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 [From the Kcport S^j^X^ftW^ of Agriculture for 1870.] 
 
 The External Parasites of Domestic Animals, 
 
 THEIR EFFECTS AND REMEDIES.* 
 
 BY A. E. YERBILL. 
 
 The external parasites of our domestic animals nearly all 
 belong to the great class of animals which we call Insects, but 
 the internal parasites are, with few exceptions, representatives 
 of the class of Worms. The division of the subjects of these 
 lectures is, therefore, both convenient and natural. 
 
 The class of Insects includes a far greater number of spe- 
 cies than any other class of animals, the number actually 
 amounting to several hundred thousands, each country having 
 a vast number peculiar to itself. They are also exceedingly 
 diverse in habits, as well as in form and structure. 
 
 In order to show the affinities of the insect-parasites and 
 their position among other insects, it will be necessary to give 
 a brief sketch of the whole class, with a few remarks on the 
 more important peculiarities of their anatomy. 
 
 All insects, like the other articulated animals (worms and 
 Crustacea), have a body composed of a series of segments or 
 rings, placed one behind the other, and together forming a 
 sort of irregular tube, which incloses in one cavity all the in- 
 
 * In the preparation of the reports of these lectures on the parasites of domes- 
 tic animals, we are greatly indebted to Dr. A. S. Packard for the use of many 
 cuts of insects from his excellent "Guide to the Study of Insects" and the 
 "American Naturalist," published at Salem, Mass.; and to Donald G. Mitchell, 
 Esq., editor of the "Hearth and Home," published by Pettingill, Bates & Co., New 
 York, for the use of several excellent cuts of parasitic worms, prepared to illus- 
 trate a series of articles on parasites of man and domestic animals by the writer. 
 Without this assistance the lectures could have been illustrated only imperfectly. 
 In addition to these we have added, so far as the available funds would admit, fig- 
 ures of the more important parasitic insects and worms, copied from Cuvier, Gue- 
 rin, Clark, Leuckart, Cobbold, and others. A. E. Verrill. 
 
Fig. 2. 
 
 z BOARD OF AGRICULTURE. 
 
 ternal organs. The nervous system consists of 
 a double nerve-centre or ganglion in the upper 
 part of the head, connected with another below 
 by nerves that pass around the gullet on each 
 side, so as to enclose it as in a ring, and this 
 lower double ganglion is connected by a double 
 nervous cord with a series of similar ganglions 
 or nerve-masses, which are arranged along the 
 lower side of the body, below the intestine, each 
 ganglion sending off small nerves to the adja- 
 cent organs (figure 2). The rings of the body 
 are thickened in certain parts, and in the head 
 and middle region of the body are more or less 
 consolidated. They thus form a somewhat firm 
 external skeleton, composed of 
 a peculiar substance, called 
 chitin. When the rings are 
 movable this outer covering, 
 where it connects the rings to- 
 gether, is thinner and flexible, 
 and often folded inward so as 
 to form peculiar joints. The 
 legs, jaws, and other external 
 organs, are merely hollow out- 
 foldings of the outer covering, 
 and contain, like the body, the 
 muscles that move the various 
 parts, while their cavities com- 
 municate freely with that of 
 the body, and thus receive their 
 supply of blood, nerves, etc. 
 Each joint of the legs and other 
 appendages is also formed by 
 a thinner portion of the outer 
 covering, which is folded in 
 upon itself in various ways. 
 The wings, when present, are 
 also outfoldings of the integu- 
 
 For description of Figures see next page. 
 
 Fig. 1. 
 
PARASITES OP ANIMALS. 
 
 Fig. 3. 
 
 ment, which appear at first in the form of 
 little sacks containing fluid, but finally ex- 
 pand into broad membranes and the sides 
 of the sack unite so as to appear like a 
 simple membrane, supported by little 
 branching, hollow rods, or tubes, which 
 communicate with the cavity of the body, 
 and also form the joints of the wings. The 
 legs and jaws originate from the lower part 
 of the sides of each ring that bears such 
 appendages, so that there must be as many rings or segments 
 in any part of the body as there are pairs of such organs, but 
 
 Fig. 4. 
 
 FIGURE 1. " Hundred-legs," ( Scolo^ocryptops sexspinosa Say), natural size; color 
 deep orange, with yellow feet. From Packard's Guide. 
 
 FIGURE 2. Nervous system of Corydalus cornutas, a large neuropterous insect; 
 a and b, ganglions of the head; c, the three ganglions of the thorax, which send 
 nerves to the three pairs of legs ; d, d, the eight double ganglions of the abdomen. 
 From Packard's Guide, after Leidy. 
 
 FIGURE 3. Portion of one of the tracheae or breathing tubes, prepared so as 
 to show the spiral fibre a, a part of which has been unwound; c, a secondary 
 branch. From Packard's Guide. 
 
 FIGURE 4. Transverse section of the thorax of a bee; a, one of the nervous 
 ganglions ; 6, breathing pore or spiracle, opening into the tracheae, which branch 
 in the interior, and send small tubes into the legs and wings; c, the dorsal vessel 
 or pulsating organ, which circulates the blood; d, the intestine. From Packard's 
 Guide. 
 
4 BOARD OF AGRICULTURE. 
 
 the wings originate from the upper part of the same rings that 
 bear legs below (fig. 4). Most insects breathe air by means of 
 a complicated system of finely branched air tubes, having a 
 sort of spiral spring to keep them open (fig. 3), which are con- 
 nected with valvular openings, called spiracles, along each side 
 of the body. Some species of spiders have respiratory cavities 
 that somewhat resemble lungs, and contain numerous thin 
 membranes, arranged like the leaves of a book. These are, 
 however, connected with openings in the lower side of the 
 body, and may be regarded as a peculiar modification of the 
 air tubes or tracheae found in other insects. In many flying 
 insects the air tubes expand in certain parts into large hollow 
 vesicles, which give greater lightness to their bodies. In all 
 insects we can distinguish three regions of the body: the 
 head, composed of several rings closely united together, and 
 bearing the organs of the mouth and senses as many pairs 
 as there are rings ; the thorax, composed of either three or 
 four rings, which bear as many pairs of legs, and sometimes 
 one or two pairs of wings above ; the abdomen, composed of 
 numerous rings, which are not consolidated, and generally bear 
 only the external reproductive organs ; but in the spiders they 
 bear the spinnerets, in many Iarva3 several pairs of fleshy legs, 
 in centipeds, etc., numerous legs, (figures 1 and 6), and in 
 some insects long, slender, feeler-like organs (figure 5). 
 
 Insects are naturally divided into three great 
 groups or sub-classes,* founded on important 
 differences in their internal anatomy and the 
 arrangement of their external parts. 
 
 I. HEXAPOD INSECTS. 
 
 The highest sub-class contains the Hexapod 
 or six-legged insects, including all the flying 
 insects, and many that are destitute of wings. 
 In these the head, thorax, and abdomen, are 
 distinctly separated as three regions of the body. 
 
 * According to some writers these divisions are called orders. 
 FIGURE 5. "Furniture-bug," or Shiner, (Lepisma), natural size. A smooth, 
 shining, neuropterous insect, covered with minute silvery scales, but destitute of 
 wings. It lives in houses among books, papers, clothing, or in furniture, etc., 
 eating them in various ways ; it is very fond of the paste of books, and will often 
 loosen wall-paper. 
 
PARASITES OP ANIMALS. 5 
 
 The head appears to be composed of seven rings, and there 
 are three pairs of mouth organs. They all breathe by means 
 of air tubes or tracheae. 
 
 II. ARACHNIDS. 
 
 The next sub-division, called AracJtmda, includes the spi- 
 ders, scorpions, " daddy-long-legs," or harvest men, mites, etc. 
 In these the head is generally more or less united to, or sunken 
 in, the thorax, as in the spiders, which have the abdomen very 
 distinct; or the abdomen may be closely united to the thorax, 
 Fig. 6. as in the mites (figure 48). When mature they 
 have eight legs. The head bears but few organs. 
 There are no antennas. The eyes are simple, but 
 often numerous. Many breathe by tracheae, but 
 some spiders by lung-like organs, and others by 
 both combined. 
 
 III. MYRIAPODS. 
 
 The lowest sub-elass, called Myriapoda, includes 
 the centipeds, "thousand-legs," etc., (figures 1 
 and 6.) These have the rings of the thorax and 
 abdomen all very similar, and the rings of the ab- 
 domen in some become very numerous, sometimes amounting 
 to several hundred. Each ring usually bears a pair of legs, 
 aiid contains a nerve ganglion. The head is similar to that of 
 the six-legged insects, and bears antennae, and sometimes com- 
 pound eyes. They breathe by air tubes or tracheae. This 
 last sub-class contains no parasites, but in both the others 
 there are numerous examples. Yet in those they are confined 
 to particular orders and families. 
 
 Among the Arachnids we find parasites only in the lowest 
 order, which includes the mites, the true ticks, the itch-insect, 
 etc., but among the Hexapod insects we find that the parasites 
 belong mostly to two of the seven orders into which they are 
 naturally divided. 
 
 The seven orders of six-legged insects are based on many 
 anatomical differences, but they are characterized, also, by 
 
 FIGURE 6. Lithobius Americanus Newport, natural size; color yellowish brown. 
 From Packard's Guide. 
 
6 BOARD OP AGRICULTURE. 
 
 differences in their transformations, and peculiarities in their 
 habits. The most obvious distinctions are found in the 
 structure of the organs composing the mouth, and in the 
 wings, when these exist. Their names are derived from the 
 character of their wings. The orders are as follows : 
 
 I. Hymenoptera, (membrane-winged). This order includes 
 the bees, wasps, ichneumon-flies, saw-flies (figures 7, 7 a), etc. 
 
 Fig. 7 a. 
 Fig. 7. 
 
 They have four small but strong membranous wings, the front 
 pair largest. The body is compact, the head large, and the 
 three regions of the body very distinct. The head (figure 8) 
 usually has three simple eyes Fig. 8. 
 
 in front, forming a triangle ; a 
 pair of slender antenna3 or 
 feelers, and a pair of very large 
 compound eyes ; connected 
 with the mouth we find a pair 
 of powerful, often toothed, 
 mandibles or jaws; a pair of 
 orceps-like maxillce, bearing 
 near the base a jointed palpus 
 or small feeler ; and finally the 
 labium or lower-lip, which bears 
 a pair of palpi or feelers, and 
 the. ligula or tongue, which is 
 long and highly developed and 
 covered with hairs in the bees. 
 They have, therefore, all the 
 parts of the mouth symmetri- 
 
 FIGURE 7. The Pear-slug or Saw-fly (Selandria cerasi Peck), enlarged. Color 
 black, with white spots on four anterior legs and feet. 
 
 FIGURE 7a. Larvae of the same on leaf of pear, natural size ; and a, enlarged. 
 It is covered with sticky slime. Both from Packard's Guide. 
 
 FIGURE 8. Head of wild Bee (Anthophora), much enlarged ; a, compound 
 
PARASITES OP ANIMALS. 
 
 cally developed. The jaws are used for biting and cutting the 
 materials used in constructing their nests ; the maxillae are 
 used in manipulating and arranging ; the tongue is used for 
 lapping up honey and other liquid food. The Iarva3 are gen- 
 erally soft, footless, and white, but those of the saw flies re- 
 semble caterpillars, and have numerous abdominal legs. 
 
 II. Diptera (two-winged). Insects belonging to this order 
 have but one pair of wings. The three regions of the body 
 are very distinct. The common house-fly, meat-flies, mos- 
 quito, Hessian-fly, wheat-midge, onion-fly (figure 9), bot-fly, 
 Fig. 9. horse-fly, and the fleas 
 
 are examples. The 
 mouth organs- corres- 
 pond in number with 
 those of the Hymen- 
 optera, but the mandi- 
 bles and maxillce are 
 usually formed like 
 long sharp lancets, as 
 in the horse-fly (fig. 
 
 10), or have the shape of slender and 
 sharp piercing organs, as in the mosquito. 
 The labium and tongue together generally 
 form a long proboscis, often with the 
 tongue curiously bilobed and expanded at 
 the end as in the horse-fly and house-fly. 
 The sharp mandibles and maxillaB are used 
 to penetrate the skin of animals, or the 
 bark of plants, and rind of fruits, and the fleshy tongue is 
 used to suck up the blood or other liquid food. The larvae 
 
 eyes ; b, clypeus ; c, the three simple eyes or ocelli ; d, the antennae ; e, labrum or 
 upper lip ;.f, mandibles ; h, maxillary palpi, borne upon the base -of the maxillae 
 i, which are slender and hairy ; j, labial palpi ; k, ligula or tongue ; /, palpifer ; 
 m, paraglossae or lateral lobes of the ligula. From Packard's Guide, after New - 
 port. 
 
 FIGURE 9. Onion-fly (Anthomyia ceparum), considerably enlarged, with larvae, 
 a and 6. From Packard's Guide. 
 
 FIGURE 10. Head of Green-head fly or Horse-fly (Tabanus lineola Fabr.), much 
 enlarged ; a, antennae ; m, mandibles ; mx, maxillae ; mp, the large, two-jointed 
 maxillary palpi ; /, the ligula or tongue ; lb, the labrum. From Packard's Guide. 
 
 Fig. 10. 
 
8 BOARD OF AGRICULTURE. 
 
 are usually soft, white, and footless, and generally pass under 
 the name of maggots. In this order we find many parasites, 
 of which the fleas, sheep-tick, bat-ticks, horse-tick, forest-flies, 
 bot-flies, etc., are examples. This order contains some bene- 
 ficial and very many injurious insects. 
 
 III. Lepidoptera (scaly wings). This order includes the 
 butterflies, moths, millers, army worm (figure 11), canker- 
 worms, cut-worms, silk-worms, etc. 
 
 The wings are four in number, usually 
 broad, and covered with minute scales, 
 looking somewhat like beautiful feath- 
 ers under the microscope, but appear- 
 ing like fine dust to the naked eye. 
 The mandibles are nearly abortive, but 
 the maxilla3 are usually very long, slen- 
 der, and hollowed out on the inside, so that when fitted to- 
 gether they form a long hollow tube or proboscis, through 
 which they suck up their liquid food. The proboscis can be 
 rolled up beneath the head when not in use. The larvae 
 mostly feed upon plants, and are generally known as cater- 
 pillars. They are often bright colored, sometimes hairy, and 
 usually have, in addition to three pair of small true legs, two 
 or more pairs of fleshy legs under the abdomen. Most of the 
 insects of this order are injurious to vegetation. 
 
 IV. Coleoptera (shield-wings). Insects of this order are 
 known as beetles, weevils, etc. The front wings are thick- 
 ened and stiff, not used in flight, but serve to protect the 
 hinder wings, which are larger and thin, and can be folded up 
 and tucked away under them. The mandibles and maxilla 
 are both used as jaws for biting and chewing. The larvae 
 have usually three pair of legs, and many are well known as 
 grubs and borers in wood. The apple-tree borer (figure 12), 
 is an example. This great order includes many beneficial 
 carnivorous insects, as well as many that are injurious to 
 vegetation. 
 
 Y. Hemiptera (half-wings). This order embraces those 
 
 FIGURE 11. Southern Army-worm (Leucania) imago; and larva, a, natural 
 size. From Packard's Guide, after Glover. 
 
PARASITES OF ANIMALS. 
 
 9 
 
 insects properly called bugs, such as the squash-bug (figure 
 13), strawberry-bug, bed-bug, and also the cicada or "seven- 
 Fig. 12. 
 
 teen-year locust," the plant-lice, bark-lice, cuckoo-spits, the 
 true lice, bird-lice, etc. In this order we find, therefore, the 
 greatest number of external parasites. The wings, when 
 present, are often crossed upon the back, and the front wings 
 are often thickened toward the base, but in other cases, as in 
 the cicada and plant-lice, the wings are transparent and not 
 crossed. The mouth organs form a sharp hollow proboscis, 
 for piercing the bark of plants or skin of animals, in order to 
 suck up the blood or sap. When not in use the proboscis can 
 be folded down upon the breast, by means of three joints. 
 The mandibles and maxillae are four, long, slender, very 
 sharp, piercing organs, often barbed near the points. These 
 are enclosed in the jointed proboscis, as in a sheath, but can 
 be thrust out through the opening in the end. The proboscis 
 is formed mostly by the lower lip or labium, but the opening 
 in the upper side is covered by the shorter upper lip. The 
 larvae of many Hemiptera resemble the adults from the first, 
 except that they lack wings ; the pupae are also active and 
 have the same habits. They therefore undergo less remark- 
 able transformations than those of the preceding orders. 
 Many of these insects are beneficial by destroying other in- 
 sects, but most are injurious to vegetation by sucking sap. 
 
 FIGURE 12. Apple-tree Borer (Saperda Candida Fabr.), natural size. Color 
 light brown with two white stripes ; the lower figure represents the larvas. From-, 
 Packard's Guide. 
 
 FIGURE 13. Squash-bug ( Coreus tristis DeGeer.), natural size. Color dart 
 brown. From Packard's Guide. 
 
 2 
 
10 
 
 BOARD OF AGRICULTURE. 
 
 VI. Orfhoptera (straight-wings). This order includes the 
 grasshoppers, true locusts, katydid, crickets, cockroaches, etc. 
 
 Fig. u. The front wings are generally 
 
 long and straight, somewhat 
 thickened, and in the male often 
 have some sort of musical ap- 
 paratus, as in crickets, katydids, 
 etc. The hind wings are broad, 
 fan shaped, and can be folded 
 up like a fan beneath the front 
 wings, which when folded gen- 
 erally lie lengthwise of the body, 
 forming a sort of roof. 
 
 The mandibles and maxillae 
 are chewing organs. The larva& 
 have nearly the same form as the 
 adults, but lack wings ; they have 
 similar habits; the pupae are also active. Most of these 
 insects, except the Mantis, are injurious to vegetation by eat- 
 ing the leaves. 
 
 VII. Neuroptera (nerve-winged). The dragon-flies, lace- 
 winged flies (Figure 15), May Kg. is. 
 
 flies, Lepisma (Figure 3), and 
 white ants, belong to this order. 
 The wings, when present, are 
 thin, membranous, and subdivided by very numerous rods or 
 nervures into small spaces, which are often squarish. The 
 mandibles and maxilla are chewing organs. The abdomen 
 is generally long. The larvae are of many forms, often 
 aquatic, generally carnivorous and predacious in habits, and 
 usually undergo a complete metamorphosis ; the pupae are 
 mostly inactive. Most insects of this order, excepting the 
 
 Figure 14. Katydid ( Cyrtophyllum concavum Say), male, natural szie. Color 
 bright green. From Packard's Guide. 
 
 Figure 15. The Lace-wing Fly (Chrysopa oculata Say), natural size, with the 
 eggs attached to the tips of slender pedicels. Body light green. This insect 
 lays its eggs among plant-lice (Aphis), which the larvae, when hatched, destroy. 
 From Packard's Guide. 
 
PARASITES OP ANIMALS. 11 
 
 white ants and Lepisma, are beneficial by destroying noxious 
 insects. 
 
 To those who desire more information upon the struc- 
 ture, habits, and classification of insects generally, we would 
 especially recommend Packard's Guide to the Study of In- 
 sects, Salem, Mass., 1869, and Harris' Treatise on Insects 
 Injurious to Vegetation (illustrated edition), Boston, 1862. 
 
 PARASITES BELONGING TO THE DIPTERA. 
 
 The Fleas. 
 
 PULICI D^B. 
 
 It is somewhat singular that parasites are almost always 
 degraded species of the orders and families to which they 
 belong. This is very evident in the case of parasitic insects, 
 for they are mostly destitute of wings, and are imperfectly 
 organized in other respects when contrasted with their self- 
 supporting allies. The fleas furnish us with examples of 
 degraded diptera, and the sheep-tick is even more degraded 
 than the fleas. Of fleas there are several species that attack 
 man and domestic animals ; but the species do not appear to 
 be so strictly limited to particular animals as are the lice and 
 some other parasites ; for the common dog-flea and cat-flea 
 will attack man without hesitation, and in New England ap- 
 pear to be far more troublesome to the human race than is 
 the species commonly regarded as the real human flea (Pulex 
 irritans), which so far as I have observed, is comparatively 
 rare, though in some localities it may be sufficiently common, 
 as it is in parts of Europe. 
 
 In the genus Pulex, which includes the common species of 
 fleas, the body is compressed and the integument is very firm, 
 so that they are well adapted for gliding among hairs or 
 feathers, and are not liable to be injured by any ordinary 
 pressure. The wings are represented only by two pairs of 
 short, stiff scales, which have little or no power of motion. 
 The posterior legs are large and powerful, enabling them to 
 leap with remarkable agility. The head is small ; the eyes 
 
12 BOARD OP AGRICULTURE. 
 
 are simple, in some species very minute ; the antennae are curi- 
 ously constructed with three broad, flat, singularly lobed 
 joints, and are, in nearly all species, closely folded away out 
 of sight, in a socket or cavity behind the eyes ; though in 
 the males of the mouse-flea and pigeon-flea they are exposed 
 and carried erect. The mouth organs are peculiarly con- 
 structed and well adapted for piercing the skin and sucking 
 the blood. The maxillae (Figure 16, a), are a pair of broad, 
 flat, thin, somewhat lance-shaped organs, bearing at base the 
 long, four-jointed feelers or palpi (5). The mandibles (#) 
 are slender, flattened, sharp, piercing organs, finely serrated 
 along their sides, like a minute saw. The Figure IG. 
 
 labium (tT) is a round, slender, piercing 
 organ, forming the central lancet. The 
 lower lip and labial palpi (<?) form to- a, 
 gether a sort of sheath, with a groove on 
 the inside, which receives the mandibles 
 and labium, when in their natural posi- d * 
 tion ; the labial palpi are four-jointed in the cat and dog 
 fleas, if not in all, though some writers say they are three- 
 jointed. The mandibles (c) and labium (d) form together 
 three slender lancets, and it is by means of these that the 
 flea perforates the skin. The blood is then drawn up through 
 the channels or spaces between these organs and the labial 
 palpi and lower lip, by means of a sucking stomach. 
 
 The Gat-flea (Pulex felis Bouch4). Figures IT, 18. 
 This species of flea is perhaps the best known and most 
 common kind in New England. It not only infests nearly all 
 cats and the places where they sleep, but is also more or less 
 common in dwellings of all classes, especially when cats are 
 allowed to roam about over the carpets. It often becomes 
 exceedingly troublesome in sleeping rooms, for it prefers to 
 spend the day about the floor, in and beneath the carpet, 
 or in some similar place of concealment ; but when oppor- 
 
 Figure 16. Head of the dog-flea (Pulex ranis Curtis), highly magnified; a, 
 the hroad, thin maxillae ; b, their four-jointed palpi ; c, the mandibles ; d, the 
 labrum or central seta of the proboscis ; e, the labium and labial palpi. From 
 Duges. 
 
PARASITES OP ANIMALS. 
 
 13 
 
 tunities offer it is always ready to jump upon the naked feet 
 or ankles, and may thus gain entrance to the bed. Many 
 persons, especially ladies and children, are badly poisoned by 
 
 Figure 17. Figure 18. 
 
 them, and may suffer severely for several days from the bite 
 of a single flea; for, unlike the mosquito and other blood- 
 sucking insects, they are never satisfied with a single bite, or 
 with one spot, but must travel about and bite as they go, 
 literally " biting on the run." In these respects, however, it 
 agrees closely with the so-called human flea (Pulex irritans). 
 
 The cat-flea (Figure 17) is dark chestnut-brown in color, 
 and is stouter and thicker in the thoracic region than Pulex 
 irritans, which has a rather slender waist and darker color. 
 There is a row of sharp spines along the lower side of the 
 head on each side, and another row of similar spines on the 
 posterior edge of the first segment of the thorax; but the 
 human flea lacks both these sets of spines. Other good dis- 
 tinctions are found in the joints of the feet or tarsi, and in 
 the mouth organs. In all fleas the males and females differ 
 considerably in form and size, the males being smaller and 
 shorter. 
 
 The female cat-flea lays her eggs among the fur of the cat, 
 to which they are but slightly attached ; these eggs are very 
 small, white, and long-oval. As the cat walks or runs about, 
 the eggs are constantly being scattered around, often in great 
 numbers. On one occasion I was able to collect fully a tea- 
 spoonful of these eggs from the dress of a lady in whose lap a 
 half-grown kitten had been held for a short time. The places 
 
14 BOARD OF AGRICULTURE. 
 
 where cats sleep become well filled with the eggs. These 
 hatch in about two weeks into little, white, footless, maggot- 
 like larvae (Figure 18), which have small tufts of hairs along 
 the sides. They are at first about one-sixteenth of an inch 
 long. The head is pale yellow, and the posterior end of the 
 body bears two spines. These larvae feed upon the decaying 
 particles of animal and vegetable matter always to be found 
 in the dirt in which they live. They move about by means of 
 their hairs and spines. They grow rapidly in warm weather, 
 and in about twelve days, when they mature, spin a slight 
 silken cocoon and change to a pupa, which is inactive. 
 This looks more like the mature flea and has the legs free. 
 In a short time, varying from ten to sixteen days or more, 
 according to temperature, the pupa matures, and the full 
 formed flea comes forth from the cocoon, ready and willing 
 to take care of itself. This it does by leaping upon the first 
 living creature that comes within range ; but no doubt it is 
 better suited with the cat than with other animals. This 
 mode of increase and the habits of the young will explain the 
 reason why fleas are often obtained out of doors, especially in 
 gardens frequented by cats or dogs. Such fleas are often 
 called " sand-fleas," but they are simply the progeny from eggs 
 of cat or dog fleas that have been hatched and lived in the 
 dirt or soil. They pass the winter both in the mature and 
 larval states, and perhaps also as eggs and pupae. There are 
 several broods each season. 
 
 The Dog-Flea (Pulex canis Curtis). Figure 19. 
 This species is very similar to the last, and is considered 
 the same by several writers. It has the same form and color, 
 and the same TOWS of spines below the sides of the head and 
 on the thorax. But there appears to be some difference in 
 the mouth organs. The posterior tarsi in this species are 
 
 Figure 17. -Cat-flea (Pulex felis Bouche), much enlarged; a, the maxillary 
 palpi arising from the bases of the maxillae, b ; c, the labial palpi ; d, the slender 
 mandibles. The labrum is not shown. From Packard's Guide. 
 
 Figure 18. Larva of Cat-flea (Pulex felis Bouche), much enlarged; a, one of 
 the antennae more highly magnified; 6, posterior end of the body, showing the 
 two spines. From Packard's Guide. 
 
PARASITES OF ANIMALS. 15 
 
 said to have the fifth joint longer than Figure 19. 
 
 the second, while in the cat-flea the second 
 is longer than the fifth. The habits are 
 essentially the same, except that tins one 
 seems to prefer the dog's blood. It will 
 also attack human beings when oppor- 
 tunities offer. 
 
 The Hen-Flea (Pulex gallince Schank) lives upon the hen 
 and about poultry-houses and yards. 
 
 The Pigeon-Flea (Pulex columboe Gervais) lives upon do- 
 mestic pigeons and in pigeon-houses. 
 
 Other species infest rats, mice, bats, rabbits, swallows, and 
 various other wild animals and birds. 
 
 Remedies for Fleas. 
 
 From the description of the habits of the larvae given above, 
 it is evident that dirt and filth of all kinds afford facilities for 
 the increase of fleas, and that dogs and cats are the means of 
 diffusing their own peculiar species, and also, no doubt, the 
 true human flea. The first care, therefore, should be to see 
 that the dogs and cats, if such are kept, are freed from their 
 parasites. To this end they should be made to sleep. on some 
 material like shavings or chips, that can be easily burned, 
 and their sleeping places should be often cleaned and their 
 beds renewed. To remove the fleas themselves from the 
 animals a wash of water containing 6 to 10 per cent, of petro- 
 leum, naphtha, or benzine, well shaken together, may be used. 
 A weak solution of carbolic acid in water, about 2 or 3 parts 
 of the acid to 100 of water, will also be efficacious for fleas 
 and other parasites. Decoctions of tobacco and strong soap 
 suds are also recommended. 
 
 When fleas are troublesome in dwelling houses, a thorough 
 cleaning of the floors and an equally thorough beating and 
 cleaning of the carpets, rugs, etc., will generally be effectual. 
 When cracks or crevices exist in the floors, a thorough wash- 
 ing with the petroleum, naphtha, or carbolic acid water, will 
 be useful to destroy the eggs and young. Persian Insect 
 
 Figure 19. Head of Dog-flea (Pulex cants Curtis), much enlarged. The parts 
 are the same as in Figure 16. From Duges. 
 
16 [BOARD OF AGRICULTURE. 
 
 Powder, which is a preparation from the flowers of a plant, is 
 often used to expel fleas both from carpets and the fur or 
 hair of animals. It appears to be particularly obnoxious to 
 them. But after applying the powder to an animal it should 
 soon after be thoroughly washed off. 
 
 It often happens that there are really but few fleas, perhaps 
 less than a half dozen, in a room that is supposed to be over- 
 run by them ; for owing to their habit of biting repeatedly, a 
 single one may do the mischief attributed to a large number. 
 In such cases a careful search for and capture of the of- 
 fenders will soon remedy the evil. When caught, a drop or 
 two of benzine will kill them instantly. 
 
 The Sheep-Tick, Forest-Flies or Horse-Ticks, etc. 
 
 HlPPOBOSCID-SJ. 
 
 These are degraded Dipterous parasites, and must not be 
 confounded with the true ticks, which have eight legs. Some 
 of them are destitute of wings, like the sheep-tick ; others 
 have long, narrow, simple wings, like the species infesting the 
 horse, and those of the swallow and other birds, bats, etc. 
 The body is flattened from above, and is hard and firm, with 
 a horn-like or leathery texture. The head is somewhat 
 sunken into the front edge of the thorax, without a distinct 
 neck. The antennae or feelers are Tery small and near to- 
 gether. The eyes are large and often occupy most of the 
 sides of the head. The proboscis consists of two lateral, nar- 
 row, elongated, bristly plates (regarded as maxilla by some 
 authors), which project in front of the head. Below and 
 between the bases of these there is a small orifice from which, 
 when about to draw blood, three, long, slender, piercing 
 organs are protruded; but these can be withdrawn when not 
 in use. These are unequal in size, but equal in length. The 
 lower one, which is largest and channeled along the upper 
 side and dilated at base, receives the two smaller ones into 
 its groove. These organs penetrate deeply into the skin, 
 and through the channel formed by the setae the blood is 
 sucked up. 
 
 They live like lice among the feathers of birds or hairs of 
 
PARASITES OP ANIMALS. 17 
 
 animals, and run with agility either forward, sideways, or 
 backward, somewhat like a crab. Their feet or tarsi are fur- 
 nished with powerful denticulated claws, with which they 
 cling securely. Their most remarkable peculiarity is their 
 mode of reproduction. Each female produces but one or two 
 young at a time, but these are born as living, fully developed 
 larvae, which are enclosed in a smooth oval skin, notched at 
 one end, within which they change to pupae immediately 
 after birth, the enclosing case becoming dark colored. The 
 female has an uterus-like enlargement of the oviduct, in which 
 the eggs hatch, and this organ has the power of secreting a 
 milk-like substance for the nourishment of the larvae until 
 full grown. 
 
 The Horse-tick or Forest-fly (Hippobosca equina). Figure 20. 
 
 This species is almost as large as the house-fly, nearly black, 
 with conspicuous yellow markings on the thorax. It some- 
 Figure 20 " . times infests the horse 
 
 to such an extent as to 
 be very troublesome. 
 It attacks by. prefer- 
 ence those parts where 
 the hair is thinnest 
 and the skin softest, 
 especially under the 
 belly and between the 
 hind-logs. Their bites 
 cause severe pain, and will irritate the gentlest horses, often 
 rendering them almost unmanageable, and causing them to 
 kick dangerously. When found they cling so firmly as to be 
 removed with some difficulty, and they are so tough as not to 
 be readily crushed. If one escapes when captured, it will in- 
 stantly return to the horse, or perchance to the head of its 
 captor, where it is an undesirable guest. Another species 
 sometimes infests the ox. 
 
 Figure 20. The Horse-tick (Eippobosca equina Linn.), enlarged. From 
 Cuvier. 
 
18 BOARD OP AGRICULTURE. 
 
 The Sheep-tick (Melophagus ovinus Linnaeus). Figure 21. 
 
 This insect never acquires wings. It has a broad head, 
 wider than the thorax. The abdomen is roundish and hairy, 
 not showing distinct rings, and in the gravid female becomes 
 much enlarged. The legs are short and stout, and the claws 
 very strong. The proboscis is as long as the head. Like the 
 horse-tick, it is viviparous, producing a full-grown larva, en- 
 closed in an oval case, as shown in Figure 21. 
 
 It is often very troublesome to sheep, especially lambs. 
 There have been numerous remedies proposed. In general, 
 when there are but few, they can easily Figure 21. 
 
 be removed by hand when the sheep are 
 sheared ; but when numerous on lambs, 
 they may be destroyed by various washes 
 or baths. Snuff, or sulphur in powder, 
 rubbed thoroughly in to the wool, is some- 
 times used with good results. A bath 
 made by steeping tobacco in water, about 
 2 pounds to 10 gallons of water, in which the lambs are 
 entirely immersed, with the exception of the face, is said to 
 be effectual, but in some cases, has proved injurious to the 
 health of the lambs. Probably the same solutions recom- 
 mended for fleas would be equally effectual for these ; but 
 the strength of petroleum water, or naphtha water, or car- 
 bolic acid water, ought to be adapted to the age and strength 
 of the animals to which it is applied, young lambs having a 
 much more tender skin than dogs or old sheep. 
 
 The Sot-flies of Horses, Cattle, and Sheep. 
 
 The insects belonging to this family are much less degraded 
 than the other parasitic Diptera. But in reality these are not 
 parasites, except in the larval state. They pass the pupa state 
 in the soil, and in the winged state are powerful fliers, seek- 
 ing the quadrupeds only for the purpose of depositing their 
 
 Figure 21. Sheep-tick (Melophagus ovinus Linnaeus), enlarged. The figure on 
 the left represents the puparium when first born. From Packard's Guide. 
 
'PARASITES OP ANIMALS. 19 
 
 eggs. There are numerous genera and species, each of which 
 lives, in the larval state, upon some particular species of 
 mammalia, and usually in some particular part of the ani- 
 mal. In the tropical parts of America there are species which 
 live beneath the human skin, in tumors that they cause. The 
 larvas are usually thick, fleshy grubs, destitute of feet, but 
 generally provided with rows of hooks or spines, by means of 
 which they move about in their burrows. The breathing 
 pores are in one or two scaly plates at the thick posterior end 
 of the body. In those that are parasitic in the stomach, the 
 mouth lias horny hooks by means of which they cliii^ to the 
 lining membrane ; but in those that live in tumors under the 
 skin, there are no hooks to the mouth, but only fleshy 
 tubercles. They live on the matter, or pus, which is caused 
 by the irritation that they produce. 
 
 The flies generally have a stout, hairy body, sometimes 
 looking somewhat like humble-bees. The female has a more 
 pointed abdomen, with an extensible ovipositor. The an- 
 tenna3 are very small, and placed in little pits. The mouth 
 organs are almost abortive, and the mouth very small, for 
 these flies take little or no food in their winged state, this 
 period of their lives being wholly devoted to the reproduction 
 of their kind. The species that infest cattle, sheep, and 
 horses have been transported to nearly all parts of the world 
 where these animals are reared ; but there are many native 
 species that are found only in the wild animals. * 
 
 The Bot-fly of Cattle (Hypoderma bovis Latr). Figures 22, 23. 
 This fly is densely covered with hairs, except upon the 
 thorax, which is partially naked and black, broadly banded 
 with white and yellow. The abdomen is banded alternately 
 with yellowish white and black, and with reddish orange at 
 the end. The front of the head is dirty ashen, with yellowish 
 white hairs. They appear from June to September, and the 
 females lay their eggs on the backs of cattle. According to 
 
 * One species, Cuterebra emasculator, described by Fitch, lives in the scrotum of 
 squirrels, and destroys one or both testicles. In some parts of .the country it is 
 often quite common, and doubtless greatly diminishes the number of squirrels. 
 
20 
 
 BOAED OF AGRICULTURE. 
 
 some writers, they pierce the skin, by means of their peculiar 
 gimlet-like ovipositor ; but others deny this, and say that the 
 eggs are merely attached to the skin, and that the young 
 larvae, which very soon hatch, eat their way in. At any rate 
 
 Figure 22. Figure 23. 
 
 the cattle are often greatly alarmed by their attacks, and run 
 frantically about, sometimes even taking to the water for 
 safety, which would hardly -be the case unless they had suf- 
 fered pain from their attacks. Working oxen, when thus 
 attacked, sometimes cause serious trouble. 
 
 The larvae having entered the skin increase the size and 
 depth of their burrows as they grow larger, but always keep 
 up an opening with the exterior, and keep the posterior end 
 of the body, in which the breathing pores are situated, near 
 this opening to get air. In this way they cause, by the irrita- 
 tion and inflammation that they produce, tumors or abscesses 
 of considerable size beneath the skin, and live upon the 
 matter formed by the inflammatory action. When young, 
 they are white, but afterwards become brownish ; when ma- 
 ture, deep brown. 
 
 They have transverse rows of minute hooks ; the narrower 
 rows are on the posterior part of each segment, and the hooks 
 point backward ; those of the wider rows, point forward. These 
 
 Figure 22. The Bot-fly of Cattle (Hypoderma bovis Latreille), considerably en- 
 larged. 
 
 Figure 23. The full grown larva, enlarged. Both from Packard's Guide. 
 
PARASITES OF ANIMALS. 21 
 
 hooks are used in moving about, and no doubt cause consid- 
 erable irritation. The mouth is small and inconspicuous, 
 with small papillae. The posterior end of the body bears two 
 small plates in which the spiracles or breathing pores are 
 situated ; and this end of the body is kept next to the external 
 orifice of the tumor. When the larva is mature, which hap- 
 pens from May to July, it is about an inch long (Figure 23). 
 It then works its way out of the opening backward, and falls 
 to the earth, where, in a day or two, it changes to a pupa, 
 the dried-up skin of the larva serving as a covering for the 
 pupa. They remain in the pupa state from four to six weeks 
 during summer, when the end of the pupa-case comes off, 
 like a lid or cap, and the mature fly comes forth. The sores 
 caused by them heal very soon after the larvae leave. 
 
 Although these insects probably cause some pain, especially 
 at first, they do not appear to cause any permanent injury, 
 and but little inconvenience, unless in large numbers. They 
 can usually be pressed out of their burrows with the thumb ; 
 but care should be taken not to crush or burst them in the 
 burrows. Or the openings of the tumors may be enlarged with 
 a sharp knife or lancet, and then they can be easily removed 
 and the wounds will soon heal. They attack by preference 
 young and healthy or fat animals, perhaps because the skin 
 is softer and thinner in these. They frequent chiefly the 
 uplands, and especially the vicinity of trees, and seem to 
 particularly avoid water or damp localities a fact that cattle 
 seem to learn by experience. Owing to this habit, cattle that 
 graze upon meadows are generally free from them, or nearly 
 so, although those upon the neighboring hills may be at- 
 tacked. The eggs are laid soon after the flies emerge from 
 the pupa ; but as there is considerable variation in the time 
 when the larvae mature, the flies may occur from June to 
 September. The larvae live during the entire winter in the 
 tumors, and perhaps some of the pupae remain over winter. 
 
 The Sheep Bot-fly (CEstrus ovis Linn.). Figure 24. 
 This species somewhat resembles the preceding in form, 
 but is considerably smaller, with a rounder abdomen in the 
 
22 BOARD OP AGRICULTURE. 
 
 male, and the color is lighter. The thorax is ash-colored, 
 with four black lines and small black spots. The abdomen is 
 light ash, more or less spotted with blackish. The female has 
 a tapering abdomen, with a long ovipositor, which is curved 
 forward when about to deposit the eggs. 
 
 The flies appear during the whole summer, and according 
 to Mr. Riley, deposit the young larvae previously hatched in 
 the oviduct, on the margins of the nostrils of 
 sheep. u The moment the fly touches this part of 
 the sheep, they shake their heads and strike the 
 ground violently with their fore-feet ; at the same 
 time holding their noses close to the earth, they 
 run away, looking about them on every side to 
 see if the fly pursues. They also " smell to the 
 grass " as they go, lest one should be lying in 
 wait for them. If they observe one, they gallop back, or take 
 some other direction. As they cannot, like the horses, take 
 refuge in the water, they have recourse to a rut or dry, 
 dusty road, or gravel pits, where they crowd close together 
 during the heat of the day, with their noses close to the 
 ground, which renders it difficult for the fly conveniently to 
 get at the nostril." (Clark, 1796). This description, al- 
 though written long ago, applies equally well to the habits 
 both of the fly and sheep, as observed at the present day. 
 The young larvae at once proceed to ascend into the nostrils 
 by means of their hooks and writhing motions, thus causing 
 great irritation and an increased secretion of mucus, upon 
 which they feed. They finally reach the frontal and maxil- 
 lary sinuses and other cavities, connected with the nose, and 
 attach themselves securely to the mucus membranes by means 
 of the two sharp hooks upon their heads. They thus cause 
 great inflammation, if in considerable numbers, and severe 
 illness, or even at times convulsions and death result. This 
 disease is often known as " grub in the head " among farm- 
 ers. The disease is indicated by loss of appetite, frequent 
 coughing or sneezing, unusual discharge of matter from the 
 nose, slow and weak gait, dullness, inability to stand, tossing 
 
 Figure 24. Larva of the Sheep-bot ( (Estrus ovis), natural size. From Clark. 
 
PARASITES OF ANIMALS. 23 
 
 or turning of the head, inclination to butt and push with the 
 head, fits of frenzy, and general appearance of suffering and 
 weakness, which sometimes goes so far as to render the animal 
 unable to rise, when death generally results. The gums, back 
 part of mouth, and lining of the nasal cavities are often red and 
 inflamed. Sometimes the larvae even force their way, by the 
 openings through which the nerves pass, into the brain, when 
 death quickly follows. 
 
 These Iarva3, when full grown (Figure 24) are about an 
 inch long, and have lost more or less of the white color which 
 they had when younger, and each ring is crossed above by two 
 dark brown bands ; there are also small, round, raised brown 
 spots on the sides of each segment. The small end, or head, 
 has two sharp hooks and two papillae ; but the posterior seg- 
 ment bears two small brown plates, in which the spiracles 
 are placed, and this segment can be drawn into and con- 
 cealed by the next, which give a truncated appearance to 
 the posterior end. The under side is flattish, and each seg- 
 ment has a median row of minute brown spines, which are 
 directed backward. 
 
 When full grown, they descend from the nostrils and fall 
 to the earth, where, in the soil or among the roots of grass, 
 they change to pupae in about two days. They remain in 
 this state from six weeks to two months, when a sort of lid is 
 forced off from one end of the pupae cases, and the mature 
 flies come forth, pair, and immediately proceed with the work 
 of perpetuating the race, for in the winged state they seem to 
 have no other instinct ; and not having any mouth, they take 
 no food. When not engaged in depositing the eggs, they 
 seem sluggish and lazy. The flies appear irregularly in June, 
 July, and August, and larvae of all sizes may be found at one 
 time in the same sheep. Each female produces several hun- 
 dreds of young. According to Mr. Riley, * Over 300 living 
 larvae have been taken from one female fly, by Mr. Cockrill. 
 
 The amount of injury which these insects do to the sheep 
 has long been a matter of discussion among veterinary sur- 
 geons and others ; but it appears to be the universal testi- 
 
 * First Annual Keport on the Noxious Insects of Missouri, p. 164, in Report of 
 of Agriculture, 1868. 
 
24 BOARD OF AGRICULTURE. 
 
 mony of those who are most immediately interested the 
 breeders of sheep that their effects are evil, and evil only, 
 and that the amount of injury is in direct proportion to their 
 numbers, as is the case with all other parasites. That, when 
 as abundant as they often are, they are capable of causing 
 death, seems to be well established. As a preventive, it 
 has been recommended to move the sheep to distant pastures 
 after most of the grubs or larvae have left the sheep and are 
 in the earth in the pupae state, which happens during June or 
 July, according to locality. In this State probably the latter 
 half of June would be the best time for this. Others smear the 
 noses of the sheep with tar, or make them do so themselves 
 by boring large augur holes in logs to contain salt, and fre- 
 quently smearing the adjacent wood with tar. Many provide 
 spots of light, dry soil into which the sheep may thrust their 
 noses when pursued by the fly. When the larva? have ac- 
 tually entered the nostrils in large numbers, they may be 
 removed to a considerable extent by a feather wet with oil of 
 turpentine, camphor, or a weak solution of carbolic acid, or 
 of creosote. Lime, in fine powder, is sometimes used; for 
 by sniffing it, they sneeze, and thus expel the larvae. Salt 
 water or diluted carbolic acid solution may also be injected 
 into the nose with a syringe. It is doubtful, however, 
 whether any remedies will reach the larvae which have taken 
 up their abode in the more remote cavities in the bones of the 
 forehead and beneath the bases of the horns. Therefore it is 
 better to apply these remedies early and often, if necessary. 
 
 Another species of bot-fly (Hypoderma lineata Brauer), 
 lays its eggs upon the backs of sheep and cattle, and the 
 larvae live in tumors beneath the skin, like the more com- 
 mon Hypoderma bovis of cattle. It appears to be rare in this 
 country, but has been observed in Kentucky. This fly may 
 be known by three, longitudinal, naked, black stripes on the 
 thorax. The abdomen is very hairy, blackish, with three 
 bands, the base whitish or yellowish, the middle black, the 
 apex orange-red. The wings are transparent, somewhat 
 brownish, unspotted. In New Grenada another species, the 
 Dermatobia noxialis Goud., has the same habits, and also at- 
 
PARASITES OF ANIMALS. 25 
 
 tacks men in the same way, forming painful tumors beneath 
 the skin. The same or a similar species also infests the dogs 
 in the tropical parts of America. 
 
 Several peculiar species of Hypoderma live beneath the skin 
 of the moose, elk, and other species of the deer family. These 
 animals are also infested by several species of the genus 
 CepTienomya, which live in the larval state in the throat, or at 
 the root of the tongue. 
 
 The goat is attacked by a species of Hypoderma, which 
 makes tumors under the skin, and by a species of (Estrus, 
 that enters the frontal sinuses, and has the same habits as the 
 common species of the sheep ; but these two species have not 
 been determined and are little known. The camel is infested 
 by the larvse of Cephalomya maculata Wd., which lives in. the 
 nasal cavities, like the larvae of the sheep-bot. Even the ele- 
 phant and rhinoceros have their peculiar parasites of this 
 kind. The latter is attacked by a bot-fly, allied to that of the 
 horse, which lives in the stomach in its larval state. 
 
 Bot-fly of the Horse (Grastrophilus equi). Figures 25, 26. 
 
 The " bots " of horses are the larvae of several species of 
 flies, belonging to the genus called Gf-astrophilus. The largest 
 and most common kind is Gr. equi, the female of which is 
 represented in Figure 25. This species is very hairy, and has 
 dark spots on the wings. The eyes are black and distant ; the 
 top of the head is brown, the front whitish ; the thorax is brown, 
 with a darker brown or blackish central spot ; the abdomen is 
 brown with the transverse divisions and spots blackish. The 
 male has a rounder or broad-oval abdomen, which is browner. 
 This fly lays its eggs by preference upon the hairs about the 
 knees of horses, especially on the inside ; it also frequently at- 
 taches them to the hairs of the side and back part of the shoul- 
 der, and occasionally to the tips of the hairs of the mane. These 
 eggs are of considerable size, of a long oval form, pointed at 
 one end and blunt at the other, and adhere firmly by one 
 side. They may easily be seen and can be removed either 
 by thorough washing and brushing, or by cutting the hairs 
 off with scissors. A wash of carbolic acid soap has been re- 
 commended to destroy them. Sometimes 500 or more may 
 4 
 
26 BOARD OF AGRICULTURE. 
 
 be found on one horse. In depositing the eggs, the female 
 fly hovers around the horse, and as each egg is ready to be 
 deposited, she quickly advances and bends the abdomen for- 
 ward, with the egg at the end, and applies it to the hair, to 
 
 Figure 26. 
 Figure 25. 
 
 which it instantly adheres by the glutinous secretion which 
 covers it. She then retreats and prepares another egg Jo r 
 the same operation. This does not disturb the horse, unless 
 by a tickling sensation, causing the muscles of the skin to 
 contract with a tremulous motion. The eggs contain more 
 or less perfectly developed larvae when laid ; and when they 
 are mature, or have been a few days attached to the hair, 
 they burst open and allow the young to escape almost instan- 
 taneously, when moistened. Thus, when the horse licks itself 
 or its companions, the moisture hatches the eggs, and the 
 young larvae are transferred to the mouth by the tongue or 
 lips, and thence to the stomach, where they fasten themselves 
 to the lining membrane by their two hooks. They generally 
 occur in clusters, and are most common in the vicinity of the 
 pylorus, but are found attached to all parts of the stomach. 
 In this situation they slowly grow to be large fleshy larvae, 
 with a round body, about an inch long (Figure 25). The 
 segments of the body are provided with double rows of spines, 
 pointing backward. These are reddish with black tips. The 
 
 Figure 25. Bot-fly of the horse ( Gastrophilus equi Leach), female, natural 
 size. 
 
 Figure 26. Larva of the same, enlarged. From Packard's Guide. 
 
PARASITES OP ANIMALS. 27 
 
 two last segments do ftot show -the spines, and the posterior 
 end of the body is rather truncate, with two fleshy lobes, 
 which cover, more or less completely, a chitinous plate, in 
 which the spiracles are situated. The mouth is at the small 
 end, between the hooks, which represent the maxillae ; the 
 mandibles, above and between these, are small and slender. 
 At the places where they attach themselves there are found 
 small pits or depressions ; but they do not appear to cause 
 ordinarily much irritation or inflammation, unless in great 
 numbers, as they sometimes are. They have been accused of 
 perforating the walls of the stomach, and this may possibly 
 be the case in very rare instances ; but the perforations of 
 the stomach, so often found in post-mortem examinations, 
 are generally caused by the digestive action of the gastric 
 juice after the death of the animal ; for after death this fluid 
 will attack the stomach as quickly as any other flesh. 
 
 When full grown they loosen their hold, and passing 
 through the intestine, fall to the earth. But they often fix 
 themselves for a few days upon the lining of the intestine, 
 and then cause considerable irritation and pain. Probably 
 most of the acute symptoms of " bots " in horses are caused 
 in this way. They often attach themselves in and about the 
 anal orifice, and in that situation cause much suffering and 
 trouble to the horses, which under these circumstances, re- 
 fuse to travel rapidly, and even after whipping, soon relapse 
 into a slow walk, as if lazy. But the bots can be easily re- 
 moved from this location, much to the relief of the horse. 
 The bot-larvge get their growth and leave the horses from the 
 latter part of May to July, or even later. They enter the 
 surface of the soil and change to pupae within the shrunken 
 skins of the larvae. They remain in the pupa state forty or 
 fifty days, and emerge in the same way as the preceding spe- 
 cies ; consequently the flies may occur from the last of June 
 till September, or later. 
 
 The amount of injury caused by the bots of horses has long 
 been a matter of dispute, many writers claiming that they are 
 very injurious, and evert at times, fatal ; while others deny this, 
 and consider them as harmless, or even beneficial. This can 
 
28 BOARD OP AGRICULTURE. 
 
 be definitely settled only by experiment; but most reasonable 
 men would be content to forego any possible benefit, and be 
 satisfied with a healthy horse destitute of bots. No doubt 
 many diseases due to other causes are commonly attributed 
 to these insects, but that they are frequently the cause of 
 serious trouble is generally believed and admitted. In this 
 instance prevention is comparatively easy, while all writers 
 admit that there is no reliable cure, no mattter how much 
 they may differ in other respects. The means of prevention 
 consist chiefly in frequently removing or destroying the eggs, 
 as mentioned above, and also in removing and destroying the 
 full-grown Iarva3 when observed attached to the rectum. In 
 some countries the grooms frequently wash out the mouths 
 of the horses with a suitable brush in order to remove the 
 young larvae. Many drugs have been recommended to re- 
 move bots from the stomach, but none that do not endanger 
 the life of the horse can be relied upon ; and in cases where 
 they bring away the larvae, it is possible that those that are 
 already in ' the intestines are the only ones affected. Spirits 
 (or oil) of turpentine is a remedy in common use, but should 
 be used with caution, if at all. A better plan, under ordi- 
 nary circumstances, is to keep the horses in good health in 
 other respects, so that they can the better sustain the attacks 
 of the larvae until they naturally pass away, which will usually 
 take place without serious injury. In exceptional and severe 
 cases only, resort should be had to special medicines of a dan- 
 gerous or doubtful character ; and then they should be given, 
 if possible, in accordance with the advice of a competent phy- 
 sician. There are several other species of bot-flies of the 
 horse, which are less known, however, in this country. 
 
 The Gastrophilus nasalis is a smaller species, densely 
 hairy, with the thorax yellowish red or rust-colored. The 
 abdomen is either whitish at base, with the middle black and 
 the apex yellowish-brown and hairy ; or the base is whitish 
 and all the rest brown ; or the middle is black, with the base 
 and apex whitish, with grayish hairs. The wings are un- 
 spotted. The larvae are much like tliose of the preceding, 
 except that they are smaller, and also live in the stomach of 
 
PARASITES OF ANIMALS. 29 
 
 horses. They change to pupae beneath the manure, and the 
 flies appear from June to September. It also infests the ass 
 and mule, and some authors say that it lives even in cattle. 
 
 The Gaslrophilus pecorum is densely covered with yellow 
 hairs, with a band of black hairs on the thorax behind the 
 suture, in the male. The female is yellowish brown, the 
 abdomen black, with yellowish hairs at its base, as well as 
 on the thorax. The wings are grayish or light brownish, 
 clouded with yellowish brown. The larvae are similar to 
 those of the more common G-. equi, and have similar habits. 
 The flies appear at the same time. 
 
 The Gastrophilus hcemorrhoidalis, or red-tailed bot-fly, is 
 a small species, easily distinguished by the bright orange-red 
 tip of the abdomen. The thorax above is olive-gray and hairy, 
 with a black band behind the suture. The base of the abdo- 
 men is whitish and the middle blackish, in strange contrast- 
 with the orange-red of the end. The larvae have the same 
 habits and are found in the same situations with those of 
 the common bot-fly, which they much resemble, except that 
 they are whiter and smaller, their length not exceeding one- 
 half or five-eighths of an inch. They change to pupae within 
 two days after leaving the horse, and the pupae are deep red. 
 They remain in the pupa state about two months, and the flies 
 appear from the last of June till the cool weather of autumn. 
 In depositing the eggs, the female fly differs in habit from 
 the common bot-fly, for she selects the lips and nose of the 
 horse as the most suitable place for this purpose. In deposit- 
 ing her eggs she therefore causes the horse much trouble and 
 uneasiness. Mr. Clark described the operation as follows : 
 " At the sight of this fly the horse appears much agitated, 
 and moves his head backwards and forwards in the air to 
 baulk its touch and prevent its darting on the lips ; but the 
 fly, waiting for a favorable opportunity, continues to repeat 
 the operation from time to time ; till at length, finding this 
 mode of defence insufficient, the enraged animal endeavors 
 to avoid it by galloping away to a distant part of the field. If 
 it still continues to follow and tease him, his last resource is 
 in the water, where the (Estrus is never observed to follow 
 
30 BOARD OP AGRICULTURE. 
 
 him. At other times, this (Estrus gets between the fore-legs 
 of the horse whilst he is grazing, and thus makes its attack on 
 the lower lip. The titillation occasions the horse to stamp vio- 
 lently with his fore-foot against the ground, and often strike 
 with his foot, as if aiming a blow at the fly. They also some- 
 times hide themselves in the grass, and as the horse stoops to 
 graze, they dart on the mouth or lips, and are always observed 
 to poise themselves during a few seconds in the air, while the 
 egg is preparing on the point of the abdomen." The eggs are 
 darker colored than those of the common bot-fly, and contain 
 a nearly developed embryo, so that they very soon hatch, and 
 the young larvas are transferred to the mouth by the tongue, 
 and thence get into the stomach. 
 
 In other countries there are still other species of bot-flies 
 that infest the horse, ass, and mule ; among them Gast- 
 rophilus inermis Br., which lives in the horse ; 6r. flavipes 
 Oliv., which inhabits the stomach of the ass and mule ; and a 
 species of Hypoderma, which lives beneath the skin of all three. 
 But I am not aware that either of these has been observed in 
 this country. 
 
 The Meat-fly, Blowflies, etc. Figure 27. 
 
 These flies are not true parasites, but naturally feed, while 
 in the larval state, upon decaying flesh and other animal 
 matter. Their larvae are, however, frequently Fio . 07 
 found in wounds and sores, both of animals 
 and men, feeding upon the purulent matter, 
 and when allowed to live undisturbed, not uii- 
 unfrequently attack the living flesh, when 
 their food becomes exhausted ; and in this wa, 
 if they gain access to wounds in large numbers, 
 they will not only greatly aggravate and enlarge 
 them, but in many cases, when neglected for a 
 short time, they have caused the death of men 
 and animals by actually eating away living tis- 
 sues. The females in this group of flies are 
 viviparous, the eggs being retained in capa- 
 
 Figure 27. Larva or maggot of the Blue-bottle fly (Musca Ccesar Linn.), en- 
 larged. From Packard's Guide. 
 
PARASITES OP ANIMALS. 81 
 
 cious spiral dilations of the oviducts, until hatched into small 
 larvae or maggots, when they are deposited by the mother, with 
 almost unerring instinct, upon or near decaying flesh. The 
 female flesh-fly {Sarcophaga carnaria Linn.), is said to de- 
 posit at least 20,000 of these young larvae. They are ready 
 to commence feeding at once, and grow with remarkable 
 rapidity, often becoming half an inch long in two or three 
 days. When mature, they crawl out of the flesh and change 
 to long-oval, brown pupae, in the earth or any other conven- 
 ient place, and the mature flies come forth in a few days. 
 By this rapid increase the progeny of a few pairs would in a 
 short time devour the carcass of a large animal. The blue- 
 bottle fly {Musca Ccesar Linn.), the meat-fly (Musca vomi- 
 toria Linn.), and others allied to them, are common and well 
 known species, having similar habits. The larvae of all these 
 are long, soft-bodied, footless maggots, smaller toward the 
 head, thicker and blunt behind. The larva of the blue-bottle 
 fly is represented in Figure 27. The eggs or larvae and 
 those of other similar flies are not rarely swallowed with 
 food by men and animals, and are capable of living, for a 
 time at least, in the stomach and intestine, sometimes giving 
 serious trouble. To keep them out of wounds or sores, the 
 old females should be kept away. If this cannot be done by 
 bandages, frequently washing the wounds with a weak solu- 
 tion of carbolic acid will be an effectual remedy and pre- 
 ventive. 
 
 PARASITES BELONGING TO THE HEMIPTERA. 
 
 The parasitic Hemiptera are all degraded, and mostly 
 wingless forms, belonging to three very different families : 
 the Cimicidce, including the bed-bug; Pediculidoe, including 
 the true lice ; and the Mallophagidce, including bird-lice, etc. 
 
 This family, as restricted by Westwood, includes only the 
 genus Cimex, or the bed-bug and its allies. These have a 
 smoothish, oval, flat body, with a broad metathorax ; a small 
 head ; a slender, three-jointed proboscis or beak, which reaches 
 as far as the front legs when folded down, and slender, four- 
 
32 BOARD OF AGRICULTURE. 
 
 jointed antennae, the last joint not enlarged or clavate. They 
 seldom, if ever, have wings. In addition to the common bed- 
 bug, there are species infesting pigeons (<7. columbarim 
 Jenyns) ; swallows (C. hirundinis J.) ; and bats ((7. pipistrelli 
 J.). It is doubtful, however, whether all these be not identical 
 with the common species. At any rate, it appears that the 
 common bed-bug will attach itself to bats and various birds, 
 when opportunities occur. 
 
 The Bed-Bug, (Cimex lectularius Linn.). Figure 28. 
 
 This species has long been notorious. It was mentioned 
 by Pliny, Aristophanes, Aristotle, Dioscorides, and other an- 
 cient writers. Yet English writers have argued that it was 
 first carried to that country from America, and thence to 
 the continent of Europe. Moffitt mentions it, however, as 
 having been seen in England as early as 1503, though it does 
 not appear to have been common there until a century later. 
 Its early English name was " wall louse " ; the term " bug " 
 was applied to it much later, its original meaning having been 
 nearly synonymous with " bug-bear." 
 
 At the present day this insect is sufficiently common 
 throughout the civilized world, if not among the barbarians 
 also. Its form and general appearance are well shown in Fig- 
 ure 28, which represents it considerably larger than ordinary 
 specimens. Its size varies greatly, however, according to its 
 locality and the amount of blood it has been able to imbibe. 
 Its color, when young, is pale yellowish, the blood in the in- 
 testine showing through; as it grows older it becomes darker, 
 until, when full grown, it is reddish brown, the color being 
 darker when filled with blood. The eyes are small and bright 
 red ; the proboscis is much like that of the ordinary blood- 
 sucking Hemiptera, which prey on other insects ; the labium 
 forms a three-jointed sheath or tube, the middle joint being 
 broadest, the last one sharply pointed ; the labrum is broader 
 than the basal joint, which it overlaps. According to Dr. 
 Packard, the internal structure is as follows: " The mandibles 
 and maxilla3 arise near each other, in the middle of the head, 
 opposite the eyes, their bases slightly diverging. Thence they 
 converge to the mouth, over which they meet, and beyond are 
 
PARASITES OP ANIMALS. 33 
 
 free, being hollow, thin bands of chitine, meeting like the 
 maxillas, or tongue, of butterflies, to form a hollow tube for suc- 
 tion. The mandibles each suddenly end in a curved, slender 
 filament, which is probably used as a tactile organ to explore 
 the best sites in the flesh of their victim for 
 Figure 28. ^ drawing blood. On the other hand, the 
 maxilla3, which are much narrower than the 
 mandibles, become rounded toward the end, 
 bristle-like, and tipped with numerous ex- 
 'ceedingly fine barbs, by which the bug 
 anchors itself in the flesh, while the blood is 
 pumped through the mandibles. The base 
 of the large, tubular labium, or beak, which ensheathes the 
 mandibles and maxilla?, is opposite the end of the clypeus, or 
 front edge of the upper side of the head, and at a distance 
 beyond the mouth equal to the breadth of the labium itself. 
 The labium, which is divided into three joints, becomes flat- 
 tened toward the tip, which is square, and ends in two thin 
 membranous lobes, probably endowed with a slight sense of 
 touch." At the same time that the blood is sucked up, some 
 poisonous secretion or saliva is introduced into the wound, 
 perhaps to render the blood more liquid. To some persons 
 these bites are extremely poisonous and cause large inflamed 
 swellings and violent itching, while in other persons no such 
 effects occur, and the bites are scarcely noticed. 
 
 These insects are inclined to be gregarious in their habits, 
 and are fond of herding together, a dozen or more in aplace, 
 whether in a crack, knot-hole, chink in the walls of houses, or 
 any snug corners about a bedstead. They are also fond of 
 returning constantly to the same hiding-place, morning after 
 morning, after their nocturnal raids, just as many birds re- 
 turn regularly to their roosts. On this account their retreats 
 become discolored by dark spots of excrement. When 
 much disturbed, or when food fails, they will disperse, how- 
 ever, and each one will migrate on its own account. In the 
 night they are quite lively and nimble, and run about with 
 
 Figure 28. Bed-bug (Cimex leetularius Linn.), enlarged. The straight line 
 shows the ordinary length. From Packard's Guide. 
 
 5 
 
34 BOARD OP AGRICULTURE. 
 
 great rapidity, and can then evidently see better than by day. 
 They are capable of making long journeys even during the day? 
 and may thus migrate from house to house. They are, how- 
 ever, not restricted to human dwellings or to human blood, 
 for they often take up their residences in poultry houses and 
 yards, at times completely swarming in such, places. They 
 will also attack dogs and cats, and may live about the places 
 where those animals sleep. They have even been found in 
 the woods under the bark of dead trees. The same species, 
 apparently, also attacks bats, and may thus enter houses. In 
 fact, there are a great many ways in which they may get into 
 the best of houses, besides the well known method of adhering 
 to clothing, etc. It is, therefore, no disgrace to any house- 
 keeper that a bug should now and then be detected in the 
 house ; but the disgrace consists in allowing them to remain 
 undisturbed until their numbers increase to a great extent, as 
 they will most surely do if neglected. Many kinds of Hem- 
 iptera, like the squash-bug, etc., have the power of forming a 
 peculiar odorous secretion, which, from the similarity of the 
 odor, probably consists in part of formate of amylic ether ; 
 but in the bed-bug this odor is combined with others that 
 are far more disagreeable. 
 
 The eggs are long-oval and white, and are laid in clusters 
 in the cracks, etc., about bedsteads and other places that they 
 frequent. The young hatch by forcing off one end of the egg- 
 shell like a lid. The young, when first hatched, are whitish 
 and translucent, and although having three legs and the gen- 
 eral features and habits of the old ones, they differ considerably 
 in form, being more louse-shaped. They have a broader and 
 more triangular head, and shorter and thicker antenna. 
 They cast their skins several times during growth, each time 
 looking a little more like the adult than before. It is said 
 that they require eleven weeks to -mature, but this probably 
 differs according to the temperature and food. They are, 
 however, lively and blood-thirsty from the first, and are well 
 able to look out for themselves. Their skill in finding a 
 sleeping person and reaching him is marvelous indeed. 
 
 In ordinary cases there is no great difficulty in eradicating 
 
PARASITES OF ANIMA.LS 35 
 
 these insects completely, if a proper amount of care is be- 
 stowed in the way of keeping the house and beds clean and 
 neat. The principal trouble arises from neglect on the part 
 of housekeepers to examine the beds frequently, for, as al- 
 ready intimated, no bed is sure to escape their attentions for 
 any great length of time, especially in cities, where they may 
 at any time walk in from some neighbor's house for a friendly 
 visit or morning call. 
 
 When they are merely located in bedsteads, or bedding, there 
 is no better way than to make a careful and thorough examina- 
 tion of all cracks and corners, and when any are seen, a little 
 benzine poured upon them will kill them instantly, and the 
 benzine should be poured into all suspicious cracks, which 
 cannot otherwise be reached. Scalding hot water thoroughly 
 applied is also effectual, but is liable to injure the varnish of 
 furniture. One examination of a bed is seldom sufficient, for 
 eggs that have escaped observation, may subsequently hatch. 
 Therefore two or three searches, with benzine in hand, should 
 be made at intervals of a week or ten days. The use of cor- 
 rosive sublimate and similar poisons is unnecessary and 
 objectionable, for such preparations are not more dangerous 
 to the bugs than to the persons who occupy the beds, and are 
 less fatal, even when applied directly to the bugs, than ben- 
 zine. When the bugs have also taken up their residence in 
 the cracks and crevices in-the walls of old houses, it is much 
 more difficult to destroy them. If very bad, the house, when 
 empty, may receive a thorough fumigation with burning sul- 
 phur, which will generally prove very effectual. Hen-houses 
 and other out-buildings may be thoroughly drenched with a 
 mixture of crude petroleum and water, or with the solution 
 of carbolic acid. 
 
 Bed-bugs are extremely tenacious of life and have wonder- 
 ful powers of fasting. They have been kept hermetically 
 sealed in glass bottles for more than a year without any food, 
 and were still lively and had a good appetite. 
 
 PEDICULID^. 
 
 This family includes the ordinary lice of man and quadru^ 
 peds, which are furnished with a sucking mouth. They are 
 
36 
 
 BOARD OP AGRICULTURE. 
 
 Figure 29. 
 
 very low, degraded Hemiptera, destitute of wings. The head 
 is small, conical, and narrow ; the thorax is small and in- 
 distinctly separated into segments ; the 
 abdomen is large, flattish, rounded or 
 oval, with nine segments. The antenna 
 are very slender and five-jointed. The 
 eyes are simple and very minute. The 
 feet, or tarsi, have two joints, the 
 last joint forming a strong hook for 
 grasping the hairs firmly while crawling 
 and climbing among it. The mouth- 
 parts form a long and extremely slender 
 fleshy tube, which is retracted when not 
 in use, and is capable of being intro- 
 duced into the skin, for the purpose of 
 sucking blood. The structure of the 
 mouth is as follows, according to 
 Schiodte : u The peculiar attenuation of 
 the head in front of the antennae at once 
 suggests to the practised eye the exist- 
 ence of a mouth adapted for suction. 
 This mouth differs from that of Rhyn- 
 chota [Hemiptera, bed-bug, etc.] gen- 
 erally, in the circumstance that the 
 labium is capable of being retracted into 
 the upper part of the head, which there- 
 fore presents a little fold, which is ex- 
 tended when the labium is protruded. 
 In order to strengthen this part, a flat 
 band of chitine is placed on the under 
 surface, just as the shoemaker puts a 
 
 Figure 29. Proboscis of body-louse (Pediculus corporis DeG6er), entirely pro- 
 truded and seen from above, magnified one hundred and sixty times ; aa, the 
 summit of the head, with four bristles on each side ; bb, the chitinous band, and 
 c, the hind part of the lower lip such as they appear through the skin by strong 
 transmitted light; dd, the foremost protruding part of the lower lip (the haus- 
 tellum); ee, the hooks turned outwards ; /, the inner tube of suction, slightly 
 bent and twisted ; the two pairs of jaws are perceived on the outside as thin 
 lines ; a few blood globules are seen in the interior of the tube. From American 
 Naturalist. 
 
PARASITES OF ANIMALS. 37 
 
 small piece of gutta-percha into the back of an India-rubber 
 shoe ; as, however, the chitine is not very elastic, this band is 
 rather thinner in the middle, in order that it may bend and 
 fold a little when the skin is not extended by the lower lip. 
 The latter consists, as usual, of two hard lateral pieces, of 
 which the fore ends are united by a membrane so that they 
 form a tube, of which the interior covering is a continuation 
 of the elastic membrane in the top of the head ; inside its 
 orifice there are a number of small hooks, which assume 
 different positions according to the degree of protrusion ; if 
 this is at its highest point the orifice is turned inside out, like 
 a collar, whereby the small hooks are directed backward, so 
 that they can serve as barbs. These are the movements 
 which the animal executes after having first inserted the 
 labium through a sweat-pore. When the hooks have got a 
 firm hold, the first pair of setae (the real mandibles trans- 
 formed) are protruded ; these are, towards their points, united 
 by a membrane so as to form a closed tube, from which, 
 again, is exserted the second pair of setae, or maxillae, which 
 in the same manner are transformed into a tube ending in 
 four small lobes placed crosswise. It follows that when the 
 whole instrument is exserted. we perceive a long membranous 
 flexible tube hanging down from the labium, and along the 
 walls of this tube the setiform mandibles and maxillae in the 
 shape of long narrow bands of chitine. In this way the tube 
 of suction can be made longer or shorter as required, and 
 easily adjusted to the thickness of the skin in the particular 
 place where the animal is sucking, whereby access to the 
 capillary system is secured at any part of the body. It is 
 apparent, from the whole structure of the instrument, that it 
 is by no means calculated for being used as a sting, but is 
 rather to be compared to a delicate elastic probe, in the use of 
 which the terminal lobes probably serve as feelers. As soon 
 as the capillary system is reached, the blood will at once 
 ascend into the narrow tube, after which the current is con- 
 tinued with increasing rapidity by means of the pulsation of 
 the pumping ventricle and the powerful peristaltic movement 
 of the digestive tube." 
 
38 BOARD OP AGRICULTURE. 
 
 The various species of these lice have similar habits, and all are 
 blood suckers, but each species inhabits only certain kinds of 
 animals, and some are restricted to particular parts of the 
 skin. Many animals have two or more species of these para- 
 sites. Five species have been described as parasitic upon man, 
 though but three are common. 
 
 When they become very abundant, as they soon will if the 
 animals upon which they once get well established be neg- 
 lected, they cause great irritation of the skin and nervous 
 system, and the itching that they produce causes the animals 
 to rub themselves against buildings, fences, etc., and thus the 
 hair is often worn off and the skin abraded. Such animals 
 generally soon become weak and emaciated, and are, there- 
 fore, more liable to be attacked by other diseases. 
 
 There are various washes which, if properly applied, will 
 very rapidly destroy all species of lice, without much trouble. 
 The use of preparations of mercury and arsenic, and all similar 
 poisons, should be avoided, for they often poison the animals, 
 as well as the persons who use them, and thus the remedy 
 may be worse than the disease. 
 
 A strong solution of tobacco, made by boiling cheap tobacco 
 in water, is an effectual remedy, in common use. Snuff 
 rubbed into the hair is also used. Ordinary whale-oil, such as 
 was formerly used in lamps, poured upon the skin along the 
 back of an ox, cow, calf, or sheep, will diffuse itself over the 
 skin and kill the lice. Weak petroleum water, or carbolic 
 acid solution, or carbolic soap, may be used as a wash, or 
 small animals may be immersed in a bath, taking care to 
 keep the nose, mouth, and eyes out of it. But perhaps one of 
 the best and simplest, as well as safest, washes for this pur- 
 pose, as well as to destroy fleas, mites, itch-insects, mange- 
 acari, and all other external parasites of man and animals, is 
 a solution of sulphuret of potassium in water, two to four 
 ounces to the gallon of cold water, varying the strength ac- 
 cording to the age and tenderness of the skin of the animal, 
 for the solution will contain some free potash, which, if too 
 strong, might irritate a delicate skin. There is otherwise no 
 danger from its use, though its odor, like sulphuretted hydro- 
 
PARASITES OF ANIMALS. 39 
 
 gen, is disagreeable, and it should be used, therefore, where 
 there is plenty of ventilation. This is an exceedingly valua- 
 ble remedy, also, for the itch of man, as well as the " mange" 
 of animals. The sulphuret of potassium comes in the form 
 of grayish or greenish lumps, put up in tight bottles. It is 
 used in photography and can usually be bought at the princi- 
 pal drug stores. 
 
 An equally useful preparation, having the same properties, 
 may be easily made by taking fresh quick-lime, slacking it 
 gradually with water, and forming a milky solution by the 
 addition of more water, as in the preparation of white-wash. 
 Into this put as much flowers of sulphur as will dissolve by 
 boiling for some time. This will produce a deep yellow solu- 
 tion like that of the sulphuret of potassium in odor and 
 effects. It may be diluted if too strong. It contains sul- 
 phuret of calcium, upon which its usefulness depends. Sul- 
 phur may also be boiled in potash lye, to produce a similar 
 preparation, and to this, while boiling, tobacco is sometimes 
 added, but the sulphur is, no doubt, sufficient for all practical 
 purposes. But in no case can we be certain of destroying all 
 the eggs of these parasites by any wash whatever, that would 
 not be dangerous to the animal. Therefore the treatment 
 should be repeated two or three times, at intervals of ten or 
 twelve days, in order to destroy any young that may have 
 hatched in the meantime. 
 
 The Head-louse of man (Pediculus capitis DeGder). Fig. 30. 
 This is, probably, the best known species of the genus 
 Pediculus. It is still sufficiently common among persons who 
 Figure so. neglect personal cleanliness, though much less 
 so than it is said to have been formerly , when it 
 was thought no disgrace in some parts of the 
 old world, but was regarded as fashionable, 
 rather than otherwise. This insect is almost 
 exclusively confined to the human head. It 
 attaches its eggs firmly to the hair, near the 
 roots. These eggs are long-oval, with several 
 little conical prominences at the large end, 
 
 Figure 30. Head-louse (Pediculus capitis DeGcer), greatly magnified. 
 From Packard's Guide. 
 
40 BOARD OF AGRICULTURE. 
 
 which are open at the top, while the small end oears a cluster 
 of bristles. The habits and treatment are too well known to 
 need further description. 
 
 The Body-louse of Man (Pediculus corporis DeGeer). 
 
 Figure 31. 
 
 This species very closely resembles the last, but is usually 
 larger. It attaches itself especially to the clothing, and at- 
 tacks various parts of the body. It attaches its eggs chiefly 
 to the clothing which it frequents, especially Figure si. 
 
 along the seams, and when the clothing is sel- 
 dom changed, as often necessarily happens in 
 time of war, it increases rapidly and becomes 
 a great source of annoyance. Many unfortu- 
 nate soldiers, who were confined in the south- 
 ern prisons and prison-pens during the late 
 war, can testify to the abundance of this par- 
 asite under such circumstances. Nor were 
 the ordinary camps free from them, especially during active 
 campaigns. 
 
 The Crab-louse (Phthirius puUs Leach). Figure 32. 
 
 In the genus Phthirius the thorax is broad and not distinct 
 from the abdomen, which is flat and has eight segments, the 
 first one being composed of two united. Figure 32. 
 
 The first pair of legs are terminated by 
 slender tarsi, not changed to grasping 
 claws, but the claws of the other two 
 pairs are large and strong. 
 
 This species lives among the hairs of 
 the pubic regions of man, and also, 
 though much less commonly, upon the breast, arm-pits, in the 
 beard, eye-brows, and also upon the head. It sometimes also 
 clings to linen and clothing, and, not unfrequently, may be 
 found in the beds of those persons harboring them. They 
 may be destroyed by simple ointments and unguents, or by 
 the sulphuret washes described above. 
 
 Figure 31. Body-louse (Pediculus corporis DeGe ), greatly magnified. From 
 Packard's Guide. 
 
 Figure 32. Crab-louse (Phthirius pubis Leach), much enlarged. From Pack 
 ard's Guide. 
 
PARASITES OF ANIMALS. 
 
 41 
 
 Figure 33. 
 
 The Cattle-louse (Hcematopinus vituli Denny). Figure 33- 
 In the genus Hcematopinus, which includes a large number 
 of species, the head is obtuse or truncated in front, the middle 
 segments of the abdomen well separated, and the posterior 
 legs much the longest. The eyes are very minute. They are 
 all small and some are minute species. 
 
 H. vituli is brownish, with a pale 
 abdomen, the abdominal segments 
 bearing lateral chitinous pieces, in 
 which the spiracles are situated. The 
 head is elongated with a constriction 
 behind the antennse. It is about j 1 ^ 
 of an inch in length, or a little more. 
 It is parasitic both on cattle and horses, 
 and sometimes becomes very abun- 
 dant. 
 
 Another species (H. eurysternus 
 Denny), also infests both cattle and 
 horses. In this the head, thorax, and feet are horn-colored. 
 The thorax is very broad. The length is about T V of an 
 inch. 
 
 The Hog-louse (Hcematopinus suis Leach). Figure 34. 
 Figure 34. This species is brown, with a white 
 
 abdomen. The spiracles are placed in 
 blackish, horny plates along each 
 side of the abdomen. Length -J of an 
 inch. 
 
 H. stenopsis infests the goat. It is 
 a horn-colored species, with along oval 
 hairy abdomen. 
 
 If. asini Denny is parasitic on the 
 ass. 
 
 H. piliferus Denny lives upon the dog. It is uniformly 
 horn-colored. The body is slender and covered with pale 
 hairs. Length $ of an inch. 
 
 Figure 33. Cattle-louse (Hcematopinus vituli Denny), much enlarged. From 
 American Naturalist. 
 
 Figure 34. Hog-louse (H. suis Leach), much enlarged. From Cuvier. 
 6 
 
42 
 
 BOARD OP AGRICULTURE. 
 
 MALLOPHAGA (Bird-lice). 
 
 These insects live both among the feathers of birds and hair 
 of mammals. They are peculiar in having distinct jaws (Figure 
 36), instead of a sucking tube. The body is flat, corneous, 
 and firm above. The head is horizontal and generally broad. 
 The antennae have three to five joints. The mandibles are 
 small and hook-like. The maxillary palpi, when present, are 
 four-jointed ; and the labial palpi two-jointed. The legs are 
 short and stout,, with one or two strong claws. There are sev- 
 eral hundreds of species already described, nearly every bird 
 having one or several peculiar species. They produce nearly 
 the same effects as the true lice, and may be destroyed by the 
 same remedies. 
 
 Figure 35. 
 
 a Figure 36. 
 
 The Turkey-louse (Goniodes stylifer Denny). 
 
 This is a large species, conspicuously marked with transverse 
 black bands. It is very common both on the domestic and 
 wild turkey, together with three or more other species, one of 
 which is much longer and nearly black. Some of the other 
 species parasitic on the turkey are Liotheum stramineum 
 Nitzsch, Philoplerus polytrapeziusNitzsch. 
 
 The Hen-lice (Liotheum pallidum Nitzsch, Philoplerus 
 variabilis N., P. heterographus N., P. dissimilis N., and P. 
 
 Figure 35. Turkey-louse ( Goniodes stylifer Denny), much enlarged. 
 Figure 36. Head of same, seen from below, more magnified ; a, mouth organs ; 
 b, antenna. Both from Cuvier. 
 
PARASITES OF ANIMALS. 
 
 43 
 
 ho/og-aster N., Gf-oniocotes Burnettii Packard, Figure 37) are 
 common enemies of domestic fowls. 
 
 Figure 37. 
 
 Figure 38. 
 
 The Pigeon-lice (Liolheum giganteum Denny, Philopterus 
 bar/ulus Nitzsch, Nirmus clavicornis, Goniodes compar N.) 
 infest domestic pigeons. 
 
 Figure 39. 
 
 Figure 40. 
 
 The Goose-louse ( Trinotum squalidum Denny) is found with 
 other species on the goose. 
 
 The Duck-lice (Philopterus squalidus Nitzsch), Figure 38, 
 with other species, inhabit the common duck. 
 
 Figure 37. Hen-louse (Goniocotes Burnettii Pack.). American Naturalist. 
 Figure 38. Duck-louse (Philopterus squalidus N.) From Gervais. 
 Figure 39. Cat-louse (Trichodectes subrostratwN.) From American Naturalist. 
 Figure 40. Goat-louse (T. caprce Packard). From American Naturalist 
 
44 BOARD OF AGRICULTURE. 
 
 The Peacock-lice (Philopterus faldcornis N., P. reclangula- 
 tus N.) are very common on the peacock. 
 
 The Cat-louse (Tricliodectes subrostratus Nitzsch), Figure 
 39, is one of the parasites of the house cat. This species is 
 whitish, with the head and thorax pale honey-yellow. 
 
 The Goat-louse ( Trichodectes caprce Packard, probably the 
 same as T. limbatus Gervais), Figure 40, lives with other 
 species upon the domestic goat. It is reddish yellow, trans- 
 versely Barred with reddish brown, the abdomen edged with 
 red. 
 
 SUB-CLASS, ARACHNIDA. 
 
 ACARINA (Mites). 
 
 These are characterized by their simple,' usually rounded or 
 oval bodies, in which there is no distinct separation into 
 thorax and abdomen. They have eight legs, which are gen- 
 erally short, but when young many of them are six-legged. 
 The species are numerous. Their habits are very 
 diverse ; many are parasitic upon man, various quadrupeds, 
 birds, reptiles, insects, etc., some externally and others in- 
 ternally. Species have even been found within the abdo- 
 minal cavity and skull. Other species live under the water, 
 and are parasitic on mollusca. Many attack plants and prove 
 very injurious. Others are carnivorous and prey on small 
 insects. Some, like the meal-mite, sugar-mite, cheese-mite, 
 fig-mite, and many others attack and greatly injure articles of 
 food. Many lead a solitary, wandering life, others occur 
 together in vast numbers at certain times. 
 
 DERMANYSSUS DugGS. 
 
 The insects of this genus are small, soft-bodied parasites, 
 which infest various birds, bats, insects, and some of them 
 are at times parasitic upon man. 
 
 The fifth joint of the palpi is smallest. The lip is sharp. 
 The mandibles of the male are forceps-like, with long hooks ; 
 those of the female ensiform. The anterior feet are the 
 longest. Young with six legs. 
 
 Dermanyssus gallinoe is found among the feathers of the 
 domestic fowl, and lives by sucking the blood. 
 
PARASITES OP ANIMALS. 45 
 
 D. Grallopavonis infests the turkey. The body is marked 
 by peculiar, delicate, transverse strias, and with numerous 
 small circular impressions on the back. 
 
 D. avium torments small cage birds, like the canary. It 
 often takes refuge in cracks about the perches, which should 
 therefore be kept clean. 
 
 ARGAS Latreille. 
 
 This genus includes the famous Argas Persicus, which 
 infests old dwellings in Persia, especially at Mi ana, and is 
 said to be so poisonous that its bite produces convulsions and 
 speedy death ; or even its juices, if crushed upon the skin, 
 may produce the same results. 
 
 These are larger- than most of the mites, and somewhat 
 resemble the ticks. The body is broad-oval or roundish. 
 The upper side of the head so projects as to conceal the mouth 
 parts. The jaws are suctorial. The lower side of the body 
 is granulous, not scaly, and covered by a single piece. 
 
 Argas reflexus Latreille lives upon pigeons and sucks their 
 blood. It especially infests the young, upon which there are 
 sometimes great numbers. The body is marked with curious 
 tortuous grooves and pits. The color is yellowish, but when 
 filled with blood violaceous.. 
 
 IXODES Latreille. (Ticks). 
 
 These are the largest of the Acariaris, and all are parasitic, 
 chiefly upon quadrupeds and reptiles, but sometimes on birds. 
 The body is broad-oval or round, and when not swollen with 
 blood is flatish, and the integument is firm and tough. Their 
 mandibles (Figure 43, b,) are covered with teeth and have ter- 
 minal hooks ; their maxilla are small, not reaching beyond the 
 beak, but bear a peculiar organ called the glossoid (Figure 
 43, a,) also covered with hook-like teeth. The legs are slender 
 and have two claws, and in the young have pads or suckers 
 (d). The young are six-legged (Figure 42). The ovarial 
 opening is near the mouth, between the first pair of legs. 
 These parasites, when young, cling in large clusters to the 
 tips of leaves and twigs of herbs and shrubs, with part of 
 their six slender legs extended. When brushed by a passing 
 
46 
 
 BOARD OF AGRICULTURE. 
 
 animal, they instantly leave the plant and quickly disperse 
 over their host. They insert their glossoids and mandibles into 
 the skin, where they cling firmly by means of the numerous 
 hooks, and live by sucking the blood. The abdomen soon be- 
 comes very much swollen, and sometimes grows so large as to 
 resemble a tumor. They attack various animals and even man, 
 indiscriminately. In many parts of the Southern States the 
 " wood ticks " are extremely troublesome to persons who have 
 occasion to go into the forests, as well as to animals. The 
 eggs of Ixodes albipictus are laid in large masses, from the 
 first of May until the last of June. Early in July the eggs 
 hatch out simultaneously, " the shell opening like a clam." 
 The young when first hatched have six slender legs. 
 
 Figure 41. Figure 42. 
 
 tj 
 
 Figure 44. Figure 43. 
 
 The Cattle-tick (Ixodes bovis). Figure 41. 
 This is a flattened, leathery, reddish, seed-like species, with 
 an oblong-oval body. It sometimes grows to be nearly half 
 an inch long. It infests cattle, and is very troublesome in the 
 Western and Southern States, but is far less common in the 
 North. It also attacks the horse and many other quadrupeds, 
 as well as reptiles, including the rattle-snake. 
 
 Figure 41. Cattle-tick (Ixodes bovis Riley), enlarged. 
 
 Figure 42 Ixodes albiptctm Packard ; six-legged young, much enlarged ; d, 
 foot with sucker. 
 
 Figure 43. Head of the same, more enlarged ; a, glossoid ; b, mandibles ; c 
 maxillary palpi. 
 
 Figure 44. Adult of the same, gorged with blood, natural size. All from 
 Packard's Gu,ide. 
 
PARASITES OP ANIMALS. 47 
 
 Ixodes albipidus Packard. Figures 42, 43,44. 
 
 This was originally found upon a tame moose by Mr. W. 
 G. Hays, but doubtless infests other animals. 
 Ixodes unipictus Packard. 
 
 This is about a quarter of an inch long and has an oval 
 form. Is is reddish brown, or mahogany-color, with a central 
 silvery spot upon the back. It often attacks men and vari- 
 ous animals. It has been found in New England, but is more 
 common southward. 
 
 In Europe, numerous species have been found. 
 
 Ixodes vicinus is very troublesome to dogs. It is of a brown- 
 ish violet color, crenulated posteriorly. It has five radiating 
 brown spots and some brown dots. 
 
 Ixodes reduvius infest sheep and dogs. It has a pale red or 
 yellowish color, and becomes more than a quarter of an inch 
 long. It must not be confounded with the ordinary " sheep- 
 tick" (see page 89). 
 
 Mites, ACARUS Linn. 
 
 This genus, which originally included all the mites, is now 
 restricted to those that are allied to the cheese-mite. The 
 mouth parts are prolonged into a rostrum or beak. There is 
 a constriction of the body between the second and third pair 
 of legs, dividing it somewhat into two parts. 
 
 The Cheese-mite (Acarus siro Linn.). 
 This species ordinarily lives in cheese and other articles of 
 food; but has sometimes been observed parasitic upon man, in 
 certain diseased conditions. 
 
 The Meal-mite (Acarus farince De Ge*er). 
 
 This species, found in meal and flour that has been in- 
 jured is sometimes accidentally swallowed while living. 
 
 Acarus dysmterice Linn, was found living in the excreta of 
 a person attacked by violent dysentery. It also sometimes oc- 
 curs in large numbers about wine and beer casks, and may 
 therefore be swallowed accidentally. 
 
 Glycipliagus hippopodos has been found in the ulcerated feet 
 of horses. A species of mite also occurs in the diseased 
 feet of sheep. 
 
48 BOARD OP AGRICULTURE. 
 
 Mange-insect of the Horse {Psoroptes equi Gervais). 
 
 This insect is readily visible to the naked eye and swarms 
 on horses afflicted with the mange, which is a disease anala- 
 gous to the itch in man. It has a soft, depressed body, spiny 
 beneath at the base of the legs and on the thorax. One or 
 both >f the two posterior pairs of feet bear suckers, and all 
 are more or less covered with long slender hairs. 
 
 Figure 45. 
 
 Fig. 46. 
 
 This insect may be destroyed by the same remedies used for 
 lice and for the human itch. The best remedy is probably the 
 solution of sulphuret of potassium, described on page 109. 
 
 The Itch-insect {Sar copies scabieiL&tY.'). Figure 47. 
 This is a very minute, whitish species, barely visible to the 
 naked eye, unless on a dark surface. It has been, in former 
 times, the subject of many lengthy discussions, in reference 
 to its causing the itch. It is, however, at the present time 
 fully ascertained to be the sole cause of the ordinary itch, 
 though other species of similar parasites may cause different 
 varieties of itch. The body is rounded and soft, with small 
 round pustules on the middle of the back, and with radiating 
 lines or ridges, the sides of the body and legs bearing long 
 bristle-like hairs. The mandibles are needle-like. The 
 female is largest and has the two pairs of hind legs but little 
 developed, ending a bristle ; in the male they are well devel- 
 oped and terminate in a slender sucker. These creatures, as 
 seen under the microscope, have something of the unwieldy 
 
 Figure 45. Psoroptes equi Gervais, female ; ventral side, much enlarged. 
 Figure 46. Head of the same, more magnified. Both from Cuvier. 
 
PARASITES OF ANIMALS. 
 
 49 
 
 Figure 47. 
 
 appearance of a tortoise, and are ordinarily sluggish, yet they 
 are capable of leaping to a considerable distance. They bury 
 themselves in the human skin, especially in the more delicate 
 and less exposed parts, and excavate minute galleries for them- 
 selves, in a manner something like that 
 in which moles excavate galleries in 
 the soil. These galleries are at first 
 perpendicular, and then go off horizon- 
 tally to some distance. The females 
 lay their eggs in these galleries as 
 they progress. 
 
 These mining and boring operations 
 cause much irritation of the nerves of 
 the skin and induce an intolerable itch- 
 ing, and the inflammation that they 
 cause produces pustules, filled with a 
 watery exudation. The insects them- 
 selves are not found in the pustules but 
 in their minute galleries, off to one 
 
 side, the pustule generally marking the place where they en- 
 tered. The itch is contagious, simply because the insects, 
 especially in their young and more active state, pass from one 
 person to another, or are transmitted by clothing. They are 
 most active at night and, therefore, sleeping with an infested 
 person is pretty sure to be attended by the transfer of the 
 insects. The longer the parasites are neglected, the more 
 numerous they become. .The increase is, however, quite slow 
 at first, owing to the small number of eggs. There are 
 various remedies for this disease, but the different preparation 
 of sulphur are no doubt the best and safest. The solutions 
 of sulpha ret of potassium, described on page 109, is probably 
 the simplest and most efficacious preparation for this purpose. 
 Its use should be accompanied by a thorough change of gar- 
 ments and bedding, and it should be used by all the members 
 of an infected family simultaneously. It should be appliedat 
 
 Figure 47. Itch-insect (Sarcoptes scabiei Latreille), female, upper side, much 
 enlarged. From Guerin. 
 
 7 
 
09 BOARD OF AGRICULTURE. 
 
 least three times, at intervals of three or four days, to destroy 
 the young as fast as they hatch. 
 
 Species of Sarcoptes, closely allied to the itch-insect, have 
 been found on the domestic animals, causing diseases analo- 
 gous to the itch in man. Such diseases, caused by quite a 
 number of distinct parasites, are called " mange." They 
 have been observed on the cat, dog, camel,* and hog. 
 
 The genus Dermatodectes is closely allied to Sarcoples, and 
 the species likewise live on animals, burrowing in the skin. 
 D. bovis infests cattle, and D. ovis lives in the skin of sheep. 
 The genus Dermaleichus infests birds in a similar manner. 
 
 All these parasites should be treated like the itch-insect of 
 man. The sulphuret of potassium solution, applied with a 
 brush that has long bristles, like a white-wash brush, is 
 probably the best and simplest remedy. 
 
 The Face^mile (Demodex folliculorum Owen). Figure 48. 
 
 This singular but minute parasite lives in the diseased and 
 enlarged follicles in the skin of the human face, especially in 
 those about the nose and chin. The follicles, when thus dis- 
 eased, are enlarged and filled with a thickened 
 sebaceous matter, the orifice being usually ob- 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<irnal parasites of animals have long been the sub- 
 ject of laborious and careful research by many of the ablest 
 naturalists and physiologists,* owing to the remarkable 
 
 *The following are some of the more important and useful of the recent gen- 
 eral works on parasitic worms : 
 
 Felix Dajardin, Histoire naturelle des Helminthes au vers intestinaux, 8vo, 
 with plates, Paris, 1845. (Suites a Buffon.) 
 
 C. M. Diesing, Systema Helminthum. Two volumes, 8vo. Vindobonae, 1850. 
 
 J. Leidy. A Flora and Fauna within living animals. Smithsonian contribu 
 tions, 1852. 
 
 C. Davaine, Traite" des Entozoaires et des mala-lies vermineuses de rhomme et 
 des animaux domestiques, 8vo, 930 pages, with 88 figures. Paris, 1860. 
 
 D. F. Weinland. An Essay on the tape-worms of man ; 8vo pamphlet, with 
 figures. Cambridge, Mass., 1858. 
 
 T. S. Cobbold. Entozoa ; an Introduction to the study of Helminthology, with 
 
PARASITES OP ANIMALS. 53 
 
 peculiarities of their structure, habits, andmodes of reproduc- 
 tion, as well as to their great practical importance with refer- 
 ence to human health and property. 
 
 The total number of species hitherto described, from all 
 animals, is more than 2,000. Of these upwards of 100 species 
 are found in domestic animals and man. 
 
 The parasitic worms of man and domestic animals are nat- 
 urally divided into four principal orders, which are character- 
 ized by important anatomical and physiological peculiarities. 
 I. CESTODES. (Tape-worms). 
 
 This order includes the numerous kinds of tape-worms and 
 their young, the " measles," hydatids, and bladder-worms, 
 found in more or less abundance in all classes of vertebrate 
 animals, as well as in insects, mollusca, etc. These tape- 
 worms belong to three very distinct families and to numerous 
 genera. About 250 species have been hitherto described. 
 
 These worms in the sexually mature condition have a more 
 or less enlarged roundish, oval, angular, or lobedhead, desti- 
 tute of a mouth, but provided with two or four suckers, or 
 pits, and often with one or four proboscis-like organs, sur- 
 rounded by hooks, by means of which they fasten themselves 
 securely to the mucous membrane of the intestine of the 
 animal in which they live. There is no intestine or other di- 
 gestive system. The head is followed by a series of many 
 flattish joints or segments, those near the head being small 
 and short, while those that are more distant are larger and 
 usually oblong or squarish. These joints, as they mature, are 
 spontaneously detached and may enjoy a short independent 
 existence, and are then called proglottides. Each joint con- 
 tains distinct male and female reproductive organs, and 
 matures a vast number of eggs, which are generally liberated 
 
 reference more particularly to the internal parasites of man. Large 8vo, 480 
 pages, *with numerous figures and 21 plates. London, 1864. 
 
 J. L. W. Thudichum. On the Parasitic Diseases of Quadrupeds used for food. 
 In the Seventh Report of the medical officer of the Privy Council, p. 303. Lon- 
 don, 1865. 
 
 T. S. Cobbold. Tape-worms (Human Entozoa), their sources, nature, and treat- 
 ment; 12mo, 83 pages, with figures. London, 1866. 
 
 R. Leuckart, Die Menschlichen Parasiten, und die von ihnen herrahrenden 
 Krankhciten. Two volumes, 8vo, with numerous figures. Leipzig and Heidel- 
 berg, 1862 to 1868. 
 
54 BOARD OP AGRICULTURE. 
 
 from the enclosing proglottid after the latter has been dis- 
 charged from the animal that nourishes the parent tape-worm. 
 The eggs usually escape by the bursting of the integument of 
 the proglottid, owing to their increase in size, as the embryos 
 develop within them. While attached to the tape-worm the 
 successive joints are connected -together by longitudinal tubes 
 or ducts that pass through the entire length of the worm-, gen- 
 erally one near each edge of the joints. These are connected 
 together by transverse tubes in each end of the successive 
 joints (Figure 54). 
 
 The reproductive organs occupy variously branched and 
 ramified cavities in the interior of the joints, communicating 
 by ducts with the external male and female organs, which are 
 placed side by side, either on the edge of each joint, as in 
 Tcenia, or in the middle of one side, as in BotTiriocephalus. 
 The remainder of the joint is composed of a firm, more or 
 less solid tissue. 
 
 All the species of this order undergo remarkable metamor- 
 phoses ; the larva living in one animal must be swallowed by 
 another before it can become mature. 
 
 II. TREMATODES. (Flukes). 
 
 This order includes a great number of more or less flattened 
 worms, of which the " fluke," frequently found in the liver of 
 sheep, causing the " rot," is an example (Figure 73). 
 
 The body is generally broad and more or less oval, some- 
 times elongated, but never divided into distinct joints. On 
 the lower side there is usually one or two prominent suckers, 
 and sometimes several. There is a small mouth on the lower 
 side, usually near one end, but no head. The mouth com- 
 municates with a small, dilated oasophagus or stomach, and 
 this with a more or less branched and subdivided, sometimes 
 arborescent, intestine, the branches ending in closed tubes or 
 blind-sacs. Another system of branched and often much sub- 
 divided tubes arises in the more or less solid tissues of the 
 body. These tubes are at first small, like rootlets, but grad- 
 ually uniting into larger and larger branches, finally empty 
 their contents into one or two main trunks, which open ex- 
 ternally by one, or sometimes two orifices, near the posterior 
 end of the body. This is called the water-vascular system, 
 
PARASITES OF ANIMALS. 55 
 
 and is supposed to perform the office of excretory organs, 
 analogous to the kidneys and liver of vertebrate animals. In 
 the central region of the body there is a well developed repro- 
 ductive system, both male and female organs being generally 
 contained in the same individual worm ; but in some species 
 the sexes are separate. All the -rest of the body, around these 
 organs, is composed of a rather firm and solid tissue, the or- 
 gans not being contained in a distinct cavity. 
 
 The species constituting this order are very numerous, be- 
 longing to several distinct families and many genera. About 
 400 species have been described. They are found in all classes 
 of vertebrate animals, and are numerous in their larval states 
 in many invertebrates, especially in fresh-water snails. They 
 particularly abound in fishes, frogs, and aquatic birds. Nearly 
 all the species undergo very remarkable transformations, with 
 alternate generations, some of them passing different stages of 
 their lives free in water, and then in two or more distinct an- 
 imals, as parasites. So that the adult forms, found in the 
 higher animals, are generally derived from larvae swallowed 
 in small mollusks, like the river snails, and perhaps in insects. 
 
 III. ACANTHOCEPHALA. (Thorn-headed worms.) 
 
 This order includes elongated, more or less cylindrical 
 worms, usually with the body encircled by distinct transverse 
 ridges and wrinkles, and which have at the anterior end a 
 prominent, elongated or conical, retractile proboscis, covered 
 with numerous recurved hooks, by means of which they at- 
 tach themselves to the mucous membrane in the intestine of the 
 animals that they inhabit. The body contains a large cavity, 
 in which the reproductive organs are contained. The sexes are 
 distinct. The ovary, situated in the anterior part of the body, 
 sets free large roundish masses of cells from which the ova are 
 afterward developed, while these masses, or " cocoons," are 
 free in the abdominal cavity, each mass containing a large 
 number of eggs, often several hundred. In the male the two 
 testicles are attached to the lower closed end of the digestive 
 sac, and are connected by ducts with the intromittent organ, 
 which is a slender spiculum, enclosed in a sheath, situated at 
 the posterior end of the body. 
 
56 BOARD OP AGRICULTURE. 
 
 4| 
 
 Many observers state that these worms have no mouth and 
 no digestive organs whatever, but obtain their nutriment by 
 absorbing the nutritive materials by which they are surrounded 
 in the intestine of their host directly into their own tissues, 
 after the manner of the tape-worms. M. Lespes* states, how- 
 ever, that Echinorhynchus clauceveps, found in the minnow, etc., 
 has a complete alimentary system. The mouth is very small, in 
 form of a pore, opening at the end of the proboscis and raised 
 upon a small mobile papilla. This mouth communicates with 
 a short digestive cavity, in the form of a blind sac. He states 
 that he has seen the refuse of the food ejected from the mouth. 
 
 Upwards of 100 species of these worms have been described, 
 nearly all of which are referred to the genus Uchinorhynchus. 
 
 They are especially abundant in birds and fishes. 
 
 Those species in which the development has been studied, 
 have a kind of alternate generation, the young embryo be- 
 ing very different from the parent, and afterward developing 
 in its interior another form, which in turn becomes like the 
 grandparent. M. Lespes states that E. clavceceps produces 
 " cocoons " containing 150 to 200 eggs. The embryos devel- 
 oped in the eggs are capable of moving while still in the shell, 
 and remain alive for a year. On feeding a snail with food 
 containing these eggs, they hatched in his intestine, and the 
 free embryos were quite lively and active, and furnished with 
 two pairs of hooks for boring purposes. They had consider- 
 able resemblance to the free embryos of tape-worms and no 
 doubt have similar habits, but they failed to undergo their 
 transformations in the snail. 
 
 Leuckart fed the eggs of E. proteus, found in the trout and 
 other fishes, to a small crustacean, Gammarus pulex. The eggs 
 hatched in a few days and the young embryos bored their way 
 through the intestine into the general cavity of the body, some 
 of them penetrating into the limbs. In the course of three 
 weeks they grew larger and the granular mass still in the inte- 
 rior of the body of these embryos developed into a distinct or- 
 ganism, which afterwards developed a proboscis, muscles, and 
 the other peculiar organs of an Echinorhynchus, becoming gradu- 
 
 *Journal de 1' Anatomic, 1864, p. 683 ; Gunther's Zoological Record, 1865, p. 747. 
 
k PARASITES OF ANIMALS. 57 
 
 ally more and more like its grandparent. It finally fills up 
 the whole interior of the body of the enclosing embryo, sexual 
 organs appear, and then the outer skin of the latter is cast off*. 
 Thus the young Echinorhynchus. is formed, but in order to be- 
 come mature it must be swallowed, with its crustacean host, 
 by some fish. In the intestine of the fish it becomes sexually 
 mature in about a week. 
 
 The giant Ecliinorhynchus of the hog (^JE. gigas). Figure 74, 
 is the only species known to infest domestic quadrupeds. 
 IV. NEMATODES. (Round-worms). 
 
 This order includes a great number of worms, which occur 
 in all classes of animals, both vertebrates and invertebrates, 
 together with some that are not parasitic, but live in water, 
 moist earth, or decaying animal or vegetable matters. They 
 are much more highly erganized than those of the preceding 
 orders. The pin -worms of children, the common round-worms 
 of man and domestic animals, and the notorious Trichina spi 
 ralis are examples of this order. (See figures 76 to 83.) 
 
 These worms are almost without exception long, round, and 
 rather slender, varying in length from a tenth of an inch or 
 less to three feet, or even more, and usually tapering to one or 
 both ends. The external surface of the body Js generally 
 smooth and uniform, without suckers or other appendages. In 
 the interior of the body there is a continuous visceral cavity, 
 containing a distinct digestive system, the intestine generally 
 extending from one end of the body to the other, and well de- 
 veloped reproductive organs, the sexes being separated. The 
 mouth is usually at the smaller end of the body and is often 
 surrounded by papillae or other organs. Some of the species 
 are viviparous, like Trichina ; others produce eggs, like the com- 
 mon round-worms and pin-worms. There is great diversity 
 in their habits and modes of development. Some of them 
 pass through alternate generations and remarkable trans- 
 formations, living in some cases, like Trichina, in two different 
 animals in the larval and adult states, in other cases pass- 
 ing the young states in the water, as free worms, and after- 
 wards becoming parasitic, when swallowed by the proper ani- 
 mal, in which alone they develop their reproductive organs 
 
'58 BOARD OF AGRICULTURE. 
 
 and become mature. Some species seem to have a much 
 more simple history during development. There are but few 
 species, however, of which the complete history is known. 
 The Trichina spiralis is, perhaps, better understood in all 
 stages of its life than any other species. Important discov- 
 eries remain to be made, without doubt, concerning other 
 species that infest our own bodies, as well as those of our 
 domestic animals ; At present the complete histories of the 
 two commonest human parasites, the round-worm and pin- 
 worm, are still unknown, although they have been most care- 
 fully investigated and experimented upon by many able nat- 
 uralists. 
 
 Of this order about 1,000 species have been already described, 
 but it is probable that a considerable number of these will event- 
 ually prove to be only the young of others. They particu- 
 larly abound in mammals, birds, and fishes, inhabiting the in- 
 testine, stomach, windpipe, lungs, kidneys, muscles, brain, and 
 various other parts of the body. Twelve species or more are 
 liable to infest human beings. 
 
 ACARINA. 
 
 In addition to the internal parasitic worms, there are certain 
 parasites which belong to other groups. Among these are 
 certain forms of acarina, or mites, some of which are, perhaps, 
 only accidentally parasitic, like the Acarus dysenteries mentioned 
 in our previous lecture. But the genus Pentastoma includes 
 species which are true parasites and have nearly the same 
 habits as some of the parasitic worms, which, indeed, they 
 closely resemble in general appearance. Formerly these par- 
 asites were regarded as worms by all authors, but they are 
 now generally referred to the Acarina, although they differ 
 greatly from the more typical forms. One of these species 
 is represented in Figure 84. 
 
 PROTOZOA. 
 
 Several genera and species of infusoria have been found liv- 
 ing in the human body, or in the excreta, especially of pa- 
 tients attacked with certain contagious diseases. The effects 
 of these parasites and their relations to diseases are not well 
 understood. 
 
PARASITES OF ANIMALS. 59 
 
 Lists of the Parasites of Man and Domestic Animals. 
 
 The number of species of these internal parasites now 
 known is upwards of 100. Therefore it will be impossible, at 
 this time, to do more than enumerate the species, with their 
 principal modes of occurrence, and then describe more fully 
 some of the most important kinds, with their effects and rem- 
 edies, so far as space will admit. It is hoped that the lists 
 will serve as a key or index for those who wish to pursue the 
 subject further, in the more extensive works upon this subject. 
 
 INTERNAL PARASITES OF MAN. 
 
 CESTODES. 
 
 Iccnia solium Linnaeus. Intestine, young in hog ; common. 
 T. mediocancUala Kuch. Intestine, young in beef; common. 
 T. flauopunctata Weinland. Intestine ; one case only, in the 
 
 United States. ' 
 T. lophosoma Cobbold. Intestine, larva unknown ; one 
 
 case. 
 
 T. elliptica Batsch. Intestine ; rare, common in cats. 
 T. nana Siebold. Intestine ; only observed in Egypt. 
 Bothriocepha j us latus Bremser. Intestine, larva in fish (?) ; 
 
 Europe, rare in America. 
 B. cordatus Leuckart. Intestine ; common in Greenland. 
 
 In the larval state. 
 
 Tccnia solium Linn. In muscles, brain, eye, etc. ; not rare. 
 
 T. marginata Batsch. Abdominal viscera ; very rare. 
 
 T. acanthotrias Weinland. In muscles, mature worm un- 
 known ; observed once only, in Virginia. 
 
 T. echinococcus Siebold. Tumors in liver, brain, lungs, ab- 
 domen, muscles, etc., adult in dog ; common. 
 
 TREMATODES. 
 
 Billiarzia Jicematobia Cobbold. Inhabits the blood-vessels, es- 
 pecially the portal veins and those of the kidneys and blad- 
 der ; very common in Africa, producing a very serious disease. 
 
 Fasciola hepatica Linnaeus. Gall-bladder and ducts, and 
 sometimes beneath the skin ; common in sheep, rare in 
 man. 
 
60 BOARD OP AGRICULTURE. 
 
 Distoma lanceolatum Mehlis. Gall-ducts ; rare. 
 
 D. crassum Busk. Duodenum ; one case. 
 
 D. heterophyes Siebold and Bilharz. Small intestine, in large 
 
 numbers ; two cases, in Egypt. 
 D. ophthalmobium Diesing, (perhaps young of D. lanceola- 
 
 tum). Eye, several together ; two cases. 
 Tetrastoma renale Delle Chiage. Kidney ; one case. 
 Hexanthyridium pinguicola Treutler. In an ovarian tumor ; 
 
 one case. 
 H. nenat wn Treutler, (probably young). Veins ; rare. 
 
 NEMATODES. 
 
 Trichina spiralis Owen. Adult in intestine, young in muscles ; 
 common. 
 
 Trichocephalus dispar Rudolphi. Small intestine. 
 
 Filaria trachealis Cobbold. Trachea and larynx ; one case. 
 ' F. lentis Diesing, (larval form). Eye; very rare. 
 
 Dracunculus medinensis. Gmelin, (Guinea-worm). In the 
 connective tissue beneath the skin and among the muscles. 
 Yery common in Arabia, Guinea, Upper Egypt, and other 
 parts of tropical Asia and Africa ; also in some parts of the 
 West Indies. 
 
 D. oculi Diesing, (loa). Orbit of the eye, in the conjunctiva, 
 etc. Not uncommon in tropical Africa and America, chief- 
 ly in the African races. 
 
 Oxyuris vermicularis Brernser, (pin-worm). In the large in- 
 testine, chiefly in the rectum and near the anus, sometimes 
 in the genital passage ; very common, especially in chil- 
 dren. 
 
 Ascaris lumbricoides Linn., (round- worm). Intestine, some- 
 times ascending into the stomach, rarely passing into the 
 abdominal cavity by perforating the intestine ; very com- 
 mon. 
 
 A. mystax Rud. (round-worm of cats). Intestine ; rare in 
 man, common in the cat. 
 
 Eustrongylus gigas Diesing, (kidney-worm). Kidney ; rare 
 in man. 
 
 Strongylus bronchialis Cobbold. Bronchial tubes ; very rare. 
 
PARASITES OP ANIMALS. 61 
 
 Dochmius duodenalis Leuckart. Small intestine ; Italy, 
 much more common in Egypt, causing very serious disease. 
 
 ACARINA. 
 
 Pentastoma dentimlatum Rud. (Probably the young of P. 
 
 tcenioides of the dog.) In cysts on the liver, etc. ; not very 
 
 rare. 
 P. comtrictum Siebold. Liver and lungs ; common in Egypt. 
 
 PROTOZOA. 
 
 Paramecium coli Malmstein. Colon, excreta. 
 Cercomonas intesiinalis Lambl. ((7. ^ommisDavaine). Intes- 
 tine ; from a cholera patient. 
 Variety B. From a typhoid fever patient. 
 C. urinarius Hassal. In urine. 
 C. saltans Ehrenberg. 
 
 Trichomonas vaginalis Donne". Vagina, in mucus. 
 PsorospermSj (perhaps the eggs of Distoma). 
 
 In addition to the preceding species of true parasites, 
 various kinds of insect larvae have been known to live for a 
 time in the human stomach and intestine, from which they 
 have been discharged either by vomiting or purging. 
 
 Among the most common larvae that may thus live in the 
 human body are those of the various species of meat-flies, blue- 
 bottle-flies, blow-flies, or flesh-flies (see page 101), and those 
 of the house-fly. Several species of the genus Homalomyia 
 have also been known to occur in this way, the eggs or larvae 
 having been swallowed with fruit, and more especially in de- 
 cayed fruit, in which they naturally live.* Such larvae often 
 cause considerable irritation of the intestine, and diarrhoea, 
 but as their life in the larval state is very short, they must 
 soon pass from the intestine or perish in it. 
 
 INTERNAL PARASITES OF THE DOG. 
 
 CESTODES. 
 
 Tcenia echinococcus Siebold. Intestine, many together ; larvae 
 in sheep, cattle, and man ; common. 
 
 *These insects are well described by Mr. B. D. Walsh in the American En- 
 tomologist, vol. II, page 137, 1870. 
 
62 BOARD OP AGRICULTURE. 
 
 T. coenurus Kiich. Intestine, many together ; not rare. 
 Larvae in sheep. 
 
 T. marginata Batsch. Intestine, few or singly ; common. 
 Larvae in sheep and cattle. 
 
 T. serrata Goeze. Intestine ; common. Larvae in rabbits. 
 
 T. canis-lagopodis Rud. Intestine ; in Iceland common. Lar- 
 vae unknown. Perhaps same as T. Utter ata Batsch. 
 
 T. cucumerina Bloch. Intestine ; very common. Larvae un- 
 known. 
 
 T. solium Linn., (in cysticercus state). Muscles, brain, etc. 
 
 Bothriocephalus lalus Bremser. Intestine ; not common. 
 
 B. cordatus Leuckart. Intestine ; very common in Green- 
 land. 
 
 B. fuscus Krabbe. Intestine ; not rare in Iceland. 
 " " var. reticulalus Kr. " " " 
 
 "" " var. dubiusKr. " " " 
 
 Dibothrium serratum Diesing. Intestine ; very rare. 
 
 TREMATODES. 
 
 Holostoma alatum Nitzsch. Intestine ; less common than in 
 the fox. 
 
 NEMATODES. 
 
 Trichina spiralis Owen. Intestine (mature) ; larvae in 
 
 muscles. 
 Spiroptera sanguinolenta Rudolphi. (Esophagus, stomach, and 
 
 heart, larvae in blood ; very common in China. 
 Irichosoma plica Rudolphi. Bladder ; rare. 
 Trichocephalus depressiusculus Rud. Coecum ; not common. 
 Ascaris marginata Rud. Small intestine ; very common. 
 Pseudalius filum Duj.(?). Heart and pulmonary artery, 
 
 recorded by Collas ; originally from porpoise. 
 Eustrongylm gigas Diesing. Kidney ; rare. 
 Dochmius trigonocephalus Duj. Intestine, larvae in water ; 
 
 rare. 
 
 Filaria trispinulosa (larval form) . Eye. 
 F. sanguinis (larval form). In blood. 
 F. immitis Leidy. Heart. 
 
PARASITES OP ANIMALS. 63 
 
 Dracunculus medinensis Cobbold. Sub-cutaneous tissues ; in 
 tropical- Asia, Africa, and America. 
 
 ACARINA. 
 
 Pentastoma tcenioides Rudolphi. Nostrils ; not rare. Larvae 
 
 in man and cattle. 
 
 That thousands of lambs and sheep are annually killed by 
 dogs that have a taste for mutton of their own procuring is 
 unfortunately too well known to most of the farmers in this 
 country, especially in those States where neither stringent 
 laws nor severe taxes have diminished the numbers of these 
 useless curs. 
 
 That the number of dogs in every part of the country is by 
 far too great, and even dangerously so, is generally admitted, 
 especially during the summer, when mad dogs and hydropho- 
 bia are the constant theme of conversation in our cities. That 
 the laws of every State ought to impose restrictions, or, at 
 least, very high taxes upon the owners of dogs is evident and 
 advocated by many legislators. Yet it is not, by any means, 
 generally known to what an alarming extent our flocks are in- 
 jured in health and depreciated in value by the parasites de- 
 rived directly from dogs. Still less is it known to what an 
 extent human lives and health are sacrificed on account of 
 these animals. 
 
 There are three principal and very important parasites of 
 sheep derived from tape-worms of dogs. These are : 1. The 
 " water-brain" of sheep, which is produced by the young or 
 larvas of a small tape-worm (Tcenia ccenurus) ; 2. The ech- 
 inococcus, or hydatid tumors of sheep, of cattle, and of man, 
 found Jn various organs, but most commonly in the liver, 
 brain, and kidneys, which are caused by the young of a very 
 small dog tape-worm (Tcenia echinococeus) ; 3. The diving 
 bladder-worm, or u water-bladder," often found in the abdo- 
 men of sheep, cattle, and pigs, frequently forming tumors as 
 large as a hen's-egg, or even a goose-egg, which is the young 
 of a larger tape-worm of the dog (Tcenia marginata). There 
 are, also, others of less importance obtained by sheep from 
 dogs, as indicated in the lists. 
 
64 BOARD OF AGRICULTURE. 
 
 It is perfectly safe to say that at least twenty-five sheep are 
 killed by parasites derived from dogs, for every one killed by 
 the teeth of dogs ! It is also safe to say that more than fifty 
 persons die from the same parasites, for every one that dies of 
 hydrophobia ! And yet this work of destruction goes on 
 silently and almost unobserved, except by professional men 
 week after week and year after year. The loss of human life 
 every year more than counterbalances all the good that all the 
 dogs in the civilized world can possibly do. In Iceland it is 
 stated that one-sixth of all the deaths are caused by one of 
 the dog-parasites (EchinococcMs) . The same parasite occurs 
 also, not unfrequently, in all other parts of the world where 
 dogs are kept, and causes most horrible disease and death. 
 To this we may add the Pentastoma^ which man also derives 
 from dogs, and in all probability several other parasites, in- 
 ternal and external. 
 
 INTERNAL PARASITES OF THE CAT. 
 
 CESTODES. 
 
 Tcenia crassicollis Rud. Intestine, young in rats and mice. 
 T. elliptica Batscli. Small intestine ; common. 
 T. canis-lagopodis Rud. Intestine ; common in Iceland. 
 Dibothrium dedpiens Diesing. Intestine, also in leopard, 
 ounce, etc. Perhaps Bothriocephalus felis Creplin. 
 
 TREMATODES. 
 
 Amphistoma truncatum Rud. 
 
 Distoma lanceolatum Mehlis. Bile ducts ; rare. 
 
 NEMATODES. 
 
 Trichina spiralis Owen. Intestine, young in muscles. 
 Dochmius tubceformis Dujadin. Duodenum. 
 Ollulanus tricuspis Leuck. Intestine, and young in muscles. 
 Ascarismystax Rud. Small intestine ; common. 
 
 ACARINA. 
 
 Pentastoma denticulatum Rud. Cysts on liver, etc. 
 
 This list includes all those that I have found recorded from 
 the house cat, but doubtless many others may occur. 
 
PARASITES OF ANIMALS. 
 
 INTERNAL PARASITES OF SHEEP. 
 
 65 
 
 CESTODES. 
 
 Tcenia expansa Rud. Mature, in small intestine. 
 
 Tcenia. (Undetermined species with hooks.) In cysticercus 
 state in muscles. 
 
 T. marginata Batsch. Young or cysticercus state in viscera, 
 adult in dog ; common. 
 
 T. coenurm Kuch. Young or encysted state in large tumors 
 in the brain, adult in dog ; common. 
 
 T. echinococctts Siebold. Young or hydatid condition in liv- 
 er, lungs, brain, and other organs, adult in dog ; common. 
 
 TREMATODES. 
 
 Fasciola Jiepatiea Linn. Liver and bile ducts. 
 Distoma lanceolatum Mehlis. Bile ducts. 
 Ampkistoma conicum Rud. First stomach. 
 
 NEMATODES. 
 
 Ascaris ovis Rudolphi. Intestine ; rare. 
 Trichocephalus ovis (affinisf). Large intestine ; common. 
 Sclerostoma hypostomum Dujadin. Intestine. 
 Strongylus contortus Rud. Small intestine. 
 S. filicollis R,ud.. Small intestine. Perhaps same^ as last. 
 S. filaria Rud. Trachea and bronchial tubes ; common ; also 
 in the goat. 
 
 ACARINA. 
 
 Pentastoma tcenioides Rud. Larynx, nostrils, etc. 
 
 The goat is infested by many of the parasites found in 
 sheep. Besides these, there are a few peculiar species; 
 among them are Tcenia caprce and Strongylus venulosus Ru- 
 dolphi, both found in the intestine. 
 
 INTERNAL PARASITES OF CATTLE. 
 
 CESTODES. 
 
 Tcenia expansa Rudolphi. Intestine, mature ; not common. 
 T. denticulata Rud. Intestine, mature ; rare. 
 T. mediocanellata Kiich. Young or cysticercus state in mus- 
 cles, adult in man ; common. 
 9 
 
66 BOARD OF AGRICULTURE. 
 
 T. marginata Batsch. Young or cysticercus state in viscera, 
 
 adult in dog ; common. 
 T. echinococcus Siebold. Young or hydatid state in liver, 
 
 brain, and various other organs, adult in dog ; common. 
 T. coenurus Kiich. Young state in brain, adult in dog ; rare. 
 
 TREMATODES. 
 
 Fasciola Tiepatica Linn. Liver, gall-ducts, etc.; not rare. 
 Distoma lanceolatum Mehlis. Liver ; not uncommon. 
 Amphistoma conicum Rud. First stomach ; common. 
 A. crumeniferum Creplin. Stomach. 
 A. explanatum Creplin. Bile ducts. 
 
 NEMATODES. 
 
 Trichina spiralis Owen. Observed only in experimental an- 
 imals. 
 
 Trichoceplialus affinis Rud. Large intestine ; frequent. 
 Strongylus radialus Rud. Duodenum, colon, small intestine. 
 S micrurus Mehlis. Trachea and bronchial tubes. 
 Eustrongylus gigas Diesing. Kidney ; rare. 
 Filaria lachrymalis Gurlt. Lachrymal ducts, etc. 
 F.papillosa Rudolphi. Abdominal cavity, etc.; rare. 
 
 ACARTNA. 
 
 Pentastoma tcenioides Rud. Nasal cavaties, larynx, etc. 
 P. denticulatum Rud. (Young of preceding.) In cysts on 
 liver, etc. 
 
 INTERNAL PARASITES OF THE HORSE. 
 
 CESTODES. 
 
 Tcenia perfollata Goeze. Swell intestine, colon, ccecum ; 
 
 common, and sometimes in vast numbers. 
 T. plicata Rud. Stomach and small intestine ; common. 
 T. mamillana Mehlis. Large intestine ; common. 
 Tcenia, (species undetermined). Young state {cysticercus 
 
 fistularis) in peritoneum. 
 
 T. coenurus Kuch. Young or encysted state in brain ; rare. 
 T. echinococcus Siebold. Hydatid state in liver, etc.; not 
 
 common. 
 
 TEMATODES. 
 
 Fasciola hepatica Linn. Liver, gall-bladder, etc. 
 
PARASITES OP ANIMALS. 67 
 
 NEMATODES. 
 
 Ascaris megalocephala Cloquet. Small intestine ; common. 
 
 Oxyuris curvula Rudolphi. Colon, coecum, rectum ; common. 
 
 Eustrongylus gigas Diesing. Kidney, etc. 
 
 Sclerostoma equinum Blainv. Duodenum, colon, coecum, pan- 
 creas, sometimes very numerous, and in enlargements of 
 the arteries; common. 
 
 S. tetraoanthum Diesing. Duodenum, ccecum, .colon. 
 
 Strongylus micrurus Mehlis. Trachea and bronchial tubes. 
 
 Filaria microstoma Schneider. 
 
 F. papillosa Rud. Abdomen, thorax, brain, eye, intestine. 
 
 F. lachrymal Gurlt. About the eyes, in lachrymal ducts, etc. 
 
 Spiroptera megastoma Rud. Tubercles in stomach. 
 
 Dracunculus medinensis Cobbold. (Guinea-worm). Subcu- 
 taneous tissues ; only in tropical parts of Africa, Asia, and 
 America. 
 
 ACARINA. 
 
 Pentastoma tamioides Rud. Nasal cavities, larynx, etc. 
 
 The mule and ass are subject to the same parasites as the 
 horse, but not to the same extent. The number of species 
 hitherto observed is less, and they are far less common. 
 
 INTERNAL PARASITES OF THE HOG. 
 
 CESTODES. 
 
 Tcenia solium Linn. In the larval or cysticurcus state in the 
 
 abdominal viscera. 
 
 T. marginata Kiich. Cysticercus state in the abdominal viscera. 
 T. echmococcus Siebold. Hydatid state in liver, etc.; not 
 
 common. 
 
 TREMATODES. 
 
 Fasciola hepatica Linn. Liver and bile ducts. 
 Distoma lanceolatum Mehlis. Bile ducts. 
 
 ACANTHOCEPHALA. 
 
 Echinorhynchus gigas Goeze. Small intestine ; common. 
 
 NEMATODES. 
 
 Trichina spiralis Owen. Mature in intestine, young in mus- 
 cles ; common. 
 
68 BOARD OF AGRICULTURE. 
 
 Ascaris suilla Dujardin. Small intestine ; common. 
 Spiroptera strongs/Una Rud. Stomach. 
 Simondsia paradoxa Cobbold. Stomach, in cysts ; one case. 
 Trichocephalus crenatus Rud. Large intestine. 
 Strongylus dentatus Rud. Coecum, colon. 
 S. elongatus Dujardin. Bronchial tubes. 
 S. paradoxus Mehlis. Trachea and bronchial tubes. 
 EustrongyluB gigas Diesing. Kidneys, etc. 
 Sclerostoma pinguicola Verrill. In fat about kidneys and "spare- 
 ribs," in large numbers ; probably common. 
 
 ACARINA. 
 
 Pentastoma denticulatum Rud. Cysts on liver, etc. 
 INTERNAL PARASITES OF POULTRY. 
 
 CESTODES. 
 
 Tcenia infundibuliformis Goeze. Intestine of hens, ducks, 
 
 geese, etc. 
 
 T. proglotlina Davaine. Duodenum of hens ; common. 
 T. crassula Rud. Intestine of pigeons, hens, and geese. 
 T. malleus Goeze. Intestine of geese and ducks, etc. 
 T. lanceolata Goeze. Intestine of geese and ducks, etc. 
 T. setigera Froh. Intestine of geese ; common. 
 T. sinuosa Rud. Intestine of geese and ducks. 
 T.fasciata Rud. Intestine of geese ; common. 
 
 TREMATODES. 
 
 Monostoma mutabile Zeder. Sub-orbital cavities of geese, etc. 
 
 M. variabile. Geese. 
 
 M. triseriale. Geese. Perhaps same as the next. 
 
 M. verrucosum Zeder. Ducks, in coecum. 
 
 M. caryophyllinum Bremser. Ducks. Originally described 
 
 from fish. 
 
 Distoma ovatum Rud. Oviducts, etc., of geese and ducks. 
 D. linear e Zeder. Large intestine of hens. 
 D. dilitatum Miram. With last. 
 D. echinatum Zeder. Intestine of ducks and geese. 
 D. oxycephalum Rud. Same habits as last. 
 
 ACANTHOCEPHALA. 
 
 Echinorhynchus polymorplius Bremser. Intestine of ducks. 
 
PARASITES OF ANIMALS. 69 
 
 NEMATODES. 
 
 Heterakis compressa Schneider. Intestine of chicken. 
 
 If. vesicularis Duj. Intestine of hens and turkeys. 
 
 H. dispar Duj. Intestine of geese. 
 
 Ascaris crassa Desl. Intestine of ducks. 
 
 A. inflexa Rud. Intestine of hens. 
 
 A.perspicillum Rud. Intestine of turkey. 
 
 A. maculosa Rud. Intestine of pigeon. 
 
 jSpirotera hamulosa. Gizzard of hens. 
 
 S. uncinata Rud. Tubercles in oesophagus of geese. 
 
 Syngamus trachealis Siebold. Windpipe, causing "gapes.'' 
 
 Strongylus nodularis Rud. Gizzard and intestine of ducks 
 
 and geese. 
 
 In the preceding lists we have brought together most of the 
 parasites hitherto discovered in our more common domestic 
 animals. There can be no doubt but that many more will 
 hereafter be discovered. In the rabbit, Guinea-pig, parrots, 
 singing birds, and other animals often domesticated, many 
 additional species occur. 
 
 In the following pages only the more common and impor- 
 tant species will be described. 
 
 The Armed Tape-worm or Pork Tape-worm of Man (Tcenia 
 solium Linn.) ; and its young, the " measles" of pork and hu- 
 man flesh. 
 
 This is perhaps the best known of all the numerous kinds of 
 tape-worms. Its young or larvae are common in the muscles 
 and other organs of hogs, and not very rare in man. (See 
 Figures 49-51.) In the adult stale it is, so far as known, pe- 
 culiar to the human intestine, where it is unnecessarily com- 
 mon! It grows to a great length, frequently ten to fifteen 
 feet, or even more, and is then composed of upwards of 800 
 joints, those that are sexually mature commencing at about the 
 450th segment. The head is small, about the size of a pin- 
 head, roundish, with four prominent suckers on the sides, and 
 a conical, proboscis-like top, around which there are two cir- 
 cles of sharp hooks, 22 to 28 in each circle (Figure 53). 
 The neck portion is slender, crossed by fine lines, which are 
 wider apart as they recede from the head, finally forming dis- 
 
70 
 
 BOARD OP AGRICULTURE. 
 
 tinct joints. These are at first very small and short, gradually 
 becoming broader and squarish, then oblong. The largest 
 are about a third of an inch in breadth and quite thin and flat 
 (Figure 52). The sexually mature joints or proglottides are 
 twice as long as broad, and contain the ovaries and a long 
 central egg cavity or uterus, with 7 to 12 lateral branches, 
 which are irregularly lobed and divided (Figure 54) ; and also 
 the male organ, or testicle, in the form of branched tubes, 
 communicating with a penis, which is situated on one edge 
 of the joint, in front of the female genital orifice, and has a 
 curved or sickle-shaped form. The genital openings are either 
 on the right or left edge indifferently, in the successive joints. 
 
 Figure 49. Figure 52. 
 
 The young or larval state produces the white spots known as 
 
 Figure 49. Pork " measles" ; natural size; Hearth and Home, after Owen. 
 
 Figure 50. Young tape worm from measles of pork; and Fig. 51, head of same, 
 more enlarged ; Hearth and Home, after Owen. 
 
 Figure 52. Pork tape-worm (Tcenia solium), less than natural size ; Hearth and 
 Home, after Owen. 
 
PARASITES OP ANIMALS. 
 
 71 
 
 / measles " in pork (Figure 49)-. These are cavities or cysts 
 produced by inflammation, containing whitish fluid and enclos- 
 ing small, bladder-like, translucent, vesicles, filled with a watery 
 fluid, and which contain the proper head and neck of the young 
 worm coiled up spirally in the interior in an inverted position. 
 By gentle pressure the head and neck may be made to protrude 
 by inversion, like the finger of a glove, and will then present 
 the appearance shown in figure 50, the vesicle of fluid now 
 forming the flask-like caudal portion of the worm. The head 
 may now be seen to have four suckers and a central promi- 
 nence surrounded by two circles of hooks, as in the adult. In 
 this condition, enclosed in the cysts, they will remain living 
 
 Figure 53. Figure 54. 
 
 V 
 
 for a long time in the hog, even surviving the death of their 
 host for a considerable period. If one or more of these young 
 worms or measles be swallowed by a human being, the mus- 
 cular fibres and the cysts will be digested, and each young 
 worm thus liberated will evert its head, and losing its bladder- 
 like portion, will pass into the intestine. There it will fasten 
 itself to the inner membrane by its suckers and hooks, and 
 grow rapidly by absorbing the digested food by which it is 
 surrounded. New joints will be rapidly formed as the older 
 ones grow larger, until it becomes a mature tape-worm, with 
 joints ready to be cast off. There may be but one tape-worm in 
 
 Figure 53. Head of Tcenia solium, magnified. From Cob bold. 
 Figure 54. A joint or proglottis of Tcenia solium, magnified ; a, branches of the 
 uterus ; &, external orifice ; c, male organ. From Cobbold. 
 
72 BOARD OF AGRICULTURE. 
 
 the human intestine, or there may be several together, the 
 number depending only upon the number of living young- 
 swallowed. 
 
 It is, therefore, obvious that this tape-worm can be acquired 
 only by eating raw or under-done pork. In this country the 
 principal kinds of food serving as sources of this tape-worm 
 are raw smoked ham and raw sausages, but soldiers and others 
 are often obliged to eat their pork-rations uncooked, and thus 
 obtain the parasites. Our recent war was the means of greatly 
 increasing the numbers of this and other parasites, both in- 
 ternal and external. 
 
 Persons harboring the mature tape-worms become in their 
 turn the means of diffusing the race. Each mature joint cast 
 off contains several thousands of eggs, each of which encloses 
 an embryo, nearly ready to hatch, and as these joints are con- 
 tinually being discharged during the whole life of the worm, 
 which may be ten or twelve years, it is evident that one per- 
 son may thus be the means of diffusing many millions of eggs, 
 most of which will no doubt perish, but the chances are good 
 that some of them will find their way into the stomachs of 
 hogs, either with their food or in water. 
 
 The free joints or proglottides have an independent life for 
 a few days and are capable of moving and crawling about to 
 a considerable extent. In a short time, however, the myriads 
 of embryos in the interior so increase in size that the walls of 
 the proglottis burst open and thus liberate the eggs. The 
 eggs are globular and very small, their average diameter 
 being about ^4 of an inch ; the shell is comparatively 
 thick, being s^W of an inch. They are so small that they 
 may be blown about by the winds, carried on the feet of in- 
 sects, or may be suspended in unfiltered waters. They may, 
 therefore, also readily adhere to lettuce, celery, and other 
 garden plants, or to fallen fruit, especially when night-soil is 
 used as manure, and unless such food be carefully and 
 thoroughly washed, there is always more or less danger of 
 eating the eggs of this and other parasites. When these eggs 
 are swallowed, either by hogs or human beings, they hatch as 
 soon as acted upon by the gastric juice, and disclose their con- 
 
PARASITES OP ANIMALS. 73 
 
 tained embryos, which are very different from both the old 
 worm and the measle-worm. They are provided with six 
 hooks or spines, placed in three pairs upon the head. By 
 means of these they quickly bore their way through the walls 
 of the intestine into the blood-vessels, and are thus carried to 
 all parts of the body. They finally lodge in various organs, 
 but especially in the muscles, liver, brain, eyes, lungs, and 
 heart. They then excavate galleries for themselves in these 
 situations, causing, if in large numbers, a great amount of 
 inflammation and disease, which in some cases proves fatal. 
 The inflammation soon causes cysts to be formed around the 
 intruders, by which they are enclosed and restricted in their 
 motions. Thus the " measles" in the muscles of hogs and 
 man are formed. After this the patient may recover, unless 
 these parasites have lodged in the brain or other vital organs, so 
 as to produce serious symptoms subsequently. In the human 
 subject more than 100 cases have been recorded in which 
 these parasites have taken up their abode in the brain, causing 
 epilepsy, insanity, and sometimes sudden death. In such 
 cases, which are probably more common than is generally im- 
 agined, there can be no relief. There have also been recorded 
 quite as many instances in which these cysticerci or larval tape- 
 worms have been situated within the ball of the eye, causing 
 a partial or total loss of sight, and sometimes great inflamma- 
 tion. Many of these have been successfully removed. In 
 other important organs they are liable to produce serious 
 trouble. But when in the subcutaneous, areolar, or inter- 
 muscular tissues, they may often be easily removed by the 
 surgeon. In hogs they are much more liable to produce these 
 results, because hogs are likely to swallow whole joints, or 
 even entire tape-worms, while human beings seldom swallow 
 more than a few dozens of eggs. 
 
 The effects and symptoms caused by the adult tape-worms 
 are discussed under the next species, together with the 
 remedies. 
 
 As means of prevention every one should avoid eating pork, 
 in any form, that has not been .thoroughly cooked. In this 
 way it is easy to avoid the mature tape-worm of this species. 
 10 
 
74 BOARD OF AGRICULTURE. 
 
 To prevent measles in hogs they should not be allowed to have 
 access to human excrement, the reverse of which is too often 
 specially provided for by farmers. To avoid the same para- 
 sites in our own flesh we must take care to have all fruit and 
 other uncooked vegetable food well washed and our drinking 
 water pure. 
 
 The Beef Tape-worm of Man (Tcenia, mediocanellata Kuch.) ; 
 and its young, the " measles" of veal and beef. 
 
 This is a very large species, which was formerly generally 
 known as the unarmed variety of the human tape-worm. It 
 is known to occur among all beef-eating people, and is the 
 common species in Africa, Western Asia, and several European 
 countries, especially in Austria, Turkey, and certain parts of 
 Russia. 
 
 It has long been known that Jews, Mohammedans, and other 
 people who never eat pork, are nevertheless liable to be in- 
 fested by tape-worms. It was also observed, many years ago, 
 that infants fed upon dried beef a custom much practised at 
 St. Petersburg were liable to have the same parasites ; and 
 these facts were formerly brought forward as arguments 
 against the doctrine that the common tape-worm is derived 
 from eating the larval form contained in measly pork. BUG 
 it was soon discovered that nearly all the tape-worms obtained 
 from patients in Mohammedan countries, as well as in Austria, 
 and some other parts of Europe where pork is little used, were 
 destitute of the two circles of peculiar hooks around the cen- 
 tral, proboscis-like prominence of the head, as well as the 
 prominence itself, which are very conspicuous features in the 
 common tape-worm of pork-eating people. Owing to these 
 peculiarities, naturalists began to consider the two forms 
 either as different varieties or different species. The source 
 of the unarmed tape-worm remained uncertain, however, until 
 direct experiments were undertaken by Leuckart, Mosler, and 
 others to settle this question. Thus it was discovered that 
 when the joints or eggs of the unarmed tape-worm ( Tcenia 
 mediocanellata) were given to calves, the eggs hatched in the 
 stomach, and the young embryos worked their way, by means 
 
PARASITES OP ANIMALS. 75 
 
 of their six boring hooks, through the intestine into the cir- 
 culation and, lodging in the muscles, caused serious disease 
 or death, if in too large numbers, and after a time became 
 enclosed in little capsules, producing, in fact, " measly" veal 
 or beef, as shown in Figure 55, which represents part of a 
 muscle of the hind leg from a calf that had been fed by Drs. 
 Cobbold and Simonds upon the eggs of this tape-worm, and 
 killed three months afterward. The flesh of this calf was 
 estimated to contain over eight thousand measles, and yet, 
 although at first it had been seriously ill from the effects of 
 the parasites, it was at the time when slaughtered perfectly 
 
 Figure 55. Figure 56. 
 
 healthy and fat. The measles of veal or beef are much 
 smaller than those of pork, and if they existed only in 
 moderate numbers, would scarcely be detected either by the 
 butchers or consumers. They are seldom larger than a small 
 pea. One of these u measles," when examined with the 
 microscope, is found to consist of an outer oval cyst or mem- 
 branous sac, enclosing loosely in its cavity a more delicate 
 vesicle filled with fluid and containing the inverted head of 
 the young tape-worm, as represented in Figure 56. The head 
 has four well-marked suckers, but has no central proboscis 
 and no circle of hooks differing therefore from the pork- 
 measle, or cysticercus, in just the same way that the heads of 
 the mature tape-worms differ from each other. Thus it was 
 definitely settled that the unarmed or bookless tape-worm of 
 
 Figure 55. Measles in veal,"reduced. Hearth and Home, after Cobbold. 
 Figure 56. One of the measles magnified. Hearth and Home, after Cobbold* 
 
76 
 
 BOARD OP AGRICULTURE. 
 
 man ( Tcenia mediocanellata) is obtained by eating the young, 
 in the shape of "measles," in raw or slightly cooked beef and 
 
 Figure 57. Figure 58. 
 
 Figure 59. 
 
 veal. And thus the presence of tape-worms in infants fed on 
 dried beef, as well as in Jews and others not guilty of eating 
 
 Figure 57. Tcenia mediocanellata, natural size. Hearth and Home, after 
 Leuckart. 
 
 Figure 58. Head of beef tape- worm, magnified. Hearth and Home, after 
 Leuckart. 
 
 Figure 59. A joint of the beef tape-worm, showing the ovaries, enlarged. Hearth 
 arid Home, after Leuckart. 
 
PARASITES OP ANIMALS. 77 
 
 pork, is fully explained. Since these facts have been ascer- 
 tained, search has been made for " measles" in beef from 
 animals not experimented upon, and they have been found in 
 several instances. 
 
 When such beef is swallowed by man, without cooking, the 
 young tape-worms are liberated from their capsules or cysts 
 by the process of digestion ; the head becomes protruded, and, 
 passing into the intestine, it fastens upon the lining mem- 
 brane by its suckers. There it rapidly grows larger, new 
 joints are developed, and the body grows longer and longer, 
 the form of the joints changing as they grow, until those that 
 are most mature become square, and finally oblong, as shown 
 in Figure 57, which represents a beef tape-worm, of natural 
 size, in several sections, the intermediate joints being omitted. 
 When full grown, which requires three or four months, one of 
 these tape-worms may contain over 800 joints, of which 860 
 to 400 of the last ones will be sexually mature, each one con- 
 taining 5000 or more eggs. This species is much larger than 
 the pork tape-worm (T. solium}, as well as longer, its length 
 being sometimes twenty feet, and its greatest breadth half an 
 inch, while the joints are thicker and stouter, or have a plump 
 look, instead of being thin and flat, as in the other. The 
 head, as already intimated, is quite different in the two species 
 that of the beef-worm being larger and flat, or even concave, 
 at the end, with four large suckers on the sides, as shown, 
 greatly magnified, in Figure 58. The joints themselves are 
 very different internally, the egg-masses or uteri being very 
 numerous, and crowded together in a more parallel manner 
 (Figure 59) in this than in the pork tape-worm, in which 
 they are fewer and more aborescently branched. The mature 
 joints, filled with eggs, are cast off, as in other tape-worms, 
 and leaving the intestine, have an independent existence for 
 a few days, when they burst by the enlargement of the embryos 
 in the eggs. The eggs are thus scattered about in manure, in 
 water, in the drainage of cess-pools and sewers, by the winds, 
 and by insects. It is not strange, therefore, that cattle should 
 occasionally swallow such eggs with their food and drink, 
 especially if we reflect that one man, harboring only one of 
 
78 BOARD OF AGRICULTURE. 
 
 these worms, may thus scatter about, during a single year, 
 more than a thousand joints, and if each of these contains but 
 5000 eggs, he would thus diffuse 5,000,000 eggs, each con- 
 taining an active embryo, ready to leave its shell the moment 
 that it enters the stomach of a calf, cow, or ox. Young ani- 
 mals seem to be more liable to be infected by them than old 
 ones. Fortunately these young worms retain their vitality 
 for but one year when enclosed in the flesh, and after* that 
 die and, withering away, leave only a very small yellowish 
 spot, containing calcareous particles. The adult worm, if 
 left undisturbed, will live in a person ten or twelve years, 
 constantly dropping its joints. Among the Burates, or Cos- 
 sacks of ihe Baikal region, this species is very abundant. 
 Their habits of eating chiefly the raw or slightly cooked flesh 
 of cattle, sheep, camels, horses, and goats, while they devour 
 the liver, kidneys, and fat quite raw, would lead us to expect 
 that this and other parasites might abound in their bodies, 
 which proves to be the case. According to Dr. Kaschin in 130 
 post mortem examinations only two bodies were found with 
 out this tape-worm, and among 500 hospital patients every 
 one had it. Sometimes as many as fifteen specimens were 
 found in one person. 
 
 It has been supposed until within a short time that the 
 beef tape-worm (Tcenia, mediocanellata) was very rare in 
 Great Britain and the United States, where the pork tape- 
 worm was thought to be the only one that was at all common 
 in man. Dr. Cobbold has shown, however, in his late works 
 on parasitic worms, that the beef tape-worm is really quite as 
 common in England as the pork tape worm, the wealthier 
 classes generally harboring the former, and the poorer people 
 the latter. I am convinced that, even if not so common as 
 the pork tape-worm, the beef tape-worm is by no means so 
 rare in America as is generally supposed. The Museum oi 
 Yale College possesses one large specimen, raised by a citizen 
 of New Haven, and many other museums in the United States 
 no doubt contain them, labelled, however, " Tceniq solium." In 
 fact, probably not one physician in a thousand, in the country 
 at large, possesses the knowledge of the subject requisite for 
 
PARASITES OF ANIMALS. 79 
 
 distinguishing the two species and, therefore, both are con- 
 founded together as " the common tape-worm." 
 
 In this country persons generally obtain this parasite by 
 eating dried beef and Bologna sausages uncooked. In the lat- 
 ter, there may be not only the young of this tape-worm, but 
 also those of the pork tape-worm and Trichina, since there is 
 also an admixture of pork. It is therefore evident that it is 
 unsafe for the individual, and even a wrong to the community 
 for persons to indulge in eating raw meats of any kind, for 
 we find that pork, beef, and mutton may each contain the 
 young of different tape-worms and other parasites, and per- 
 sons who harbor these worms in their own bodies become, in 
 one sense, a nuisance, since they thus serve as the propaga- 
 tors and disseminators of parasites. And although one or 
 two of these tape-worms may not cause any serious trouble in 
 the bowels of one man, in another they may produce very 
 grave consequences, and still more so, if, as often happens, 
 several live together in one person. 
 
 Symptoms. 
 
 The symptoms and treatment are the same for both species 
 of human tape-worms, but the species now under considera- 
 tion is said to be more easily destroyed than T. solium, per- 
 haps because it does not have so secure an anchorage as the 
 latter has, with its hooks well imbedded in the membranes. 
 
 The symptoms vary greatly, according to the temperament 
 and other peculiarities of the person affected. Sometimes it 
 causes little or no marked disturbance of the health, though 
 causing perhaps more or less weakness, lassitude, and sense of 
 weariness, often accompanied by restlessness, nervous irritabil- 
 ity, and headache, which are nearly always attributed to other 
 causes. In more severe cases, these symptoms become much 
 increased, the headache especially, which is often accompa- 
 nied by giddiness. " The sight and hearing may be affected ; 
 noises in the head, itchings at the nose and anus, obscure 
 pains about the body and limbs, loss of appetite, -and other 
 dyspeptic symptoms, show themselves in greater or less de- 
 gree in different cases. One of the most common symptoms, 
 however, which I have noticed, is the tendency to faintness. 
 This is sometimes so marked as to create much alarm, and a 
 
80 BOARD OF AGRICULTURE. 
 
 person uninformed as to the true cause of the disorder might 
 be led to treat the symptom as arising from a totally different 
 source. In female patients the nervous symptoms display 
 features more or less peculiar to the sex. The restlessness 
 and anxiety are excessive, and at times accompanied by cho- 
 rea and fits of hysteria. In the worst cases, in both sexes, 
 the cerebral disturbance may show itself in convulsions and 
 epileptiform seizures. I regret to have to add that in not a 
 few instances even mania itself has been entirely attributable 
 to the presence of tape-worms in the intestinal canal." Such 
 are the usual symptoms, according to Dr. Cobbold. Many un- 
 usual and remarkable cases are on record. In one instance, 
 mania of eight years duration was completely cured by the 
 removal of the parasite. In another, hysteria was caused by 
 eighteen tape-worms in one patient. Many cases of insanity, 
 due to this cause, arc also on record. The best and perhaps 
 only sure evidence of tape-worms is the passage of the joints 
 from the intestine. 
 
 Remedies. 
 
 The remedies for tape-worms are numerous and, if fresh 
 and pure drugs be used, there are several that appear to be 
 perfectly reliable in most cases. These remedies should, how- 
 ever, be administered with proper precautions. Therefore, pa- 
 tients afflicted in this way should immediately place them- 
 selves under the care of a reliable and competent physician. 
 
 The remedies chiefly used are the oil or root of male-fern, 
 kousso, kamala, oil of turpentine, panna, pumpkin-seeds, and 
 pomegranate-root bark. These are generally administered 
 while the patient fasts. The pumpkin-seeds are perhaps the 
 most domestic remedy, as well as one of the best, and safest in 
 the hands of inexperienced persons. The fresh seeds may be 
 bruised or pounded in a mortar, and mixed with water into a 
 paste, of which the patient may eat freely, morning and even- 
 ing, at the same time fasting, or eating sparingly soups or similar 
 food. The root of the male-fern (Aspidium filix mas) is gen- 
 erally regarded as the most certain remedy, if fresh and pure. 
 The dose for an adult is ten to fifteen grammes of the powder, 
 morning and evening, followed by a purgative. The etherial 
 
PARASITES OP ANIMALS. 81 
 
 extract is generally more effectual, however. The patient 
 should have a sparing diet of soup, etc., for twelve or fifteen 
 hours before taking the medicine, and the second dose should 
 be followed, after an hour or two, by a purgative like castor- 
 oil. These remedies are mentioned here not to encourage 
 self-treatment, but for the benefit of those who may not be 
 within reach of a reliable physician. 
 
 The margined Tape-worm of the Dog (Tcenia marginata 
 Batsch) ; and its young, the " diving bladder-worm " of 
 Sheep and Cattle. 
 
 The young of this parasite are very frequently found in the 
 abdominal cavity of sheep, either attached to various parts of 
 the viscera, especially the liver and mesentery, or else nearly 
 or quite free among the organs, so that when the sheep are 
 opened, the bladder-like sacs fall out, of their own accord. 
 These are usually known to butchers as " water-bladders." 
 When attached to the organs, these bladders or sacs are usu- 
 ally enclosed in a cyst or membrane, formed by the inflamma- 
 tory action that they cause. The sac is soft and whitish, en- 
 closing a watery fluid, and varies in size from that of a pig- 
 eon's egg, or less, to that of a child's head ; but it is rather un- 
 common to find them larger than a hen's egg. In form they 
 are often globular, but more frequently pear-shaped, as repre- 
 sented in Figure 60. If one of these bladders, while still en- 
 closed in its cyst, be placed in a plate of warm water and care- 
 fully examined in a good light, there may be dimly seen in the 
 interior, near the upper end, the outlines of the head and neck, 
 which are turned inward, as usual in most young tape-worms ; 
 but what is singular in this case, the head and neck alternately 
 rise and sink in the fluid of the interior, with remarkable reg- 
 ularity. From this peculiarity it lias received the name of 
 " diving blacbder-worm." This motion is produced by a pe- 
 culiar arrangement of muscular fibres in the interior, which 
 are attached to the neck. At the top of the little knob on the 
 upper end of the bladder there is a small slit, from which, by 
 gentle pressure, the neck may be gradually forced out, so as 
 to project externally, and finally the head also appears. In 
 11 
 
82 BOARD OP AGRICULTURE. 
 
 this condition the creature has a flask-shaped form. The neck 
 tapers gradually from the bladder to the head, and is divided 
 transversely into a series of many short joints. The head is 
 but little enlarged, bearing four suckers, as usual, and in the 
 
 Figure 60. 
 
 Figure 61. 
 
 center has a proboscis, surrounded by two rows of hooks, con- 
 taining from sixteen to twenty-four pairs. Sometimes there 
 are found in large bladders of this kind a few secondary blad- 
 ders attached to the inside of the large one, produced by a 
 process of budding, somewhat as in the water-brain, or coenu- 
 rus. This parasite, as thus characterized, was formerly sup- 
 posed to be a distinct and peculiar species, and received the 
 name of " Cysticercus tenuicollis" or slender necked bladder- 
 worm. Recent investigation and experiments have, however, 
 proved it to be only the young or larval condition of one of the 
 common tape-worms of the dog (Tcenia marginata). Blad- 
 der-worms of the same kind are found, though less commonly, in 
 cattle and horses, as well as in pigs, monkeys, and many other 
 animals, and very rarely in man. Owing to the large size to 
 
 Figure 60. Diving bladder-worm, from a sheep ; natural size. Hearth and 
 Home, after Thudichum. 
 
 Figure 61. Head of Ttenia marginata, enlarged. Hearth and Home, after 
 Thudichum. 
 
PARASITES OF ANIMALS. 83 
 
 which this parasite grows, it is always liable to produce se- 
 rious disease, or even death; but the symptoms that it causes 
 and the danger will depend very much upon the situation of the 
 tumors. In some districts it is extremely common. According 
 to Dr. Thudichum, it occurs in nearly every sheep slaughtered 
 in London ; and the dogs that feed upon the offal of slaughter- 
 houses nearly always have the mature tape-worms in abun- 
 dance. 
 
 When a dog swallows one of these bladders, either free or 
 in its cyst, the bladder portion is digested, and the head be- 
 comes protruded ; on reaching the intestine, it fastens itself to 
 the membrane by means of its suckers and hooks. In this 
 situation, it rapidly develops new joints, and in the course of 
 three or four months becomes a mature tape-worm, about 
 three feet in length, and begins to discharge its ripe joints 
 filled with eggs. A dozen or more of these tape-worms may 
 exist together in the intestine of one dog. In general appear- 
 ance, this tape-worm (Tcenia marginata) resembles the pork 
 tape-worm of man (Tcenia solium), but never grows so large, 
 and its neck portion is much thicker, compared with the size 
 of the head as shown in Figure 61. 
 
 The first hundred joints are very short ; the mature joints are 
 squarish, the posterior end of one somewhat overlapping the 
 anterior end of the next. These joints contain a very much 
 branched and subdivided female organ, with an oviduct ter- 
 minating on one edge in a bell-shaped orifice ; and an arbor- 
 escently branched male organ or spermary, with small, round 
 dilations connected with the small branches. Dogs harbor- 
 ing these tape-worms scatter the mature joints and thousands 
 of eggs everywhere over the fields, and in the water of 
 streams and ponds. The sheep and cattle swallow the eggs, 
 either with their food or water or both. The eggs are hatched 
 in the stomach of the sheep, and liberate minute worms, 
 which are armed with three pairs of hooks for boring their 
 way through the tissues, like the embryos of other tape-worms. 
 By this means, these embryos force their way through the 
 lining membrane of the intestine into the blood-vessels, and 
 are carried to various parts of the body. Many lodge in the 
 
84 BOARD OF AGRICULTURE. 
 
 lungs, heart, and other organs, and cause for a time great irri- 
 tation and inflammation of these and other parts by their move- 
 ments in forcing and boring passages for themselves in the 
 tissues ; but they all eventually perish, while still small, in 
 such localities, and those that get into the liver and abdomi- 
 nal viscera are the only ones that survive and develop to their 
 full size, becoming the water-bladders, or " Cysticercus tenu- 
 icollis" first described. 
 
 The complete history of this, like the other tape-worms, 
 previously described, has been ascertained beyond doubt by 
 direct experiment. In this case the water-bladders have been 
 given to dogs, and at the proper time the dogs have been killed, 
 when the mature tape-worms have always been found corres- 
 ponding in number to the number of water-bladders eaten, 
 and in size to the length of time. And then the eggs or joints 
 of the tape-worms have been given to lambs ; and although 
 such lambs generally die in the course of five or six days, 
 when they swallow large numbers, yet even in that short time 
 the young worms have been found in vast numbers already 
 distributed in the system ; but when only a few eggs are em- 
 ployed, they do not cause immediate death. And in this way 
 Prof. Leuckart has studied their complete development. This 
 tape-worm, in its mature state, does not inhabit the human 
 body. Dr. Moller even swallowed several of the living blad- 
 der-worms without any result. 
 
 When these young worms have once got into the system of 
 a sheep, there is no remedy. In this case, prevention is our 
 only hope ; and to this end the same means should be used as 
 against the Tcenia coenurus and T. ec/iinococcus, to be de- 
 scribed farther on. Especial care should always be taken to 
 destroy the water-bladders and all other parasites observed in 
 slaughtering animals, as well as those removed from living 
 animals by medicines or surgical operations ; for in many cases 
 the eggs are capable of retaining their vitality for many weeks 
 or months. They should never be thrown aside as harmless, 
 or even buried, but should be destroyed by scalding hot water 
 or fire. Much may be done, also, in diminishing the numbers 
 of this and other parasites by frequently doctoring those dogs 
 
PARASITES OF ANIMALS. 
 
 85 
 
 that are worth keeping, or are necessary, in order to expel 
 their parasitic worms, of which there are generally many 
 kinds. There are numerous drugs that are efficacious for this 
 purpose, some of which are mentioned under the beef tape- 
 worm (page 191). But the principal difficiiltyis this those 
 who keep the most dogs, the worst dogs, and the dogs most 
 likely to harbor parasites in abundance, are the very persons 
 who are least likely to adopt such measures, either not know- 
 ing or not caring for the consequences. 
 
 Tcenia coenurus Kuch.,0//*e Dog ; audits young, the "water- 
 
 brain" of Sheep. 
 
 In the substance of the brain of sheep there is often found 
 a soft tumor, often as large as a pigeon's egg, and sometimes 
 larger than a hen's egg, which is filled with a watery fluid. 
 Such tumors would go on increasing in size indefinitely, until 
 
 Figure 62. 
 
 death ensues. But even long before the result becomes fatal, 
 the health is seriously impaired. The brain is often found 
 much diseased, and in part quite disorganized a state of 
 things which in man would produce incurable insanity. In 
 sheep, it causes " staggers," " gid," "vertigo," or " sturdy," 
 and other cerebral derangements. This disease is, in most 
 
 Figure 62. Coenurus or water-brain of sheep. Natural size. Hearth and 
 Home, after Thudichum. 
 
86 
 
 BOARD OF AGRICULTURE. 
 
 cases, incurable, and such diseased sheep are too often sent 
 to the market. Fortunately, man cannot be infected with 
 this parasite. 
 
 When one of these tumors is removed with care, it will be 
 found to consist of a thin, white, translucent cyst or sac, 
 roundish, oval, or irregular in shape. On one side may be 
 
 Figure 63. 
 
 Figure 64. 
 
 seen clusters of little white spots (Figure 62). If the spots 
 be examined with a lens, each one will be found to consist of 
 the minute head and neck of a young tape-worm, projecting 
 from the surface, and provided with four suckers and a -circle of 
 
 Figure 65. 
 
 hooks, as usual in young tape-worms in this stage of their 
 growth (Figure 63). Or else the heads will be found to be 
 withdrawn into the sac, each in its own capsule, and then 
 the spots are made by small depressions or pits, with a slit- 
 like opening at the bottom. If the interior of the sac-mem- 
 brane be examined with a microscope, each pit will be found 
 
 Figure 63. Portion of the outer membrane, with the heads of Ccenurus. En- 
 larged four diameters. From Davaine. 
 
 Figure 64. Inner surface of the membrane of the cyst, with inverted heads, 
 magnified. Hearth and Home, after Thudichum. 
 
 Figure 65. Brain of shesp in which the young embryos of C.cenurus have ex- 
 cavated galleries. Davaine, after Van Benedeu. 
 
PARASITES OF ANIMALS. 87 
 
 to correspond to one of the withdrawn and inverted worms, 
 as represented in Figure 64. 
 
 Each little worm has a head with a circle of hooks in the 
 middle, surrounded by four suckers, just as in the measle- 
 worm of pork. In this case, each little worm with a head is 
 the larva of one of the dog tape-worms (Tcenia caenurus), 
 hut in this the young worms have the power of propagating 
 themselves by a kind of budding, in a manner similar to that 
 by which the coral-animals bud from each other and so 
 build great colonies. Thus it is that one of these little 
 worms, lodged in the brain, by budding produces hundreds of 
 others like itself, all connected together by the membrane of 
 the sac ; and thus the tumor constantly grows larger, instead 
 of always remaining small, as does the measle-worm. 
 
 Effects. 
 
 Now, if a dog gnaws a skull containing such a tumor, and 
 swallows the whole cyst, or any part of the membrane that 
 has heads on it, the heads will be liberated from the mem- 
 brane, and each one will fasten to the lining of the dog's 
 intestine by means of its suckers and hooks. There they will 
 rapidly grow larger and larger ; new joints will be formed for 
 the body, and in the course of three months each one will become 
 a small tape-worm, with many joints, and each of the larger 
 joints will have both male and female organs, and will be 
 capable of propagating the race by itself. The female organs 
 of each joint contain thousands of eggs, which are discharged 
 when mature, and passing from the intestine of the dog in 
 large numbers, they will be scattered about freely over the 
 pastures and fields wherever the dogs go. If a lamb or sheep 
 accidentally swallows some of the eggs with grass or in water, 
 the eggs will hatch in the stomach into minute worms. These 
 force their way, by means of their six little hooks, through 
 the lining of the intestine into the blood-vessels, and are thus 
 carried to different parts of the system ; but usually only 
 those that lodge in the brain live, and there excavate galleries 
 (Figure 65) and grow, and bud, thus forming the " water- 
 brain," and finally kill the sheep. Ccenurus cysts have been 
 observed, however, beneath the skin of sheep, in the cellular 
 tissue. Similar cysts have, also, been found in the liver 
 
88 BOARD OF AGRICULTURE. 
 
 of rabbits, and in squirrels, and other animals, so that dogs 
 may perhaps obtain the same tape-worms by eating rabbits, and 
 then give the "water-brain" in turn to lambs. But the. 
 coenurus-like cysts of rabbits, etc., may prove to be a distinct 
 species, which does not produce the same dog tape-worm, as 
 several writers suppose. Young lambs are more liable to be 
 infected by this parasite than sheep, the liability decreasing 
 with age. This parasite is by no means uncommon, and is 
 always abundant in proportion to the number of dogs in any 
 country. Thus, in Iceland, where both dogs and sheep are 
 kept in large numbers, Dr. Krabbe found this tape-worm in 
 eighteen per cent, of the dogs, while the two other tape-worms 
 dangerous to sheep were found even in much greater num- 
 bers. "Giddy" sheep are, of course, very abundant in that 
 unfortunate country. In this country the disease is far more 
 common than most persons suppose. 
 
 That this disease is caused in the manner described above, 
 has been repeatedly proved by direct experiments made by a 
 number of naturalists. The following by Dr. Kiichenmeister, 
 was one of the earliest : " On the 6th of January, 1854, at 8 
 o'clock in the evening, and on the 7th of January, at 11 o'clock 
 in the forenoon, I gave some mature proglottides (joints) of the 
 Tcenia coenurus of the dog to six lambs of from six to nine 
 months old, taken from three different flocks, which were not 
 subject to vertigo. On the 20th of January the animals exhibit- 
 ed the first symptoms of vertigo. They were then successive- 
 ly killed, and presented the following phenomena on exami- 
 nation. 
 
 On the seventeenth day after the introduction, from twenty 
 to thirty vesicles (Coenuri) inhabited the surface of the brain ; 
 the substance of the brain was hollowed into galleries as though 
 a Sarcoptes had been formingits passages (see Figure 65) ; the 
 vesicles were still free and without envelopes, and of the size 
 of a grain of millet. 
 
 On the twenty-fifth day the vesicles were larger. On the 
 twenty-sixth day they were of the size of a lentil ; the envel- 
 opes began to be formed, and the first traces of heads appear- 
 ed. On the thirtieth day, the heads, under the form of tuber- 
 
PARASITES OF ANIMALS. 89 
 
 cles, were visible to the naked eye. On the thirty-eighth day, 
 the eminences appeared more distinctly on the surface, and 
 the heads exhibited signs of their suckers and hooks. 
 Toward the forty-fifth day the Coenuri were of the size of a 
 bean, and the cavities in which the heads are lodged were 
 formed." Encysted vesicles, containing strayed and aborted 
 worms, were also found in the heart, the diaphragm, and the 
 oesophagus. Some of the " water-brains" obtained in this ex- 
 periment were given to a dog early in March, and in due time 
 a good crop of the mature tape-worm (Taznia coenurus) was 
 obtained by killing the dog, which was done May 24th. These 
 were immersed in white of eggs, in which some of them were 
 kept alive, by changing it daily, for eight days, and sent to 
 several other naturalists residing in other parts of Europe, at 
 Louvain, Copenhagen, and Giessen. Prof. Von Beneden re- 
 ceived his at Louvain, May 27th, and tried the following ex- 
 periments : " On the day of their arrival, at 9 o'clock A. M., 
 half a proglottis was given to each of two young sheep, about 
 two months old, and in the afternoon each of them took an 
 entire proglottis. On the 3d of June, one of them, marked 
 No. 1, swallowed another proglottis. The first symptoms of 
 vertigo made their appearance on the*13th of June ; on the 
 morning of the 15th, I was told that the one marked No. 2 
 was dying. Its head was burning hot, its eyes red, its legs 
 bent under its body ; it beat with its head against the railings, 
 and turned it constantly in one direction. It was then killed. 
 The upper and lower surfaces of the two hemispheres of the 
 brain presented irregular grooves which might be taken for 
 the deserted tubes of certain annelids (Figure 65) ; these have 
 been already mentioned by M. Kiichenmeister. There were 
 about a dozen of them. At the end of these tubes there were 
 the same number of Coenuri , almost all lodged in the cortical 
 substance of the brain. Some of them were removed with the 
 membranes of the brain. They were of nearly the same size, 
 about three or four millimetres in diameter. These Coenuri 
 as yet only consisted of a simple milk-white vesicle filled with 
 fluid. The heads were not yet to be seen. * * 
 
 The second sheep (No 1), was killed on the 
 12 
 
90 BOARD OF AGRICULTURE. 
 
 29th of June. It presented nearly the same symptoms as th e 
 former. For the last few days of its existence the right fore- 
 leg was always bent, and in walking it could not support it- 1 
 self upon its hoofs. In removing the brain from the cranium, 
 a Ooenurus of the size of a small nut fell upon the dissecting 
 table. Two other Ccenuri, of the same size, were found in 
 the right hemisphere, one above, the other behind ; and in 
 separating the hemispheres of the cerebellum, I found two 
 others touching the quadrigeminal tubercles. The left lobe 
 of the cerebellum also contained one. Eight were found in 
 all. These Ooenuri were nearly all of the same size, except 
 two or three, which were scarcely larger than a cherry-stone. 
 Through the walls of the larger ones the naked eye could dis- 
 tinguish some little whitish flakes, the indications of so many 
 heads (scolices). The smaller ones had no appearance of 
 heads, nor of the place where they were to rise. The Coenuri 
 were enclosed in a membrane of recent formation, produced 
 by the inflammation of the neighboring surfaces." 
 
 Similar experiments, with the same results, were tried by 
 Eschricht at Copenhagen, and Leuckart at Giessen, to whom 
 tape-worms from the same dog were sent. Three sheep were 
 fed by Dr. Esckricht. Of these one was not affected, but the 
 other two became ill on the 15th and 16th days and died four 
 days afterward with the symptoms already described, and in 
 their brains the same kind of young Coenuri were found. 
 
 In these experimental cases, where large numbers of eggs 
 are given, the symptoms come on violently and death takes 
 place at an early stage in the development of the worms, but 
 under ordinary circumstances only a few eggs are swallowed 
 and then the sheep may live long enough to allow the cysts to 
 become much larger, with more numerous heads. The num- 
 ber of the heads is often 300 or more on a large cyst, and each 
 head is capable of forming a complete tape-worm, with many 
 joints. Allowing 500 sexual joints to each tape-worm, and 
 each joint to contain 5000 eggs, there might result, as the pro- 
 geny of one egg in a single generation, 150,000 joints, con- 
 taining 750,000,000 eggs ! 
 
 Remedies. The only remedy for sheep with this parasite at 
 
PARASITES OP ANIMALS. 91 
 
 work in the brain, would be trepanning, and that can seldom 
 be effectual, unless the cysts be small and favorably situated, 
 which is not often the case. As with most internal parasites, 
 instead of remedies, we must seek means of prevention. It is 
 very apparent that, in this case, prevention simply demands 
 the absence of dogs that harbor the tape-worms, from all 
 places where the sheep feed or drink. Prevention on the 
 part of dogs can be secured by not allowing them to feed on 
 the offal of slaughter-houses, and especially the heads of sheep. 
 The mature tape-worms can be expelled from dogs by the or- 
 dinary remedies for other tape- worms, some of which are men- 
 tioned under Tcenia mediocanellata. 
 
 Perhaps the most effectual of these remedies is oil or spir- 
 its of turpentine mixed with castor oil. 
 
 Tcenia echinococcus Siebold, of the Dog ; and its young, the 
 hydatid tumors of Man, Sheep, and Cattle. 
 
 This is by far the most important and dangerous of all ces- 
 tode worms. In the mature state it lives in the intestine of 
 dogs and wolves in great numbers, as a very small tape-worm, 
 about an eighth of an inch long, with only three sexual joints 
 or proglottides (Figure 70). In its larval state it forms com- 
 pound cysts and tumors in a great variety of animals. 
 
 Not imfrequently there may be found imbedded in the sub- 
 stance of the liver and lungs of sheep, watery tumors of con- 
 siderable size, sometimes becoming several inches in diameter 
 and causing serious disease, and even the death of the ani- 
 mal. Similar tumors occur, though less frequently, in the 
 brain, kidneys, ovaries, among the muscles, and in various 
 other situations in sheep. They occur also in pigs, horses, and 
 cattle, though less commonly than in sheep, but unlike the Ccen- 
 urus, or " water-brain," these tumors are not confined to the 
 lower animals. They are also found in the human body, and 
 give rise to incurable and most horrible diseases, to which per- 
 sons of ail classes are liable, 110 matter how wealthy or refined. 
 That large numbers of human beings of all ages and condi- 
 tions die annually from diseases caused by this parasite is es- 
 tablished beyond a doubt. And although such diseases are 
 
92 BOARD OP AGRICULTURE. 
 
 most common among the poorer classes of society, and espec- 
 ially among those who associate most familiarly with dogs, 
 
 Figure 66. 
 
 Figure 67. 
 
 they are by no means confined to them. Many men of great 
 eminence and talent have likewise perished from the same 
 cause. And, unfortunately, society is so constituted that no 
 one can be certain of escaping so long as the parasites that 
 produce the eggs exist in the dogs of every country. It is 
 estimated that 500 persons die annually by this parasite in 
 Great Britain. 
 
 These tumors, in their simplest form, or when young, con- 
 tain a roundish cyst or membranous sac, enclosing a watery 
 fluid, as shown in Figure 66, which represents of natural size 
 a parasite of this kind from the human kidney. More fre- 
 quently the cysts become compound by a process of budding, 
 either upon the outside or inside, or both without and within 
 the membrane of the original cyst, so that its size goes on in- 
 creasing indefinitely, sometimes becoming as large as a child's 
 head, and often completely permeating and destroying the 
 liver, lungs, or other organs. Thus the danger becomes con- 
 stantly greater and greater by reason of the pressure upon 
 and destruction of the adjacent organs. When the budding 
 is external, it results in a cluster of secondary cysts, often a 
 dozen or more, and sometimes hundreds, all more or less con- 
 nected together (Figure 67). And each of the external second- 
 ary or daughter cysts, may increase and multiply itself in the 
 same way, thus, at times, producing many hundreds of other 
 tertiary cysts or " grand-daughter cysts." By internal budding, 
 
 Figure 66 rHydatid or echinococcus cyst, natural size. Hearth and Home, 
 after Thudichum. 
 
 Figure 67. Secondary cysts from a tumor in the liver, natural size. From 
 Cobbold. 
 
PARASITES OF ANIMALS. 93 
 
 secondary or daughter cysts are formed inside the primary 
 ones, and then others inside the secondary ones, within which 
 the heads of the future tape-worms are formed by a peculiar 
 budding process. If the inner membrane of one of the small 
 cysts be examined when quite fresh with a good microscope, 
 there will be seen attached to it by means of slender stalks, 
 numbers of small oval or rounded heads, looking something 
 like fruit on a miniature plant, as shown in Figure 68, which 
 shows a few of these heads attached to the inner mem- 
 brane of a cyst from an echinococcus tumor of a sheep. The 
 heads may also bud forth from the outer as well as the inner 
 surface of the cysts, or brood-capsules, as they are called. And 
 these heads, either external or internal, may become changed 
 by an enlargement of their bladder-like portion into new 
 brood-capsules or cysts, and by budding produce other heads 
 in their interior, as shown in Figure 69. The heads are found 
 attached to the inner membrane of the primary cyst, together 
 with secondary cysts or brood-capsules ; they occur in the same 
 way in the interior of the secondary cysts, sometimes associ- 
 ated with tertiary cysts, or grand-daughter vesicles; and also 
 on the interior of the tertiary cysts. They sometimes appear 
 even on the exterior surface of the secondary and tertiary 
 vesicles. In all these situations they are similar in appear- 
 ance and structure, and all are equally capable of developing 
 into tape-worms in the intestine of a dog. Many of the 
 smaller secondary and tertiary brood-capsules or cysts are not 
 more than T ^ of an inch in diamter, and then generally coil- 
 tain only three or four heads. 
 
 Each of the oval heads is a hollow sac, which contains the 
 real head of the young tape-worm turned in like the finger of 
 a glove, just as the heads are turned inward in the ccenurus 
 and in the measles of pork, or the young of any other tape- 
 worm. Often the head is turned outward, as is seen in one 
 case in Figure 68, which shows well the four suckers around 
 the head and the proboscis in the middle with its circle 
 of hooks. These same organs can be seen indistinctly even 
 when in their inverted position, as in the other he.ads shown 
 in Figure 68, owing to the partial transparency of the mem- 
 
94 BOARD" OP AGRICULTURE. 
 
 branes. As long as these cysts remain in a living animal, 
 new heads are constantly formed, by their peculiar methods 
 of budding, and when new cysts are formed either within or 
 outside of the older ones, they develop on their inner mem- 
 branes other heads in the same way, so that if the sheep or 
 other animal lives long enough to develop a large tumor, it will 
 finally contain many thousands of these minute tape-worm 
 heads. In examining one of these tumors taken from a dead 
 animal, most of the heads and also the internal secondary cysts 
 are usually found floating freely in the watery fluid in great 
 numbers, giving it a turbid appearance, and on standing they 
 settle to the bottom as a granular sediment. This is 
 due to changes after the death of the parasite, though some 
 of the secondary cysts may be free during life. 
 
 Development. 
 
 Now, if a dog eats the liver, lungs, kidney, or other parts 
 containing such tumors, and swallows either the cysts or the 
 detached heads, these will lose the enclosing membrane, stems, 
 and other parts that are no longer useful, the heads with their 
 suckers and hooks will be protruded, and, passing into the 
 dog's intestine, each one will fasten itself by means of the 
 hooks and suckers to the soft membrane lining the intestine. 
 In this situation they remain and soon develop a small body, 
 having only three separable sexual joints, as shown in Figure 
 70, which represents the mature tape- worm {Tcenia echinococ- 
 cus) greatly magnified. This tape-worm never becomes long, 
 with hundreds of joints, as do the pork and beef tape-worms of 
 man. It is only about an eighth of an inch long when ma- 
 ture. The last joint, which is much the largest, contains both 
 male and female organs, and is perhaps capable of self-impreg- 
 nation ; it is therefore a complete hermaphrodite. After this 
 has matured and discharged its eggs, the two next in turn de- 
 velop their sexual organs and take its place. In Figure 70 
 the male organ may be seen projecting from one side, and the 
 ovaries, containing many eggs, occupy the bulk of the 
 joint. The eggs pass out through a duct that opens by 
 the side of the male organ, and each egg is fertilized 
 before being discharged. Thousands of these little tape- 
 worms, derived from one large cyst, often live together in 
 
PARASITES OF ANIMALS. 
 
 95 
 
 the intestinefof one dog, so that they make up by numbers 
 what they lack in size. Such a dog is constantly discharging 
 and scattering thousands or millions of the extremely mi- 
 nute eggs of this tape-worm wherever he goeskJ^Tf^JBJR 
 
 /%**' -^ 
 
 Fiirare 68. 
 
 JLibrary 
 
 They are scattered among the grass in fields and pas- 
 tures ; they get into the water of brooks and springs ; they 
 are liable to adhere to fruit that has fallen, or to lettuce 
 and other garden vegetables. 
 
 Dr. Cobbold has calculated the number of progeny that 
 might proceed from one egg during a single generative cycle. 
 Allowing 500 secondary cysts to be formed and 10,000 
 heads or scolices to be developed by each hydatid cyst of 
 average size, these might produce 5,000,000 tape-worms, 
 each of which having three joints that become free, would 
 give 15,000,000 joints or proglottides, and if each of these 
 contains 10,000 eggs, the whole number of eggs in one gen- 
 eration, would be 150,000,000,000! 
 
 Figure 68. Echinococcus heads attached to inside of brood-capsule, greatly 
 magnified. Hearth and Home, after Thudichum. 
 Figure 69. A head or scolex, becoming a brood-capsule. From Leuckart. 
 
96 BOARD OF AGRICULTURE. 
 
 Effects and Remedies. 
 
 These eggs are well protected by a shell, but when taken 
 into the human stomach, or into the stomach of sheep, cattle, 
 or pigs, they are acted upon by the gastric-juice and then im- 
 mediately hatch, The embryo is a very minute worm, very 
 different from the parent, and provided with six little hooks, 
 by means of which it digs its way through the lining of the 
 intestine into the blood-vessels, and entering the circulation 
 they are carried to the various organs of the body, where they 
 develop into the peculiar cysts first described, and thus cause 
 disease and death. When lodged in the brain, they are most 
 dangerous, soon causing insanity and death by their rapid 
 growth and consequent pressure. In the lungs they are also 
 very dangerous and often fatal ; in the liver they cause severe 
 disease, often terminating fatally ; and in other organs the 
 effects differ according to the nature of the organ. When 
 the lodgment is among the muscles, or near the exterior of 
 the body, the tumors may be removed by a surgical operation, 
 or even by simple puncture, they maybe destroyed. The dis- 
 charge of the contents is fatal to the life of the hydatid 
 opened, but there may be many others adjacent that will not 
 be affected. Injections of iodine, etc., after opening, are un- 
 necessary. When in the internal organs there is generally 
 no remedy, though by chance the cyst may of itself burst, as 
 sometimes happens, when, if the discharge takes place through 
 some natural channel, recovery is possible, but such cases are 
 of very rare occurrence. In the majority of cases the true 
 nature of the disease is not suspected until a post mortem 
 examination reveals it, or until the tumors burst or are 
 opened, when a microscopic examination of the matters dis- 
 charged gives reliable evidence ; but many of these hydatid 
 tumors are no doubt observed and treated by physicians, who 
 do not even suspect what their real character may be, because 
 they have neither suitable instruments nor sufficient knowl- 
 edge to make the requisite examinations. Chemical tests 
 may be applied to the liquid discharged, it is said, with satis- 
 factory results. The properties of the fluid are described as 
 follows: "If the sac be not inflamed, it is limpid, has a 
 specific gravity of 1007 or 1009, and contains no albumen, 
 
PARASITES OF ANIMALS. 
 
 97 
 
 but throws down a copious precipitate with a solution of 
 nitrate of silver, owing to its strong impregnation with com- 
 mon salt. These characters apply to no other fluid in the 
 Figure 70. body, whether healthy or morbid." Dr. 
 Murchison. In some cases hydatid tumors 
 situated in the liver and other internal organs 
 have been opened from the exterior, with suc- 
 cess, by skillful surgeons, but these operations 
 are always dangerous and often immediately 
 fatal. The escape of the fluid, with the 
 minute cysts and heads contained in it, into 
 the abdominal cavity, will give rise to other 
 tumors, and thus increase the disease, even if 
 death does not immediately result. 
 
 This is. eminently a case where " an ounce 
 of prevention is worth a pound of cure." The 
 means of prevention are simple, though not 
 easy of application in all cases. The iirst and 
 most important rule is to diminish the num- 
 ber of dogs to the utmost possible extent, and 
 then to keep them at the minimum number ; 
 second, avoid as much as possible the prox- 
 imity of dogs and sheep ; third, avoid feeding 
 dogs with uncooked livers or other offal of 
 sheep containing these parasites, or never give 
 them such raw food without careful exami- 
 nation ; fourth, avoid too much familiarity 
 with dogs, and especially between children 
 and dogs ; fifth,, be careful not to eat lettuce, 
 fallen fruit, or other raw food that has not 
 been thoroughly washed, both on account of 
 this and other parasites j sixth, avoid by all 
 means possible the use of impure water, or water liable to 
 be contaminated by eggs of parasites and excreta of animals, 
 both for household purposes and to supply sheep, cattle, and 
 horses, for such water is not only liable to contain echino- 
 
 Figure 70. Mature Tcenia echinococcus, much enlarged. Hearth and Home, 
 after Leuckart. 
 
 13 
 
98 BOARD OF AGRICULTURE. 
 
 coccus eggs, but those of several other tape-worms, round- 
 worms, and many other parasites, and is of itself unhealthy 
 and often the prolific cause of disease. If water from a good 
 well, or a well protected spring, cannot be had, the water 
 should be carefully filtered, and by preference through char- 
 coal. Most of the water consumed in our cities, both from 
 wells and the water-works, is wholly unfit to drink without 
 filtering. In cities with loose sandy soils the well-water is 
 the worst possible. 
 
 Finally, dog-kennels and other places much frequented by 
 dogs, should be frequently cleaned and the litter burned, 
 while frequent sprinklings with strong petroleum water or a 
 solution of carbolic acid in water should be used to destroy 
 the eggs that may have escaped from the intestine. By these 
 precautions the numbers of this and several other dog-parasites 
 might be much diminished. Dogs might also receive a 
 thorough course of medical treatment, once in three months 
 to expel all their intestinal worms, with great advantage, and 
 this might, with propriety, be made obligatory by law. In 
 this case the dogs should be confined while treated and all 
 excreta should be burned. 
 
 The frequency of this parasite is in direct proportion to the 
 extent to which the precautions are neglected in different 
 countries. In Iceland, the conditions for its rapid increase 
 and perpetuation have been favorable, and in that unfortunate 
 country, Dr. Krabbe states that there are at all times about 
 eighteen hundred patients suffering with severe forms of this 
 parasitic disease a number equal to about one-fortieth of all 
 the inhabitants. In some districts, the proportion is said to 
 be one in every seven, and scarcely a family can be found 
 without two or more cases ! It is also stated that one-sixth 
 of all the deaths are due to diseases caused by this parasite ! 
 The number both of dogs and sheep in Iceland is very large, 
 and the dogs mingle with the natives and live with them in 
 their rude dwellings, and are used in bringing the sheep to- 
 gether, so that abundant opportunities occur for propagating 
 the parasite. According to Dr. Krabbe, there is one dog for 
 every three to five inhabitants in Iceland, while in Great 
 
PARASITES OF ANIMALS. 99 
 
 Britain, with a high tax on dogs, there is only one to fifty. 
 Doctor Krabbe found the echinococcus tape-worms in twenty- 
 eight out of one hundred Icelandic dogs examined, while in 
 Denmark he found them in less than one per cent, of the 
 three hundred and seventeen dogs examined for this purpose. 
 
 Tape-worm of the Horse ( Tcenia perfoliata Goeze). 
 
 This is a small species, seldom becoming more than three 
 inches long and a third of an inch broad. The head is rather 
 square, with four prominent suckers, but without a proboscis 
 and hooks. There is no distinct neck, the first joints behind 
 
 Figure 71. Figure 72. 
 
 the head being broad, but short. There are about 45 joints 
 in full-grown specimens. The reproductive organs open on 
 one edge of the joints, the first 22 segments having both male 
 and female organs, the rest only female. 
 
 It occurs quite frequently, in considerable numbers, in the 
 coecum and colon of the horse, and more rarely in the small 
 intestine. The development and the source from which 
 horses derive them are unknown. The larvae may, perhaps, 
 live in insects accidentally swallowed with grass. It does not 
 appear to produce any serious disease, unless in great num- 
 bers, and may be expelled by the same medicines used against 
 the human tape-worms. 
 
 A still smaller species, T. mamillana Mehlis, only about 
 half an inch long, and also without a distinct neck, but with 
 wedge-shaped joints, lives in the large intestine of the horse. 
 A much larger species than either of these (T. plicata Rud.) 
 lives in the small intestine and sometimes in the stomach of 
 the horse. It grows to the length of three feet or more, and 
 has a remarkably large head, with four suckers, but no hooks 
 
 Figure 71. Young Tcenia perfoliata, natural size. From Cuvier. 
 Figure 72. Head of T . perfoliata, magnified. From Cuvier. 
 
100 BOARD OF AGRICULTURE. 
 
 or proboscis. The neck is short and thick, transversely 
 plicated, and the reproductive organs are in a single series on 
 one edge. If in considerable numbers, this species may pro- 
 duce serious symptoms, such as loss of flesh, tight skin, loss 
 of strength and spirit, and general debility. 
 
 The Sheep Tape-worm ( Tcenia expansa Rudolphi) . 
 
 This species, which is found both in sheep and cattle, grows 
 to the length of eight or ten feet, varying in breadth from a 
 quarter of an inch to upward of an inch, in large specimens. 
 The head is very small with four suckers directed forward, 
 and close together. The neck is scarcely distinct, or very 
 short. The posterior border of the joints are uneven, divided 
 up into rounded lobes and notches, or wavy. The reproduc- 
 tive organs are double, opening on each edge of every joint. 
 Its young stage is unknown, and consequently the source 
 from which the sheep obtain it. It does not appear to be very 
 common in this country, judging from the few cases recorded. 
 In Germany it is very common in sheep. It does, without 
 doubt, produce effects in sheep similar to those caused by the 
 tape-worms in man. 
 
 Tcenia cucwnerina Bloch, of the Dog. 
 
 This species is very common in the small intestine of the 
 dog. It grows to the length of ten or fifteen inches up to 
 nearly ten feet, with a width of one-twelfth to one-eighth of 
 an inch. The head is somewhat rhomboidal, with four sucke rs 
 and a central proboscis, which is surrounded by three circles 
 of claw-shaped hooks, the whole number being about 48. 
 The mature joints are elliptical, or shaped somewhat like the 
 seed of a melon or cuciimber. From this peculiarity it takes 
 its name. There are two genital orifices to each joint, one 
 in the middle of each edge. The eggs are much fewer in 
 each joint than in most other tape-worms. Its development 
 is unknown. It has been supposed that the larvae live in flies 
 or other insects. 
 
 When in large numbers in a dog, it occasions more or less 
 severe symptoms, especially if associated, as it usually is, 
 with several other species of tape-worms and round-worms. 
 It can be expelled by the same remedies mentioned under 
 some of the previous species. 
 
PARASITES OF ANIMALS. 101 
 
 Tcenia elliptica Batsch is a similar species living in the cat, 
 and by some is thought to be the same. 
 
 Several tape-worms of the dog have already been de 
 scribed (Tasnia echinococcus, T. coenurus, T. marginata), 
 but there is another that is equally common in some districts. 
 
 Tcenia serrata Goeze closely resembles T. ccenurus and T. 
 marginata. The larva? live among tho viscera of rabbits and 
 hares, producing small round cysts, and the dogs get this tape- 
 worm by eating rabbits or the refuse thrown aside in dressing 
 them. The young state or larva was formerly named Cysti- 
 cercus pisiformis, in allusion to the pea-shaped cysts. 
 
 The Broad Tape-worm of Man (Bothriocephalus latus 
 Bremser) . 
 
 The genus Bothriocephalus differs greatly from the true 
 tape- worms (Tcenia) in many anatomical characters, but has 
 a similar form of body, divided into many flat joints. The 
 head has no suckers, but is long-oval in shape, with a long 
 and deep, groove on each side. It has no proboscis and no 
 hooks. The reproductive organs open at the middle of the 
 side of each joint, instead of the edge. 
 
 There are numerous species living in fishes and quite a 
 number in birds. The present species grows to an enormous 
 s i ze probably larger than any other known tape-worm. It 
 grows to the length of 25 or 30 feet, and according to some 
 authors to 50 or 60 feet. It is sometimes an inch wide. The 
 joints seldom break off, either singly or in chains, but the 
 eggs are discharged by the bursting of the joints while still 
 attached within the body of the infested person. The male 
 and female organs oprn separately, the male organ being a 
 little in advance of the female orifice. The female uterine 
 organ forms a sort of rosette, with eight or ten lobes, around 
 the external orifice. 
 
 Its fertility is remarkable, even for a tape-worm. Prof. 
 Eschricht found in one specimen 10,000 joints ; allowing each 
 of these to contain only a thousand eggs, this worm would 
 have produced 10,000,000 young. The full history of this 
 parasite is not yet known. The eggs, however, will hatch in 
 water, producing curious embryos, which are provided with 
 vibrating cilia by means of which they swim around for a 
 
102 
 
 BOARD OF AGRICULTURE. 
 
 few days. The external skin, with the cilia, is then cast off, 
 liberating a very different looking embryo or larva, which is 
 provided with six boring hooks, similar to those of the em- 
 bryos of ordinary tape-worms. Their subsequent history has 
 not been ascertained, but it is probable that they enter some 
 fish (most likely trout and salmon) and become encysted 
 among the muscles, and that persons who eat imperfectly 
 cooked or raw dried fish get the parasite in that way. 
 
 It is remarkable that this species is not known to be indig- 
 enous in any but European countries, and even in Europe it 
 is peculiar to certain districts. It is particularly common in 
 certain parts of Switzerland. In Geneva it is said that about 
 one-fourth of all the inhabitants are afflicted with this worm. 
 It occurs also in some parts of Russia, Poland, and Prussia. 
 In America it has only been observed in emigrants from 
 Europe, and in persons who have traveled in the European 
 countries where it naturally occurs. It causes similar symp- 
 toms and is removed by the same remedies as the common 
 tape -worms. 
 
 TREMATODE WORMS. 
 
 The Liver-fluke of Sheep and Cattle (Fasciolahepatica Linn.). 
 This common and notorious parasite has a very flat body, 
 different on the two sides, and more or less oval in form, the 
 anterior end suddenly narrowing to a sort of neck, which 
 tapers off to the mouth end, where it is either rounded or 
 pointed. The posterior end of the body is Figure 78. 
 somewhat tapering, but blunt. Ordinary speci- 
 mens are about three-quarters of an inch long 
 and half an inch wide, but large ones become 
 an inch and a quarter long and three-quarters 
 broad. While living they often curl up the ends 
 of the body, toward the lower side. The color 
 is pale brownish or greenish yellow, sometimes 
 with a faint rosy tint. At the anterior end of 
 the body there is a small, cup-shaped sucker, at 
 the bottom of which the mouth is situated 
 (Figure 73, a) ; near the origin of the neck- 
 like portion, on the middle line of the lower side, there is 
 
PARASITES OF ANIMALS. 103 
 
 another larger sucker (6), with no opening at its bottom ; 
 just in advance of this there are situated, side by side, the 
 male and female genital orifices (c). The external male 
 organ is long, slender, and when protruded is curved in a 
 spiral. It can be retracted into a small cavity. 
 
 Anatomy. 
 
 The reproductive system is very largely developed and com- 
 plicated. The male organs, or testicles, consist of large 
 clusters of vermiform, convoluted, yellowish tubes, situated 
 in the middle region of the body, and filling up about one- 
 half of the whole interior. The female organs, for they are 
 hermaphrodites, are also largely developed and complicated. 
 The lateral and hinder parts of the body are filled with in- 
 numerable, very small, yolk-sacks, which communicate, by a 
 complicated system of branched ducts, with a heart-shaped 
 ovary, and this in turn has a short duct leading to the uterus- 
 like organ, which consists of a convoluted, wide tube, forming 
 a sort of rosette behind and around the ventral sucker. The 
 uterine tubes show through the skin and are brownish yellow, 
 owing to the numerous minute eggs with which they are filled. 
 These eggs are discharged, one by one, from the small ex- 
 ternal orifice as fast as they become mature. The mouth 
 communicates with a small dilated oesophagus, and this gives 
 rise to two large intestinal tubes, which diverge in advance of 
 the genital orifice and extend backward, along each side, to 
 near the posterior end, sending off numerous lateral branches, 
 which again subdivide into many short divergent branchlets, 
 as shown in Figure 73, d. The branches of these digestive 
 tubes are all closed at the ends, and they communicate with 
 the exterior only through the mouth. In life these tubes are 
 all filled with food, consisting chiefly of bile, with some blood- 
 corpuscles, etc. Another system of numerous, arborescently 
 branched tubes is found nearer the dorsal surface, and as they 
 show through the skin, on that side, they may be examined 
 
 Figure 73. Fasciola hepatica, natural size, seen from below ; a, mouth and 
 oral sucker ; b, ventral sucker ; c, genital orifice ; d, branches of intestine. From 
 Cuvier. 
 
104 BOARD OF AGRICULTURE. 
 
 with an ordinary lens. These tubes commence in fine, rootlet- 
 like branches, with rounded and closed ends, but the small 
 branches constantly unite into larger trunks, which in turn 
 all unite into one main trunk, running along the middle line 
 of the body, and this terminates in an external orifice at the 
 posterior end. The use of this system of tubes is to remove 
 the waste materials from the body. It may therefore take 
 the place both of the kidneys and liver of the higher animals. 
 There is 110 blood circulation and no true blood in these 
 animals. 
 
 Development. 
 
 The fluke is a very prolific creature. Prof. Leuckart esti- 
 mates that the ovaries may at any one time contain 45,000 
 eggs. The number of broods that they produce is not known. 
 The eggs that are discharged pass out of the intestine of the 
 sheep, or other animal in which they live, with the excre- 
 ment. Those that get into water or moist places hatch after 
 several weeks, producing minute conical embryos, which are 
 covered with vibrating cilia or lashes, by means of which 
 they swim freely about in the water. In this state the em- 
 bryo is YJJTJ- of an inch long and -$$ of an inch broad at the 
 larger end. The cilia are T ^ of an inch long. 
 
 In a few days the external skin, with the cilia, is cast off, 
 and after that the embryos are obliged to creep about, instead 
 of swimming. Its farther development has not been traced, 
 but it probably has a history similar to that of other species 
 of flukes of which the entire history is known. Therefore it 
 is supposed that the young embryos, above described, attach 
 themselves to the bodies or enter the tissues of the fresh- 
 water spiral snails, such as Limncea and Physa. In this 
 situation the form probably changes, and they become the so- 
 called " nurses," and then a brood of larvae of another form 
 is developed in their interior, by a process of internal budding. 
 These larvae are provided with a tail and have a form some- 
 what resembling minute tad-poles. In this state they are 
 known as cercarice. They are finally discharged from the 
 body of the " nurses," and escaping from the snails, may 
 again swim actively about in the water, by means of 
 
PARASITES OP ANIMALS. 105 
 
 their tails, but eventually they, in all probability, again enter 
 the bodies of other small snails, and losing their tails, become 
 encysted ih Mttle capsules. Finally these snails, with their 
 parasites, are swallowed by sheep and cattle, while adhering 
 to the herbage growing on moist land or near the water, 
 or when adhering to water-cresses they might be swallowed 
 by mankind. In the stomach and intestine of these higher 
 animals they are again liberated from their cysts. They then 
 gain access to the liver, where they rapidly develop their 
 sexual organs and become mature. Eventually, after they 
 have matured and perhaps discharged a large part of their 
 eggs, they themselves, or at least a part of them, enter the 
 intestine and are discharged, while still living, in company 
 with innumerable eggs. The eggs that they still contain may 
 be laid after they reach the earth or water. These eggs are 
 exceedingly minute and may be diffused in various ways, as 
 by rains, winds, insects, and the feet of animals, and getting 
 into water, or moist situations, they are ready to hatch and 
 commence another series of transformations. 
 
 The history of most of the flukes, which have hitherto been 
 fully investigated, agrees in the main with that above given, 
 and there can be little doubt but that this will prove to be the 
 case with the common fluke, when its full history shall have 
 been ascertained. At any rate it is certain that the eggs can 
 hatch only in water, or in moist places. Therefore it is evi- 
 dent that sheep and cattle will be much more liable to the 
 disease when kept in low wet pastures, than in dryer and 
 more elevated situations ; and also that wet seasons will be 
 favorable for the parasites and dry ones unfavorable. These 
 conclusions have been fully sustained by the experience of 
 sheep-owners in all countries. 
 
 Modes of Occurrence. 
 
 The liver-fluke is one of the few internal parasites that is 
 capable of living in several very different animals. It is most 
 common in sheep ; less so in cattle, goats, horses, and the 
 ass ; and quite rare in man. It has also been found in the 
 hog, elephant, camel, beaver, squirrels, rabbit, hare, deer, 
 and antelopes of several kinds, and in the great kangaroo. 
 14 
 
106 BOARD OF AGRICULTURE. 
 
 It is chiefly found in the gall-bladder and bile ducts, but 
 occurs also in the intestine, and sometimes in blood vessels. 
 In the human subject it has, in some instances, been found in 
 tumors beneath the skin. In these cases it is supposed that 
 the larvae entered from the exterior by boring through the 
 skin. 
 
 Effects. 
 
 The injurious effect of this parasite is best known in the 
 case of sheep. In these animals it produces the fatal disease 
 generally known as " rot,"* " water-rot," or " fluke-rot." In 
 severe cases of this disease there are always large numbers of 
 flukes in the bile-ducts- and gall-bladder, often several dozens 
 and sometimes several hundreds, or even a thousand in some 
 fatal cases. A few may exist in a sheep without causing any 
 marked disease ; in proportion to the number, the symptoms 
 become more marked and the disease more fatal. In some 
 wet seasons, and in certain districts, these parasites have 
 destroyed immense numbers of sheep. Thus in 1830-1 it is 
 estimated that between one and two million sheep died of 
 this disease in Great Britain. If the number was but 1,500,- 
 000, it would represent a loss equal to about $20,000,000. In 
 a single year, in England, individual farmers have lost from 
 300 to 800 sheep in the same way. In France, during the 
 year 1812, according to Davaine, 300,000 sheep died by the 
 same cause in the vicinity of Aries, and 90,000 at Nimes 
 and Montpellier. In Germany, Holland, and most other 
 European countries similar disastrous outbreaks of the dis- 
 ease have occurred every few years, while during the most 
 favorable years the aggregate annual loss is far greater than 
 is generally supposed. In this country there are no reliable 
 statistics by which the losses from this cause can be estimated. 
 Yet there can be no doubt but that it amounts in reality to a 
 large sum annually. Even those sLeep that have the disease 
 in a milder form and are sent to the market before they be- 
 come too sick to be moved, lose very much in value, and are 
 
 *This must not be confounded with an entirely different disease, known as 
 " foot-rot." 
 
PARASITES OF ANIMALS. 107 
 
 really unfit for -food, though it is to be feared that farmers, as 
 well as butchers, are not always over scrupulous in such cases. 
 
 Symptoms. 
 
 In severe cases any one at all familiar with sheep can 
 readily detect the disease even by the general looks of the 
 animal. They also show a peculiar weakness in the loins 
 when the hand is pressed along the back over that region. 
 In very bad cases the back becomes hollow and the belly 
 hangs down, while the sheep become more and more 
 emaciated and weak, dull, and dejected, with a feeble gait. 
 The skin loses its natural color and becomes dry, while the 
 wool is also harsh and dry, and conies off easily. 
 
 The skin on the inner parts of the thigh, especially where it 
 is naked, becomes dry or scaly early in the progress of the dis- 
 ease. The eye affords very certain evidence, even at an early 
 stage, so that even shepherd boys are able to select from a 
 flock those that are diseased, by this symptom alone. If the 
 lids be turned back and the membrane at the corner of the eye 
 be pushed away, the conjunctiva and other parts will present 
 an unnatural watery appearance, the vessels being swollen 
 and filled with pale or yellowish colored blood, When the 
 disease is farther advanced the blood-vessels lose their color 
 and are scarcely distinguishable, though a few of them may 
 be swollen and filled with dark, unhealthy looking blood. 
 
 Remedies. 
 
 It can be safely stated that when these parasites have once 
 entered the liver in considerable numbers there is no known 
 specific remedy. All that can be done is to keep up the 
 general health and strength of the animal until nature effects 
 a cure, or until the parasites complete the natural course of 
 their lives and voluntarily leave the sheep. To this end the 
 afflicted animals should be removed to a dry pasture or good 
 shelter, and be liberally fed with a variety of nutritious and 
 palatable food, while they should be freely supplied with salt. 
 
 This is another of those instances where prevention is far 
 easier and better than cure. From what we already know of 
 the history of the parasite it is evident that sheep will be 
 
108 BOARD OF AGRICULTURE. 
 
 little liable to get it if pastured on uplands, or other dry 
 places, and supplied with pure spring water, by preference 
 from a trough or other similar arrangement. On the other 
 hand, sheep pastured on meadows, or swampy lands, or in 
 places where they have access to the marshy banks of streams, 
 ponds, and swamps, will be far more liable to get this and 
 several other parasites. 
 
 An exception should, however, be made in the case of salt 
 marshes and meadows, for sheep pastured in such places sel- 
 dom get the disease. This is probably owing to the fact that 
 the fresh water snails, that harbor the young flukes, cannot 
 live in salt or brackish water. 
 
 Smaller Liver-fluke (Distoma lanceolatum Mehlis). 
 
 This species is also found in the bile-duct and gall-bladder 
 of sheep and cattle, and occasionally in man. It is sometimes 
 associated with the common fluke. It is much smaller, the 
 length being about one-third of an inch and the breadth an 
 eighth. It has a smooth, flat, lance-shaped body, broadest 
 behind the middle, narrowing to each end, the mouth-end 
 being most pointed. There are two suckers, as in the com- 
 mon fluke, the one at the front end having the mouth at the 
 bottom. 
 
 The anatomy is quite different, for in this, as in all other 
 true Distomas, the digestive tube only forks once, each branch 
 remaining a simple, closed tube, running down on each side 
 of the middle region of the body. The testicles are two 
 large, roundish, but somewhat lobed organs, just below and 
 near the ventral sucker. The uterine tube has numerous 
 branches arranged on each side of a main central trunk, in the 
 hinder part of the body. The ovaries are comparatively 
 small and situated on each side of the middle region of the 
 body. 
 
 Development. 
 
 The eggs hatch in water, after several weeks, producing 
 very small, nearly round embryos, which have the vibrating 
 cilia only on the head end, which is a little smaller than the 
 other end. They are not such lively swimmers as the em- 
 
PARASITES OF ANIMALS. 109 
 
 bryos of the common fluke. They are about ^ to -^ of an 
 inch long, and ^-^^ of an inch broad. The head end is pro- 
 vided with a dagger-like boring spine, which can be alternate- 
 ly thrust out and withdrawn. It is supposed that these em- 
 bryos become parasitic in fresh-water snails, for a time, and 
 undergo transformations like those described under the pre- 
 ceding species. Their effects and remedies are the same as 
 for the common fluke, though owing to their small size they 
 would be less injurious, unless in much greater numbers. 
 
 The Stomach-flukes of Cattle (AmpTiistoma conicum Rud. and 
 A. crumeniferum Creplin). 
 
 The flukes belonging to the genus Amphistoma, which in- 
 cludes, besides the two indicated, A. explanatum from the 
 bile-ducts of cattle and A. truncatum from the cat, have a 
 small, rather thick, and somewhat conical body, the mouth- 
 sucker being at the small end. The large end is rounded and 
 bears the other sucker, which is always much larger, near the 
 posterior end. The stomach and reproductive organs are 
 nearly like those of Distoma. The eggs also produce ciliated 
 embryos in the water, and they are supposed to go through 
 similar transformations. I do not know that either of them 
 have been observed in sufficient numbers to produce serious 
 diseases in cattle. 
 
 ACANTHOCEPHALA. 
 
 (Thorn-headed worms. ) 
 Echinorhynchm gig as Goeze. Figures 74, 75. 
 This, which is the only representative of the order hitherto 
 found in our domestic mammals, is quite frequent in the intes- 
 tine of hogs. It may at once be known by the peculiar pro- 
 boscis, which bears several circles of small but sharp hooks, 
 which are arranged alternately, in quincunx, mostly toward 
 the end of the proboscis (Figure 75). These worms have a 
 long roundish body, tapering to the posterior end. The skin 
 is generally crossed by numerous transverse wrinkles, but is 
 sometimes smoothish. The color is whitish or a little bluish. 
 The males grow to the length of three or four inches, with a 
 
110 
 
 BOARD OF AGRICULTURE. 
 
 diameter of one-eighth to one-fifth of an inch. The females 
 may become six inches, or even a foot in length, and some- 
 times one-quarter of an inch in diameter, though generally 
 
 Figure 74. 
 
 smaller. The female is very prolific, producing an immense 
 number of somewhat oblong-oval eggs. 
 
 The history of its development and transformations has 
 not yet been made out. There can be little or no doubt, 
 however, that the young worms are parasitic in some other 
 animals, most likely in insects, worms, or snails, and that 
 the hogs get them by devouring the embryos included in 
 some such small animals. 
 
 Effects and Symptoms. 
 
 This is the commonest and most injurious intestinal worm 
 found in swine. These parasites live in the small intestine, 
 and more rarely in the large intestine. They usually adhere 
 to the lining, or mucus membrane, by means Figure 75. 
 of the hooks on the proboscis, which is thrust 
 into the substance of the membrane. Not 
 unfrequently they perforate the walls of the 
 intestine and stray into other parts of the 
 viscera, producing serious disease. Some- 
 times the intestine of a hog is found per- 
 forated by so many of these holes that it can- 
 not be used in the manufacture of sausages ! 
 
 In severe cases, hogs afflicted with this parasite are weak 
 in the loins, and have the membranes in the corners of the 
 eyes swollen, watery, and lighter colored than usual. The 
 excrement is hardened and highly colored, and the animal 
 often keeps up a continual squealing and grunting, especially 
 in the morning. Such hogs are generally cross and morose, 
 
 Figure 74. Echinorkynchus gigas, natural size. From Cuvier. 
 Figure 75. Head of E. gigas, enlarged showing the reticulated vessels in the 
 skin. From Curier. 
 
PARASITES OF ANIMALS. Ill 
 
 biting and snarling at its companions, but is usually too weak 
 to defend himself, if attacked in return, and is easily thrown 
 down. Finally the weakness increases until the poor crea- 
 ture is unable to walk about, or to stand. This parasite will 
 probably yield to the same remedies used for tape-worms, or 
 those employed against the common round-worms of man (As- 
 caris lumbricoides) , to which, therefore, the reader should refer. 
 
 NEMATODES. 
 
 (Round-worms and Thre ad-worms J) 
 The Flesh-worm (Trichina spiralis Owen). Figure 76. 
 This most important and most dangerous of all human para- 
 sites, is a very minute round worm, which in the larval state 
 lives in the muscles of man, swine, dogs, cats, rats, mice, 
 rabbits, Guinea-pigs, and many other animals, and in the ma- 
 ture state inhabits the intestines of the same animals. The 
 body is slender, smooth, and round. The intestine is com- 
 posed of a series of small, bead-like swellings, separated by 
 constrictions. The male is much smaller than the female, 
 when mature measuring only T V of an inch ; its body is filiform, 
 pointed at the head, enlarged at the opposite end, generally 
 somewhat bent or curved upon itself ; the head is very small 
 and pointed, unarmed, but with a minute central mouth ; the 
 posterior end of the body is furnished with a bilobed ap- 
 pendage, the anal opening being between the lobes ; the penis 
 is a single spiculum, cleft above so as to have a V-shaped out- 
 line. The female is stouter than the male and longer, meas- 
 uring about -J- of an inch, when mature ; the posterior end is 
 bluntly rounded ; the genital orifice is at about a fifth of the 
 length from the anterior end of the body. They are viviparous 
 and the uterus occupies most of the body, in the form of along 
 and wide tube, in which the embryos are closely packed. The 
 eggs are T ^ 7 o of an inch long. The young Trichinae, like young 
 tape-worms, occur imbedded in the muscles of the hog and 
 various other animals, and man. But unlike the young tape- 
 worms or " measles," the young Trichince are so small as to be 
 quite invisible to the eye, and millions of them may ex- 
 ist in the flesh of a pig without producing any unusual appear- 
 ance in the meat sufficient to attract the attention even of an 
 
112 
 
 BOARD OF AGRICULTURE. 
 
 expert, unless examined with a powerful microscope. This is 
 one reason why deaths so frequently occur from eating pork 
 filled with this parasite. When recently introduced into pork 
 or human flesh, the little worms are free and coiled up among 
 the muscular fibres, but after four or five weeks they become 
 enclosed in minute, whitish, elongated, oval or roundish cysts 
 or capsules, due to the irritation and inflammation that they 
 cause by feeding and moving (Fig. 76). After a year or more 
 these cysts become calcified by a deposit of carbonate of lime 
 in the membrane, and at this time are visible to the 
 eye as minute specks, about the size of hemp-seed, scattered 
 through the muscles. When enclosed in the cyst, the worms 
 become dormant, and though they may live for years, and 
 even some weeks after the death of their host, they can do no 
 further harm unless swallowed by man or some animal. Each 
 cyst contains a little slender worm about one twenty-fifth or 
 one thirtieth of an inch long, and one seven hundredth thick, 
 coiled up in two or three 
 
 turns. The cysts average Ei ure 76> 
 
 about one eightieth of an 
 inch long and a hundred 
 and thirtieth thick. 
 
 If pork or other flesh 
 containing these worms, 
 either free or enclosed in 
 cysts, be eaten by man, 
 they become liberated in 
 the stomach, and, en- 
 tering the intestine at- 
 tach themselves to its soft 
 lining, and there, sur- 
 rounded with abundant 
 food, they grow very rap- 
 idly and become mature, 
 with fully developed sex- 
 ual organs, in two days. 
 
 Figure 76. A small piece of human muscle containing encysted young of 
 Trichina spircdis Owen, enlarged forty-five diameters. From Hearth and Home, 
 after Leuckart. 
 
PARASITES OF ANIMALS. 113 
 
 The females are larger and more numerous than the males, 
 and become about one-eighth of an inch long when full grown. 
 They pair as soon as mature, and the males soon die ; 
 but the females begin to give birth to living young in five 
 or six days from the time when they enter the stomach, 
 and they live long enough to produce a brood of from five hun- 
 dred to one thousand young worms each. As one ounce of pork 
 sometimes contains a quarter of a million or more of the worms, 
 it is not surprising that the millions of adult worms and their 
 offspring, sometimes resulting from a single meal of raw 
 pork, should, by their presence, produce great irritation and 
 inflammation of the intestine and violent diarrhoea and vomit- 
 ing, which are often the first symptoms in severe cases. But 
 the young worms, almost as soon as born, begin to eat or 
 force their way through the membranes of ' the intestine into 
 the minute blood-vessels and other organs, thus vastly in- 
 creasing the irritation. Entering the circulation they 
 are carried by the blood to the heart, thence to the lungs, 
 and then become diffused through the whole system. Accord- 
 ing to other observers, the young worms force their way di- 
 rectly through the intestine and all other intervening organs, 
 until they finally reach a suitable habitation in the voluntary 
 muscles. It is, however, difficult to understand how they can 
 become so evenly and generally distributed through the whole 
 muscular system as they often are, if this be their only mode 
 of diffusing themselves. It is, therefore, not improbable that 
 they migrate by both these methods, part entering the circu- 
 lation and part going directly through the tissues, while in 
 either case, if they find themselves in an unfavorable locality, 
 they have the power of changing their position while still in 
 the free state. According to Dr. Leuckart, they travel by the 
 way of the intermuscular connective tissues, and are found 
 most abundantly in the groups of muscles nearest the abdomi- 
 nal cavity, especially in those that are smallest and have the 
 most connective tissue. 
 
 Effects. 
 
 Large numbers often lodge in the heart, lungs, and various 
 other organs, producing great irritation and various danger- 
 15 
 
114 BOARD OP AGRICULTURE. 
 
 ous symptoms, but the majority finally reach and remain in 
 the voluntary muscles, where they live and thrive for some 
 weeks, making for themselves passages, and even entering and 
 destroying the fibres themselves. All these operations cause, 
 of course, an immense amount of inflammation and irritation, 
 if, as often happens, millions of these flesh-worms are at work 
 at the same time in all parts of the system ; and it is no won- 
 der that many violent symptoms and high fever result, or that 
 there should be intense soreness and pain or paralysis of the 
 muscles, and dropsical swellings. Death in severe cases may 
 occur at any time from the fifth to the fiftieth day. The du- 
 ration of the disease, like its severity, is in direct proportion to 
 the number of living Trichinae swallowed, and varies from two 
 weeks to three or four months. Even in many comparatively 
 mild cases, the sutfering is intense and the recovery slow and 
 tedious, while many secondary diseases, like pneumonia,etc.,are 
 liable to ensue. When all the worms have become lodged in 
 the muscles and enclosed in cysts, the direct symptoms cease, 
 and, if the strength of the patient has been kept up, recovery 
 is probable. Some persons, especially females, are much more 
 severely affected than others, by the same number of the para- 
 sites. 
 
 Persons in robust health may be able to survive the attack 
 of half a million or more of these flesh-worms and recover, 
 but there is a limit to all human endurance, and the numbers 
 often contained in the muscles of animals or persons who 
 have been killed by them, are almost incredible. In a cat fed 
 with trichinous flesh by Leuckart, they were so numerous that 
 he estimated that one ounce of the flesh contained at least 
 325,000 worms. Microscopic preparations, not much larger 
 than a pin's head, often contain from ten to forty worms, and 
 one bit of muscle, weighing about one-fifth of a grain, from a 
 child that died on the seventy-ninth day, contained fifty- 
 eight. Allowing only one hundred worms to a grain of mus- 
 cle, a man weighing 150 pounds might contain over forty 
 millions of the parasites, and the length of the muscular 
 fibres actively inflamed by such a number, if placed in a line, 
 would amount to more than 120 miles. 
 
PARASITES OF ANIMALS. 115 
 
 In some very severe cases the numbers contained in human 
 bodies have been estimated, by reliable authorities, as 
 high as forty and sixty millions. 
 
 The cysts containing Trichince were first observed in human 
 muscles in 1822, but the worms from similar cysts were first 
 named and described by Owen, in 1835, but were only regarded 
 as anatomical curiosities of no practical importance, until 1860, 
 when Zenker proved that they are capable of producing the 
 severe and often fatal disease now well known under the name 
 of Trichiniasis, but which had been previously (as it often is 
 still) confounded with typhoid fever, inflammatory rheuma- 
 tism or rheumatic fever, poisoning, and various other 
 diseases. 
 
 Symptoms and treatment of the disease. 
 
 The disease caused by this parasite has three more or less 
 distinct phases : 
 
 First. While the mature worms and young remain in the 
 intestine, and while passing through its walls. In this stage 
 the symptoms are derangement and inflammation of the in- 
 testine, often resulting in severe diarrhoea, nausea and vomit- 
 ing, swelling and pain, and sometimes peritonitis, due to the 
 perforations of the intestinal walls. These symptoms ensue 
 in two or three days after swallowing the trichinous flesh, and 
 may last a fortnight or more. Animals experimented upon often 
 die in this stage. Purgatives and anthelmintics are used in 
 this stage to expel the mature and pregnant females, but after 
 three or four weeks have passed this will be useless. Castor- 
 oil and calomel have been used with success for this purpose. 
 
 Second. While the young worms are migrating and work- 
 ing in the muscles, a variety of symptoms are developed, 
 varying in different persons, and depending, also, upon the 
 number of worms. This stage commences in ten to fourteen 
 days, and generally lasts four or five weeks. The principal 
 symptoms are lassitude and swelling of the muscles, with 
 soreness, or intolerable pains, resembling rheumatic pains but 
 not affecting the joints ; profuse sweating sometimes occurs ; 
 the pulse is very rapid, but the heat of the body is usually 
 
116 BOARD OF AGRICULTURE . 
 
 low, often never exceeding 102 Fahr. ; the face frequently 
 becomes suddenly and greatly swollen, and sometimes the 
 whole body is affected in the same way. In certain cases, a 
 peculiar congestion of the eyes has been observed. In general, 
 many of the symptoms in this stage resemble those of typhoid 
 fever. 
 
 In very severe cases the patient is unable to use the mus- 
 cles or move the limbs without the most intense agony, and 
 filially is obliged to lie passively, flat upon the back, with the 
 arms and legs somewhat bent, in the position that gives the 
 least pain ; and later the limbs are rigidly stretched out, some- 
 what apart, the body stiff, and the muscular system in a state 
 of more or less complete paralysis. Children generally lie 
 on the side, with the body bent and the legs drawn up. The 
 jaws are sometimes closed as in lock-jaw. The breathing is 
 difficult, shallow, and rapid. The lungs are often affected, 
 and frequently, also, the heart ; and many secondary diseases 
 are liable to ensue. 
 
 The most that can be done in this stage of the disease by 
 the physician relates to the relief of special symptoms and 
 secondary diseases, and sustaining the strength of the system 
 until nature may in time effect a cure. Most experimental 
 animals die in this stage, and human patients, also, frequently 
 perish even during the early part of this period. 
 
 Third. In case the patient survives the two first stages, the 
 inflammation gradually ceases, breathing becomes more 
 natural, and recovery generally commences, but in very severe 
 cases the muscles and other organs have been so much in- 
 jured as not to perform their proper functions, and general de- 
 bility often results, ending in a kind of consumption that finally 
 proves fatal. In many cases of recovery, lameness lasts for 
 several months. In many cases, however, the final recovery 
 is complete and may be followed by robust health, although 
 tens of thousands of living worms may be still enclosed in 
 the capsules in the muscles. 
 
 From this it is obvious that a hog may be fat and appear in 
 every respect healthy, and yet his flesh may contain such im- 
 mense numbers of the parasites as to be capable of killing a 
 
PARASITES OF ANIMALS. 117 
 
 hundred or more persons, should they eat it raw or but slightly 
 
 cooked. 
 
 Oases of Trichiniasis. 
 
 Since 1860 thousands of cases have been observed and hun- 
 dreds of deaths are known to have occurred, especially in 
 Germany, where the custom of eating various forms of raw 
 or imperfectly cooked pork is much more common than in 
 this country. At Hettstadt, in 1863, the flesh of one pig in- 
 fected one hundred and thirty-five persons, of whom twenty 
 died. Several other similar " epidemics" have also occurred 
 in the same country. In the United States, many sad cases 
 have also been recorded, as the following in stances will show: 
 
 At Marion, Iowa, May, 1866, Mr. Bemis and eight mem- 
 bers of his family ate rare -done and raw ham, and were im- 
 mediately taken sick. Up to June 3d, three had died, and 
 others were considered critical. A post-mortem examination 
 showed about two hundred thousand worms to a cubic inch of 
 muscle in one of those who died. 
 
 AtDubuque, Iowa, according to Dr. Asa Horr, two families 
 were attacked. In one five persons died ; in the other, five 
 or six. Through him we also learn of a case where the 
 mother of a family ate of the interior, rare-done part of a 
 ham and took the disease, while those who ate the outside 
 escaped. 
 
 At Springfield, Mass., February, 1867, Mr. Ransley Hall 
 and family ate of raw ham, and all seven were attacked in 
 various degrees, according to the amount eaten. A daughter, 
 aged seventeen, died, and the father had a long and very 
 dangerous illness. 
 
 At Albany, N. Y., January, 1869, two boys ate of raw ham 
 and were infected ; the rest of the family ate of the same 
 ham, when cooked, and escaped. 
 
 At Rome, Oneida County, N. Y., December, 1868, Mr. 
 John Wilbrecht and family, nine persons in all, ate raw 
 smoked and dried sausages. All were dangerously sick, and 
 four adults, the father, son, and two daughters died before 
 January 15th. Their sausages and salt pork were examined 
 and found to be full of Trichina, as were also the muscles of 
 those who died. 
 
118 BOARD OF AGRICULTURE. 
 
 In New York City, January, 1869, eight cases occurred in 
 a boarding-house in Carlisle Street, from eating sausages. 
 Two of the victims died in the New York Hospital, and others 
 were dangerously sick. It is a significant fact that the physi- 
 cians in two hospitals mistook these cases at first for typhoid 
 fever, and only discovered the mistake after one death had 
 occurred. 
 
 In Bridgeport, Conn., January 30th, 1870, raw smoked 
 ham was eaten by five persons. Of these Mrs. Koch died of 
 acute Trichiiiiasis, February 15th ; Mrs. Winter died February 
 16th ; Mr. Winter died March 1st ; a daughter of Mrs. Koch, 
 aged two and a half years, died March 7th. Mr. Strasburg 
 was for a long time very dangerously ill, and was left in a very 
 feeble condition. Another person who ate some of the same 
 ham fried, escaped entirely. Mr. Winter thought himself not 
 seriously ill when his wife died. Some portions of his pec- 
 toral muscles, which I have had an opportunity to examine, 
 were filled with Trichincs, not yet encysted. There were 
 perhaps 100,000 to the cubic inch. 
 
 Prevention. 
 
 Experiments have fully shown that nothing less than the 
 most thorough cooking, so prolonged as to destroy all redness 
 of the juices even in the interior of the meat, is capable of 
 destroying these parasites and rendering pork a safe article 
 of food. Cases, some of them fatal, have occurred from eat- 
 ing ordinary fried sausages, roast pork, and pork that had 
 boiled two hours. But the majority of severe and fatal cases 
 have happened from eating smoked ham, raw or partly cooked, 
 and various kinds of smoked and dried sausages, which are 
 often eaten raw, or but slightly cooked. 
 
 Therefore, if people will eat pork at all, they should make 
 it a fixed rule never to eat it unless thoroughly cooked, if 
 they would avoid one of the most painful and dangerous dis- 
 eases known. 
 
 There appears to be no certain way of preventing the 
 disease in hogs, for it is probable that in most cases they get 
 it by eating rats or mice, which are often full of Trichince, 
 but it is quite probable that they may often be infected by 
 
PARASITES OF ANIMALS. 119 
 
 eating slaughter-house offal. It is possible, also, to infect 
 hogs and other animals by means of the mature female 
 Trichince that have been discharged from the intestines of 
 men or animals, before all the young worms contained in their 
 uteri have been born. Therefore hogs may obtain this, as 
 well as the Iarva3 of the tape-worm of man and many other 
 parasites, by being kept in places where they have access to 
 manure, as is too often the case. Cats, rats, mice, rabbits, 
 Guinea-pigs, young dogs, and various other animals may be 
 infected, but adult dogs, like old hogs, are not nearly so likely 
 to become infected as the young. Although lambs, calves, 
 and horses may be infected by forcing them to eat trichinous 
 meat, it is probable that they seldom or never become infected 
 naturally. 
 
 Trichocephalus dispar Rudolphi. Figure 77. 
 This is a small round-worm, living in the human intestine, 
 and remarkable for its long, very slender, filiform neck, which 
 Figure 77. * s about two-thirds of the entire length. The 
 male grows to the length of one inch and a 
 half, and the female to two inches. The sur- 
 face of the body appears smooth to the naked 
 eye, but when magnified, a longitudinal band of 
 minute, wart-like papillae is seen on one side. 
 The male has the posterior end of the body 
 spirally curved, with a single spicule, which is 
 emitted from the extremity of the body, and is 
 enclosed in. a short, tubular sheath, that is cov- 
 ered with minute recurved spinules. The female 
 has the posterior end of the body nearly straight 
 and bluntly pointed (Figure 77). The genital 
 orifice is situated at the origin of the neck. The eggs are 
 elliptical, with a small projection at each end, and are -&G to 
 ?fa of an inch long. They are discharged from the human in- 
 testine before the contained embryos are fully developed. If 
 kept in water for six months or more they hatch, liberat- 
 ing a minute embryo 3^ of an inch long, which tapers 
 from behind toward the head. 
 
 Figure 7 '7. Trichocephalus dispar,' a, female, natural size ; b, posterior end, en- 
 larged. From Guerin. 
 
120 BOARD OF AGRICULTURE. 
 
 It is therefore probable that they are taken into the 
 human system in impure water. In some regions it is very 
 common. Davaine estimates that one-half of the inhabitants 
 of Paris entertain this parasite. Its effects are not well made 
 out, but it does not seem to cause, ordinarily, any marked in- 
 convenience. It lives in the coecum and small intestine. 
 TricJiocephalus affinis Rud. 
 
 This species lives in the coecum of cattle, sheep, deer, and 
 antelopes. It closely resembles the preceding, but the reck 
 part is still longer and more slender. The posterior end of 
 the male is curved in a close, conical spiral, and the spicule, 
 like its sheath, is much longer, being equal to about a third of 
 the length of the body. The genital orifice,of the female is 
 situated at the summit of a prominent, hour-glass shaped 
 papilla, which is obliquely truncated at the summit and 
 covered with minute spinules, like those of the spicule-sheath 
 in the male. The eggs are similar to those of the preceding 
 species and, without doubt, develop in the same way. It is 
 not known to cause any serious disease. 
 
 Spiroptera strongylina Rud., from the Hog. Figure 78. 
 
 The genus Spiroptera includes numerous species of small, 
 whitish or reddish, slender, round worms, which taper some- 
 what toward the anterior end, or toward both Figure 78. 
 ends. The head is small, and either naked, or 
 with small papillae. The male has the posterior 
 end curved in a spiral, with membranous expan- 
 sions, and with two unequal intromittent 
 spicules. In the female the posterior end of the 
 body is nearly straight and conical, and the 
 ovary is either simple or double, with the genital 
 orifice situated at one side of the body. 
 
 The 8. strongylina has a smooth, tapering body, with a 
 simple head and mouth. The male spicules are very long, 
 relatively to the entire length of the body. The male grows 
 to the length of half an inch or more. The female to more 
 than three-fourths of an inch. It lives in the stomach of the 
 hog, but ordinarily does not produce any serious disease. 
 
 Figure 78. Spiroptera str any y Una ; a, male, natural size; b, spicnles and pos- 
 terior end of the body, enlarged. From Guerin, 
 
PARASITES OF ANIMALS. 121 
 
 Spiroptera megastoma Rudolphi, of the Horse. 
 This is a small species, which has a more cylindrical body, 
 tapering a little toward each end. The head is separated by 
 a slight constriction and bears four lobes. The mouth is 
 large. The male becomes rather more than a quarter of an 
 inch long, and the female nearly half an inch. It lives in 
 the stomach and oesophagus of the horse and produces 
 tubercles, or hard tumors, of considerable size, most frequent- 
 ly situated near the pylorus. These contain many cavities, 
 connected together and filled with purulent matter, in which 
 there are numerous specimens of the parasite. The tumors 
 are sometimes one and a half inches in diameter, and there 
 are at times several in the same stomach. 
 
 Spiroptera sanguinolenta Rudolphi, of the Dog. 
 This is a larger, reddish species, which produces similar 
 tumors in the oesophagus and stomach of the dog. This 
 species usually grows to the length of one and a half to three 
 inches, but it has been found ten inches long, living in the 
 cavities of the ventricles of the heart of dogs at Shanghai, 
 China, where it appears to be very common. Its complete 
 history is unknown, and therefore little can be said about the 
 special means of prevention, or cure. It often produces death. 
 
 Pin-worm of the Horse (Oxyuris curvula Rudolphi). 
 Figure 79. 
 
 This is a small, whitish worm, quite commonly found in 
 the coecum and colon of the horse and ass. The female is 
 about one inch and a half to two inches long, when mature. 
 The male is far more rare and but one-third to two-thirds of 
 an inch long. The body is fusiform, tapering to a slender 
 tail, thicker in front, with the anterior end more or less 
 pointed. The mouth is situated at the end, and usually has 
 the form of a small, round pore, but is provided with three or 
 four small retractile papillae, which can be protruded. The 
 buccal cavity contains a peculiar apparatus of folds and tooth- 
 like processes ; the oesophagus is long and muscular, round 
 externally, but with a three-cornered cavity ; it is separated 
 from the round, gizzard-like stomach by a constriction, and 
 16 
 
122 BOARD OP AGRICULTURE. 
 
 then a second constriction separates the stomach or gizzard 
 from another somewhat enlarged cavity, which tapers grad 
 ually into the slender intestine. The anal orifice is near the 
 posterior end of the body, and in the male also gives exit to 
 the intromittent organ, which is a single, sharp, grooved 
 ticuluna^ with a very small accessory one. The female 
 
 *^ 
 
 orifice is situated near the anterior third of the body. This, 
 like the other species of Oxyuris^ produces eggs having firm 
 shells. These probably hatch in water, and the embryos may 
 thus be swallowed in drinking. The intestines of these para- 
 "sites are generally filled with vegetable matters derived from 
 the food of the animals in which they live, and the structure 
 of the digestive organ seems to be adapted to vegetable food. 
 For this reason it is probable that they ordinarily cause little 
 or no inconvenience to the horses that they inhabit. 
 
 The Pin-worm of Man (Oxyuris vermicularis Bremser). 
 
 This is a much smaller species than the preceding, but is 
 similar inform. It is very common, often in great numbers, in 
 children, and occurs also in adults, especially in aged and 
 debilitated persons, and inhabits chiefly the lower part of the 
 rectum and the vicinity of the anus. 
 
 The male is about one-eighth of an inch long, with the tail 
 curved in a spiral form, terminating in a very short point. 
 The female is about four-tenths of an inch long and one- 
 fiftieth in diameter, with the posterior part of the body taper- 
 ing to a very slender tail. 
 
 The digestive system and structure of the mouth is similar 
 to that of the preceding species. But the head sometimes 
 shows inflated lateral lobes. 
 
 Reproduction. 
 
 This species is very prolific ; each female produces thou- 
 
 Eigure 79. Oxyuris curvula, female, twice natural size. From Guerin. 
 
PARASITES OF ANIMALS. 123 
 
 sands of eggs, in which the embryos are considerably de- 
 veloped before they are laid. The embryos enclosed within 
 the eggs are shaped somewhat like tad-poles, the slender tail 
 being bent up against the lower side of the body, which faces 
 the flattened side of the egg. The body is broad and well 
 fills the egg. The full history of the development of the eggs 
 is not yet known. It is probable, however, that a portion of 
 the eggs imbedded in the mucus membrane of the intestine 
 hatch in that situation, remaining thus in the same person. 
 But it is also probable that the eggs that are discharged will 
 hatch in water, and that persons become infested by swallow- 
 ing the embryos with their food and drink. 
 
 Symptoms. 
 
 The most marked symptom of these parasites is an intoler- 
 able itching in and about the anal orifice, which is generally 
 worst in the evening or during the night, when the worms are 
 migrating or changing their localities. This is usually accom- 
 panied by sensations of heat and inflammation. Not unfre- 
 quently, by irritation of the adjacent nerves, they cause 
 similar sensations in the genital and urinary organs, which 
 sometimes become very distressing. They sometimes even 
 migrate into the genital passages of female children, causing 
 great irritation and very serious symptoms. By the irritation 
 of the sexual organs, in both sexes, various unfortunate sec- 
 ondary diseases and bad habits not unfrequently result, 
 especially if they occur at the period of early puberty. Other 
 symptoms caused by the irritation of the nervous system, are 
 restlessness, general nervousness, involuntary twitchings, 
 itching of the nose, chorea, convulsions, and sometimes 
 epileptiform seizures. 
 
 Remedies. 
 
 The various medicines ordinarily used as anthelmintics, or 
 vermifuges, will often bring away large numbers of these 
 worms. Of these the etherial extract of male fern is probably 
 the best, but santonine and panna have been used with good 
 results. Ordinarily they can be treated more easily and 
 effectively by means of injections of cold, or nearly cold, 
 
124 BOARD OP AGRICULTURE. 
 
 water, to which may be added a small amount of salt, oil of 
 anise-seed, or assafoetida. Sometimes decoctions of quassia, 
 worm-wood, or southern-wood {Artemisia abrotanum) are 
 used for this purpose, with good results. To these a portion 
 of olive-oil may be added. But any remedy that may be em- 
 ployed must be repeated as often as once every three or four 
 days for at least three weeks, in order to destroy the young 
 ones as fast as they develop. An application of mercurial 
 ointment to the parts about the anus is recommended to pre- 
 vent the migrations of the parasites and the uncomfortable 
 itching sensations that they thus produce. 
 
 The common Hound-worm of Man (Ascaris lumbricoides 
 
 Linn.). 
 
 This species is well known as a parasite of the human in- 
 testine, especially in children, though often found in persons 
 of all ages. The round-worm of cattle is generally regarded 
 as the same species. 
 
 These worms are round and smooth, tapering to both ends, 
 with a tough, elastic skin. The mouth is situated at the more 
 pointed end, and is provided with three prominent papillae, or 
 fleshy lobes. The male grows to the length of six inches, 
 and has the posterior end curved and provided with two 
 slender spicules. The female is much larger, sometimes be- 
 coming twelve or fourteen inches long and one-fourth of an 
 inch in diameter ; the female genital orifice is in advance of 
 the middle of the body. 
 
 Development. 
 
 The females produce great numbers of minute eggs, which 
 are provided with thick, rough .shells. The eggs are dis- 
 charged and pass from the human intestine before the 
 development of the embryos commences. If kept 
 in water the embryos go on developing slowly and 
 gradually, the whole process requiring from six months 
 to nearly a year. The fully developed embryos are 
 round and slender, about T o of an inch long, with 
 an obtuse head and an acute tail. They have not been ob- 
 served to quit the eggs of their own accord, but may live for 
 at least a year within the egg-shell, after they attain their full 
 
PARASITES OP ANIMALS^ 125 
 
 size. It is probable that such eggs, containing embryos, 
 when swallowed in the water that we drink, will be hatched 
 in our stomachs by the action of the gastric juice, and that 
 the young worms thus reach their destined abode. It is 
 possible, however, that under the proper circumstances the 
 eggs will hatch in the water, and that the free swimming em- 
 bryos may be swallpwed in the same way. This part of their 
 history still remains uncertain. 
 
 Symptoms. 
 
 The presence of one or two of these parasites in the human 
 intestine does not ordinarily cause any marked effects or 
 noticeable symptoms. But when they occur in persons of 
 delicate health, and when in great numbers, as sometimes 
 happens, they may cause great disturbance of the natural 
 functions of the digestive system, and induce various serious 
 consequences. Cases have occurred in which from 100 to 
 500 of these worms have passed from one child. They live 
 chiefly in the small intestine, but sometimes enter the stomach 
 and may even be expelled by vomiting. In some instances 
 they have been known to perforate the walls of the intestine 
 and enter the abdominal cavity, and thus even to get into the 
 other organs, including the lungs, pleura, gall-bladder, etc. 
 In such cases death often results. 
 
 Their presence in the stomach and intestine causes colic 
 and shooting pains, often accompanied by nausea, vomiting, 
 dyspepsia, itching of the nose, and diarrhoea. Owing to the 
 irritation of the nervous system they may cause restlessness, 
 convulsive twitchings, especially during sleep, and various 
 mental disturbances. In some cases, serious convulsions, 
 epilepsy, and insanity have been caused by them, and have 
 been cured at once by expulsion of the worms. 
 
 Remedies. 
 
 The most reliable remedy appears to be santonine, but this 
 is a powerful preparation, and must be used with caution. 
 For children the dose is one to three grains, in the form of 
 powder, which does best if taken in castor- oil or. honey, 
 though it may be sprinkled over a piece of bread and butter. 
 
126 BOARD OF AGRICULTURE. 
 
 For an adult the dose is four or five grains, twice a day, on 
 every second day, for a week, the quantity to be diminished if 
 the medicine causes ill effects, such as spasms, tenesmus, etc. 
 It often causes temporary perversion of vision, things appear- 
 ing of unnatural colors, etc., but this effect soon passes away. 
 
 The root of male fern (see page 191), given in powder, in 
 connection with purgative medicines, is also recommended. 
 
 As means of prevention, the use of impure water should be 
 avoided. And if water from streams and ponds must be 
 used for drinking, as in most large cities, it should be 
 thoroughly filtered through powdered charcoal. 
 
 The Round-worm of the Horse (Ascaris megalocephala 
 Cloquet) . 
 
 This species inhabits the intestine of the horse, ass, and 
 mule, and is quite common. It closely resembles the preced- 
 ing species in form and general appearance, but grows to a 
 larger size, the male becoming ten inches long, and the female 
 twelve inches or more. The mouth is surrounded by three 
 large, rounded, very prominent lobes or papilla. In the male 
 the tail is provided with wing-like folds along the sides ; in 
 the female it is conical, terminating in a point, the female 
 genital opening being situated in the anterior fourth of the 
 body. 
 
 This species likewise produces vast numbers of eggs, which 
 develop embryos externally to the body, in water. Dr. Cob- 
 bold states that he has reared free, active embryos from these 
 eggs by keeping them five months in water. The horses, 
 most probably, swallow these embryos in the water that they 
 drink. 
 
 These parasites, when numerous, will no doubt produce 
 effects analogous to those caused in the human body by the 
 preceding species, and the remedies will be similar. 
 
 The Round-worm of the Cat (Ascaris mystaxRndolphi). 
 
 Although very common in the cat, this parasite is of inter- 
 est chiefly on account of its occasional occurrence in the 
 human intestine. 
 
 It may be easily distinguished by the presence of peculiar 
 
PARASITES OF ANIMALS. 127 
 
 wing-like membranous expansions on each side of the head 
 or anterior end of the body. The male grows to the length 
 of two and one-half inches ; the female sometimes becomes 
 four inches long and one-twelfth in diameter. 
 
 This worm probably propagates its kind in a manner similar 
 to that of the two preceding species, and no doubt gains ad- 
 mittance to the human intestine, as well as to that of the cat, 
 by the medium of impure water and unclean vegetable food. 
 
 Its effects and remedies are the same as those of the com- 
 mon round-worm. 
 
 The Round-worm of the Hog (Ascaris suilla Dujardin). 
 
 This very closely resembles the Ascarislumbricoides of man, 
 and probably has nearly the same habits. It differs chiefly in 
 the structure of the reproductive organs. The male spicules 
 are not so sharp, and the tubes of the uterus are much longer. 
 The eggs are smaller. It appears to be less common than 
 the Echinorhynchus gigas in the intestine of hogs, and prob- 
 ably produces less injurious effects. 
 
 STEONGYLUS. 
 
 The genus Strongylus includes slender, filiform worms, 
 mostly of small size, and often reddish in color. Several of 
 them live in the windpipe and bronchial tubes of various 
 animals, including sheep, deer, cattle, pigs, etc., and when 
 numerous may occasion the death of the animals that they 
 infest, by suffocation. 
 
 The body generally tapers toward the head, and sometimes 
 in both directions. The mouth is small, situated at the end 
 of the small head, which is either simple or with lateral ex- 
 pansions. It is sometimes surrounded by small papilla, but is 
 often simple, and either round or triangular, but not enclosed 
 by a hard or chitinous organ, as in Sclerostoma, etc. The 
 oasophagus is enlarged, club-shaped, and muscular. 
 
 The male has the posterior end of the body provided with 
 an expanded, often lobed pouch, or bursa, for adhering to the 
 female during copulation. The spicule is slender and filiform, 
 enclosed in a sheath. In the female the posterior end is 
 
128 BOARD OF AGRICULTURE. 
 
 conical or pointed, and the genital orifice is placed in advance 
 of the middle of the body, or more rarely toward the pos- 
 terior end. 
 
 The Strongylus of Sheep {Strongylus filaria Rud.). 
 Figure 80. 
 
 The present species is whitish, very long and slender. Th 
 head is obtuse and without appendages, the mouth surrounded 
 by three small papillae. The caudal pouch of Figure so. 
 the male is entire, with ten rays (Figure 80). 
 The male is about two and a half inches long, 
 and the female three and a half, though gener- 
 ally not more than two or three inches long, the 
 interior of the body of the female is mostly oc- 
 cupied by two long convoluted uterine tubes, 
 containing eggs in which the embryos are in all 
 stages of development. These open at an 
 orifice situated at about one-third of the length 
 of the body from the head. 
 
 Habits. 
 
 This species lives in the lungs, air-passages, 
 and bronchial tubes of sheep and other rumi- 
 nants. They often occur, singly or several to- 
 gether, in cavities in the substance of the lungs, 
 producing great inflammation and destruction 
 of the tissue, which often results in the death of 
 great numbers of lambs, and greatly injures the 
 health of old sheep, even if it does not actually 
 kill them. In this way many thousands of 
 lambs are annually lost in certain districts in 
 England. In this country we have far less in- 
 formation concerning the extent of its ravages, 
 but have no reason to suppose that it is less 
 common than in Europe, in localities that are favorable for its 
 development. Sheep infested by this parasite continually 
 cough up the eggs and embryos of the worms, and either dis- 
 charge them directly from the nose or mouth, or swallow them 
 
 Figure 80. Strongylus filar ia, male, enlarged. From Thudichura. 
 
PARASITES OF ANIMALS. 129 
 
 and thus pass them with the faeces. In either case they will 
 often adhere to grass *nd other herbage, and may thus be 
 swallowed by other sheep or lambs, fed in the same pastures, 
 and pass directly into the windpipe, or else do so when the 
 cud is raised for mastication. Therefore lambs should never 
 be put into fields or pastures where diseased animals have 
 been kept, but such infected lands should be tilled, or at least 
 left at rest for several months. As soon as an animal gives 
 any indication of the presence of the parasites by the 
 peculiar cough, it should be separated from the rest of the 
 flock for treatment ; or else immediately killed and the para- 
 sites should be effectively destroyed, and not thrown on the 
 ground as harmless, for all these worms are remarkably 
 tenacious of life, and often may even be dried up completely 
 for months, and then revive when moistened. 
 
 Remedies. 
 
 When these parasites are once lodged in numbers in the 
 substance of the lungs, there is probably no reliable remedy 
 whatever. When merely in the windpipe and bronchial tubes, 
 expectorant medicines that will produce a copious secretion 
 of mucus may be useful. It might be possible to remove 
 them by a surgical operation, opening the windpipe from 'the 
 exterior, but this would require surgical skill and would not 
 pay, perhaps, except as a last resort for valuable animals. 
 
 The Strongylus of Cattle and Horses (Strongylus micrurus 
 
 Mehlis). 
 
 This species closely resembles the preceding. The male 
 grows to the length of about one inch and a half ; and the 
 female to three inches or a little more. The body is very 
 slender with a simple, blunt head. The bursa of the male 
 has five rays. The female genital orifice is near the middle 
 of the body. It is said to be viviparous. 
 
 The habits of this species are nearly the same as those of 
 the last, except that this inhabits the air-passages of cattle, 
 horses, asses, and mules, instead of sheep. It is much more 
 liable, like the former, to infest young animals than adults. 
 Calves less than a year old are particularly liable to be in- 
 17 
 
130 BOARD OF AGRICULTURE. 
 
 vaded, and those that are once attacked seldom or never re- 
 cover. The same remarks, concerning the means of preven- 
 tion, made under the preceding species, will apply equally to 
 this. If neglected, these parasites increase with great 
 rapidity, and thus the disease that they cause appears like an 
 epidemic, in certain localities destroying hundreds or thou- 
 sands of animals, while adjacent farms may be entirely free 
 from it. 
 
 The Strongylus of the Hog (Strongylus parodoxus Mehlis). 
 
 This is a slender, whitish or brownish worm, with a small, 
 simple head. The mouth has three small papillae. The 
 oesophagus is long and muscular. The anus is situated some- 
 what in advance of the posterior end of the body at the sum- 
 mit of a small papilla. The male becomes half an inch or 
 more in length, and has the caudal bursa bilobed, each lobe 
 with five rays, the lateral ones divided. The female grows to 
 the length of about an inch and a half, but is usually about 
 an inch long ; the tail is terminated by a point, turned to one 
 side ; the genital opening is near the posterior end and a little 
 prominent. This species is viAdparous. It inhabits the wind- 
 pipe, bronchial tubes, and lungs of swine. Its history and 
 the effects it produces are nearly the same as those of the 
 Strongylus filar ia. 
 
 The Strongylus of the Intestine of the Hog (Strongylus 
 dentatus Rud.). 
 
 This is a slender filiform species, about half an inch long, 
 which lives in the small intestine, coecum, and colon of hogs. 
 The head is obtuse and surrounded by six acute papillae. The 
 oesophagus is short and thick, muscular. In the male the 
 tail is truncated and provided with an oblique bursa, formed 
 of a single piece, strengthened by three subdivided rays ; 
 there are two slender spicules. The tail of the female is 
 elongated and slender, ending in a fine point ; the genital 
 opening is near the posterior end. 
 
 The effects of this species and its history are little known. 
 
PARASITES OF ANIMALS. 131 
 
 The Strongylus of the Intestine of Sheep ( Strongylus contortus 
 
 Rud.). 
 
 This is a filiform species, tapering to both ends, but more 
 slender toward the head, which is provided with two semi- 
 elliptical, wing-like appendages ; the mouth with three small 
 papillse. The male is about three-fourths of an inch long, 
 with a bilobed bursa, each lobe with about eight rays : the 
 sheath of the male spicule is very long. The female sometimes 
 becomes four inches long. 
 
 It is not uncommon in the small intestine of sheep, but its 
 history is very imperfectly known. When abundant it may, 
 without doubt, cause serious trouble. 
 
 Strongylus filicollis Rudolphi . 
 
 This species also inhabits the small intestine of sheep. The 
 body is very slender and whitish or reddish. The head has 
 two, very small, lateral, wing-like appendages. The male 
 bursa is bilobed, each lobe with six rays. It is from a third 
 to four-fifths of an inch long. 
 
 Strongylus radiatus Rudolphi. 
 
 This worm lives in the small intestine and colon of cattle 
 and several other ruminants. The head is simple ; the mouth 
 naked. The male is about half an inch long, with a bilobed 
 caudal bursa, the lobes many rayed. The female is about 
 three-quarters of an inch long ; the genital opening is near 
 the tail. 
 
 Its complete history is unknown. 
 
 The Kidney-worm (Euslrongylus gig as Diesing). Figure 81. 
 
 This is the largest of all the Nematode worms, the females 
 sometimes becoming three feet long and half an inch in 
 diameter, though usually much less. The body is smooth, 
 cylindrical, tapering somewhat to each end, and more or less 
 deeply tinged with red. The head is simple, obtuse. The 
 mouth is terminal and surrounded by six rounded, chitinous 
 papillse. The male becomes ten to twelve inches long and 
 one-fourth of an inch in diameter ; the caudal bursa is cup- 
 shaped, circular and entire, without rays ; the male spicule or 
 
132 
 
 BOARD OP AGRICULTURE. 
 
 penis is very slender. The female has a nearly straight, 
 obtuse tail ; the anus is triangular, near the end ; the genital 
 orifice is anterior, near the mouth ; the ovaries and oviducts 
 are simple, but long and convoluted. The intestine is large 
 and blackish, with thin walls, and quite simple, running 
 directly from one end of the body to the other, and is attached 
 to the sides of the body, along its whole length, by fibres. 
 
 Habits. 
 
 This formidable parasite lives in the kidneys of man and 
 various animals. It has been found in the dog, horse, cattle, 
 hog, wolf, \veasles, mink, otter, seal, glutton, raccoon, and coati. 
 In this country it has been found quite frequently in the kid- 
 Figure si. 
 
 neys of the mink. It has been found very rarely in the blad- 
 der, in the abdominal cavity, and, it is said, in the heart. In 
 man it is very rare. When lodged in the kidney it gradually, 
 but completely, destroys the substance of the organ, which 
 becomes filled with purulent and bloody matter, upon which 
 the worm feeds, while the walls often become hardened with 
 calcareous deposits. The effects and symptoms are the same 
 as in other acute diseases or abscesses in one of the kidneys. 
 The only positive evidence of the presence of the worm would 
 be the discovery of the eggs in the urine. It is probable that 
 no remedy can be applied when the parasite is once lodged in 
 the kidney. 
 
 The history of this worm is not fully known. According 
 to Leuckart, a slender worm found coiled up in cysts in 
 the muscles and peritoneum of fishes is the young or larva of 
 some species of Eustrongylus. The larval form referred to 
 
 Figure 81. Eustrongylus gigas, male, less than natural size; a, spiculum and 
 bursa ; 6, anus of female, enlarged. From Guerin. 
 
PARASITES OF ANIMALS. 133 
 
 is the Filaria cystica Rudolplii, originally found in a Brazilian 
 fish (^SymbrancTius lalicaudus). It is, therefore, probable that 
 the eggs or young embryos of E. gigas are swallowed by 
 fishes, and in their bodies develop into the larval form and be- 
 come encysted, and if then swallowed by some mammal, 
 migrate into its kidneys to become sexually mature. The 
 frequency of these parasites in those animals that feed chiefly 
 on fish, such as the otter, mink, and seal, renders this view 
 very probable. 
 
 The Crape-worm of Chickens, etc., (Syngamus trachealis 
 
 Siebold). Figure 82. 
 
 This parasite lives in the windpipe and bronchial tubes of 
 chickens, turkeys, pheasants, partridges, crows, wood-peckers, 
 and many other birds. In young chickens and turkeys it 
 Figure 82. often proves very destructive, by filling up 
 
 the air passages, and thus quickly killing 
 whole flocks. In some parts of this 
 country at least three-quarters of all the 
 young chickens and turkeys are some- 
 times destroyed by this parasite. The 
 \l \\ 1! / S worms are reddish in color and have a 
 I \KwJl H smo th skin, but spiral depressions run 
 I rm around the body, giving it a twisted 
 
 I iH 1 appearance. The reproductive organs 
 
 show through the skin, as slender, 
 whitish, convoluted tubes. The males 
 and females are almost invariably found united firmly to- 
 gether, as shown in the figures, the integument of the male 
 soon becoming organically united to that of the female, so 
 that the copulation is permanent or for life. The females are 
 very much larger than the males, becoming about three- 
 quarters of an inch in length, and one : sixteenth of an inch 
 in diameter. The anterior end, in both sexes, suddenly ex- 
 pands into a trumpet-shaped, concave disk, in the middle of 
 which the mouth is situated, surrounded by six small chitinous 
 lobes ; the posterior portion of the body of the female is more 
 
 Figure 82. Syngamus trachealis Siebold ; a, male and female united, natural 
 size ; 6, anterior part of female, enlarged ; c, male, enlarged. From Cobbold. 
 
134 BOARD OP AGRICULTURE. 
 
 or less bent and folded, and suddenly narrows at the end, 
 terminating in a small point. The genital orifice is near the 
 anterior fourth of the body, where the caudal bursa of the 
 male is attached and conceals it. The male is only one-eighth 
 or one-seventh of an inch long and very slender ; the caudal 
 bursa is simple, sucker-like, with an entire margin, strength- 
 ened by about ten rays ; the penis consists of two very small, 
 cylindrical spicules, about 225 of an inch long. The eggs are 
 oval, about 250 of an inch long. The embryos develop while 
 the eggs are still in the oviducts and uterine tubes, and the 
 eggs or young probably escape by a rupture of the integument 
 of the body of the female. 
 
 The history of the young worms, after they are expelled 
 from the windpipes of the birds, is not yet known, however. 
 Possibly they may enter the bodies of insects to pass their 
 larval state, but it is more probable that they bury themselves 
 in the surface of the soil or other moist places, and are thus 
 picked up directly by the birds and gain admittance to the 
 windpipe by their own active motions. 
 
 Symptoms. 
 
 The disease commonly known as " the gapes " is caused 
 solely by the presence of numbers of these worms in the wind- 
 pipe, which thus becomes so filled up as to render respiration 
 difficult, and if in considerable numbers, by their growth the 
 obstruction becomes complete, and death results from suffoca- 
 tion. Young chickens, thus attacked, seldom recover without 
 special treatment for the removal of the worms. Chickens 
 only three or four days old often show symptoms of the dis- 
 ease by opening wide their mouth and gasping for breath, and 
 attempting to swallow. They also frequently sneeze. As the 
 disease grows worse these symptoms become more marked; 
 they continually gasp and struggle for breath, grow weak and 
 dispirited, and finally 'droop and die. In fatal cases, one or 
 two dozen of these worms are often found in the windpipe, 
 completely filling it up. 
 
 Remedies. 
 
 The worms may be removed by a feather from which the 
 web has been stripped, except a small portion near the tip. 
 
PARASITES OP ANIMALS. 135 
 
 This may be moistened with oil, salt-water, or a weak solution 
 of carbolic acid, and' introduced into the windpipe, when if it 
 be twisted round once or twice and removed, it will usually 
 bring away several of the worms. The operation should be 
 repeated at intervals until all the worms are destroyed. All 
 worms removed in this or any other way should be carefully 
 destroyed, preferably by fire, for the embryos are extremely 
 tenacious of life, and if left upon the ground are likely to 
 spread the disease. For the same reason, those birds that are 
 infected should be separated from the healthy ones, and poultry 
 should never be allowed to run in the same yards or grounds, 
 or be kept in the same houses where infected ones have previ- 
 ously been kept, unless the premises- have first been thor- 
 oughly sprinkled with a strong solution of carbolic acid or 
 petroleum-water, to destroy those old worms or the eggs and 
 embryos that may have been discharged from the sick ones. 
 The vessels from which they feed should be frequently and 
 thoroughly cleansed, and they should be supplied with pure 
 water, frequently renewed. 
 
 In extreme cases, the worms may be safely removed by a 
 surgical operation ; but this requires some skill. This is done 
 by first carefully securing the bird, or still better by adminis- 
 tering a few drops of chloroform, placed upon cotton and 
 held to the nostrils. The skin of the neck is then to be di- 
 vided with a very sharp knife, and the windpipe opened by a 
 longitudinal slit about a quarter of an inch long. The worms 
 may then be removed by a pair of small forceps or other suit- 
 able instrument. , The incision in the skin may be closed by 
 one or two stitches, and the wound will generally heal in a 
 few days. By this operation an almost instantaneous cure 
 may be effected, even when the disease has progressed nearly 
 to the point of suffocation ; but in unskilful hands it is not 
 likely to be so successful as the remedies already described. 
 
 The Sclerostoma of the Horse (Sclerostoma equinum Dujardin, 
 or S. armatum Davaine). Figure 83. 
 
 This is a small, slender, cylindrical worm, reddish or brown- 
 ish in color, which lives in the intestines, and in peculiar 
 enlargements of the arteries of horses, asses, and mules. The 
 
136 BOARD OP AGRICULTURE. 
 
 head is round, nearly globular, supported by a cliitinous bulb 
 or capsule, truncated at the end, where the large, round 
 mouth is situated. The mouth is surrounded by one to sev- 
 eral circles of fine denticles, or converging hooks. The oesc- 
 phagus is muscular and thick, club-shaped, separated from 
 the intestine by a strong constriction. 
 
 The male is an inch or an inch and a quarter long, with a 
 large, membranous, caudal bursa, divided into two lateral 
 lobes, which are strengthened by numerous rays ; there arc 
 two long and slender spicules. The female grows to the length 
 of one and a half to two inches, with a long, tapering, caudal 
 portion, the anus not terminal ; the ovaries long and con- 
 voluted around the intestines, and showing through the integu- 
 ments ; the uterine tubes are double and contain great num- 
 bers of eggs, in which embryos are developed. 
 
 Habits. 
 
 This parasite is very common in the horse, generally living 
 attached by the hooks of its head to the lining membrane of 
 the intestine, particularly in the coecum and colon, but some- 
 times in the small intestine and duodenum, and even in the 
 pancreas. At the points where it adheres it Figure 83. 
 causes small, dark-colored, raised spots. They 
 sometimes occur in vast numbers in the large 
 intestine, completely covering the surface ; 
 the number sometimes amounting, it is said, 
 to a million or more. Ordinarily, however, 
 these parasites, when lodged in the intestines, 
 do not appear to produce any marked dis- 
 ease or notable symptoms, although when in 
 great numbers, there can be no doubt but 
 that they must cause some inflammation and 
 pain. More serious results, sometimes prov- 
 ing fatal, happen when the worms enter the 
 blood-vessels. They produce large aneurisms or dilations of 
 the arteries, chiefly in the anterior mesenteric artery, but 
 
 Figure 83. Sclerostoma equinum, female, natural size ; and anterior portion en- 
 larged ; a, mouth ; b, circle of hooks ; c, oesophagus ; d, intestine ; e, reproductive 
 organs. From Cuvier. 
 
PARASITES OP ANIMALS. 137 
 
 also in the arteries of the colon, coecum, small intestine, and 
 liver, as well as in the posterior mesenteric and renal arteries, 
 and others adjacent to the intestine. These tumors are gen- 
 erally fusiform, and as large as a man's finger ; but they are 
 sometimes globular, and may become as large as a man's 
 head. The middle membrane of the artery in these dilations 
 becomes enormously thickened, sometimes being twelve times 
 as thick as in the healthy artery. In old tumors various hard 
 or calcareous deposits often take place in the thickened walls 
 or in the inner membrane ; and in such cases, the walls being 
 weakened, are liable to be ruptured by some unusual exertion 
 of the animal, when death results almost instantly. In the 
 interior of the aneurism there is generally a deposit of fibrin, 
 firmly adherent to the inner surface. In this and in the dif- 
 ferent layers of the walls the worms are found, sometimes 
 only a few, but frequently large numbers. This disease is 
 very prevalent among old horses. In France, as many as 
 ninety-six out of one hundred have been found affected with 
 the disease. 
 
 I am not aware that any remedies have ever proved useful. 
 Generally it would be impossible to detect the disease during 
 life, unless the tumors became very large. 
 
 Sclerostoma pinguicola Yerrill. 
 
 On two occasions I have received specimens of a rather 
 large parasitic worm, which lives in the fat of hogs. In the 
 first case, five specimens were obtained, at New Haven, by 
 Dr. M. C. White, from the fatty portion of a spare-rib ; in the 
 second instance, at Middletown, Conn., Dr. N. Cressy found 
 large numbers of the worms in the fat about the kidneys of a 
 young Suffolk pig, brought from New Jersey. Un- 
 fortunately, none of these specimens are in so good a state 
 .of preservation as to enable me to determine with certainty 
 all the points of their structure. Those which I owe to the 
 kindness of Dr. White, had been mounted in glycerine as 
 microscopic objects and pressed out flat, before they came 
 into my possession, and the tissues were thus injured and 
 the organs deranged. Those from Dr. Cressy, were both 
 pressed flat and dried. Yet by careful masceration, and 
 with much labor, I believe that most of the important char- 
 18 
 
138 
 
 BOARD OF AGRICULTURE. 
 
 acters have been made out. The body is rather robust, es- 
 pecially in the female, and tapers to both ends ; the color is 
 yellowish white, and the integument is seen to be finely 
 striated transversely, when considerably magnified. The 
 head is smaller than the body, truncated at Figure 83 a. 
 the end ; the mouth is terminal, roundish, or 
 somewhat angular, surrounded by the thick- 
 ened rim of the chitinous capsule, or pharynx. 
 This chitinous ring rises at intervals into four 
 to six denticles, or very small teeth, which 
 correspond to thickened longitudinal, chitin- 
 ous bands, that strengthen the pharynx, and 
 give a slightly angular form to the mouth. 
 The pharynx itself is small, short, and rather 
 squarish, when seen in profile, and has three 
 or four small, conical teeth at the bottom. 
 The oesophagus is thick, club-shaped, and very muscular. 
 
 The male is 1.12 of an inch long, and about .05 of 
 an inch in diameter ; the tail ends in a small blunt lobe, 
 united with two small, entire, membranous expansions, 
 one on each side, forming a small bursa, which is 
 strengthened by several short rays, the exact number of 
 which could not be determined in my specimens ; there 
 are two long, slender spicules. The females are 1.25 
 to two inches in length, and, as flattened between glass, 
 they are .10 to .13 of an inch in breadth. The posterior 
 end suddenly and obliquely narrows to a small conical 
 point, which is turned to one side. The anal opening is close 
 to the end, and the genital orifice appears to be adjacent to 
 it. The oviducts are long, voluminous, much convoluted, 
 and unite in a large and capacious uterus, which fills most 
 of the cavity of the body near the posterior end. The uterus 
 and oviducts are both filled, in the larger specimens, with im- 
 mense numbers of small oval eggs. 
 
 It is probable that this parasite is by no means uncommon. 
 
 Pentastoma tcenioides Rudolphi. Figure 84. 
 This parasite is not a true worm, but is now generally re- 
 Figure 83 a. Sclerostoma pinguicola ; a, male, natural size ; b, posterior end, en- 
 larged; c, female, natural si/e; d, head, enlarged. Original. 
 
PARASITES OF ANIMALS. 
 
 139 
 
 garded as belonging to the Acarians, with the true mites. In 
 the adult state it inhabits the nostrils and frontal sinuses of 
 dogs and wolves, and more rarely, of horses and sheep. The 
 larvse, formerly described under the name of Pentastoma den- 
 ticulatum, lives in, cysts on the outside, or in the outer por- 
 tion, of the liver of sheep, deer, antelopes, . peccary, porcu- 
 pine, Guinea-pig, rabbit, hare, rat, and cat ; and some- 
 times invades the human body in the same way. It has also 
 been found free in the visceral cavity of the body. 
 
 In the mature state (Figure 84) the body is long, lance- 
 shaped, tapering behind, flattened below, and divided into 
 about ninety segments by transverse lines. The segments 
 next to the head bear two pairs of small, but strong and 
 Figure 84. sharp, retractile claws, which represent the true 
 legs of ordinary mites. The mouth is broad- 
 oval, and provided with a hard chitinous lip. 
 The segments behind the head are perforated 
 by small openings, regarded by many as 
 spiracles, or breathing pores. The adult is 
 smooth, but the larvae are covered with many 
 rows of small, sharp spines. The male is 
 only .07 to .08 of an inch in length, but 
 the female becomes three or four inches long, 
 and half an inch wide. The female genital 
 opening is in the tail, that of the male, in the 
 middle of the front part of the abdomen. They 
 are oviparous, and the young undergo a com- 
 plete and remarkable metamorphosis. 
 The adults live in the nasal cavities of dogs, and 
 produce an irritation of the delicate membranes, which 
 causes a flow of mucus, often accompanied by sneez- 
 ing. The eggs discharged with the mucus .may ad- 
 here to vegetables or fruit, or get into drinking- 
 water, and in these ways gain admittance to the stomach of 
 man, or other animals. In the stomach they hatch into mi- 
 nute embryos, furnished with a boring apparatus and two pairs 
 of double claws. They bore their way through the intestines 
 and lodge in the liver or other parts, and soon become dor- 
 
140 BOARD OF AGRICULTURE. 
 
 mant and enclosed in cysts, in which they pass a sort of 
 pupa state. During this period of their life, the skin is cast 
 several times, and the appearance changes at each moult, un- 
 til they attain the next period of their life, when they 
 again become active ; this is the state described as Petastoma 
 denticlatum. These larvae are long-oval, broadest anterior- 
 ly, and covered with numerous rows of transverse tooth-like 
 spinules. They have two pairs of sharp, curved claws, which 
 are situated near the mouth and placed obliquely, diverging 
 from the median line of the body, and directed downward. 
 Each claw has a sort of hood or capsule, into which it can be 
 retracted. If dogs feed on the liver or other viscera of animals 
 containing these larvae, they come in contact with, and man- 
 age to enter the nose, working their way up by means of the 
 motions of the body, aided by their spines and claws. In 
 this situation they gradually become mature. 
 
 In the human body the larval form is quite frequent, es- 
 pecially in some parts of Europe ; but there is little known 
 concerning the effects that it produces. When in small num- 
 bers, it probably causes very little disturbance, but if in large 
 numbers, in the liver and lungs, it would no doubt produce 
 serious disease, as does another species (P. constrictuin) , 
 which is very common in Egypt, living in the same way en- 
 cysted in the liver and lungs. The latter, when in consider- 
 able numbers, frequently proves fatal. 
 
 As a means of prevention, dogs that show symptoms of 
 the parasites in the nose, should be treated to a solution of 
 carbolic acid, thrown up the nostrils by a small syringe. 
 Feeding dogs with the offal of slaughter houses, or with un- 
 cooked livers, etc., should be avoided, both on account of this 
 and the other dangerous parasites that they get in this way, 
 (see Tcenia echinococcm, p. 202, T. marginata, p. 192, T. 
 ccenurus, p. 196, and Trichina spiralis, p. 222). Too much 
 familiarity, especially of children, with dogs is always liable 
 to result in the transfer of these and other parasites to the 
 human body. 
 
ERRATA. 
 
 In making up the author's copies, and repaging, several errors have been intro- 
 duced, which the reader should correct : 
 Page 3 third line of foot notes, for Corydalus cornutas, read Corydalis cornutus. 
 
 " 6, line 19, for orceps, read forceps. 
 
 " 8, " 31, for pair, read pairs. 
 
 "12, " 13, for labium, read labrum. 
 
 " 13, figure 18 is inverted. 
 
 " 4*7, " 17.. for page 89, read page 16. 
 
 " 48, " 10, for page 109, read page 38. 
 
 " 49, " 31, for page 109, read page 38. 
 
 '' 60, " 10, for nemarum, read venarum. 
 
 " 61, " 23, for page 101, read page 30. 
 
 " 85, " 5, for page 191, read page 80. 
 
 " 100, " 34. It should be stated that Dr. Cobbold, in 1860, fed dogs with a 
 small cysticercus, from the liver of rabbits, but distinct from 
 " G. pisiformis" and obtained specimens of Tcenia cucwnerina, 
 which he thought were developed from them. 
 
 " 110, " 30, for " such hogs are," read such a hog is. 
 
 "126, <l 6, for page 191, read page 80. 
 
 "140, lines 32 and 33, for page 202, read 91; for 192, read 81; for 196, read 
 85; for 222, read 111. 
 

 
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