by about ten rays ; the penis consists of two very small, cylindrical spicules, about 225 of an inch long. The eggs are oval, about 250 of an inch long. The embryos develop while the eggs are still in the oviducts and uterine tubes, and the eggs or young probably escape by a rupture of the integument of the body of the female. The history of the young worms, after they are expelled from the windpipes of the birds, is not yet known, however. Possibly they may enter the bodies of insects to pass their larval state, but it is more probable that they bury themselves in the surface of the soil or other moist places, and are thus picked up directly by the birds and gain admittance to the windpipe by their own active motions. Symptoms. The disease commonly known as " the gapes " is caused solely by the presence of numbers of these worms in the wind- pipe, which thus becomes so filled up as to render respiration difficult, and if in considerable numbers, by their growth the obstruction becomes complete, and death results from suffoca- tion. Young chickens, thus attacked, seldom recover without special treatment for the removal of the worms. Chickens only three or four days old often show symptoms of the dis- ease by opening wide their mouth and gasping for breath, and attempting to swallow. They also frequently sneeze. As the disease grows worse these symptoms become more marked; they continually gasp and struggle for breath, grow weak and dispirited, and finally 'droop and die. In fatal cases, one or two dozen of these worms are often found in the windpipe, completely filling it up. Remedies. The worms may be removed by a feather from which the web has been stripped, except a small portion near the tip. PARASITES OP ANIMALS. 135 This may be moistened with oil, salt-water, or a weak solution of carbolic acid, and' introduced into the windpipe, when if it be twisted round once or twice and removed, it will usually bring away several of the worms. The operation should be repeated at intervals until all the worms are destroyed. All worms removed in this or any other way should be carefully destroyed, preferably by fire, for the embryos are extremely tenacious of life, and if left upon the ground are likely to spread the disease. For the same reason, those birds that are infected should be separated from the healthy ones, and poultry should never be allowed to run in the same yards or grounds, or be kept in the same houses where infected ones have previ- ously been kept, unless the premises- have first been thor- oughly sprinkled with a strong solution of carbolic acid or petroleum-water, to destroy those old worms or the eggs and embryos that may have been discharged from the sick ones. The vessels from which they feed should be frequently and thoroughly cleansed, and they should be supplied with pure water, frequently renewed. In extreme cases, the worms may be safely removed by a surgical operation ; but this requires some skill. This is done by first carefully securing the bird, or still better by adminis- tering a few drops of chloroform, placed upon cotton and held to the nostrils. The skin of the neck is then to be di- vided with a very sharp knife, and the windpipe opened by a longitudinal slit about a quarter of an inch long. The worms may then be removed by a pair of small forceps or other suit- able instrument. , The incision in the skin may be closed by one or two stitches, and the wound will generally heal in a few days. By this operation an almost instantaneous cure may be effected, even when the disease has progressed nearly to the point of suffocation ; but in unskilful hands it is not likely to be so successful as the remedies already described. The Sclerostoma of the Horse (Sclerostoma equinum Dujardin, or S. armatum Davaine). Figure 83. This is a small, slender, cylindrical worm, reddish or brown- ish in color, which lives in the intestines, and in peculiar enlargements of the arteries of horses, asses, and mules. The 136 BOARD OP AGRICULTURE. head is round, nearly globular, supported by a cliitinous bulb or capsule, truncated at the end, where the large, round mouth is situated. The mouth is surrounded by one to sev- eral circles of fine denticles, or converging hooks. The oesc- phagus is muscular and thick, club-shaped, separated from the intestine by a strong constriction. The male is an inch or an inch and a quarter long, with a large, membranous, caudal bursa, divided into two lateral lobes, which are strengthened by numerous rays ; there arc two long and slender spicules. The female grows to the length of one and a half to two inches, with a long, tapering, caudal portion, the anus not terminal ; the ovaries long and con- voluted around the intestines, and showing through the integu- ments ; the uterine tubes are double and contain great num- bers of eggs, in which embryos are developed. Habits. This parasite is very common in the horse, generally living attached by the hooks of its head to the lining membrane of the intestine, particularly in the coecum and colon, but some- times in the small intestine and duodenum, and even in the pancreas. At the points where it adheres it Figure 83. causes small, dark-colored, raised spots. They sometimes occur in vast numbers in the large intestine, completely covering the surface ; the number sometimes amounting, it is said, to a million or more. Ordinarily, however, these parasites, when lodged in the intestines, do not appear to produce any marked dis- ease or notable symptoms, although when in great numbers, there can be no doubt but that they must cause some inflammation and pain. More serious results, sometimes prov- ing fatal, happen when the worms enter the blood-vessels. They produce large aneurisms or dilations of the arteries, chiefly in the anterior mesenteric artery, but Figure 83. Sclerostoma equinum, female, natural size ; and anterior portion en- larged ; a, mouth ; b, circle of hooks ; c, oesophagus ; d, intestine ; e, reproductive organs. From Cuvier. PARASITES OP ANIMALS. 137 also in the arteries of the colon, coecum, small intestine, and liver, as well as in the posterior mesenteric and renal arteries, and others adjacent to the intestine. These tumors are gen- erally fusiform, and as large as a man's finger ; but they are sometimes globular, and may become as large as a man's head. The middle membrane of the artery in these dilations becomes enormously thickened, sometimes being twelve times as thick as in the healthy artery. In old tumors various hard or calcareous deposits often take place in the thickened walls or in the inner membrane ; and in such cases, the walls being weakened, are liable to be ruptured by some unusual exertion of the animal, when death results almost instantly. In the interior of the aneurism there is generally a deposit of fibrin, firmly adherent to the inner surface. In this and in the dif- ferent layers of the walls the worms are found, sometimes only a few, but frequently large numbers. This disease is very prevalent among old horses. In France, as many as ninety-six out of one hundred have been found affected with the disease. I am not aware that any remedies have ever proved useful. Generally it would be impossible to detect the disease during life, unless the tumors became very large. Sclerostoma pinguicola Yerrill. On two occasions I have received specimens of a rather large parasitic worm, which lives in the fat of hogs. In the first case, five specimens were obtained, at New Haven, by Dr. M. C. White, from the fatty portion of a spare-rib ; in the second instance, at Middletown, Conn., Dr. N. Cressy found large numbers of the worms in the fat about the kidneys of a young Suffolk pig, brought from New Jersey. Un- fortunately, none of these specimens are in so good a state .of preservation as to enable me to determine with certainty all the points of their structure. Those which I owe to the kindness of Dr. White, had been mounted in glycerine as microscopic objects and pressed out flat, before they came into my possession, and the tissues were thus injured and the organs deranged. Those from Dr. Cressy, were both pressed flat and dried. Yet by careful masceration, and with much labor, I believe that most of the important char- 18 138 BOARD OF AGRICULTURE. acters have been made out. The body is rather robust, es- pecially in the female, and tapers to both ends ; the color is yellowish white, and the integument is seen to be finely striated transversely, when considerably magnified. The head is smaller than the body, truncated at Figure 83 a. the end ; the mouth is terminal, roundish, or somewhat angular, surrounded by the thick- ened rim of the chitinous capsule, or pharynx. This chitinous ring rises at intervals into four to six denticles, or very small teeth, which correspond to thickened longitudinal, chitin- ous bands, that strengthen the pharynx, and give a slightly angular form to the mouth. The pharynx itself is small, short, and rather squarish, when seen in profile, and has three or four small, conical teeth at the bottom. The oesophagus is thick, club-shaped, and very muscular. The male is 1.12 of an inch long, and about .05 of an inch in diameter ; the tail ends in a small blunt lobe, united with two small, entire, membranous expansions, one on each side, forming a small bursa, which is strengthened by several short rays, the exact number of which could not be determined in my specimens ; there are two long, slender spicules. The females are 1.25 to two inches in length, and, as flattened between glass, they are .10 to .13 of an inch in breadth. The posterior end suddenly and obliquely narrows to a small conical point, which is turned to one side. The anal opening is close to the end, and the genital orifice appears to be adjacent to it. The oviducts are long, voluminous, much convoluted, and unite in a large and capacious uterus, which fills most of the cavity of the body near the posterior end. The uterus and oviducts are both filled, in the larger specimens, with im- mense numbers of small oval eggs. It is probable that this parasite is by no means uncommon. Pentastoma tcenioides Rudolphi. Figure 84. This parasite is not a true worm, but is now generally re- Figure 83 a. Sclerostoma pinguicola ; a, male, natural size ; b, posterior end, en- larged; c, female, natural si/e; d, head, enlarged. Original. PARASITES OF ANIMALS. 139 garded as belonging to the Acarians, with the true mites. In the adult state it inhabits the nostrils and frontal sinuses of dogs and wolves, and more rarely, of horses and sheep. The larvse, formerly described under the name of Pentastoma den- ticulatum, lives in, cysts on the outside, or in the outer por- tion, of the liver of sheep, deer, antelopes, . peccary, porcu- pine, Guinea-pig, rabbit, hare, rat, and cat ; and some- times invades the human body in the same way. It has also been found free in the visceral cavity of the body. In the mature state (Figure 84) the body is long, lance- shaped, tapering behind, flattened below, and divided into about ninety segments by transverse lines. The segments next to the head bear two pairs of small, but strong and Figure 84. sharp, retractile claws, which represent the true legs of ordinary mites. The mouth is broad- oval, and provided with a hard chitinous lip. The segments behind the head are perforated by small openings, regarded by many as spiracles, or breathing pores. The adult is smooth, but the larvae are covered with many rows of small, sharp spines. The male is only .07 to .08 of an inch in length, but the female becomes three or four inches long, and half an inch wide. The female genital opening is in the tail, that of the male, in the middle of the front part of the abdomen. They are oviparous, and the young undergo a com- plete and remarkable metamorphosis. The adults live in the nasal cavities of dogs, and produce an irritation of the delicate membranes, which causes a flow of mucus, often accompanied by sneez- ing. The eggs discharged with the mucus .may ad- here to vegetables or fruit, or get into drinking- water, and in these ways gain admittance to the stomach of man, or other animals. In the stomach they hatch into mi- nute embryos, furnished with a boring apparatus and two pairs of double claws. They bore their way through the intestines and lodge in the liver or other parts, and soon become dor- 140 BOARD OF AGRICULTURE. mant and enclosed in cysts, in which they pass a sort of pupa state. During this period of their life, the skin is cast several times, and the appearance changes at each moult, un- til they attain the next period of their life, when they again become active ; this is the state described as Petastoma denticlatum. These larvae are long-oval, broadest anterior- ly, and covered with numerous rows of transverse tooth-like spinules. They have two pairs of sharp, curved claws, which are situated near the mouth and placed obliquely, diverging from the median line of the body, and directed downward. Each claw has a sort of hood or capsule, into which it can be retracted. If dogs feed on the liver or other viscera of animals containing these larvae, they come in contact with, and man- age to enter the nose, working their way up by means of the motions of the body, aided by their spines and claws. In this situation they gradually become mature. In the human body the larval form is quite frequent, es- pecially in some parts of Europe ; but there is little known concerning the effects that it produces. When in small num- bers, it probably causes very little disturbance, but if in large numbers, in the liver and lungs, it would no doubt produce serious disease, as does another species (P. constrictuin) , which is very common in Egypt, living in the same way en- cysted in the liver and lungs. The latter, when in consider- able numbers, frequently proves fatal. As a means of prevention, dogs that show symptoms of the parasites in the nose, should be treated to a solution of carbolic acid, thrown up the nostrils by a small syringe. Feeding dogs with the offal of slaughter houses, or with un- cooked livers, etc., should be avoided, both on account of this and the other dangerous parasites that they get in this way, (see Tcenia echinococcm, p. 202, T. marginata, p. 192, T. ccenurus, p. 196, and Trichina spiralis, p. 222). Too much familiarity, especially of children, with dogs is always liable to result in the transfer of these and other parasites to the human body. ERRATA. In making up the author's copies, and repaging, several errors have been intro- duced, which the reader should correct : Page 3 third line of foot notes, for Corydalus cornutas, read Corydalis cornutus. " 6, line 19, for orceps, read forceps. " 8, " 31, for pair, read pairs. "12, " 13, for labium, read labrum. " 13, figure 18 is inverted. " 4*7, " 17.. for page 89, read page 16. " 48, " 10, for page 109, read page 38. " 49, " 31, for page 109, read page 38. '' 60, " 10, for nemarum, read venarum. " 61, " 23, for page 101, read page 30. " 85, " 5, for page 191, read page 80. " 100, " 34. It should be stated that Dr. Cobbold, in 1860, fed dogs with a small cysticercus, from the liver of rabbits, but distinct from " G. pisiformis" and obtained specimens of Tcenia cucwnerina, which he thought were developed from them. " 110, " 30, for " such hogs are," read such a hog is. "126, i > ^ > ! > > >r ^P> ?> idB^ - M - '- @5^&> > ^^ 'Jigtei^ss! ^ r^> ^ ^> UBRARY