UNITED STATES OF AMERICA. vjieyataA^ c^/^^""^^^ U.S. DEPARTMENT OF AGRICULTURE. B0EEAU OF ANIMAL INDUSTRY. THE ANIMAL PARASITES OF SHEEP. BY COOPER CURTICE, D. V. S., M. D. i PUBLISHED BY AUTHORITY OF THE SECRETARY OF AURICULTURE. 2^(?> WASHINGTON : GOVERNMENT PRINTING OFFICE. 1890. TABLE OF CONTENTS. Paga Letter of transmittal 7 General remarks 9 Parasites of the nose : Grub in the head, (Estrus ovis, Linn 25 Parasites of the skin : Phthiriasis, Acariasis. The sheep tick, Melophagus ovinus, Linn 39 The sheep lonse, Trichodcctes splueroeephalus, Nitzsch 45 The goat louse, Trichodcctes limhatus, Gervais, and Trichodectes climax, Nitzsch 49 Scab insects: Acariasis, itch, scab. Head scab, Sarcoptes scabiei, de Geer, var. ovis 53 Common scab, Psoroptes communis, Fiirst, var. ovis 56 Foot scab, Chorioptes communis, Verheyen, var. ovis 65 Parasites of diverse organs : The pentastoma, Linguatulatauiioides, Rud 69 Immature tape-worms : Bladder worms, Twnia marginata, Batsch 72 Gid or staggers, Twnia cwnurus, Kiich 83 Hydat'ula, Tania echinococcus, V. Sieb 86 The mutton measle, Twnia tenella, Cobbold 87 Parasites of the alimentary canal and appendages: Adult tape- worms: The fringed tape-worm, Twnia fimbriata, Diesing 89 The broad tape-worm, Twnia expansa, Rud 113 Liver-flukes : The large liver-fluke, Distoma hepaticum, Linn 127 The small liver-fluke, Distoma lanceolatum, Mehlis 137 The stomach worms : Amphistoma conicum, Zeder 138 Stronqylus contortus, Rud 141 Intestinal round worms : Introductory remarks 145 Slrongylus filicollis, Rud 146 Strong ylus ventricosus, Rud 149 Ascaris lurnbricoides, Linn.... 151 Dochmius cernuus, Creplin 155 Sclerostoma hgpostomum, Diesing 161 The nodular disease of the intestine, CEsophagostoma Colmnhianum, n. sp 165 Trichocephalus affinis, Rud ^ 181 Parasites of the lungs: Introductory remarks 185 The hair lung- worm, Slrongylus ovis-piilmonalis, Diesing 186 The thread lung- worm, Strongglus Jilaria, Riii 201 3 INDEX OF ILLUSTRATIONS. Plate I. (Estrus ovis, luiumvus 34 II. (Estrus oins, in ^5iullse^ of the bead ~ 36 III. (Estrits oris, in nasal cavity and sinnses of the head 38 IV. Melophayun ovinus, Liumvus 44 V. Trichodecies spharocephahts, 'Nitzsch 48 VI. Trichodectes limhatus, Gervais, et T. climax, Nitzsch 52 VII. Psoroptes commmnis, Flirst., var. oris. Adult 66 VIII. Psoroptcs communis, var. ovis. Young 68 IX. Tania 7na)\\\. Adult 124 XV. To nia expansa, young stages 126 XV^I. Distoma hepaiicHm,'L\nnivus 136 XVII. Lliifjitatiihi Uvuiodes, Kudolphi, Amphistoma conicum, Zeder, et Distoma lanceolaiiim, Mehlis 140 XVIII. Strovgylus contortim, Rndolphi 144 XIX. Strongylufs filicoUis, 'Rn^\o\\^h.\ 148 XX. Strong yhis ventricosKS, Rudolphi 150 XXI. Jsearis Jumbricoides, Linuii'us 154 XXII. Dochmius ce7-nuns, Creplin 160 XXIII. ScJcrostoma hypostomum, Dujardin 164 XXIV. (Esophagostoma Cohimhianum, Curtice. Adult 174 XXV. (Esophagostoma Cohtmhiarium, youug stages 176 XXVI. (Esophagostoma Cohiynhianum, in the intestinal coats 178 XXVII. (Esophagostoma Columhianum, in the intestinal coats 180 XXVIII. Trichocephalus affinis, Rudolphi 184 XXIX. Strongylus otns-pulmonalis, Diesing 192 XXX. Strongylus oms-pulmonalis, in the lungs 194 XXXI. Strongylus ovis-pulmonalis, in the lungs 196 XXXII. Strongylus ovis-pulmonalis, in the lungs 198 XXXIII. Strongylus ovis jnilmonalis, in the lungs 200 XXXIV. Strongylus filaria, Rndolphi 210 XXXV. Strongylus filaria, in the lungs 212 XXXVI. Strongylus filaria, in the\nng% 214 LETTER OF TRANSMITTAL. Washington, D. C, April 2J , 1 800. Sir: I have the honor to submit herewith a report upon the para- sites ofsheei), whicli has been prepared with much care and will prove of permanent value to all owners of this class of our domesticated ani- mals. The information heretofore attainable on this subject in the United States has been fragmentary and in many cases unreliable, although the parasitic diseases of sheep are among the most frequent and seriouir' maladies by which this species of animals are affected. It has been the aim in the [)reparatiou of this volume to make the descriptions and the illustrations so plain that any one will be able to identify the parasites which he may find in his flock, and yet the sub- ject is in some of its aspects so technical that it could not be presented entirely in popular language. Tiie technical descriptions which it is deemed necessary to insert have, however, been placed in small type, and those not interested in the characters by which the species are identified can omit such paragraphs. The symptoms and appearances I)resented by diseased animals and the treatment of the diseases have beeuigiven at considerable length, and these will be read with interest by all who desire information on this subject. The illustrations are a ])romiuent feature of the work, haviug been drawn and lithograi)lied with the greatest care, and every attention given to make them accu- rate in tbeir most miinite details. Nearly all of these are original and were drawn from nature. The nodular disease of the intestines, together with its cause, is de- scribed for the first time in these pages. This disease is common and wide-spread, but its cause and nature were mysterious until they were discovered through the investigations of this Bureau. We have here once again a demonstration of the value of systematic, scientific in- vestigation of the diseases of animals, for the results obtained by the studyof this malady are among the most interesting contributions of modern research. The facts obtained in the investigations of the fringed ta{)eworm and the hair lung- worm are also of more than ordinary in- terest. Tlie subject of i)anisites and parasitic diseases is one of great impor- tance, and must become more prominent as the number of domesti- cated animals in the country increases and the pastures become more 7 8 limited ia comparison with the tlocks wliicli graze upon tlietn. Under such conditions parasites multiply more rapidly, and their ravages be- come more alarming. For this reason the time has come when we must pay more attention to these organisms and study more assiduously the means of controlling them, if we would preserve that healthfulness and vigor for which the animals of this country have heretofore been noted. It is hoped that the systematic treatment of the subject presented in the accompanying volume may assist in accomplishing this object. Very respectfully, D. E. salmo:n^, Chief of the Bureau of Animal Industry. Hon. J. M. Rusk, Secretary of Agriculture, ANIMAL PARASITES OF SHEEP. GENERAL REMARKS. In 1782, Goeze, a distiuguislied German naturalist, wrote : "Among all mammals except the horse, the sheep appears to be most harassed by worms." He thus called attention at that early period to the great abundance of ovine parasites, an abundance which have transmitted their posterity in comparatively undiminished numbers. The presentation of all the facts now known concerning these para- sites, their structure, their life histories, the injuries they cause, and the methods of prevention and treatment, together with such new ma- terial as may have been learned concerning them, needs no apology to the sheep owner, for he is alive to the fact that the majority of his losses is due to these parasites. The sheep industry of the United States embraces the product of 42,599,079 sheep, valued at $90,040,369.* De- pendent on these sheep and their products are an army of men and their families, from the flock-master and his help to the consumers of the flesh and the manufacturers of the fleece. Add to this the value of the plant, which is dependent on the sheep industry in all of its ramifications, and there results an accumulation of many millions of dollars, a value which, from a business stand-point alone, should cause the Government to foster and to protect it from every source of injury. As the whole growth of the industry is dependent on the health and vigor of the sheep, it follows that whatever tends to produce a better condition or ward off threatening disease from them is for the benefit of all interested in and dependent upon the success of the industry. The parasitic diseases — those produced by the animal parasites of sheep — are, if we may judge from observation and the letters* of inquiry directed to this Bureau, the chief source of losses, and if in any way this bulletin may result in promoting a better knowledge of these too little known pests, and in teaching facts which will lead to better care and treatment of the flocks as regards hygienic prevention of diseases, the cost and labor laid out upon the work in its various details will be well expended. Particular attention has been devoted to illustrating each species of parasite, and, so far as possible, the lesions of the disease produced by * United States Department of Agriculture, report on numbers and values of farm animals, January, February, 1889, pp. 5 and 6. 9 10 it. lu the illustrations of the species certain features which present specific differences have been constantly drawn. Peculiar features of anatomy and development have also been illustrated. The entire de- velopment of any species from the unimpregnated ovum to the adult form is not illustrated, but one species may show the developing ova, another the embryo, and still another small and adult forms, and thus the entire development of many of the species can be well understood. Especial attention has been devoted to representing certain organs of economic importance, *. e., those orgjins which are immediately con- cerned in injuring the tissues of the sheep. The majority of the draw- ings were made from nature by Mr. W. S. D. Haines, and the others by Dr. George Marx, both artists connected with this Department. The excellence, of their work shows for itself. Where material for original illustration has been unavailable, figures chosen from the leading text-books on the subject under consideration have been copied, and due recognition of the source acknowledged in the description at- tached. For the accuracy of these drawings the author alone is respon- sible. He believes that all the anatomical details are accurate, but such is the difficulty of seeing the minuter details that some of the latter are omitted. As their presentation belongs i)roperly to a more specific investigation than tbis their absence will scarcely be noticed. It has been the constant endeavor of both the artists and the author to make technically perfect drawings, aiul at the same time present the subject so clearly to the eye that not only a novice may, by the aid of a small magnifying glass, be able to determine the species, but that the scien- tist may also use the work profitably in subsequent investigations. The text devoted to each species is intended to contain a general description of the parasite, its life history, the way it causes disease, the disease produced and mode of treatment, both preventive and re- medial. Many of the specific descriptions are technical. To the be- ginner, who can identify the species by careful comparison with the figures, these are unnecessary, but as he advances in their study the meaning of the technical descriptions will become more apparent and useful. In a work of this character such technical specific descriptions are unavoidable. To the scientist they are absolutely necessary. Wherever possible the complete life-history of the parasite is described and illustrated ; unfortunately, however, the species whose life-histories are positively known are too few. Although the life-histories of the majority of the worms seem very evident, still the evidence upon which they are based is not deemed entirely conclusive by scientists. So skep- tical are the majority of this guild that rigorous proof alone seems to satisfy them, and this is particularly the case when the views set forth in regard to either of the si)ecies are at variance with pre-existing opinions. Rigorous demonstration of the various stages in the liie-history of a parasite demands that its eggs or embryos shall be fed to an uninfected 11 host (sheep in this case), and the parasite be found in it subsequently, at a stage of growth corresponding to the time which has elapsed dur- ing the experiment. The conditions necessary for raising embryos, for procuring uninfected sheep and for keeping them from outside sources of infection, are many and difficult to fulfill. Up to the present time, with few exceptions, infection has been secured in the experiments only by excluding or regulating certain of the conditions surrounding sheep. These conditions are such that, although the problems in each case have not been absolutely proven, there is much probability that the life- history of most species is well determined. In describing the injury wrought by the parasite and the resulting disease, technical descrip- tion has been avoided as much as possible, in order that the work may be rendered more valuable for farmers and ranchmen, who have but a limited knowledge of the terms used in medical literature. These de- scriptions are, on this account, necessarily imperfect from a scientific point of view, but it is hoped none the less efficient for the purpose* A careful study of the various diseases will show that the irritations set up and the lesions resulting therefrom are mainly due to mechan- ical causes, whatever be the organ attacked. Certain of the dis- eases, however, seem to be aggravated by nervous or reflex irritation induced by the parasite, while others are hastened by a loss of blood or nutritive material abstracted from the host by the parasites. The diagnosis of parasitic diseases is always determined by finding the parasite or its eggs. The quickest and surest determination for inter- nal parasites is made at a post-mortem examination. For intestinal parasites many authors recommend the examination of the dung. This method has not been verified by experience, but appears to be tedious and difficult, and a method better adapted to experts than layman. There are certain symptoms from which one may infer that sheep are infected with parasites. A large part or all of the flock is affected and the symptoms shown by the different individuals are similar. The ap- petite is generally good, but individual members present a poor, stunted, hidebound, bloodless, big-headed, pot-bellied appearance. Other local symptoms, depending on the organs affected, are present. The most positive characteristic is to find that a number of sheep raised together are affected in the same way. From these general symptoms those de- pending on climatic changes, and irregularity or insufficiency of food and water, must of course be excluded. The sheep owner who discovers weakness among his lambs should not wait until one of them dies before he endeavors to make a diagnosis, but should undertake to diagnose the disease in the earlier stages by sacrificing one or more of the worst affected, and thus gain time in treating and preventing the extension of the disease. By waiting for the disease to develop he allows the lambs to grow poorer and weaker, and when action is finally undertaken it is upon patients which are, in many cases, already too weak to stand vigorous treatment, and which can in no way profit by preventive 12 measures as they should. The lambs examined can, if the meat is not too poor and watery, be used on the table without harm to the consumer. If the animals are at all feverish, as is the case in the later stages of disease, the carcasses should be thrown away. It is in the beginning of the disease that treatment, both hygienic and medicinal, is needed and produces its best results, and therefore an early diagnosis and de- termination of the malady is fully as essential as in the more virulent bacterial scourges. Tiiough the treatment advised in a work of this character should be its strongest point, yet it is to be regretted that such is the state of knowledge of the life-history of these pr.rasites and of the practical re- sults of medicines used in combating them under the conditions in which sheep are held on the pastures, that it is felt that this field is yet to be properly entered and worked up from an experimental stand-point. The subject appears, as yet, to be in an empirical stage. Although the best recipes have been compiled and presented, they appear to be old and hackneyed to one who has been enabled to trace the same recipes from book to book. Indeed, some of those presented, which contain inherent virtues, come from countries where sheep-ranching is unheard of, and seem to be sufficient only in the closely settled communities where labor is cheap and where time can be devoted to saving property even though the value is not great. The medical treatment of large flocks should be investigated from a broader stand-j)oint than any yet taken. Our insufficiency of knowledge on these points arises from the small value of single animals and the hesitation of people to seek the aid of skilled veterinarians until they find that they are unable lo treat the disease themselves. The great benefit in doctoring animals wliose Individual worth is but a few dollars lies in the treatment of numbers at a time, and in making an early diagnosis of the disease. Those who have large and valuable flocks should watch their lambs for the earli- est symptoms, and then if there is a skilled veterinarian available ob- tain his services. Oftentimes the family doctor can and will give advice that will materially assist, for his knowledge of other diseases, their symptoms and lesions, and of the use and effects of medicines, make him the most available authorit^^ in the absence of the veterinarian. Upon the hi/gienic treatment, i. e., upon the care and attention the flock receives, depends in great measure its health and good condition, and the prevention of the parasitic diseases. It is out of the province of this bulletin to discuss the proper housing, food, and drink of sheep, beyond what is required for the prevention of parasitic maladies. The chief necessity as regards buildings and yards is that they should be kept clean. Periodic cleansings of wood-work and floors should be sufficient. Whitewashing and the liberal use of lye water for cleansing wood- work are desirable, and in some diseases, such as scab, absolutely indispensable. In the care of yards an economic management of the manure is to some of prime importance. It would seem that a mixture 13 of this manure with lime in the compost heap, and a frequent cleansing of the yard, would be far better, so far as the sheep are concerned, than to allow it to accumulate. The lime would not only serve to kill the eggs of parasites in the manure, but would add fertilizing material to it. Manure so treated would be a better fertilizer, and would also be less apt to infect sheep when spread upon the fields. The compost heap should never be where the liquor from it can be washed by the rains into water which the sheep drink. As the manure from these yards may prove the source of infection, sheep should never be pastured on fields recently enriched with it, unless there is absolute certainty that the previous treatment of the manure has destroyed all the em- bryos of the parasites. As frequently urged in the text, every means' should be taken to supply sheep with pure water. Although experi- ments show that sheep have other means of getting parasites than from the water they drink, yet this is at times a very fertile scource of infec- tion. The use of drinking-troughs into which water runs or is pumped, and rapidily running water, seem best suited to meet the requirements. The grain food should be fed from cleanly swept troughs or floors. Hay should be put in racks, as feeding from the ground is not only wasteful but tends to infect with parasites. Salt should be supplied in boxes placed where sheep can have ready access to it. The mixture of a small proportion of finely powdered sulphate of iron with the salt is allowable at times. Pastures, which are ordinarily uncared for further than to provide fences for securely confining the sheep, need careful supervision. Wet swails, bogs and swamps should either be fenced out or drained. Past- ures which are overstocked, and in which a flock of sheep is kept con- tinuously, are the most fertile sources of infection. Not only do the sheep become more frequently infected where they are compelled to eat the grass close to the ground, but the chances of their being compelled to graze on an infected area are largely increased by keeping them ranging over the same ground of limited area week after week. Old sheep stand such treatment much better than young ones. For the lat- ter, those fields which have not been pastured on by older sheep are better. The practice of feeding the sheep over fields from which the crops are removed is a good one, not only for the sheep but for the fields. These remarks, of course, apply more strictly to fenced farms and not to unfenced sheep ranges, but even on these certain portions of the range can be reserved for the lambs. The practice of allowing lambs, after they are old enough to wean, to feed after older sheep is also a source of infection. The relation of the dog to sheep husbandry is too imiiortant to be over- looked. Were it not that the definition of parasite excludes such ani- mals as can be considered beasts of prey, the dog would be placed at the head of the list of j^arasites as being the most destructive. Though this be unmistakably apparent to a large majority of sheep-owners, 14 there are mauy who believe that the (lo^ is man*s most faithful friend and that ho is of great use even on a sheep farm. It is unfortunate for the dog tliat the mass of testimony on this subject is against him. It is not from the stand-point of the dog as a beast of prey, however, that this work is written, but it is from the more technical stand point of the (loif as a carrier of parasites dangerous to sheep and man. In the list of parasites of sheep there are at least four which are common to the dog and sheep, viz: Ta-nia marginata, Batsch; T. co'nurus, Kiich.; T. echi- nococcus, V. Siebold, and Linguatula toenioides, Rud. The last is rare, and in justice to the dog should not be used against him, although it may subsequently aiford as damaging evidence as the other si^ecies. By referring to the descriptions of the other three species it will be found that dogs harbor in their intestines the adults of these species, and that they scatter the eggs of the parasites broadcast for the infec- tion of sheep. Thus each dog, harboring one or more, is a constant menace to the health and lives of the flocks in the neighborhood. Nor is this all, for man himself can be infected by at least two of these spe- cies — Tania cchinococcus and T. marginata — in their cystic stage. The former of these species produces a disease of slow development, but one which is nearly always fatal in results. To prevent these diseases the precautions prescribed in the text must be closely adhered to. A plan which would remove much of the loss caused by dogs by doing away with them entirely is scarcely practical in this country, where the ma- jority of these animals are owned by persons who have no direct inter- est in sheep. The hunting and the sheep dog are most to be feared, unless we except some of the fiercer watch-dogs which are kept at slaughter-houses and fed on waste bits. The day of the usefulness of hunting dogs is quite past, and their retention by sheep-men at least should be abandoned. The watch-dogs are nearly always chained and in places not accessible to sheep. In the range country the coyotes and prairie wolves still menace the flocks by killing individuals for food, and by harboring the adults of Twnia marginata and T. eoenums, the eggs of which they also scatter. In most sections, especially where a bounty is oflered for their scalps, the trap is remorsely exterminating them. Laws which would subject the mongrel curs to the same treatment would result in a great gain to the farming community and to their respective owners, if they be owned by any one. There are reports that the sheep can be infected by parasites from some of the many wild animals that still haunt the land where they were formerly so abundant. The examination of these little quadru- peds to ascertain the parasites they contain has not been as extensive as it should be for a broad generalization, but so far as it has extended it is safe to say that sheep are not infected from either rabbits, skunks, squirrels, woodchucks, gophers, prairie dogs, or foxes. Foxes may harbor some of the adult Tivnia whose cystic stages infest sheep, but 15 unless they can obtain the young forms of the parasites by eating the viscera of sheep they woukl be very unlikely to be infected with adults. It is also reported that rabbits harbor the cystic form of Taenia margin- ata ; but this statement has not been corroborated, as the rabits ex- amined contained the cystic form of T. serrata. If rabbits should be Ijroven to harbor the cysts of T. marginata then the danger wonld arise, not from them, but from hunting-dogs which eat the rabbits and the cysts they contain, and harbor the adult jiarasites that alone are the source of danger. The possibility of infection b^- parasites from deer is too small to be considered as an economic question, owing to the great scarcity of these animals. The antelope {Antilocapra ameri- cana, Ord.) may be a bearer of many of the same species of parasites as the sheep, but they also are becoming too few to be considered as n source of danger. In short, it is futile for the flockmaster to consider these sources at all while his own flocks are infecting his fields, and his dogs are constantly assisting them. Could these sources of infection be controlled, there would be no need for him to regard the wild ani- mals as his enemies. Ln purchasing sheep particular attention should be paid to the gen- eral appearance and past history of the flock from which the purchase is made in order to avoid parasitic diseases. Before adding recent pur- chases to flocks they should all be thoroughly dipped to kill external parasites. If they are coughing ever so slightly, the cause of the cough should be investigated to determine the presence or absence of lung worms. If some are hidebound or weak after allowing for the charac- ter of the season and the condition of pasturage the i^ossible presence of intestinal parasites should be next considered. It is not very prob- able that there are any farms free from all parasites, but there are many that are free from a considerable portion of the species which are prop- erly parasitic on sheep. Purchasing here and there in making up a flock brings all sorts of parasites together, thus infecting a farm to such a degree that it is difficult to get rid of them. The medical treatment must, of course, be sjiecially adapted to the dis- ease. The treatment of external parasites is effective, and well repays all efforts. The treatment of internal parasites may be divided in gen- eral into treatment for lung worms, for intestinal worms, and for liver worms. The last is by far the most unproductive of good results. Par- asites situated elsewhere in the sheep do not readily yield to medical treatment. Scab is the only parasitic disease that has been thought worthy of legislation. There are others that demand as serious considera- tion, but their importance has not yet been fully presented to the public. Little attention has been given to police interference in the management of these diseases. No doubt such interference might be profitably pushed further than it is in this country, especially with regard to scab. Not only should the highways be guarded against the 16 movement over them of scabby sheep, but a competent imspector shoukl be appointed by the State to supervise every sheep dipping, to compel the dipi)ing of every scabby flock, and to attend to the renova- tion and disinfection of the sheep-yards and walks. Every band of scabby sheep is a constant menace to the health of others. In this country there seems to be no sheep disease produced by animal para- sites which renders the flesh harmful to man, further than that some of the flesh may be less nutritious. Until the sale of meat of all kinds is guarded by more stringent regulations there does not seem to be any reason for urging police restrictions on the sale of meats of the inferior quality which some of these diseased lambs undoubtedly furnish. There are described in this volume twenty-six species of animal para- sites of sheep, as follows : 1. (Estrus ovis. 2. Melophagus ovinus. 3. Trichodectes sphwrocephalus. 4. Trichodectes climax. 5. Trichodectes limhaius. 6. I'soropies commiitiis. 7. LingnaiuJa ta-nioides. 8. Tivnia Jimhrlata. 9. Ta;nia ex2)ansa. 10. Tccnia maryinata. 11. Taenia teneUa. 12. Taenia cwnurus. 13. Tcenia echinococcus. 14. Disioma hepaticiim. 15. Amphistoma conicum. 13. Distoma lanceolatum. 17. Strongyliis coniortus. 18. Sfrongyhts fiUcoUis. 19. Stroitgylus vcntricosus, 20. Ascarin Ittmhricoides. 21. Dochmius certuius. 22. Sclerostoma h !J2>ostomum. 23. QLsophagostoma Coliimbianum. 24. Trichocephalus affinis. 25. Strongylus ovis-pulmonalis. 26. Strongylus filaria. Of the species described three genera — Bfelophagns, Trichodectes, and Psoroptes, embracing five species, 71/. ovinus, T. sjyJicerocephalus, T. cli- max, T. limbatus, and P. communis — are external parasites. The species which there is reason to think do not occur in this coun- try are Tcvnia ieneUa and AmpMstoma conicum. The former is consid- ered by continental authorities as a synonym of T. solium or T. margi- nata. The writer has not found Linguatula tccnioides, Tccnia ccenurus, T. echinococcus, Bistoma hepaticum, or D. lanceolatum in sheep, nor learned from authentic sourcesof any of these occurring here excei)tD. heimticum. The other species may eventually be found, but they will probably be rare. Une other species, Ascaris lumbricoides, seems to be a rare one in sheep. The remaining species are all more or less .abundant. Tamia fimhriata and (Esophagostoma Colnmhianum seem to be exclusively American species. The others are common to all parts of the world where there are sheep. Von Liustow {Compendium der Helminthology, 1878), catalogues nineteen species of internal parasites which infest European sheep. One of these, Monodontus Wedlii, Molin, is a synonym of Dochmius cernuus Crepliu ; another, Nematoidetim ovis, Diesing, is a lung-worm insufficiently described. Still another, Trichosoma papillosum AVedl., is a synonym of Strongylus JilicolUs, Kud. The remaining sixteen species are described in this volume. There are 17 two lung parasites of sheep in the Old World that have not been foiiud here, viz : Stronyylus ru/esceiiis, Leuckart, and S. ininutissimus, Meguiu. The former is said to occur in Germany and France, but is so meagerly described that it probably is not a distinct species, but a synonym of Strongtjlus {PseudaUus) ovis-pidmonalis, Diesing. The latter occurs in Algeria, is well described and figured, and. seems to be a well estab- lished species. Strongylns ventricosus, also a European species, has not, to my knowledge, been described as a parasite of sheep heretofore. A further comparison of the above list with those of parasites of sheep in other countries is re-assuring, because, first, native sheep have now nearly all the parasites that they can acquire in this country; second, that although nearly all the European species have been imported, Dis- toma hepaticum, L., the liver-fluke, Tcvnia .echinococcus, v. Siebold, and T. cceniirus, Kiich., are either very rare or else do not exist in this coun- try. These three parasites have been the cause of great loss among sheep in other parts of the world. The comparatively long list of parasites furnished will seem to the Eu- ropean to indicate that sheep in this country are more infected than those in Europe; but in this connection it should be remembered that much time has been spent in hunting for several of these species, and some of them are rare, inconspicuous, and do little damage. The following is a list of our most destructive ovine parasites: (Estrus ovis, L.; Psoroptes communis, Yiust.; Taniajimhriata, Diesing; T. expansa, Rud.; Strongylus eontortns, Eud.; Dochmius cenimis, Creplin; Q^sophagostoma Columhianum^ Curtice; Strongylns ovis-jmlmonaiis, Dies- ing ; and S. filar la, Rud. There are nine species in all, a list which compares favorably with that of the ovine parasites of any other coun- try ; for all but two species, T. fimhriata and 0. Columbianum, are com- mon to all countries, and these two are more than offset by the preva- lence of more destructive parasites in the Old World. On the whole, the flockmasters of the United States may be congrat- ulated on the good condition of their flocks and their comparative free- dom from both external and internal parasites. PARASITISM. Definition. — The animal parasites of sheep are those which live in or upon their living bodies and obtain nourishment from them. The term " animal parasites " is used in order to distinctly separate this group from the vegetable parasites which attack the living organs of sheep. Both animal and vegetable parasites prey upon the flocks and cause disease, but such are the differences between them, their eflects and the methods of investigating them, that an investigation of either forms a large field of research. Parasites as defined above include a large number of animals so dif- ferent from one another that parasitism is the only common character 23038 A P 2 18 which groups them together. Though this distiuctive feature is suffi- cient for the present purpose, it is a very variable character, for the degree of parasitism manifested by each of the species varies through all the scale possible from the transient momentary parasites to the permanent. The animal parasites of sheep are all embraced within three great branches of the animal kingdom : The Protozoa, Ver^nes, and Arthro- poda. None of the first branch, which includes the Goccidia and Bal- hiana gigantea, Eaillet, are described in this volume. Examjiles of the second, which includes all the worms, and of the last, which includes the insects, mites, and linguatula, are abundant. The worms live, as a rule, in the open cavities of the body — in air spaces of the lungs, the ducts of the liver, and the lumen of the intes- tine. The exceptions to this rule arise from those immature forms which penetrate into the substance and closed cavities of the bodies, e. g., the bladder stages of the tape-worms and the young embryos of (Esophagostoma. The worms are called iniernal jjarasites. It is easily understood, however, that being held in the cavities of the body which have communication with the exterior, they are really external to the body tissues, and only those embryonic forms which penetrate into the tissues of the infested animal or host are true internal parasites. As a rule the insects live on the surface of the body. They are called external parasites. The exceptions are the larva of (Estrus avis, which lives in the nasal cavities, and Litiguatula, whose young stage infests various organs of sheep. (Estrus is usually classed with the external parasites, and Linguatula is in sheep truly internal. As has been stated, those parasites which in their young stages penetrate the tissues of sheep are alone true internal parasites. Even these spend their adult stages in the open cavities of some other host and then be- come true external parasites, so that no one of these parasites is, strictly speaking, an internal one throughout its life. That every parasite should be an external one in its adult stage is a necessary condition of its existence and of the perpetuation of its species, for it is only in the open cavities that they can obtain sufficient air and food, and can mate. From these cavities, too, the eggs and young can escape for the infec- tion of other sheep. The facility offered for mating and distribution is the most important reason. In order to avoid confusion of terms those parasites infesting the surface of the body will be called, in con- formity with custom, external parasites; the others, which inhabit the tissues of the body and its cavities, internal. Though the animal organisms that infest the living bodies of sheep be small, they are endowed with all the vital functions of life. All can move, feed, feel, and reproduce. None of the worms can see or hear. The insects are more highly specialized than the worms. All of them have in the past become so adapted to their surroundings that they can live in no other, and while sheep thrive better if not infested by para- 19 sites the latter can not live without sheep. The only exceptions are those species which are also parasitic on other animals, as goats and cattle. The modifications of organs which have arisen out of the needs of parasitism are too mauy to give in detail. The great central fact of their lives is that all the parasites have arisen from their kind, and under favorable circumstances will reproduce their species, and that they are to be treated as the originators of disease and not as the products of disease. The methods by which sheep become infested diifer with the species. The external parasites are usually transmitted by actual contact of sheep against sheep. The parasites may, however, be dislodged from their former host aud afterwards make their way to another sheep. The first is known as mediate, and the second as immediate contact. The dis- eases produced by the external parasites are true contagious diseases, and should be regarded as such fully as much as any of the more act- ively virulent maladies. The transmission with this class of parasites is usually an active one; they may, however, be borne from one sheep to another by people, cattle, goats, or by locks of wool, when the trans- mission would be passive. (Estrus ovis, which seems to bridge the gap between the external and adult internnl parasites, differs from these groups in being able to act- ively infest its host with its young, without an actual contact or inter- mediate bearer. Lice, louse-flies, and scab insects may do this in a less degree, butnot to that possessed by the (Estrus. The (Estrus larvae are never transmitted by contact; they must mature, fall to the ground, metamorphose, and emerge as adults before the females can infect sheep. The internal parasites are passively conveyed into sheep along with the food aud drink consumed, and never actively enter into the trans- mission. They may be conveyed either as eggs or very young embryos. (Estrus forms the single exception. The terms ^^ contagious ^^ and '■'• infectious'''' can be applied to these parasites. The former is applicable to those parasites which usually transmit themselves to other hosts, the latter to those which are trans- mitted to their hosts along with food aud drink. The young of (Estrus have no agency in their transmission, and hence infect sheep. Parasites are frequently said to invade the hosts which harbor them. This is only true of those species which actively undertake migration, as scab insects and sheep ticks. A few species invade the organs of their hosts after the latter have been infected, thus : The larvse of (Estrus crawl from the margins of the nostrils to the sinuses of the head ; the lung worms migrate into the lungs; the young embryos of Tcenia mar- ginata tnnuel the liver; T. coenur us timuels the brain; (Esophagostoma penetrates into the intestinal walls. Those internal parasites which undertake active migration in the bodies of their hosts seem to form a minor class in the parasitic world, those which lodge in tiie intestine and ducts emptying into it forming the majority. 20 The ability to select their final lodgment belongs to each species, and is the one character on which their own life and that of the species de- pends. This is self-evident in the case of external parasites. After hosts are once infected by the internal parasites and the young embryos are endowed with activity, they either select their proper i)lace while being carried along by intestinal fluids, or force their way to it through all opposing tissues and against all counter currents of fluids. Those embryos which fail to reach these places finally die for want of the nec- essary conditions of life. The very ability that is so absolutely neces- sary to enable certain of the parasites to reach their chosen organ often proves the means of their premature death. Tccnia marginata cysts invading the liver become lost in the mass of this organ and perish. Multitudes of these parasites injure the capsule of the liver and cause the sheep invaded to die long before they have matured sufficiently to pass into dogs. The embryos of (Esophagostoma often wander into the mesenteries, the retro-peritoneal glands and liver, and perish. Parasites escape from their ovine hosts either actively, e. g., the young and adults of the louse-flies, lice, mites, and the larvte of (Estrus, or passively as eggs or young embryos, the young embryos of the Strongylus Jilaria and Ta'nia expansa^ the comi)letely segmented eggs of the Strongylus contortuSj and as eggs incompletely segmented. In the latter case they are rejected with the excreta of the lungs or intes- tines. A very few (the cystic tape-worms) escape only after the death of their host by the intervention of some carnivorous animal which swal- lows them with its food and liberates them from their imprisonment by the processes of digestion. The death of the host is usually caused by the carnivora in search of their food. The continuance of the parasites' life into the adult stages depends, therefore, on the destruction of their host. This fact is contrary to the usual rule of parasitism, which de- mands that the host continues to live in order that the parasite may live and reproduce its species. The length of time and the stage of development at which parasites infest their host varies considerably. Lambs have no parasites at birth. Within a month or two after, they become infested by a few individ- uals of certain species of round worms, and by external parasites. From this time on they may harbor any of the species to which they become exposed. It will be noticed that the commencement of infection begins when the lambs first nibble grass. The louse-flies, lice, and scab insects infest the fleeces and skin from generation to generation. Unless it should subsequently be proven that the hair-lungvvorm {/Strong- ylus ovis-jnUmonalis), and the stomach round worm {Strongylus contortus), may also perpetually infest sheep, they harbor no other species through-, out their entire life cycles. (TJsirns oris is parasitical only in its larval stage, and consumes months in developing. Because it can not take nour- ishment when adult, it is believed to pass a very ei)hemeral adult stage. The broad ta|>e-worm develops rapidly and disai)pears, its six-hooked 21 embryo apparently spending long seasons of suspended life fanctious on tbe ground. The fimbriated tapeworm develops more slowly, con- suming the greater portion of the year; its embryos may exist on the ground for indefinite periods. The cystic tapeworms pass indefinite periods as cysts in sheep, depending on their resistance to the vital forces of the organs infested and upon the date of their liberation from imprisonment. The life cycle of the liver flukes seems to be completed in a few months. The majority of the round worms seem capable of withstanding the elements while scattered over the pastures for indefi- nite i^eriods, either as ova or partially and completely developed embryos. Their cycle of life in sheep is of variable periods, depending on the species. (Esophagosfoma, some of whose embryos invade the intestinal wall, offers a retarded development lasting through months. Other species develop more rapidly. The exact cycle for each species has not been determined, but most of them become adult in less than six months, some in less time than three. The seasonal appearance of each species depends on its life cycle, the average temperature and the humidity of the season, and the age of the lambs. Spring and fall seem to offer the most outbreaks of dis- ease produced by i^arasites. Summer and winter also have their spe- cial i^arasitical diseases. Sheei)-ticks, lice, and scab are more prevalent in winter when the sheep are closely herded in yards or barns, and when they are covered with heavy fleeces. The gad-fly occurs most in June and July, but in milder climates it evidently flies the greater part of the year. The disease it develops is more prevalent in older sheep, yearlings being the youngest that show distinct signs. The broad tape- worm infests young lambs early and causes their disease in a very few months. March lambs harbor adult worms in May and June, and May lambs in August. The fimbriated tape- worm also infests lambs early, but does not produce its worst effects until late fall and winter. The liver flukes generally appear first in summer and fall. The round worms appear in young sheep of three months and upwards. The ma- jority of those that produce disease develop it as they grow adult. The thread lung-worms {Strong ylus Jilaria) infest lambs, and epidemics due to them usually occur from spring to fall. The hair lung-worm, on the other hand, develops slowly, and while their presence can be detected in the lungs of young lambs it is the lungs of old sheep which show the greatest amount of changes due to their invasion. As a rule warm, moist seasons are most ftivorable to their development. The climate of the United States so varies from North to South and East to West that no exact seasonal appearances of the various species can be given. Most of the species seem to be present in sheep in greater or less numbers the year round. The most important factors in the time of outbreak of different diseases seem to be the age of the hosts and the cycle of life of the parasite. 22 The desfnictireness of each species is dependent on the numbers of the invading ])arasites, the organ invaded, the method by which they produce disease, and the age of the host. As a rule, most parasites produce disease by their numbers, each causing its infinitesimal amount of annoyance. The sheep-grub, the broad tape-worms, Dochmius cer- mms, and Twnia cocmtrus, are notable exceptions to the rule. But few individuals of each of these species are found invading the organs of sheep. Their destructiveness depends on the character of the annoyance produced and on the organ invaded. A few of nearly all species may infest sheep, and seemingly cause no loss, but when any of the factors favoring the development of either of the species appears they increase innumerably^ and destroy the lives of their hosts. Parasites effect injury to the health of sheep in many ways, some of which are very evident to all, while others are indefinable and illusive. Tiie injuries effected by sheep-scab, by the hair liing-worms, and by (Esophagostoma, are easily discovered; but the injuries produced by the tape- worms and various species of round worms can not always be de- tected in the intestinal walls. In these the method of determining dis- ease is not by testing the various organs by the microscope or chemical analysis, but by comparing the patient with a healthy animal of the same age in action, appearance, weight, etc., and by comparing the organs of the patient with an actual or assumed standard. In these ways the effects of the subtle diseases produced by the parasites are learned and just allowance made for their importance. Most parasites mechanically injure tissues. They may either force their way through soft tissues as the cysts of Twnia marginata, break through the structure of lung tissue as Strongylus ovispidmonaUs, en- ter into the intestinal walls as G^sophngostoma^ or lacerate the tender mucous membrane as Dochmius cernuus. The adult tape- worms seem to irritate the intestines, derange their functions, and cause nervous dis- turbances. Dochmius cernuus and perhaps Strongylus contort us seem to abstract blood. Other round worms may live on the intestinal contents. The ilestruction caused by the different diseases produced by para- sites is varied. Scab, lung- worms, flukes, and tape-worms often destroy entire flocks. The ravages of other species are less patent. There is no doubt, however, that each causes more trouble than has yet been assigned to it. The least destructive of the species common to sheep in this country seems to be Trichodectes spharocejyhalus, Strongylus Jilicollis, S. ventricosus, and Trichocephalus affi,nis. No rigid system has been adhered to in the succeeding pages. Nev- ertheless, a certain plan of arrangement and treatment will be noticed. The highest insects in the zoologic classification precede. These are followed by tbe Acarinw or scab mites. The Helminths, embracing the riatoda or flat worms, and the Nematoda or round worms, follow in turn. A systematic classification of the worms among each other is not closely adhered to. It may be noticed further that such an arrange- 23 meut permits of a second subsidiary treatment of the subject by group- ing the parasites together as regards the organs they infest. The vari- ations arising are due in part to the antagonism between the two ar- rangements adopted. The above plan was adopted more for conven- ience than for its scientific accuracy from any single point of view. Concluding, the author desires to give due recognition to all sources, from which he has drawn in preparing this work. The chief sources of information have been the admirable works of Leuckart, Die Mensch- lichen Parasiten, 1868; Eaillet, Elements de Zoologie, 1885; Neumann, Traite des Maladies Parasitaires, 1888 ; and A. E. Verrill, Parasites of Domestic Animals, Rep, Conn. Board Agriculture, 1870-'71. An en- deavor has been made to mention every other source in the text. MEASUREMENTS. The following tables will assist the reader in reducing the measure- ments given in one denomination to those in another. Metric system in medicine. Grams. 1 grain or 1 minim equala 0. 06 15 grains or 15 minims equal 1-00 1 dram or 1 fluid dram equals 4. 00 1 ounce or 1 fluid ounce equals 32.00 The cubic centimeter may be considered identical with the gram for water or aqueous solutions. Metric system in measurement. Inch. 1 meter equals 39. 37 1 centimeter equals 3937 or | 1 millimeter equals 03937 or ^ One-hundredth millimeter equals 00039 or ^/oo One-thousandth millimeter equals 000039 or js^oTJ 25 millimeters equal 1 nearly. OTHER MEASUREMENTS. For approximate measurements a liter (2.113 pints) may be consid- ered equivalent to a quart ; a kilogram to 2^ pounds avoirdupois. When graduated measures of weight or volume are not at hand, the flock-master may use some of the common household utensils. Pint and quart bottles, so called, should be tested, as they vary in size. The pint contains 16 ounces, or about a pound in weight. The smaller bottles are known as 2, 4, 6, 8, and 12 ounce bottles. Vials are quite common, those made to contain 1, 2, and 4 drams being most abundant. A set of bottles can always be obtained at the drug-store and the size marked on them. It is far better, however, to buy a set of graduates and other measures, for they are of daily use. Common tumblers con- 24 tain from StolO fluid ounces; tea-cups, about 5 fluid ouces; wine-glasses, about 2 fluid ounces; tablespoons, half a fluid ounce; dessert spoons, 2 fluid drams, and teaspoons, 1 fluid dram. In spite of the fact that the use of the metric system has been legal- ized in the United States, so deeply is the old English system engrafted upon the customs of our people that there will necessarily be a con- fusion of weights and measures until the use of the former is made compulsory. This system is so easy to learn and so easy in practical api)lication that it will certainly supersede the other in use, as it has in the continental countries of Europe. THE SHEEP GADFLY-GRUB IN THE HEAD-NASAL CATARRH. CESTRUS OVIS, Linn. Plates I, II, and III. The popular names of this well-known parasite of sheep convey to the reader its epitomized life history, long known to veterinarians and farmers. Though the life history is a comparatively simple one, there are many of its details which are not only unfamiliar to the aver- age shepherd, but some of which are unknown even to those who have made a special study of these pests. The " Sheep Gadfly," the parent of the '' Grub in the Head," is, when flying, so small and so quick in its actions that it is very diflQcult to see, and still more difficalt to catch. The greater proportion of specimens in collections have been raised from the grubs, i, e., the adult grubs are collected and placed in a net-covered box, the bottom of which is covered by a couple of inches of damp sand. 'In a few minutes they bnry themselves in the sand, and in from three to four weeks they re- ai>pear as flies. C. V. Eiley (Insects Missouri, First Annual Keport, 1868, p. 161) de- scribes the fly (Plate I, Fig. 11) as follows: lu this stage it looks somethiug like an overgrown house-fly. The ground color of the uiiper part of the head and thorax is dull yellow, but they are so covered with little round, elevated black spots and atoms (scarcely distinguishable without the aid of a magnifier) that thej"^ have a brown appearance. The abdomen consists of five rings, is velvety and variegated with dark brown and straw color. On the under side it is of the same color, but not variegated in the same way, there being a dark spot in the middle of each ring. The feet are browu. The under side of the head is puffed out and white. The antenuio are extremely small and spring from two jobes which are sunk into a cavity at the anterior and under part of the head. The eyes are purplish brown, and three small eyelets are distinctly visible on the top of the head. It has no mouth, and can not therefore take any nourishment. The wings are transparent and extend beyond the body, and the winglets, which are quite large and white, entirely cover the poisers. Its only instinct seems to be the continuation of its kind. It is quite lazy, and except when attempting to deposit its young its wings are seldom used. The male is about as large as the female, but may be known by its relatively narrower forehead or space between the eyes^ Catching a male at large would be a chance operation, for though they fly to mate with the females around the sheep-yards and pastures, they never make their presence known by disturbing sheep. 35 2G Brauer (Monographie der Q^striden, p. 15) records the size of the male and female at from 10 to 12""", or about two fifths of an incli ; the width between the eyes of the male at 1""" or one-twenty-fifth of an inch, and of the female at 2.5""" or one tenth of an inch. The length of the wing is 9""", nearly two-fifths of an inch. Distribution. — The species occurs all over the world wherever there are sheep. It is now too late to learn if it was indigenous in this country, but we may believe that it was introduced with the earliest flocks im- ported, whether in Mexico or on the Atlantic coast. Brauer, in 18G3, stated that it had then lately been introduced into Chili, South America. Life history and description of larva. — The interest of the flock-master in this species begins when the fly buzzes around the noses of the sheep and deposits its young just within the opening of the nostril. Many of the older writers on this subject supposed that the fly deposited eggs, but Brauer (o. c, p. 151), in agreement with Joly and Dufour, pointed out that the genus was one which deposited their young alive. Accord- ing to lliley (o. c, p. 164) Samuel P. Boardman, of Lincoln, 111., men- tioned the two following independent discoveries: John Brown, "Old Ossawattomie," stated in the Ohio Farmer about 1851 that he saw the fly drop the jierfectly formed and living grub in the nostrils of sheep. About 1861 Dan Kelly, of Du Page County, 111., made the same discov- ery, and records the fact in the Prairie Farmer, October 14, 1865. Boardman, in 1867, received a letter from Mark Cockrill, of Tennessee, who wrote of having made the discovery years previous. Eiley claims (o. c, p. 165) that he obtained living maggots from a fly in 1866. The young larva, having been deposited within the rim of the sheep's nose, soon attaches itself by means of the hooks (Plate I, Fig. 6), and begins to make its way upward into the nostrils. The smallest specimens collected by the writer are shown in Fig. 7e, natural size, and are not much larger than when first deposited ; for the difference between their size and that of eggs deposited by flies even smaller than (Estrus oris is inconsiderable. These small larvae are in their first stage of growth. They are little, white, elongated bodies, less than 2""" long, i. e., about one- twelfth of an inch (Figs. 1 and 2). But little of their structure can be seen except with a lens. They already show the division of the body into eleven segments, two well-defined hooks (Fig. 3a, a), and tvro minute terminal breathing pores (Fig. 4a, a). The ventral surfaces (Fig. 2) show the little spines which later on are to become strong thorns; some of the spines on the sides are relatively bristle-like and longer in proportion than they are later on. In their second stage of growth (Fig. 7c, c) all the characters are well defined. The skin is white and so translucent that the digestive organs, the respiratory ap- paratus, and the fine filiform nerves and their gangiia can be readily made out ; the spines on the abdomen, the hooks, and the stigmata are all more pronounced. In the third stage — that of the mature larva 27 ready to undergo its change into a fly (Fig. 7a, a, «, and h) — the charac- ters outlined in its first stages have been perfected. It is this stage that is commonly seen by those who split open the head of an affected sheep. The mature grub averages over 20l"'" in length and 7™'" in width, or about three-fourths of an inch long by one-third of an inch wide. Its width and length when measured depend much upon its state of contraction. Its back is very convex, its abdomen is slightly curved but generally flat, its outline is a very elongated oval, with an acute head and obtuse posterior end. Half-grown specimens are more pointed at the ends and decidedly flatter on the abdomen. From the young to the mature larval state there is a decided change of color. At first they are white and semi-transparent. They quickly grow whiter and soon after take on a tinge of yellow, which, as they mature, grows darker and darker. Then, too, on the back of every segment, except the first and last, a dark narrow band appears which eventually changes from a brown black to a dead black. These bands are rather narrower in front, increasing in width backward. On the side of each segment below these bauds there is, in mature specimens, a row of dark dots. The spines show the same changes, at first white, then tipped with brown, and finally changed to black. The spines occur only on the abdomen and the closely adjacent edge. They all point backward and assist the grub in moving around. When the larva is mature it escapes from the nostrils, falls to the ground, bores into it for an inch or two, and, according to Eiley (o. c, p. 162), contracts during the next forty-eight hours to half its for- mer size, becomes smooth and hard and of a black color, tapering as in the larva towards the head (Fig. 14). It remains in this state three or four weeks, or according to some authorities from fifty to sixty days, depending on the weather. When the fly has matured within the case it pushes off a little round cap, ascends from the ground through the hole left by the larva in its descent, and emerges into day to com- plete the cycle of its existence. The ofiBce of the fly seems to be merely to reproduce its kind. On ac- count of its rudimentary mouth it is unable even to eat. After emerging the fly crawls upon some neighboring grass or twig and rests there until its wings and body have hardened. During the first part of its life, ac- cording to Brauer (o. c, p. 149), it is very sluggish, sitting around in the cracks and crevices of the walls of sheep stalls, and is so dull that it must be dragged out. When placed on the hand it seldom flies off. This dullness vanishes as soon as the fly has reached perfection and the right temperature of the air comes. It is then off with a whirr, first vertically in the air, and then in the direction of the flocks. The effects it produces on sheep and how and where the injury is in- flicted may now be stated. Bracy Clark, an English veterinarian, describes the effect of the attack 28 of the fly in Trausactions Linnean Society, 1797, vol. Ill, p, 315, as follows : Earh/ symjyioms. — The moment the lly touches this part (the nose) of the sheep, they shake their heads aud 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 everj' side, to see if the liy 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 can not, like the horses, take refuge in the water, they have recourse to a rut, dry dusty road or gravel pits where they crowd together during the heat of the day wdth their noses held close to the ground, which renders it diffi- cult for the fly conveniently to get at the nostril. This description of the action of the sheep when attacked by the fly is correct in all but one or two minor points. The sheep's actions when running indicate that they are taking every means to shake off and dodge a single rather thaTi a number of pursuers. If this quotation had also described the sheep huddled under buildings, along fences, under rock ledges and shade trees, holding their noses close under their fellows, it would have completed a picture familiar to every farmer or flock-master. The fly only works during the heat of the day, while early in the morning and late in the evening the sheep seem to enjoy feeding in freedom from its annoyance. Pathology.— The young larva deposited in the nostril of the sheep im- mediately begins its migrations upward into the dark passages of the nose. It progresses by means of its hooks and spines. By firmly fix- ing the hooks into the mucous membrane it is enabled to draw up the rear part of its body after it, and by pushing upon the spines of the abdomen it holds itself in place while it thrusts out its head for a new hold. The only appearance of limbs that the larva has is the two rows of prominences along each side of the abdomen, as shown in Fig 13. In this method of progression lies one cause of irritation to the sheep, viz., the hooks sink into the mucous membrane and not only irritate it, but cause minute points of hemorrhage which are afterwards indicated by very minute black dots scattered over the surface of the nares or in- ternal nose. AVhoever has felt the tickling and itching of a fly at tlie entrance to, or a foreign body in the nose, can imagine some of the sen- sations which induce the sheep to make such attemi^ts to escape its foes. As the larva grows in size it finds its way farther into the recesses of the nose, and by following the grooved passage (see Plate III, Figs. 1 and 2) penetrates into the furthest chambers. Fig. i, n, n, shows the young larvae wandering over the turbinated bones and in the main passage. One of these larva^, advanced in size, is shown at i in Figs. 1 and 2 fol- lowing the direction of the channel marked by the straw o, o, which emerges into the frontal sinus of the head, Ic. The larvju may also wan- der among the windings of the superior turbinated bones p, and finally growing to such a size that they can not escape, become entrapped there. The same may happen when they wander through the small ori- 29 fice, near but below that leading into the frontal sinus, which leads into ^ thesuperior maxillary sinus. (SeePlatell, «, b.) A bit of straw has been inserted into theoritice to show the place of opening. From these jilaces the larwTB never emerge, but after maturing undergo calcareous degen- eration. Those that arrive in the frontal sinuses seem to thrive, and at the proper time are able to retreat through the orifice they first trav- ersed and are finally sneezed to the ground. This history and the fig- ures illustrating it, which have been drawn from nature, should satisfy sheepmen who have thought that because the grubs were in the head they must be in the brain. A glance at Plate III, with its three larvae in the sinus (there were originally seven in the head which the artist figured), will show that there is a bony partition, a, a, a, between the brain and the larvte. This is also the case in regard to those small larvae which wander among the intricate windings of the upper turbinated bone, g. The larvae of the (Estrus, or the grubs, never do and never can penetrate into the brain. If one may judge from the black dots indicating a i)revious hemor- rhage scattered over the mucous membrane, the irritation set up by the wandering embryos is very considerable. In the sinuses of heads which contain older embryos other changes are to be noticed. They are filled with catarrhal matter which has been produced by the irritation of the larvaB, and the mucous membrane is greatly thickened. These changes may also be observed over the turbinated bones, r/, the greatest changes occurring in the superior, the one next the brain. The membrane which covers the latter is the one in which the nerves of the sense of smell are distributed, and a thickening of the membrane must greatly interfere with this sense. This is no small matter, for it is mainly by this sense that the sheep separates its food from other herbage. In addition to the catarrhal product and thickening of the membrane, it has been noticed that the membrane near the base of the turbinated bone — near m — is sometimes very dark colored. At this point the bone is exceedingly thin and pierced by a number of holes through which the olfactory nerves, or nerves of the sense of smell, pass. It is not unusual to find the membranes of the brain in the immediate vicin- ity blackened by minute dots, indicating a previous inflammation at this point. This affection of the membranes is probably caused by an extension of the inflammatory process from the nasal cavity. When the larv.e become entrapped in the maxillary sinus they ex- cite the same catarrhal secretions and thickening of the membranes as elsewhere, which finally fill the cavity, the outlet of which is at the top. All this irritation is due to the insertion of the claws and scratchiugs of the abdominal spines. The larvie live on the material in which they move. They seem to obtain plenty of air even in the most crowded recesses. They continually cover and uncover the breathing pores (Plate I, Fig. 10a), and iu so doing keep them cleaned of all foreign 30 material. Bracy Clark says that they make an audible snap in doing tills, but the writer has not heard it. Late symptoms. — The chief symptom of the disease caused by tliese larvae is the catarrhal discharge on the affected side of the nose, which gives rise to one of the popular names of the disease, "snot-nose." Even this symptom may be absent when but few larvie are present. Keumann {Traite des Maladies Parasitaires, 1888, p. 501) accurately describes the symptoms of affected sheep as follows : Three or four larvie ot Q^strm are frequently fouud in the frontal sinuses of sheep which, during life, had never manifested any symptom. It is only when these larvae are numerous, and when they are quite well advanced in their development at the commencement of spriug-time, that they occasion morbid troubles. The latter begin by a discharge, often unilateral, which is at first clear and serous, then thick and mucous. Frequently there is sneezing and snorting, accompanied by the expulsion of mucus and sometimes of (Estrm larvie. Later the animals turn the head back- ward, often shake it, rub the nose against the ground or some other object Avithin reach, or with their front feet. As the malady gradually advances the' sheep go with lowered head, lifting the feet high as if they were walkiug in water. Sometimes they quickly raise the head, carrying the nose to the wind, and then bend it back- ward convulsively. From time to time they stagger and are seized with vertigo, but do not turn in a circle. In severer cases there is difficulty of bi-eathing, the first res- piratory passages beiug obstructed by the larviu or the inflammation of the mucous membrane. The eyes are red and watery. The disease may be still further compli- cated. The sick lose appetite and rapidly grow poor; they grate their teeth; a frothy saliva runs from the mouth ; their eyes roll in the sockets; convulsions arise and finally death ensues, sometimes within six or eight days after the appearance of the first symptoms. But the disease is rarely so fatal; it lasts longer, and the larvie having been suc- cessfully cast out, the symptoms generally become more favorable and by degrees completely disappear. This affection has sometimes been mistaken for "gid, " or "turn-sick," due to Coc- nurns cereiralis, whence the name "false gid," or vertigo of CEstrus, which has been given to it. Confusion will be avoided by recalling that turning in a circle does not take place in the present disease. The latter is nearly always accompanied by nasal discharge and snortings, which do not appear in true " gid, " and which, besides, show themselves only in young subjects. Occurrence. — The larvae of CEstrus ovis may be found in the nasal cavities throughout the year, and in nearly all stages of growth. This is more especially true of the southern portions of the United States, where the winters are mild and short. During the last winter and spring, in January and March, larvaj were collected of all sizes. Those represented by natural-sized figures (Plate I, Fig. 7), were collected in January at an abattoir in Baltimore, Md. Those figured in Plate III were collected in May. From the older of these grubs a pair of flies were hatched. The presence of very young larvae during the past winter is very interesting, and indicates the presence of flies at an un- expected season. The usual time for the appearance of the fly is said to be during the months of June and July, and the usual period of pupation about two months. Two of my experiments showed that the time might be three weeks or four weeks exactly. The larvie is said to dwell in the nostrils about ten months. This statement has not yet been verified. In very young lambs only young larvjB can be found, while in yearlings the larvae may be nearly adult, depending on the exact age of the iamb and the time it was infected. In yearlings the frontal sinuses are small and the grubs easily escape detection. It is in two-year-olds and older sheep that one finds the greatest infection. In ewes the sinuses are sufiiciently roomy to hold four or five larvue without crowding, but wethers, which have small horns, or bucks which have very large frontal sinuses, can harbor many more. Earely have more than six or seven been found. Cases have been reported in other countries where far larger numbers, as many as ten to fifteen, were found. The largest recorded number seems to be from sixty to eighty. The relatively small number discovered, and the comparatively large size of the young when deposited, indicate that each female lays but few young. It is very unusual to find more than two or three larvae of the same size, especially if they be mature or nearly so. The young larvae are sometimes more numerous, six or seven of nearly equal size being found together. The presence of all sizes of larvae in the cavi- ties is a plain contradiction to the statements made that the fly appears only in June and July, for, no matter whether it takes ten months for the larvae to grow or not, young and middle sized and mature larvae found in the winter time could not all have been laid within the two months indicated. The more correct statement is that the fly may appear at any time when the temperature is not too low, but that they are more abundant in early and midsummer. Preventive treatment. — Most authorities on this subject recommend preventive measures, but practical application of the means and reme- dies proposed is necessary to demonstrate their utility. A change of pasturage or an avoidance of brush-fields does not seem to be advisa- ble unless the sheep are turned into longer grass, for the flies are able' to follow the sheep wherever they may go. A practical means of prevention consists in smearing the noses with a mixture of equal parts of tar and grease, or of tar and fish-oil, or of tar and whale-oil. The better way is to apply the preparation directly by a brush. Some recommend smearing the salt and grain troughs with the mixture, expecting the sheep while feeding to get more or less on the nose. This method is not thorough enough. Fish or whale oil alone is also recommended. Powers (American Merino, 1887, p. 300) ad- vises the following ointment for this purpose : Beeswax, 1 pound ; lin- seed-oil, 1 pint 5 carbolic acid, 4 ounces. Melt the wax and oil together, adding 2 ounces of common rosin to give body, then, as it is cooling, stir in the carbolic acid. This should be rubbed over the face and nose once in two or three days during July and August. He also recommends an apparatus which may well be used by owners of first-class breeding stock, and possibly others who own but few sheep : " A canvas face- 32 cover smeared with this mixture (tlie above), or with one of asafuetida and tallow, may be hung in such fashion as not to interfere with the sight or with grazing and yet protect the lamb against the fly." Whatever the preparation nsed it should be periodically repeated throughout the season during which the fly is known to trouble the sheep, as the nosing of the sheep in the grass, the accumulated dirt, and the rain all tend to make the preparation weaker and consequently less effective. Old authorities recommend plowing furrows iu the pastures, but these will be beneficial only while the ground is dry and mellow. Removal of the grub immediately after it has been deposited is impractical. All grubs seen on the ground should be crushed. Heads of slaughtered sheep should be cared for so that mature grubs can not escape to the ground. Sheep yards should be periodically cleaned and sprinkled with lime. Medicinal treatment. — This seems to be hopeless. A study of the life history of this parasite, which appears in the south at nearly all seasons of the year, and of the anatomy of the recesses into which the larva wanders, will convince one of the difficulties to be met with in treatment. In the first place, even if a suitable remedy were found, the shee])-owner would be compelled to resort to treatment as often as he found his sheep troubled, and would have to treat each separately. This arises from the fact that irritating fumigations or sneezing pow- ders, which pass into the lower part of the nose, would not affect the larvae in the sinuses no matter how violent the sneezing which they ex- cite. Injections of irritating substances would also fail, excepting pos- sibly in the hands of an expert, who, with a syringe and peculiarly bent nozzle, could perhaps learn to inject into the nasal sinuses. Even iu that case failure would result in a certain proportion of cases, and the maxillary sinuses could not be injected, nor would the larvae in the re- cesses of the turbinated bones be reached. In addition to all this, most remedies which would kill the larvae would injure the delicate mucous membranes. For the flockmaster who may wish to try fumi- gation or nasal injections, the following recipe for fumigation as given by Blacklock is reproduced : One person holds the head in a convenient position in front of the operator. The latter, having half-filled a pipe with tobacco and kindled it in the usual manner, places one or two folds of a handkerchief over the opening of the bowl, then passes the stem a good way up the nostril, applies his mouth to the covered bowl, and blows vigorously through the handkerchief. When this has continued for a few sec- onds the pipe is withdrawn, and the operat'ou repeated on the other nostril. Powers (o. c. p. 3()()) advises the following nasal injection, which should succeed if any will : It is best to procure at the ding store an elastic bulb syringe, price about l|l, with a small nozzle (J inches long. Mix turpentine and linseed-oil in eiiual parts. Accustom yourself to the action of tlie syringe so that you can gauge it accurately. Let the affected sheep be held before you in a natural position, and carefully probe the nos- do trils with the nozzle uutil you find its bearing and depth (the nozzle will pass up a surprising distance— six inches in grown sheeii). Then charge the syringe, intro- duce it to the extremity of the nasal cavity, and with a quick pressure inject about a teaspoonful of the mixture. Withdraw at once and let the sheep recover some- what from the effects of the shot, then treat the other nostril in the same way. » * * Keep the mixture well shaken. If the nozzle has a properly curved tip the injected mass will be more likely to reach the larvte. A trial on the head of a recently dead or slaughtered sheep would give the operator more knowledge of the re- quirements to be met than any description. Olive oil is preferable to linseed. Suiyjical treatment. — There remains but one other method of remov- ing the parasites, and that is mainly surgical. If the disease is appar- ent on but one side (it may be on both), an opening is made into the frontal sinus (see Plate II), with a special instrument called a trephine. The opening is made on the dotted lines. which connect the middle of the eyebrows, and a little nearer the middle line of the head than the eye. The operation is a tedious one, requires some skill, and if advisa- ble to undertake with a number of shee]), should only be trusted to a competent veterinarian. Moreover, the ultimate results are not such that the operation could be advised in the majority of cases. Yet, as it is the only means that offers any hope for the worst affected, Ziirn's directions (Raillet, Maladies Parasitaires, j). 504) for operating are given: Cut off the wool which covers the forehead. Trace with colored chalk a transverse line uniting the middle of the two superciliary arches (the eyebrows) and divide it by another lino passing at the middle of the forehead. The point of choice for tre- phining will be in each of the two upper angles thus obtained without engaging the lines which limit them. The operation is performed according to the ordinary rules of surgery. From the opening made one often sees the larvtv, which are extracted by forceps. To kill others benzine moderately diluted with water is injected. The Hap of skin is then cleaned, applied to the opening, and sewed to the adjoining skin. The whole is then covered with a turpentine coated leather plaster. The patient is separated for a few days from other sheep. Sheep bear the operation with the same impunity as they do marking the ears or other little operations. Trephining may also be resorted to for the large cavities at the base of buck's horns, or for the maxillary sinus. The latter is a far more difficult operation, and the vicinity of important nerves and blood-ves- sels demands that only a skilled veterinarian should undertake it. The operation is, after all, only temporary in its effects, for the next larvie laid in the nose will crawl into the same sinuses and create the same disturbances as those removed. Neumann's advice, with which he closes his chapter on this parasite, is, perhaps, the soundest to follow, except in the case of breeders of valuable sheep : At all times, if the number of animals afiected is considerable, the malady should be left to follow its course, and those which present the gravest symptoms should be sent to the shambles. 23038 A p 3 34 OESTRUS ovis, Liuu. Plate I. Fig. 1. Larva in the first stage. Dorsal view. Fig. 2. Larva in the first stage. Ventral view. Fig. 3. Head of larva in the first stage: a, books by wliicb tbe parasite attacbeg itself to tbe mucous membrane. Fig. 4. Tail of larva in the first stage : a, tbe stigmata or breathing pores. Fig. .'j. Hooks of well-developed larva. Fig. 6. Hooks of very young larva. Fig. 7. Larvte in various stages of growth ; natural size: a, a, a, fully developed larvii' in the third stage ; b, three-fourths developed ; c and d, yet younger hirvie, possibly in tbe second stage ; <;, the youngest found, and those from which figures from 1 to 4 were taken. Fig. 8, Cephalic end of full grown larva (Brauer). Fig. U. Dorsal view of full grown larva (Brauer), Fig. 10. Caudal end of full grown larva (Brauer) : a, stigmata or breathing pores. Fig. 11. Adult female fly with line indicating natural length (Brauer). Fig. 12. Front view of bead of tbe above (Brauer). Fig. 13. Ventral view of full grown larva, showing tbe spines which enable the para- site to push itself along tbe smooth, soft mucous membrane. Fig. 14. Pupa case dissected to show tbe imago or young fly within (Raillet). Fig. 15. Eggs taken from fly (Raillet). PLHTE I Haines, del. CE8TRUS OVIS, (The Gad Fly of Sheep. 36 CEsTRUS ovis, Linn. Plate II. Dissection of the head of a sheep to show the cavities into which the gad-fly grubs penetrate. The straws indicate the passages from the cavities into the iuside of the nose : a, the superior maxillary sinus, in which there is imprisoned the calci- fied remains of a fully developed larva ; b, the ridge made by the infra-orbital division of the fifth pair of nerves; c, the infra-orbital foramen; d, an opening into the nares; e, e, the frontal sinuses with young larva) in them. The dotted line /,/, indicates the level at which trepliiuiug, if it is done, should be per- formed. Figure reduced to tUree-fourths of natural size. 'V'*^3^-- '•^^jg^' 38 CEsTRUS ovis, Linn. Plate III. Fig. 1. Section of bead of sLeop inado a little to the right of mesial plane: a, a, a, a, a, section of bone surrounding h, the brain, and c, the nasial cavity; d, the lower jaw bone: e, nostril; /, opening of tear duct; g, g, g, turbi- nated bones; h, the posterior opening of the nasal cavity, and near the opening of Eustachian tube ; i, placed on the turbinated bone over a grub in the groove leading to the frontal sinus; k, the frontal sinus; I, then.asal sinus; m, the thin perforated plate of bone called the cribriform plate; v, n, n, larva; of (Estrus ascending the nares and wandering about its surface; i.'oue ascending to th« sinus; k, opposite three, nearly mature larvie in the sinus. Figure reduced to three-fourths of natural size. Fig. 2. Outline drawing of the skull surrounding the frontal sinus after removal of part of the turbinated bone, lettered as in Fig. 1 ; o, o, straws passed through the channels connecting the nares with the sinuses, marking the path by which the larva reaches the sinus ; p, cut ends of the removed bones. THE SHEEP-TICK OR LOUSE-FLY--PHTHIRIASIS. MELOPHA.GUS OVINUS, Linil. Plate IV. One of the best known of all tlie external parasites of sheep is the sbeep-tick, MelophaguH ovlnus, Linn. This pest is a very common one in the Eastern States, and although it seldom causes any serious damage either to the sheep or to the wool, it is at all times an annoyance, and occasionally causes decided losses to the flock-master. This tick, like a majority of the parasites of the domesticated animals, was introduced into this country from Europe. The name " sheep-tick," though not a misnomer, as every one knows what a sheep-tick is, is misleading. So much do they resemble the true ticks that they are often classified together. The most superficial study will, however, serve to show their differences. Bescri/ption. — The sheep-tick is a wingless fly having but six legs, whereas the true ticks are more closely related to spiders, and have eight legs in tbeir adult state. The adiilts are less than a quarter of an inch long, and have a short, flattened, bristly, leathery body. The head is slightly wider than the thorax, into which it is sunk. They have very short antennje, which are sunk in sockets in the face; the ])roboscis is tubular, and is protected externally by two flat, elongated bristly pieces, the labrum ; its end is armed with teeth. The thorax or limb-bearing portion of their bodies is nearly square when looked at from above. It is composed of three pieces, the middle being the one seen on the back. Tlie legs are very stout, covered with bristles, and each is provided with two strong, sharp claws. The last joint of each foot bears a pinniform or feather-like organ whose ofiSce is as yet un- determined, but is probably that of coiling around hair for better pre- hension. There are no wings. On either side may be seen two small, bristle-covered, round spots at points where the wings should be attached. At the posterior outer corners of the thorax arc two little projections which remind one of balancers. The abdomen, usually larger in females than in males, is flattened and bag-like, and is as large or larger than the rest of the body, especially after the louse- fly has eaten, when the red blood sucked from its host may be seen through its skin. Its skin is tough, unsegmented, semi- translucent, and permits the abdominal organs to show through. On each side there are seven stigmata or breathing pores. The anus is situated on 39 40 the veutral side and just behind the geuital orifice. The sexes resemble each other, but may be separated by their size and by the form of the external genital ai)paratus. In habit these parasites resemble lice living among the hairs of the fleece, whence the name, louse-fly. They seldom remain attached to the skin longer than a sufficient time to fill up with blood ; this they suck up through the proboscis with which they perforate the skin. They try to evade capture by runaiug into the wool, and when caught cling tena- ciously. Life history. — The family of flies to which this parasite belongs is truly wonderful, in that they bring forth their young as puparia. The puparia of Meloiihagus are laid as flat, ovoid, chestnut brown, glistening seed-like eggs, which are nearly one-third as large as the abdomen of the parent, and contain an imperfectly developed larva within theni. The eg^ cases or j)upa are marked by two rows of seven dots each on one surface, a slight depression, indented by two dots in one end, and a slight elevation at the other. The two dots are at the anal end. A dissection of one of these, taken from a female, shows the pointed end to be connected with a membrane, and to be the end through which the larva obtains food. Some authorities say that each female produces but one or two of these puparia ; others say that they can lay about eight or nine during their life-time. They lay one at a time in the wool, A portion of eacli puparium will be found to be covered with a dry, dark substance, which came from the parent when the jjuparium was laid, was sticky, and glued it to the surrounding hairs. This prevents the pupa, which becomes hard, dry, and glassy, falling from the wool. The insect emerge, with adult characters from the pupfe cases, through an opening in the end of the case made by a round lid splitting olf, and wanders into the wool. Some of these eggs collected in the course of our investigations hatched within four weeks at ordinary temperatures. Occurrence. — These ticks, or their young, may be found on the sheep at all times of the year, but appear to be most numerous in spring. They are particularly noticeable at shearing time on the old sheep after they are deprived of their shelter. At this time those that can do so take refuge in the longer avooI of the lambs, and prove veritable pests. The others perish either from being eaten hy the sheep, carried away in the wool, or dropped to the ground. They frequently become attached to the clothing and persons of people with whom they come in contact, but they prove but a slight source of discomfort, as they are easily caught and killed. It is not at all probable that they can exist many days apart from the sheep, as they are unfitted by structure for any other habitat. Their food consists wholly of the blood which th.oy suck from the sheep. They depend also on the sheep for warmth ; in warm spring days t\xe,y may be fouiul crawling near the ends of the wool, while in the colder days they will always be found either engaged in 41 feedinfv or resting at but little (listance from the roots of tlie wool. A dozeu or more of these ticks, which were moderately well fed when taken from the sheep were, with some wool, placed in a cotton-stoppered bottle and kept in a room with a temperature varying between 60° and 80° Fah. They all died in less than four days. The leanest succumbed first, in about two days, while those that were better nourished grad- ually grew smaller and thinner, and lived little longer than the third day. Others placed in wool over the damp soil of a geranium in a flower- pot died within four days. On the other hand, some young ones which were hatched out in a bottle were kept for nearly two weeks, or until their daily feeding was neglect.ed. To feed them they were placed on the back of my hand. By this means 1 could, with a lens, watch tbem bore into the skin and see the abdomen slowly enlarge as they drew in the blood. They had some difficulty in penetrating the thick skin, but usually succeeded by slipping their tube into a hair follicle. At first no itching or irritation was felt, except a slight twinge when the bills first penetrated the skin ; but little swellings came on a day or two later which itched for over a week. The itching was far more iier- sistent than with mosquito bites. TUey must in this way cause lambs much discomfort. It was at first thought that a fluid could be seen running from the parasite to the hand through the bill, but no more was thought of it until the elevations began to rise and itch ; then it ap- peared certain that the little pests had secreted a poisonous fluid. The office of this secreted fluid is probably to assist the flow of blood by keeping it from clotting. The above experiments show that the jiarasite spends its whole life on the sheep. Source of contagion. — The fact that this parasite passes its whole life on the sheep, and that it produces but few young, are very important con- siderations in eflbrts for exterminating the pest and preventing a new infection. They indicate that if all are killed the sheep will not again be infected except from other sheep. Disease. — The injury sustained by sheep from these parasites varies according to the number present. It arises from the itching and pain inflicted by them when obtaining their food. A few cause but little annoyance, and, were it not that these may become the source of future multitudes, would be scarcely worth noticing. To lambs the annoy- ance is particularly aggravating, as their skin is tender and the number of parasites attacking them after shearing is unusually large. In older sheep the irritation is the more noticeable towards spring. At this time the parasites are more numerous and the animals bite and scratch them- selves often er. Medical treatment. — The well-known means of ridding the sheep of these pests are the tobacco or other mixtures used for scab-dips. The best time of the year to dip is at shearing time. Then the older sheep can easily be handled and cleansed. The dipping should not be delayed 42 long after, for oach additional day is one of torment to tlie lambs. The lambs also should be thoroughly dipped. Oue dip is said to be sutlicneiit to kill the old parasites. However, a few of the i^upjc may remain in the tleece of the Iambs. They should be thoroughly examined two or three "weeks after, aud if there are any present they should again be capped. All the precautious taken in dipping sheep should be carefully ob- served. The shorn wool should be stored where the young ticks which may hatch from the pupa cases can not crawl back to the sheep. How- ever, they seem to have great difficulty in crawling, aud may not be able to go far. An experiment in which some of the pupjc became wet with moisture from other ticks in the same bottle demonstrated that they would not hatch, and indicates tlwit the sheep bath will very likely kill the inclosed larvie. In The American Agriculturist, October, 1889, page 490, Mr. Joseph Harris advises fall dipping for these pests. This is a good plan if the sheep have become infested with ticks after the spring dipping by some inadvertence of the master. He advises the use of tobacco, carbolic acid, and kerosene emulsion dips. The carbolic acid dip is composed of a pouud of soap and a pint of crude carbolic acid to each 50 gallons of water. Dissolve the soap in a gallon or more of boiling water, add the acid and stir thoroughly. Keep the mixture well thinned, and do not let it get into the mouths, nostrils, or eyes of the sheep. Hold each sheep in the bath not less than half a minute. The formula for kerosene emulsioii is as follows : Churn fresh skimmed milk and kerosene together in the proportion of 1 gallon of milk to 2 gallons of kerosene, either in a churn or by using a force- pump until an emulsion is made. The method of using the force-pump is to set it in the vessel containing the mixture and turn the stream back into the same vessel. The emulsion will form guickei if boiling hot milk is used. For dipping use 1 gallon of the emulsion for each 10 gallons of water required. Mr. Harris seems to think 20 gallons, with a reserve of 10 gallons, sufficient ; but he was evidently thinking of a very few sheep. He did not use this emulsion, but a variation made with soap, as follows : Boil a gallon of water, dissolving a pouud of soap in it; add 2 gal- lons kerosene; churn the mixture until it emulsifies, or until all the oil is "cut." Use 1 gallon of emulsion to 8 of water. Mr. Harris ad- vises dipi)ing twice with an interim of two weeks. Fifty gallons ot the dip will suffice for fifty sheep. Seventy would probably answer for oue hundred ; but much depends upon the amount of waste on account of the liquor being carried off by the fleece. The recipe is very easily modified for ranching purposes. The emulsion has already been advised for cattle lice in Bulletin No. 5, Iowa Agricultural Station, p. 184, May, 1889, aud for cattle ticks in Insect Life, Vol. II, No. 1, p. 20, U. S. Department of A griculture, July, 1889. Though the efficacy of this remedy against the various 43 kinds of insect parasites of domestic animals has yet to be tried in de- tail, its importance in this field has already been demonstrated. Preventive treatment. — The sheep should not be turned into the old pens or pastures until a week after the first dip, by which time it may reasonably be supposed that all parasites on the ground have died. To avoid the chance of any recently hatched parasites gettiug from the ground to sheep in places where the sheep rest, it is best to scrape out and cleanse the pens. Animals recently purchased should always be dipped before being added to the older tiock. By following out a thorough plan of treatment, and by carefully guarding the sheep from re-infection, the flockmaster should be able to rid his flocks of this pest in a siugle season. 44 Fisr. 3. Melophagus ovinus, Linn. • Tlate IV. Fig, 1. Female sheep-tick : la, larva case, each natural size. Fig. 2. Male, dorsal view, X8: a, head; h, thorax; c, abdomen; d, limbs; c, oval bristle-covered disks, whicli correspond to the points of attachment of wings in other llies ; /, rndimei;tary hal teres or poiscrs. Male, ventral view, X8: (/, Ji, audi, the three segments oC the thorax; k, the external genitals. Fig. 4. Female, dorsal view, x8. Fig. 5. Larva case, x8: a, cephalic end ; b, two rows each of seven shallow indent- ations. Fig. 6. Foot: a, the two claws between which hangs b, the pinniform prehensile organ; c, the tarsi, whose last joint d supports the preliensile onran • e distal end of the tibia. " ' ' Fig. G«. Preliensile organ, xOO : a, the segmented mnsenlar portion included within the tarsus; ft, the flexible grasping portion. Fig. 7. Front view of head: a, the compound eyes; b, the aiitenuic sunk in cnp- like cavities; c, the labruni wliich protects the sucking organ. P^ig. 8. Tlie sucking apparatus: a, the labrum ; b, the orifice from^which the tube protrudes; c, the sucking tube. Fig. 9. End of the sucking tube, XP20: a, teeth by which the tube cuts its way through tlie skin ; b, rod upon which the teeth are set ; c, tube which has lateral orifice iu it. Other details not shown. Fig. 10. External genital apparatus of female: a, spine-covered cap which tits over b, the genital oriliee above; c, two clusters of spines which seem to be for clasping; d, the terminal of the seven pair of stigmata or breathing pores ; e, anus. Fig. 11. External genital apparatus of male: a, the two lateral of the three eh it- inous styles which surround tiie projecting intromittent organ ; b, two clusters of spines which seem to be claspers; c, stigmata. Fig. 12. Larva ease, xCr. a, case with the broken operculum inside ; fc, cephalic end, sliowingline where the operculum splits off and the remains of a ceu^ tral orifice through wiiicli nourishment was obtained by the embryo from the parent ; c, caudal end showing the two dots corresponding to the two terminal stigmata. Fig. 13. Larva case with larva, xO: a, ventral view; b, dorsal view. PLffiTE IV Haines, del. MELOPHAGUS OVINUS, (The Louse-fly.) 46 ter. The markings on the under side of the head and the form of the caudal end of male and female seem to differ from others, but these difi'ereuces are unessential for the present description. The form that most nearly approaches it in general appearance is the Trichodecten pilosiis, Giebel, from the horse, but the latter is a relatively larger spe- cies. The species is to be found on poorly nourished young sheep in places where the wool is scanty. A favorite place is betweeu the legs and body, just under the shoulder. Ooarse-wooled sheep are more afdicted with them. The life history of these pests is very simple. The adults lay their eggs on the wool fibers at their base, and a glutinous material sticks them there (Plate V, Fig. G). The eggs hatch out in the wool, and the young louse emerges by pushing oft' the cap (Figs. 7 and 3). The young then grow to be adult. It is most probable that sheep can only get the lice from other sheep, as another host of Trichodectes sphwrocephalus is yet unknown. The presence of these parasites may easily be learned by searching for them or their eggs. Sheep affected manifest their presence by scratching themselves with their hind feet or by rubbing against stationary objects. Disease. — The injury wrouglit b}" this parasite is caused by its life- habits. The injury effected by species of Trichodectes is not as de- cided as that caused by those of Hwmatopimis, the genus to which the true lice belong. The mouth parts of the hitter are so arranged that it can live on the blood of its host, and in biting through the skin it causes an itching sensation and a wound. The Trichodectes, however, are not fitted for penetrating so deeply, and appear to go but little deeper than the epithelium. They can probably bite through to the young growing tissue, for animals which are severely afflicted with these pests have a roughened, scabby skin, which would not be the case if the parasite only lived on the hairs and epithelial debris. The pres- ence of these parasites on the skin not only gives discomfort to the sheep, but causes the skin to thicken, become rough and covered with little dry, black scabs, and the wool to become short, dry, gnarly and worth- less wherever the pests attack the skin, 48 Tkichodectes srH^iaiociiPHALus, N, Platk v. lu Plato- V, tigs. 1, 2, ;?, (J, ami 7, iiiid in Dale YI, lige. 1. 2, :i, f), 11, 12, K^, and 15 are equalJy enlarged, and present relalive diliereuces in size and form. Other parts are also enlarged .similarly for the sake of comparison. Fig. 1. Male, natural length indicated by line. Fig. 2. Female, natural length indicated by line: a, head; b, antenna-; c, face; (7, cheeks; e, c, dorsal sutures; /,/,/, legs; , h, wool li))ers. Fig. 8. Anterior leg: a. coxa; b, trochanter; c, femur; d, tibia; e, tarsi and claws. Fig. 9. Posterior leg. Fig. 10. Head, ventral side: a, a, antenna; h, 6, ventral continuation of dorsal sut- ure; c, c, ventral suture; d, a, mandibles; e, maxilla) showing through the chitiuous gular plate; /, the labrum. Fig. 11. Tail end of male, dorsal view : «, the last segment; fc, the genital orilice; c, chitiuous, hook-like appendages of the genital apparatus. Fig. 12. Tail end of female, ventral view: a, the last segment ; b, the genital and anal orilice ; c, the claspers. PLSTE V 11 vv: Haines, del. TRICHODECTES SPHiEROCEPHALUS, (The Sheep Louse.) /\-Hoe(i & Co, I.iih . B,-.H.'i GOAT LICE. Trichodectes limbatus, Gervais. riiite VI, Fij,^s. 1-8. BescriiHion. — Trichodectes limhatus, Gervais — the Angora louse — re- sembles T. climax closely, but differs in specific details. All the brown markings on T. limbatus are darker and wider; the head is slightly more indented in front ; the dorsal suture (Plate VI, fig. 2 e, e,) is more pronounced; the head is wider in proportion to its length. The banded margin of the abdomen is wider. The greatest difference lies in the disproportion of size between the male and female of T. limbatm, and the character of the transverse bands of the abdomen of the male ; the abdomen of the male being shorter is relatively wider in proportion to its length, and has a quadrangular appearance. The first band is nearly straight and one-third shorter than the three succeeding, which are of nearly equal length and convex anteriorly, concave posteriorly. The fourth and fifth segments bear a second narrow bandnear the posterior margin. The egg of this species is larger than that of T. splucrocepk- alas or T. climax. The marked differences shown between the bands of T. climax and T. limbatus was a constant one in all males examined. This feature, in connection with the difference in size of the eggs, and the many minor differences of form and color, seem to be specific. The males of these s[)ecies seem to offer the most tangible characters for separation. When- ever other species of this genus are described particular attention to the males should, on this account, be given. The females seem to ap- l)roach each other more closely. Occurrence and disease. — The goat louse is common, und causes more trouble to goats than the little red-headed louse does to sheep. When present it occurs among the coarse hair along the back and sides of the goat. It causes much discomfort and scabbiness of skin. If the ani- mals are severely infected they become poor and thin. The Angora goat louse caused, in the single flock in which it was seen, not only a severe scabby skin disease, but a loss of fleece. The whole back, sides, aud head seemed to be completely covered with the parasites, youug and old, and nits. Treatment. — The disease caused by these parasites is of that class which is preventible, and it is inexcusable if it be allowed to continue. The history in each case is that of infection from other sheep, goats, or Angoras, as the case may be. As the parasites spend their whole lives ,«>n these animals they may be killed on theui and not be expected to 23038 A P 1 49 50 come again except from other aniiiials of the same kiiul. Yards, where any of these animals are kept, shouhl be sprinkled with lime and the walls washed vvitli diluted lye, or whitewashed before the animals which have been treated are returned. This will ensure safety from any par- asites which may have fallen to the ground where the goats have laiu. The treatment should be thorough. As these animals are small the best method is to immerse them in tobacco water, thus insuring the de- struction of every parasite and nit, even those on the nose, by immers- ing them while holding the nostrils. If the hair is long on the Angora they should by all means be sheared. If it is not desirable to tlip them, the selected remedy may be sopped on the skin and wool and thoroughly rubbed in so as to wet the skin. Medicines may be applied in three forms: in powders, as pyrethrum or Persian insect powder, and tobacco dust; iu ointments, as oil or lard, with some added ingredient, and iu baths, as the tobacco or arsenical dips. Of these the first is the more objectionable and the least vahiable. The second is better, but not entirely successful. The third is the one which should be used in the majority of cases, as it is the most certain. The following recipes are among those iu use, and are recommended by various authorities : A decoction of stavesacre seeds, 3 ounces to 2 quarts of water, to be thoroughly rubbed in. (Neumann.) A decoction of stavesacre seeds, 1 ounce to 1 quart of water or vine- gar, or half water and half vinegar. (Finlay Dun.) In powders, tobacco, pyrethrum, stavesacre aud sabadilla may be used, but the last two are not advisable. Benzine 1 part, soft soap G parts, water 20 parts, or petroleum (kero- sene) 1 part, sweet oil 10 parts. (Neumann.) Schlegs' mixture is recommended in Germany for its efficacy and liarmlessness when prudently used. Arseuious acid one-half ounce, l)otasli one-half ounce, water 3 pints, vinegar 3 pints. (Ziirn.) The most eflicacious remedies are the tobacco, or the tobacco and sulphur dips, advised for scab. For flocks of large numbers, nearly all other recipes are unavailable. Mercurial salves should not be used. Ziirn advises tobacco 1 part, water 20 parts, or water 20 parts and vinegar 10 parts, to be made into a decoction, and vinegar added after cooling. Tlie kerosene emulsion may also prove a valuable remedy. It should be applied as directed for exterminating sheep-ticks, or by meaus of a force-pump and spray-nozzle. TEICnODECTES CLIMAX, Nltzsch. Plato VI, Figs. 11-18. The common goat, Gapra Urcm^ L., is quite coinmouly infested by a species of louse which has been identilied by the writer as Trichodcctes climaxj Nitzsf'.h, and the Angora goat, Capra hlrcusy var. Angorciisis, by 51 one wliicli seems to be Trichoflecfes llnibatus, Gervais, or T. climax, var. major, Piaget. The uaiiie applied by Gervais is accepted, for the dififer- euces between the two appear to be specitic and not varietal. Description. — The characters of Trichodcctcs climax are : Head wider thau long, quadrangular, presenting a wide but shallow indentation in front, at which the two antennal bands stop; antennte hairy, a little longer with the male than the female ; the first joint is larger and shorter than the others ; the second longer than the third ; the abdomen bears median spots, the width of which diminish as their length in- creases. The last segment of the male carries two hairy cushions. Head and thorax, reddish-brown ; abdomen, pale yellow ; spots, brown- maroon; bands, blackened. Length, female, 1.6"^'" ; male, 1.3'"'". (Neu- mann.) The female of this species is broader and the male a little shorter thau in the corresponding sexes of T. sphwroceplialus. The dorsal sutures of the head are much darker and plainer ; the edge of the head and ad- domen are margined by a pronounced dark band. The differences between the anterior and posterior feet are much more decided. The dark bands of the back of the abdomen of the male seem to offer the best characteristics, viz : They gradually increase in length to the fourth, when they begin to narrow. Beginning next the thorax the first band is narrow; the second, third, and fourth are wider; the succeeding are narrower ; posterior to the line of hairs on the second to the fifth seg- ments are extra narrow bands, which are about equal iu width. The egg of this species is shorter and narrower. 52 TRICHODECTES LIMBATUS, Gerrais. Plate VI. Fig. 1. Mule, natural length indicated by line. Fig. 3. Female, natural length iudicated by line : a, head ; h, antennie ; c, clypeus ; d, cheeks; e, e, dorsal sutures; /,/,/, legs; g, xirothorax ; h, nietathorax ; I, abdomen; k, k, dark trausverse bands; I. I, lines of hairs; m, m, breath- ing pores; n, male genital orifice; o, female genital orifice; ^>, female claspers; q, male genital hooks. Fig. :?. Head, vcutral view : a, antenna3 ; h, mandibles. Fig. 4. Posterior end of female, ventral view: a, genital and anal orifice; h, claspers. Fig. 5. Egg: fl, the cap; ft, the line where it splits oft". Fig. 6. Antenna of female. Fig. 7. Anterior leg: a, coxa; h, trochanter ; c, femur; d, tibia; c, tarsi and claws. Fig. 8. Posterior leg. Trichodectes climax, N. Figs. 11 to 18. Numbered and lettered for the same parts as Fig. 1-8. PLffiTE VI Haines, del. A. Ri>eri & Co. l.iUi . Ba TRICHODECTES LIMBATUS, (The Angora Goat Louse.) TRICHODECTES CLIMAX, (The CommoQ Goat Louse.) THE ITCH OR SCAB INSECTS-ACARIASIS-ITCH-SCAB. Sarcoptes, Latr. ; PsoROPTES, P. Gerv.; Chorioptes, p. Gerv. Of all the diseases caused by external parasites those due to the scab- makiug' iusects are of the first importance. The losses due to them are very heavy, aud are exceeded by those of no other external parasite, and equal those of the most destructive of internal parasites. Owing to the means used in preventing flocks from becoming infected, aud to the extermination of the pests by the proper use of efficacious remedies, these losses are annually becoming reduced. It is to be hoped that in the near future, through the exercise of proper sanitary laws, this most tractable of all the parasitic diseases may be completely exterminated in our country. Scab is a disease due to the presence of minute insects which lead a parasitic life on the skin of their hosts. Jt is caused by the inflamma- tion they excite in penetrating the skin, that they may procure food for themselves and young, and suitable conditions under which the eggs may be deposited and hatched and the young matured. The disease is thought by some to be aggravated by a poisonous fluid secreted by the insects, which adds to the intense itching. The malady proceeds step by step with the growth, propagation and decay of the innumerable insects which result from the acquisition of a single fertile female or a few pairs of individuals, and the spread of the disease, therefore, coincides with an increase in the numbers of the par- asites, while the limitation of the disease follows their extermination. There are at least three different species of scab-forming insects, parasitic on sheep, and each species is not only specifically different from the other, but the disease caused by each is different. This is due to the variation in the anatomical structure and habits of life in the several species of these pests, which causes them to attack the skin in different places and by different methods, and hence gives rise to the various symptoms common to each disease. These insects are known as Acari, and the tliseases they cause as acariasis. The various species parasitic on sheep are Sarcopfes scahiei, de Geer, var. ovis; Psoroptes communis, Fiirst, var. ovis; ChoriojHes communis, Verheyen, var. ovis. Of these the Sarcoptes causes scab of the head ; Psoroptes causes common vscab, and the Chorioptes foot scab. The life history of these parasites is in general very similar. They attack the external skin of the animals in which they live by biting it. Soon after scabs are formed. Under these scabs the insects lay their 53 54 ovoid eggs. After two or three days these eggs hatch, and in fifteen days the progeny become adult. Each adult female is estimated to lay about tifteeu eggs, two-thirds of which produce females. When hatched the young invade new territory and lead the life of their parents. The ex- tensioQ of the invading hosts is due to their migration and rapid propa- gation. The disease usually siH'eads as a constantly growing patch. The infected sheep sometimes scatter the scabs by scratching ; these, in turn, become new centers of infection. The multiplication of thii invading pests ceases only at the death of the host, or when thoy are killed by the use of proper remedies. To illustrate the rapid increase of the tH'^arcoptes, Gerlach. a scientist, computed that in three mouths a single female would produce 1,500,000 progeny. He esti- mated that each adult female laid fifteen eggs, of which ten were females, and that the eggs became adults in fifteen days. The result is shown in tabular form as follows : First <;eiicratiou after 15 days produces. Second 30 Third 45 Fourth GO Fifth 75 Sixth 90 Fomales. Males. 10 \i 100 50 1,000 500 10,000 5, 000 100, 000 50, 000 ,000,000 500, 000 This table presents a ver^^ moderate estimate of the rate of propaga- tion. A microscopic examination of minute particles of scab shows them to be teeming with young and old parasites, and would seem to confirm the estimate given. As but few of the parasites may be trans- ferred to a healthy animal, it is evident that up to the second month but little advance in the disease will be noticed, but after that tiuie the tenfold increase ev^ery two weeks produces an enormous number of the parasites and causes the disease to advance with wonderful rapidity. THE HEAD SCAB. Sarcoptes scabiei, de Geer, var. ovis. Description. — The insects which cause this variety of scab are almost invisible to the unaided eye, and are among the smallest of the scab- making insects. They are known as iSarcoptes scabiei, de Geer, vai-. ovis. They may be recognized by their rounded or somewhat oval bodies, their small heads, which are furnished with a biting apparatus, and by the adult having four pairs of legs. The young have but three pairs of legs. Other anatomical characters, which are different in differ- ent species, are present, but for the flockmaster these are unessen- tial, as the species can be separated by biological characters which are plainer and easily understood. Disease. — Flead scab begins on the upper lij), and about the nostrils ; more rarely it may show itself for the first time about the eyelids and 55 ears. Ill these places there is less hair and grease, affording the pests better opportnnities of getting at the skin. From these starting-points the scabs spread over the forehead, cheeks, eyelids, and occasionally over the space under the jaw. In badly infected sheep the disease may sometimes extend to the fore limbs, under the belly, around the joints, and especially between the folds of the knees, hocks, and pasterns. Sheep with coarse dry wool are more likely to suffer this extended invasion than those, with tine, oily, and soft wool. Long wool seems to offer a barrier to its progress, for the invasion of parts covered by short wool is much more rapid. The demarkatiou between the inv^aded parts of the head and the healthy wool-bearing portions is quite abrupt. In coarse-wooled breeds the disease may rarely cover the entire body. The first indication of the disease is shown by the sheep in rubbing or scratching its head. The intensity of the itching is manifested by the violence of the sheep's action. The first that can be seen ou an infected spot is little elevations with soft centers. These elevations break of themselves, or through the rubbing they receive, and from them runs a watery fluid that in drying forms little hard buuches which stick to the skin and adjacent hairs. These little elevations are made by the parasites, which sink themselves into the skin. Here the parasites find suitable food, grow and produce their young. These migrate and pene- trate into the skin as did their parents. Thus the disease spreads slowly as the parasites increase. Finally, as they become more numer- ous, they cover the invaded skin with a thin layer of scabs. As the disease advances the little scabs not only run together, forming one mass, but they become thicker, whitened, and hard. Later they run together over the nostrils, lips, face, cheeks, forehead, eyes and ears, and form a dry, hard, thick, scabby mass. By repeated rubbings this scab breaks up, and the skin tears, cracks, and bleeds. Later the wounds heal and scars are formed. When the scabs cover the eyelids the latter close up and the animal becomes practically blind, being uu- able to find its way or to see food. The insects are to be found in the moist layer underlying the scabs. Source of contagion. — The insects which cause the disease have been derived from other sheep with which the recently infected flock may hav^e come in contact, or which may have left a few parasites ou some brush or stick, or in some trough with which the uninfected flock came in contact. The methods of infection are various, but he who under- stands that these parasites always come from some where else, and always from some infected flock, will soon learn what to do to prevent his sheep from becoming infected. The variety of Sarco2)tes parasitic on sheep is similar to the variety living on goats, and it has been ex- perimentally proven that each variety may be transferred and will live on either animal. Some of the varieties living on other animals may be transferred to sheep, but they do not thrive. It is not at all prob- able, therefore, that sheep are infected from other animals than sheep. ,56 Diagnosis. — Head scab can not well be coiifoiiiuled with any other variety of scab. The seat of the disease and the presence of the para- site, which is scarcely visible to the unaided eye, are sufficient to defi- nitely diagnose the raalady. Prognosis. — This variety of scab is one of the most amenable to treat- ment. Being mostly on the head it is easy to reach with remedies. If treated it will prove of little loss to the flock-master, whileif allowed to take its course it will continue for a long period, gradually growing- worse and rendering the patient more and more unsightly and ill-fa- vored. It can cause severe inflammation of the eyes and ears. It can hinder the fattening of the animal and cause extensive alterations of the tissues of the skin. By affecting the health of the sheep, it will not only decrease its weight but materially lessen the amount of wool pro- duced. Medical treatment. — The worst feature of treating the disease is, that treatment for a complete eradication seems to be extreme and out of proportion to the end to be attained. Curative treatment always yields good results when the application is rational. In the early stages of the disease, when the scabs are just formed, simple applications of scab dips or ointment are all that are needed; in cases of longer standing it will be found necessary to first soften and loosen the scabs with some kind of grease ot oil, and then to removethem with some alkaline solution or soap. The thin oils (sweet oil) that penetrate are the best. The wool adjacent to the scabs should be cut away so as to allow the remedies to get at the newly affected portions. COMMON SCAB. PsoROPTES COMMUNIS, Fiirst., var. ovis. Plates VII and VIII. Common scab is caused by an insect known as the scab mite or itch insect— Psoro/>/es communis, Fiirst., var. ovis. This insect is much larger than the Sarcoptes, which causes head scab, being visible to the unaided eye. Disease. — Of all the diseases of sheep in this country, scab is the most feared by the tlockmaster. So insidious is its attack, so rapid its course, so destructive its effects, and so difficult is it to exterminate that it has justly earned the distinction of being more injurious than any other disease caused by external parasites. Scab alone, of the par- asitic diseases, has become the subject of legislation in most countries, and yet, if proper precautions were taken and a rational treatment fol- lowed, this disease could soon be completely eradicated. Early symtoms. — Attention to the disease is first attracted by the in- fected sheep scratching, biting, and rubbing theniselves. The coats of the animals look rough, taggy, and felted. The itching is always most violent wben the sheep have been heated by driving or Warming in a stable. Pathology. — By separating the wool and examining a recently infected spot, there can be seen some minute elevations, which differ from the surrounding skin in being slightly whiter or yellower, and which have been produced by the bites of the pests. The insects themselves can be found among the hairs at but little distance from the bites. As time l)asses and the insects multiply in numbers these elevations become more and more numerous, and closer and closer together, until they finally unite over a considerable extent. From the summit of each eleva- tion or papule, a watery, serous fluid exudes and accumulates, which transforms them into vesicles and pustules, and which in drying cover them over with a thin crust. In a few days the whole surface is cov- ered with a yellowish, greasy, scaly layer, under which the parasites are hidden. As the disease i^roceeds this layer gradually increases in thickness by an increase of the serous exudate, and in circumference by the extension of inflammation produced by the ever-multiplying par- asites which live beneath it, forming scaly crusts. These crusts, in be- ing torn out, mainly by the rubbing with which the sheep endeavors to allay its intense itching, carry with them the lags of the wool, the loss of which is an early symptom of the disease. At a later period the crusts are replaced by another set of thicker, firmer, adherent scabs, which are still further enlarged by the outward migration of the para- sites. As they abandon the center of the scabs these are again replaced by a peeling off of the external layers of the skin, which gradually heals, while the disease slowly progresses at the outside. The complete cure is very slow, and the skin remains thick and folded for a long time. In sheared sheep the skin becomes covered by a thick, dry crust, like jiarchment, while beneath it remains much swollen. Late symptoms and di'if/nosis. — The fleece of scabby sheep presents a characteristic rough look. In places the wool is stuck together in masses; in others it fails, while in others, which are apparently sound, it can be easily plucked oft'. The rubbing and scratching indulged in by the sbeep not only tend to tear away the wool but increase the irritation of the skin, which may become intensely inflamed and swollen and finally eiul in a superficial death of the part. Unlike Sarcoptes^ the Psoroptes seeks the longest, thickest wool. It begins its attack along the back and extends to the neck, flanks, and rump. The Psoroptes are rarely found in the region of the chest and abdomen. They are collected in masses on circumscribed surfaces. The scabs they produce constantly increase at their edges, aud their number depends on the number of places invaded. Owing to the closeness in which sheep con- gregate and to their violent scratching the parasites become very gen- erally scattered and finally the scabs may run together. While few of the parasites are present in the older diseased parts, at the edges of the scabs they can be found in swarms. They look like 58 little white points. with a browiiisli extremity. If picked up by the point of a knife or a sharp stick and placed on the hand they will bo seen to move. The six-legged young, the eight legged adults, the sexes, couples joined together, and the eggs of this interesting insect can easily be identified by the aid of a low-power magnifying glass. Prognosis. — Tlie disease is favored in its advance by the seasons in which the wool grows longest, and in which the sheep are brought into closer contact in sheds. Autumn and winter are the most favorable for its spread and rapid advancement. In summer, and especially after shearing in spring, the disease makes little, if any, headway until the wool has grown to a considerable length, ^ge, temperament, state of health, energy, and race of the animals, the length, fineness and abun- dance of fleece, and the hygienic surroundings have much influence on the advance, progress, and termination of the disease. The young, the weak, the closely in-bred, the long coarse-wooled sheep, and those sub- jected to bad climate, to unhealthy localities, to ])oorly constructed, illy- ventilated sheds, are all more subject to the rapid advances of the disease. Ou the other hand, healthy, well-fed, well-housed sheep may withstand the ravages of the disease for mouths. When left to itself scab causes severe disturbances of the functions of the skin, and on account of the intense itching brings on fatigue, through loss of rest and sleep. Marasmus and cachexia preceding, death may come to weak, iU-nourislied subjects in two or three months. The mortality due to scab varies much, depending on the season, gen- eral health of the flock, food, shelter, and a variety of other factors. It is most disastrous in autumn and winter among sheep poorly fed and housed, and of weak constitutions. Many otherdiseases may intervene and carry ofif the weakened animals. The death-rate is not the only occasion of loss, for whether the shepherd keeps his flocks for mutton or wool he will find a loss in either, depending much on the severity of the dis- ease. Ewe5 weakoiied by the disease will remain infertile, abort or pro- duce but weak and feeble lambs, which will eitiier die or scarcely be wortli the rearing. To this loss must be added the decreased value of the wool obtained from the first shearing after a recovery from the at- tack, due to the mixing of the ends of the old wool with those of the new, known as the double ended wool. This mixture lessens the value for manufacturing purposes. Source of contagion. — Kemembering that common scab is caused by insects which the infested flocks are continually spreading broadcast by dropping tags of wool by the wayside, by leaving them attached to brush, by rubbing posts and fences, it is easy to realize that there are many methods of transmitting the malady. Experiments with these insects have shown that they can live at a moderate temperature ou a piece of scab from ten to twenty days; that they may live after being subjected to intense cold; that they die more rapidly when they are in contact with animal matter at freezing temperature, and that they die 59 soon if tliey remain exposed to alternating high and low temperatures. These experiments show that the Psoroptes can live about the sheep sheds, yards, corrals and fences during twelve or fifteen days, at least, after they have separated from the sheep. Although this species of parasite is but a variety of the Psoroptes communis^ of which the Psoroptes parasitic on horses is another variety, the latter has not yet been made to grow on sheep experimentall}'. It is not probable that either of the varieties parasitic on cattle or rabbits would thrive on sheep. That is to say, so far as is now known, sheep are infected with common scab from other sheep, ond can not acquire it from other animals. On the other hand, the ovine variety of Psoroptes has not yet been found to growou other species of our domestic animals. Differential diagnosis. — Psoroptic, or common scab, is different from Sarcoptie or head scab, in that the former chooses to live where the fleece is longest, and the latter where there is little or none at all — the one on the back and sides, the other on the head and occasionally on the nether parts; the one is almost invisible to the naked eye, and the other is plainly seen, though small. The itch due to other parasites, such as sheep ticks and sheep-lice, can be easily separated, because they are large and can be found in the wool. Sheep are sometimes subject to an inflammation of the sebaceous glands. In this, however, there will be no parasites of any kind found. Prognosis. — Scab, as has been said before, is one of the most dreaded diseases of sheep. For the flockmaster who has but few sheep, say fifty or a hundred, the task of treatment and eradication of the scab from the flock is no easy afiair ; but for him who owns from five to twenty thousand the difficulties to be met are enormously increased. Though the disease may be easily tre'ated as far as a single sheej) is con- cerned, still the treatment would only be- palliative and would not as- snre the flockmaster that the disease would not break out again. Treatment, therefore, of a flock in which scab has appeared must be applied to every individual exposed and to the corral and sheep-pens in which they have been lodged, and is not only a serious time-consum- ing affair, but a most expensive one. Treatment. — This is of two kinds — preventive and curative. The preventive treatment, is undertaken before, during, and after the curative. Indeed, if the flockmaster exercises proper care his flocks will never require the curative treatment, for the disease always comes from transference of the insect. Preventive. — An infected flock should be quarantined so that it shall not transmit the disease to other flocks, and should be kept from public highways where other flocks may pass, until it can be thoroughly cleansed and cured. The sheds, yards, and corrals where they have been kept should also be cleansed, so that they may not transmit the disease. After treatment begins the sheep should be transferred to a temporary uninfected yard, so that the old yard may be thoroughly GO (iisiufected by carting away the soil to some safe spot, by washing all the wood-work as high as a man's head with a solution of boiling lye,* and afterwards covering it with a coat of whitewash. All old pelts which could harbor the insects should be burned. Every possible se- creting place for the insects should be overhauled. After a thorough cleansing the yards should be left vacant for three weeks. After the dipping the sheep should be driven into fresh, clean yards, and not into such as have not been sutticiently cleansed. If possible they should be kept from infected pasture ranges for three weeks, by which time all parasites which nuiy have dropped from them may be considered as dead. Sheep which have been dipped in any of the tobacco preparations can be, so it is stated, driven on the ranges im- mediately after dipi)ing with impunity, as the tobacco odor keeps the insects away. Any sheep which may have died on the range should either be buried deeply or burned. In dipping extreme care should be taken by all who handle sheep not to transfer the pests from animal to animal. Medicinal. — There are two methods of treating sheep for scab. The one of rubbing j^oisonous ointments and oils into the fleece by the hand is the oldest and least used. It is slow, tedious, and unreliable, and has been superseded by better methods. The other consists in immersing sheep in watery mixtures which will kill the parasites. This method being cheaper, quicker, and more eft'ective, is the one in general use in this country. The formuhe used and the methods of applying them vary in different portions of the coun- try according to the needs of the sheep-owner. In the East, tubs large enough to hold sufficient of the dip to com- pletely immerse the sheep, and liettles or cauldrons of a capacity to heat the required amount are used, but in the range country of the West, where thousands of sheep are to be treated, especially made dip- ping pens and tanks through which the sheep may be driven, and large boilers made for the purpose, are used. Each method is adapted to the needs of the respective localities. Although some dips are fairly eflect- ive when applied to sheep with their Heeces on, the dipping should, as a rule, be preceded by shearing. This rule should be violated only on account of season. If any of the flock are infected all should be sub- jected to treatment, otherwise the disease will be carried along and break out from time to time. The shearing should take place in a shed where all the wool can be cared for, and either i)oisoned or destroyed, or so safely stored that it could by no possibility scatter the insects. Any treatment undertaken without being preceded by shearing can at best be considered as ]>ailiative. The object of the treatment is to kill the parasites and their eggs. The parasites are killed by the direct application of a poisonous dip. The eggs have a thick shell which often resists the effect of the poison, * Use 1 part of p<)ta«li to 200 of water. 61 and the young parasite emerges in due time. They are then subjected to a second dip some six or ten days afterwards, at wbicli time it is pre- sumable that all the eggs have hatched and none of the young have be- (iome adult. If the second dip is delayed much longer than twelve or fourteen days, some of the newly hatched larvic may have become adult and laid eggs, which may in turn hatch larvte, and become new centers of infection. All dips, to be effective, contain some ingredients which are poisonous to the parasite. This poisonous element may also, if used in too con- centrated a solution, be iioisonous to the sheep, but this is to be avoided by using the dips in the exact proportions of the formula given and maintaining these proportions throughout the treatment. In addition to the poisonous element, a dip may contain other elements, as water to Fah.), in which 3 pounds soda has been dissolved. Use it at a temperature of 80° or 90° Fah., and repeat in six or seven days. There are three arsenical dips favored by European authorities, the last of which might be used while exercising proper care and precau- tion. The solution should always be kept as dilute as the formula calls for. The sheep should not be allowed to drain on the grass, but should be kept up until nearly dry, and the laborers who dip should grease their arms with linseed-oil before beginning work. Tessier's dip, the oldest, was proposed in 1810. To make a mixture for one hundred sheep, take arsenious acid 3 pounds, sulphate of iron 20 pouutls, and water 190 pounds ; boil. Tessier's dip causes a discoloration of the wool, which can be removed by washing with soap, but it is on this account more or less objectiona- ble, and to overcome this objection C16meut has modified it as follows: Arsenious acid, 1 part; sulphate of zinc, 5 parts; water, 100 parts. The water is put over the fire, the medicinal substances added, and it is allowed to boil for eight or ten minutes. After the temperature has fallen to the proper degree it is ready for use. The sheep is entirely submerged in the liquid, with the exception of the head, the udder of ewes suckling their young having beeu previously covered with some fatty substance to prevent the action of the astringent on the skin and on the secretion of milk. Matthews dip : Take arsenious acid 1 part, alum 10, and water 100 parts. Scheurle and Kehm's dip : Take arsenic 1 part, alum 12, and water 200 parts. This latter is weaker than the former, and therefore safer. Moreover, it is claimed to be as effective. The sheep dips that are put upon the market are objectionable for three reasons: First, their formulas are not given; second, the preparation may be valueless, or if not valueless of insufficient strength ; and third, the preparation may cost more than it is actually worth. Should the dip be put up by reliable houses, and have their formulas i)riuted on the outside of the package, the prepared article might prove better compounded and absolutely cheaper than the llockmaster could pre- pare it. Police sanitation. — It is not sufficient that the flockmaster thoroughly cures his flock, disinfects his sheds and quarantines his place. Another duty awaits him, and that is a public one. All flock-owners should unite and assist the State in improving and carrying out its sanitary laws. Nearly all States have laws regarding the suppressing and quarantining of sheep infected with scab, but they seem to lack in stringency and are therefore inadequate. Laws compelling strict quar- 65 antine and public supervision of the treatment, at the expense of the owner, even though it is undertaken by the State, are demanded for the complete eradication of the disease. With such laws no one could long harbor on his premises a disease which constantly threatens the tlocks of his neighbors with destruction and their owners with financial ruiu. FOOT SCAB. CiioRioPTES coMMur^is, Verheyen, var. ovis. This variety of scab, which is due to Chorioptes communis, Verheyen, var. ovis, is of rare occurrence. It has been noticed and studied in Ger- many by Ziirn. The seat of this disease is in the feet and limbs. The disease pro- gresses very slowly from the feet, and little by little invades the upper parts of the limbs and adjoining parts. It is not readily communicable to other sheep and spreads slowly. In the beginning this variety of scab is characterized by the redden- ing, followed by an abundant scaling of the skin, and later by yellowish white crusts. The animals stamp, scratch, and bite the parts, showing an intense itching. As the disease progresses the crusts become thicker; cracks may form in the folds of the pastern and the limbs become quite unsightly. The parasites swarm beneath the crusts, and when found form a certain symptom of the character of the disease. Foot-scab is not a serious malady, as it readily yields to treatment and is of slow extension. Any of the remedies proposed for the treat- ment of common scab may be used with good efl'ect. 23038 A p<=— 5 m PSOEOPTES COMMUNIS Furst., Viir. OVIS. Plate VII. Fig. 1. Adult male, dorsal view : a, head ; b b, legs; cc, suckers. Fig. 2. Adult nuile, ventral view. Fig. 3. Adult female, dorsal view. Fig. 4. Adult female, ventral view. Note.— Figs 1 to 4, Plato VII, and Figs. 1 to '^, Plate VIII, are equally magniHed. PLSTE VII .?■- Haines, del. PSOROPTES COMMUNIS, Var OVIS, (The Common Scab-Mite.) A.Kcirn&Co, r.il 68 PSOROPTES COMMUNIS Furst.. var. OVIS. Plate VIII. Fig. 1. Young female before moultiug for the last time. Fig. 2. Egg drawn from a specimen whicb was inside an adult female. Fig. 3. Young six-footed larva. Fig. 4. a, open, and h, closed sucker of Psoro^j/es from ears of rabbit; c, the rod which connects the membrane on the entl with the muscles which close the sucker. Fig. 5. Two views of the mandibles. The lateral spurs, a, a, point outward (Meguin). Fig. 6. Head and anterior limb enlarged; ventral view: a, mandibles; 6, antennae; c, maxillaj; d, membrane joining the anteunaj ; e, e, e, joints of the limb; /, the claw ; g, the ambulacrum or sucker. Fig. 7. Male and female of Psoropta communis var. equi (Megnin). PLATE VIII Haines, del. ..Kowti&Co. r.ilh. Bxll PSOROPTES COMMUNIS, Var OVIS, (The Common Scab-Mite.) THE PENTASTOMA. LiNGUATULA TyENIOIDES, Rud. See Plate XVII, li<;s. 1-6. Linguatulatamioides \s also known under the names Linguatula rhi- 7iaria, Pilger, and Fentastoma ta'nioidcs, Rud. In describing- this parasite, Neumann's excellent description in Traite dcs Maladies Parasitaires, page 491, has beeu taken as a guide. The species is probably present in this country, as iu two instances the larval form known as Pentastoma denticulatmu has beeu found. The larviB were found by Dr. F. L. Kilborne, of this Bureau, iu a rabbit, some time in the summer of 1887, and once by myself iu another rabbit in 1888. This curious parasite is classed among the Arachnids, being more closely related to the spider and mite family than to any other. The order Linguatulidce, to which they beloug, is thus defined : Eudoparasitic arachnids with elongate, vermiform, annulate body. Mouth want- ing jaws in the adnlt state, and surrounded by two pairs of hooks representing rudi- mentary feet. No heart. Respiration cutaneous. In it are two genera: (1) Lingua- tula, Frohlich, which has the body depressed with dorsal face rounded and with the borders crenulated. The cavity of the body forms diverticula in the lateral parts of the rings. ("2) Pentastoma, Rud., which has a cylindrical body and the cavity of the body continuous. It is not represented in our domestic animals, unless it be a lar- val form found once in the peritoneal cavity of a dog. Description. — The species met with in the domesticated animals has the following characters : Body white, lanceolate, very elongate, worm-like, depressed dorso-ventrally with the ventral face nearly plane and the dorsal face convex. Anterior extremity rounded, large ; posterior extremity attenuated. Cephalo-thorax short, solidified in all its width to the abdomen, from which it is scarcely distinct, and which forms by far the larger part of the body. Integument showing about ninety rings, larger in their middle •, these make the borders of the body crenulated. Hooks acute, re- curved, twice-jointed, the basal joint attenuated in its deep part. These hooks, each retractile in a pocket, are moved by muscular bundles which act in opposite direc- tions. Mouth sub-quadrangular, rounded at the angles; digestive tube simple, rec- tilinear; anus terminal. Male, white: length from 18 to 20'"'"; width, in front, 3'""' ; behind, 0.5""'", provided with saccular testicles which fill the body cavity even to the anterior fourth. Female, whitish grey, often rendered brown by the eggs along the median line where the integument is thin and semi-transparent; length from 8 to 10'^'" ; width, in front, from 8 to 10""", and behind, 21""'. Eggs ovoid ; length, O.Og""'" ; width, 0.07™'". Life history. — The female Linguatula tceyiioides lays its eggs iu the nasal cavities of the dog. These are scattered on the ground and grass 69 70 where they lie until eaten by some herbivorous animal. The shell is theu dissolved from around the embryo, nnd it bores through the walla of the stomach or intestine into the mesenteric s'bmd, liver, or lung, where it encysts itself. In its first stage of active migration tlie larva resembles the Acari (Plate XVII, Fig. 4). It has an ovoid body, flat- tened on the ventral face, rounded on the dorsal. Its posterior extrem- ity is narrowed and dentate. It is furnished with two pairs of articula- ted, two-clawed feet, and at its anterior end by a perforating apparatus formed of a median stylet and two recurved hooks. Its length is 0.13"""; its widtli ().()(>""". Having arrived at the mesenteric glands, the liver, or the lungs, as the case may be, the embryo loses its feet and is transformed into an im- movable pupa (Fig. 5), without segments, hooks, or hairs, measuring 0.250 to 0,300""" long, and 0.180""" in width. It emerges from this cyst trausformed iuto another larva, by .1 aeries of successive moults (see Fig. (J). The body is elongate, larger forward, and is divided into eighty to ninety rings bordered behind by a series of line spines. The digestive tube is large, tlie moiitli is elliptical, and surrounded with four characteristic hooiss and with accessory hooks. Tiie larva is agamic, its genital organs being rudimentary and rep- resented only by a little granular mass in the posterior part of the body. Towards the sixth or seventh month the larva is completely developed, measures (> to H""" long, and is iu the stage called LinguatuJa dcniicnJata. These larva? having escaped from the cyst, fall iuto the serous cavities and remain there for some time. They eventually escape, but the precise method is iinkuowu. Next they are seen iu the uasal cavities of dogs. Exceptionally, so it is said, they are found in the nasal cavities of sheep aud cattle, iuto which they have waudered. These larvtc can acquire their full development only iu the respiratory passages. Ouce installed iu the uasal cavities they develop iuto egg-bearing adults. Tlie males wan- der and can be found at various points of tiie cavities, but the females are more sedentary, and are never fonnd iu the etlnnoidal cavities. After tlie death of the host they may travel into the pharynx and larynx. They excejjtionally introduce themselves iuto the frontal sinuses. They are generally found at the bottom of the nasal chamber. As the adult stage is not usually found in sheep, and as its occurrence is problematical in this country, the disease it causes will not be con- sidered in this volume. Disease. — The young state, Linguatnla dentictilata, found in cysts within the glands, etc., are said to be particniarly frequent in sheep in Enrope. Sheep in which the parasite affects the mesenteric glands are generally less fat ; their flesh is paler, and they are apparently predis posed to an;emia. These glands show no evidences of the [)arasite at first, but later they grow browner, smaller, aud are crossed by galleries filled with larvae. These cavities are separate at first, but finally com- municate ; the substance of the gland is destroyed aud transformed into a brown tumor, in the middle of which are the TAngnatuhv. From these the parasites often escape through openings with irregular borders; at other times the surface is covered by dark, irregular spots, fibrinous de- posits, and false membranes, which indicate a recent departure or a de- 71 struction of tlie embryos. At hist the tissue is found thickened, indu- rated, and offers here and there tuberculoid grains formed from the old nests of Linrjnafniw. These altered glands are destroyed and are of no further use in nutrition. The larvne create further troubles in their mi- grations, but so little is known about these parasites that little can be said. There is no treatment. Prevention is also difficult. If it should be learned that we have these parasites here in considerable numbers the best remedy would be to remove the dogs, which are certainly the cause of large numbers being' scattered in Europe. IMMATURE TAPE- WORMS-BLADDER-WORMS. Plates IX, X, aud XI. Besides the adult tape-worms tbuud in the intestines of sheep, there have been four otlier species described which infest various portions of these animals in their immature stager;. These species are Tamia mar- ginata, Batsch. T. coenurus, Kiich., T. echinococcus, v. Siebold, and T. tenella, Cobbold. The forms found in sheep were first; described as Gysticerci, and have since been known as Gysficercus tenuicollis, Coenurns cerehralis, Echinococcus and Cystlcercns ovis, respectively. All these species resemble each other in their anatomical structure, their growth, and their life history. They differ in minute structure, in invading different portions of the sheep, and in the effects they produce on the animal. Tcvnia marginata is more common in the United States, and T. coenurus next. Neither of the other two species have been found in sheep in this country. TAENIA MARGINATA, BatSCh. Plate IX. Tcvnia marginata occurs in sheep as a little semi-transparent bladder filled with liquid, varying from a very minute size to a bag an inch or more in diameter, but usually having a diameter of a half or three- quarters of an inch. Occurrence. — This taenia, in its cysticcrcal stage, is usually found be- tween the layers of the serous membrane which form the omentum, or '•caul" of the abdominal cavity. It may be found in the liver, espe- cially within a week or two after the infection of the sheep by it. A very common place to find it is between the folds of serous membrane which suspends the intestine in the pelvic cavity. When one of these little fluid-sacs are found it may be cut out, with the surrounding tissue for examination. Afterwards great care should be taken in dissecting the serous tissue, which forms an outer sac, so that the cysficercus within shall not be cut, its contents allowed to escape and its walls to collapse. Diiscription of cystic stage. — The smaller bladders are apparently com- posed of a semi translucent whitish membrane, at one end of which may be seen a whitish thickening. As the bladders grow the walls become slightly thicker and the spot at the end becomes much larger and pro- jects in the form of a knob, 72 73 When the animal is placed iu a saucer of lukewarm water immedi- ately after its removal from the slaughtered sheep and examined, it can, by the aid of a low-power lens, be seen to possess considerable peristaltic movement. This movement is produced by bundles of muscles lying at right angles to each other, which may be seen appear- ing as a faint striation on the surface. The little knob end of the bag is its essential part, and contains what is to develop into the future Utnia. Sometimes the animal will extend this knob into a cone, and finally thrust out of its center the very tip of the cone. By careful handling this so-called head end may be squeezed out by the fingers. The tip, when examined by a magnifying glass, can be seen to possess four cup-like spots, with a little glittering circlet of hooks between them at the very apes of the cone. Life history. — When these cysts have attained their hooks and cups in a well developed condition, they are ready for transplanting into another animal or host. The cysticercus completes its development in about eight weeks. It may live a long time after this, and its cyst enlarge, but the modifications it may undergo are unessential. The host within which the cysts or cysticerci generally develop is the dog. They may, however, also develop in other carnivora, such' as the wolf or coyote. Their emigration is a i)assive one. They remain encysted where they are found until the sheep is slaughtered and the dogs eat the offal, or until the sheep is killed by a dog or wolf and its liver is torn from its place and devoured, together with any of the cysticerci which may be attached. Having gotten into the intestines of the host the parasite completes its development, becomes adult, and finally jiroduces young, which pass from the host along with the ejecta of the intestines. The young at this stage are egg-like. They are very small and hardly visible to the naked eye. When viewed with a glass they are seen to be a minute, jelly-like mass, furnished with six hooks and sur- rounded by at least three membranes. The outer is thin and filled with fluid ; the inner two more closely surround the embryo, and confine be- tween them an oily material which serves to protect it when exposed to the atmosphere. After passing to the ground these embryos in some way, possibly by adhering to food or by floating in drinking water, make their way into the sheep. When they arrive in the abomasum, or fourth stomach, it is supposed that the gastric juice digests the membranes surrounding the embryos and they then begin their active wandering. At this stage they penetrate the walls of the fourth stomach and make their way between the walls of serous membranes to the place where they finally find lodgment. This active migration must often be converted into a passive one after the embryo has made its way through the mucous coat of the stomach, for when the embryos have been fed in large num- bers to the sheep in the course of the experiments of different iuvesti- 74 gators tlielivtM" has been found to be filled with iimltitiules of thein. One invostij^ator has Ibiiiul thciii in the minute branchk'ts of the portal vein, which conchicts the blood from the stonuich and intestines to the liver. Now, in order to ai)pear in the liver and in the portal vein in such numbers the embryo must make its way into the little branches or capillaries which collect the blood at the stomach, ami then be washed by the blood current into the liver. When they become lodged in the liver they ai;ain migrate actively and tunnel through the mass of the liver in all directions. The little channels are made slowly. They begin as a minute point, and become gradually larger as the parasite increases in size and changes its j)osition. About the ninth day after the embryos have been swallowed some of the parasites nmy be as large as a llax- seed; most of them will be smaller. They will then be little oval water- bags, with a wliitish thickening at the end. Some of the parasites seem to pass the entire length of the intestine before they penetrate the walls; but when they reach the rectum they I)ass through, and, becoming lodged between the layers of serous mem- brane, develop there. This i)robably accounts for the presence of the considerable numbers which are found in the i)elvis. The destination at which these parasites arrive has its influence on their development. When they ha^e migrated to a point between serous tissues which may be easily spread ai)art, and offer little resist- ance to the growing [)arasite, a certain proi)ortion of them seem to thrive and arrive at a stage in which they may continue development by the proper exchange of hosts. If this exchange is not effected the parasite may remain unharmed for a long tinu^. while awaiting this opportunity. Should they die from any cause a slow change in the appearance of the i)arnsite is noticed. The fluid it contains becomes milky and limy. The serous sat; surrounding it becomes thicker; finally such changes have occurred that iu place of a soft sac a round, hard sphere of lime covered by a thick membrane may be found. The re- mains of the parasite may still be seen by careful dissection between the cover and the limy deposit. But when, on the other hand, they arrive at the liver they seem to have reached a place of destruction ; for if they do not kill the invaded host within two weeks, a period long before they could continue their life in another host, thesame degenerative processes seem to affect them, in their earlier stages, whi(;h destroy the older individuals in other or- gans of the body. This seems in part due tothe pressure which the liver cells aiid cai)sule exert upon them. These statements seem substanti- ated by the presence of either scars or calcareous nodules in the liver . and of no large ci/sticerci, except where the loose serous membrane may have permitted their growth. These parasites have occasionally been observed in other parts of the system than those mentioned, as in the lungs, heart, and muscles. Dificase. — The harm that Taiiia mar(iinnicicle every two months would be sullicient; but as T. cfcmirus develops in three or four weeks, it would be best to treat for botli at once and dose the dogs more frequentl3\ Diagnosis. — Every sheep-owner should proceed to dose his dogs with worm medicine, whetlier they are known to have tape-worms or not. The diagnosis of tape- worms in dogs is difficult, those having many often showing no symptoms. Sometimes they may be suspected from 77 the leanness of the animals or from the little white segments they pass. Such are the benefits arising from thorough medication that the time and expense giv^en is well laid out. Medical treatment. — The method of treatment consists in tying the dog and withholding its supper, not water, over night. Some admin- ister a physic at this time. The special worm medicine chosen should be given on the next morning, and followed two hours later by a dose of physic. The worms, if the treatment has been effective, should be voided inside of twelve or eighteen hours. The dog should be fed sparingly for a day or two preceding the operation. The preparatory physic may be omitted. The dog may be fed at noon on milk or meat. He should not be loosened until the following day. The excreta passed should be burned or buried in some safe place. The method of admin- istering the medicine is as follows: A man of whom the dog is not afraid should place himself in a corner and back the dog between his legs. He should then grasp the muzzle gently but firmly in one hand; with the other hand should pull out the loose cheek at the corner of the mouth. Into the pocket thus formed an assistant can put the medicine, a dessert-spoonful at a time. The lips should then be held close, and the dog will usually move his tongue sutficiently to swallow the dose. Should he refuse, his nostrils may be closed for a second or two until he gasps for breath, when the medicine will be swallowed. If any con- siderable quantity is to be given the operation should not be hurried, and should be persevered in with care and patience. Some dogs will eat their medicine mixed with milk or soui^, while others are very fas- tidious. Areca nut has proven itself the best ttenicide for dogs. The freshly ground powder is the best. The rule for measuring the dose is to allow two grains of the powder to each pound of the dog's weight. The powder is thoroughly stirred with soup or milk. If refused, another dose may be prepared by mixing it with butter or molasses until the mass is quite soft, and administered by hand. Follow the medicine in two hours by a table-spoonful of castor-oil for a motlerate sized dog. The oil can be given alone or well shaken and mixed with three times the quantity of milk. If areca nut is not available, a dose consisting of a tea-spoonful of tur- pentine and two table-spoonfuls of castor-oil, thoroughly mixed with a coffee-cup full of milk, may be substituted. This dose is one for an av^erage-sized farm dog. The final physic is not given in this case. A 2-ounce dose of castor-oil will bring away portions of the tape-worms, and sometimes the heads, without the aid of other worm medicine. Finlay Dun recommends the following prescription : Take 20 drops of the oil of male-shieldfern, 30 of the oil of turpentine, and 60 of ether. Beat them together with one egg and give to the dog in soup. Ziirn advises the use of about 4 drams of freshly powdered areca nut for a very large sized dog, 2i for a medium sized, and 1 dram for a very 78 small (log. Tbe powder is to be rubbed up with butter. Follow in two hours b^' a table-spoouful of castor-oil. Dr. Hageu advises treatment of all sheep dogs each spring and fall, thereby claiming an increased immunity for the sheep from the eysticcrci. He recomnieiuKs the lollowing: Take of the oxide of copper SO grains, of powdered chalk and Armenian bolus 40 grains each ; of water sufli- cient to mix the ingredients into an adherent mass; divide into one hnndred pills; administer one three times daily for ten days by crush- ing them in a piece of meat or bread and butter. In addition toother remedies IIoll prescribes the following: (Each dose is for large dogs. For smaller ones proportionately less ought to be given.) (1) Extract of male fern and the powder of male-fern, 2 drams each. {'2) A decoction of -5.] ounces of pomegranate-root bark in water, reduced to G fluid ounces, and add 1 dram of extract of male-fern, to be given in two doses an hour apart. (3) From one-half to 1 ounce kousso formed into pills with honey or molasses, and a little meal. (4) From 1.^ to 2i drams of Kamala stirred with honey or water, and given in two doses inside of an hour. He advises a preliminary preparation by feeding the dogs sparingly lor two or three days previous on salted food, and the administration of castor-oil the evening before. The rem- edies proposed are to be mixed with some material to make them fairly acceptable to the patients. With the excei)tion of kamala, which acts as a cathartic, all should be followed in two hours by castor-oil. After any treatment the patients should be fed with some liquid diet on the tirst day. After this they may receive any wholesome food. The necessity of repeating a treatment depends entirely on the efficacy of the tirst, and the care exercised in preventing a re-infection. If the tieatmeiit has been successful in removing the worms, heads and all, of course no further treatment will be required. If only portions have been removed, then another dosing is necessary. For t(cnia mar- (jinata another treatment need not occur under eight weeks, for the tapeworm is harmless as far as sheep are concerned ui) to that period, for, as far as is known, the worm will not throw off segments before that time. For T. cwnurus the treatment should be repeated in about two weeks. Frcveniive treatment. — The great resource of the flockmaster lies in prevention. In this he has nearly absolute control over the health of his sheep, in so far as Twuia mar into as many individuals. Most of them will j;enerally die, and oidy a few of the stron<5er will develop. Instead of tbe single worm which tbe embryo of T. manjinafa produces, this i)eculiar species develops many from each of its embryos. In this there is a compensation ; for while many of tbe T. marginata embryos come to maturity, but one or two of tbe cfeiiuri survive, aud thus the opportunities for tbe further perpetu- ation of the sjiecies are diminished. Duration of development. — Experiments bave shown tbat tbe embryo may be found iu tbe brain from two to three weeks after feeding, and is then about the size of a mustard seed. Between three and six weeks after feeding the worst symptoms of the disease occur. Tbe cwnunis becomes developed in from two to three months. After this time it continues to grow in size and iu tbe number of beads for six or eight months, when it usually causes the destruction of the aflected sheep. When the developed cwnurm is fed to a dog it usually produces adult taj)e worms within a montb. In the migrations of these parasites many are lost and destroyed. Of the hundreds of eggs wbicb leave the intestines of dogs few reach tbe stomacb of the sheep, and of these still fewer enter the cranium. Of tbe few which become adult — one or two in eacb shee[) affected — but a small percentage nowadays arrive in tbe dog again. Tbus of the thousands of embryos that left tbe dog but a single ccenurm may return. But this cwiiiirus, developing again into several tai)e-worms, is the source of many new embryos for tbe re-infection of the sheep. Disease. — Lambs and yearling sheep seem to be most liable to infection ; tbose over two years old seem to possess a degree of immunity. Sheep berded by dogs ; those breeds which eat tbe grass close to the ground; sheep which drink out of i)onds or brooks iu wbicb tbe dogs bathe ; flocks belonging to careless flockmasters, who leave tbe skulls and vis- cera of slaughtered and dead sheep strewn through the pastures, are more liable than others. In short, any of tbe conditions which help iu tbe distribution of tbe i^arasites render sbeep more subject to the disease. Si/m2>toms and progress. — The symptoms of gid iu sbeep are depend- ent upon the stage of invasion and development at wbicb the parasite has arrived. Tbe iuvasiou embraces tbe period from tbe time tbat the eujbryos bave been swalloweassing from sheep, cattle, and pigs to dogs, and from dogs back again. In method of growth it 87 differs, forming from a single embryo large masses of cysts, which con- tain many individuals capable of becoming adult. Its favorite situa- tions in sheep are the liver and lungs. It may occur elsewhere. In these places it forms large bladdery masses, whose nature can only be definitely determined by the aid of the microscope. As this parasite is also dangerous to man the bladders should be handled with care, and destroyed. The treatment of dogs is the same as for the other lamia. Twnia tenella,, Cobbold (Plate XI, Figs. 5 and G), which causes mut- ton measles, is a tape- worm of man, and is supposed to be acquired by him while eating mutton through which the cysticerci have scattered. The disease has not yet been noticed in this country, and having been observed but seldom in Europe, is yet problematical. Mutton af- fected would present little white spots as large as flaxseed scattered through it. The loin muscles are most ajit to be infected. Neither this disease nor hydatids can at present be accounted a disease of sheep in this country. 88 T^NIA CCENURUS, Kiicb. Tlatk XI. Fig. 1. Adult, natural size (Raillet). Fig. 2. Hooks, enlarged (Raillet). Fig. 3. Cyst or Cdnuriis cerehralis, Riul. Tlio. white dots arc tlio tionia beads (Raillet). Fig. 4. Ideal sectiou tlirougli two of the dots, showing inverted pouches with heads of the tienia developing at the bottom (Raillet). Taenia tenella (?), Cobbold. Fig. .5. Section of beef, showing imbedded ciislirerci. Illustrates the appearance of infected mutton. Fig. 6. Enlarged head of cijsticerus oris (T. tenella (?), Cobbold), the sheep measles. Reduced from Cobbold. Taenia echinococcus, v. Siebold. Fig. 7. Adult, natural size indicated by line (Leuckart). Fig. K Young stages, taken from broad capsule of cyst (Leuck.art). Fig. 9. Liver of pig, invaded by echinococcus (Raillet). To illustrate the appearance of invaded liver of sheep. Haines, del. I HoenX Co. lithacaustic. Baltimore. TAENIA COENURUS. CYSTICERCUS 0VI8. TAENIA ECHINOCOCCUS. ADULT TAPE-WORMS. Plates XII to XV. The flocks of this country are infested by two species of adnlt tape- worms, remarkably different in form, size, babits, and distribution. Tbey are Twnia fimhriaia, Diesing, and T. eximnsa^ llud. Each are named from pretlominant characteristics. NeniHiiun states that European sheep harbor more species of adult tapeworms than other animals, and enumerates ten species which have been described, viz: Twnia expansa, Rud; T. alba,, Kerr; T. Benedeni, Moniez; T. aculeata, Kerr; T. ovilla, Rivolta; T. Giardi, Moniez; T. F<>////, Moniez; T. ccntripunctata^'RiW) T. globijnmctata^lliv.; T.ovipimc- tafn, Riv. The majority of these species are apparently new to science, and con- sequently unconflrnied. Some seem to be well founded, while others nuiy eventually prove to be re-descriptions of other better established s])ecies. With the exception of T. expansa,, the writer has as yet found no traces of any of them, and it is probable that they do not occur here. A description of the tapeworms found here, and the diseases they cause, follows. THE FIMBRIATE TAPE-WORM. TAENIA FiMBRiATA, Diesing. Plates XII and XIII. Tape- worms in Western sheep were noticed by ranchmen in the early days of rancliiug', but did not attract the notice of veterinarians until 1883-'84, when Dr. Faville, of the Colorado State Agricultural College, first directed attention to them. (Report Veterinary Dej^artment of Colorado State Agricultural College, January, 1885.) An earlier epi- zootic, due to tape-worms, had been reported to Mr. Stewart, who, in the National Live Stock Journal, for September, 1875, records their pres- ence in Missouri sheep, and from specimens at hand determined them as Twnia plicatd. As this frr/MV^ does not occur in siieep, but in horses, it is quite likely that Mr. Stewart saw T. Jimhriata, In a recent letter to the Department of Agriculture, the late Hon. J. M. Givens reiterates an opinion formerly ex[)ressed by him in local so- cieties of wool-growers, and published by him in Denver (Colo.) papers 89 90 of lS83-'84, that these tapeworms were a cause of the larger part of the losses among sheep, and urged the necessity of a closer study of the subject, iu order that more might be learned of the parasite, the amount of loss it caused, and the means of i>rcventing it. These losses had previously beeu attributed to a weed called " loco," which tlie sheep ate. In obedience to instructions received from the Commissioner of Agri- culture, the writer proceeded to Colorado in August, 1880, ami began a study of the various intestinal parasites of sheep. Tlie studies of that year were pursued, by invitation, on the ranch of Mrs. Mary L. Givens, who, at great inconvenience to herself, did all in her power to aid me. In the spring of 1887 1 again visited Colorado Springs and prosecuted other experiments, which it was hardly possible to conduct iu the East. Early in my investigations the fact was recognized that one taenia^ identified as Tccnia Jimbriata^'Dies'mg, was the most abundant; that it was scarcely ever absent in sheep examined, and was the probable cause of most of the tape-worm disease of Western sheep. As this twnia was so constantly present attention was directed to it, and an endeavor made to obtain it iu all of its stages, and to learn how and where it passed its entire life. Another fact was soon learned, that the other species of tape- worm [Tccnia cxpansa), usually abundant in lambs, was found so infrequently that it was difficult to find sufficient material for study. The methods of study were, first, observation, and, second, experimentation. The experiments have, as yet, been productive of nothing but negative results. In determining so much of the life his- tory as has been learned post-mortem observations have been, the most useful. Not only have animals been slaughtered on the ranch for this purpose, but advantages offered by inspections of sheep slaughtered at the shambles for consumption have been utilized. From these iuspec- tions the abundance of the parasite, the first appearance in lambs, the ditterent stages iu growth, etc., could be learned, but it soon came to be necessary to study the surroundings of the sheep — the corral, the watering places, and the range — to learn under what condition the par- asite must exist while external to the sheep, i. c, while passing from sheep to sheep. The effects of the parasite on its host (the sheep) were arrived at from studies of the flocks and from observation of individuals at j^ost- mortenu. The changes found were noted and careful attention paid to the point whether certain changes were due to parasites or another dis- ease called " loco." As all of the sheep examined were called " locos," it is evident that there was here a source of error. No certain patho- gnomonic lesion of" loco " was learned ; as all of the " locos " were in- fected with t(vnia\ the separation of characters due to each disease was difficult. Indeed, it has seemed to me that all of the symptoms due to the parasitic divseasemay be ascribed to " loco." The characters of the tape- worm disease are, however, well marked in lambs which have never learned to eat this weed exclusively, and thus could be 91 studied without regard to ''loco," which, if a disease at all, belongs to yearlings and older sheep. Experimeuts were undertaken with a view of infecting lambs with the parasites, while the lambs were kept from other possible sources of in- fection ; but these were fruitless. Other experiments were entered upon with a view of removing these parasites by medicinal remedies. None of these were effective in removing the parasites from the gall-ducts, and were abandoned until more could bo learned of the life history of the parasite, when they could again be takeu up with perhaps a better prospect of success. The total results regarding this taniia, so far obtained, are as follows, viz: The parasite persists in an -adult stage in the okler sheep throughout the year. The smallest forms ai)pear in lambs soon after the second montli of their age, and may be found in sheep of any age throughout the year, excepting, possibly, the winter months. It requires at least six mouths, possibly ten, to attain an adult size. Theovaorembryosare continually passed from thesheep to the ground throughout the year. The life of the embryo from the time it leaves one sheep until it is found in another is yet undiscovered. When present in considerable numbers in sheep it determines a dis- ease which is not only detrimental to the value of the animal, but at times causes the death of large numbers. No medicinal remedies can be recommended which will assuredly re- move the parasite from the host. Many measures may be taken which may prove to be effective in two ways, first, in preventing sheep from becoming infected ; second, in enabling the sheep to better withstand the ravages of the parasite, and thus carry it over the critical stage of its existence. The lambs and yearlings are the greatest sufferers, and it is to these that the most attention must be paid. T^t:nia fimbriata, Diesing. Synonymy. — Thtjsanosoma nctinioides, Diesinj;, IS'.U. Metl. -Talirb. d. oesterr. Staat. Nene Folj^e, VII, 10r.-l]l. Taf. Ill (Fi<,^ inverse, delin.), K}- Syst. Helm. I, .'iOl iu iiota. Tirniafimhriata, Diosing. Syst. Helm. I, .^)0l. T(F.nia fimbriata, Diesing, 1856. Zwanzig Arten v. Cephalocotbylcen, p. 11, 18.56. Wien. Tamia fimbriata, Eept. Dept. Agric., 4tli audfitli Annual Eopts. of Bureau Animal Industry, 1887, 1888, p. 167, Pis. I and II. Tcenia fimbriata, Diesing, was first discovered by Natterer, in Brazil, iu 1S24, and published by Dr. K. M. Diesing in 1834, as a new genus, Thysanosoma (ictinioides. Later, in 185G, Dr. Diesing republished this parasite as Tcenia fimbriata. (See Plate XIII.) 92 The first specimens foninl were detached segments, and from these the first description was made, batterer hxter found more complete specimens and u[)on these the species was founded. The specimens were found in the intestines of the following species of deer, viz : Cer- vns palndomfi, C. rufus, G. simplicornis, C. Nambi, (]. dichotomus. A translation of the original Latin description is as follows : Arhi/ncJtota-nia', Rostellum none ; mouth unarmed. Ta'niajimhriata, Diesing. Tab. V, figs. 9-lo. (Plate XIII is a copy.) Head obtuse tetragonal, large with liemisplierical angular botbria; ueck none; body anteriorly lanceolate, with very short cuneate segments; posterior margin of the upper entire, of the following crenato, of tbe last fimbriate on each side ; the lin- ear fimbriae rounded at the apices. Genital apertures — ; length 6'" — 6"; width 1 — 3'". Mature segments, separate, 1'" long, 2'" wide, with lanceolate fimbria;. This description was necessarily imperfect, from thelick of abundant material, but is nevertheless sufficient to enable us to identify the pres- ent species with it. Fortunately, too, excellent figures enable us to clearly understand the fimbriate character of the species. At present this is the only species known to possess this character. Thougli char- acters founded on form are of doubtful value, until more decidelaces and kept constantly full. They will take no more than they want and will be all the healthier if they have all they need. If they are deprived for a time they may at first salting eat more than is good for them. A little eaten daily is physiologically better than the larger quantity eaten at interva]s. The object of feeding the salt at watering places and from boxes is to keep them from licking the dirt where salt has stood and to keep them from eating the prairie alkali. In addition to the opportunities afforded them of being infected with parasites from the salted ground there is the in- jurious effect of the swallowed sand. This sand often packs away in the gall ducts and produces disease. It may be when the gap in the life history of Twnia fimhriata is known that a single measure of prevention will eradicate it from the flocks. Until then the general measures prescribed above are to be recommended. There are various minor precautionary measures to be fulfilled that will help affected sheep to live through the colder winter, and finally to render effective service in spite of the parasite. The post-mortem examinations have led me to expect that from 80 to 95 per cent, of each flock is infected. Now, were all of these to sufler as some of the more diseased do, sheep-ranching would be at its end. Fortunately a sheep may have a few parasites and not be seriously affected by them. This is shown by the fine, large sheep slaughtered which are passably fat and yet contain tccrikc. It is a frequent remark of the ranchman that if he could carry his lambs and yearlings through they would do well enough afterwards. It is these younger and growing animals that suc- cumb soonest to the parasite. It is a rule that all young and growing animals are more seriously disturbed by the presence of parasites than older ones. Young lambs born in May or June have necessarily but a short time in which to grow before the cold season. When food is plenty, and there is no disturbance of their digestion, or other ailments, they enter winter strong enough to endure the weather without partic- ular suffering. Interference with digestion, lack of food, or any ail- ments render the lambs so much the weaker, and consequently less able 102 to endure the winter storms. The parasites interfere with digestion, and to overcome their evil effect means should be taken to supply easily digestible and fattening food, which may replace and add to that lost. Many ranchmen already feed their lambs extra grain during the fall, and have learned that not only are their losses diminished, but that the lambs become larger and stronger as well as fatter. Formerly the ranchman depended, as many do still, entirely on the prairie for grass throughout the season. Of late years many are feed- ing more anw . . . Many. .. ...do... ...do .... i-."^" and undfT 10"" and under. .... do 23 24 24 25 25 26 27 27 28 32 33 33 34 43 45 49 50 50 51 10-12 10-12 20 29 ... Nov. 9 10 3 IG Many... . . do ... ...do 10"" aud under ...do ]9 21 ....do 25 . . do Dec. 20 4 19 100+.... Many. .. 50+..,. Many. .. 25 15 .5 2"> 10 11 11 12 22 24 27 28 28 29 4 29 irn, to 4'!"' 4 30 5"'"' to IC"' 4 .T.in. 8 1887. ]c,n \q 7cin G Mar.14 Immature aud adults .. do 15 29 17 Api-. 20 7''" to 15'^"' 20 28 21 28 do 21 May 7 1 2 2. Adult 2cin 'J3 5 .. do June 25 , Many... 2cm to 5cm adult . ... 'The age i.s that of the lambs aud is estimated May 15. I*^os. 101 to 104 and M were adult sheep ; all others were lambs. Adult tccniai coutained embryo. Fost-mortem examinations — December fj6. — No. 105 died. It contained four small Ta'nia fimhriaia, the largest about 2^'" long, and iifteen cysticerci of T. marginata, each less than l*^"" in longest diameter. 106 December 20.— K\\]od No. 107. It contained nineteen Hmall T. fimhriata, the largest about 4'"' in length, and twenty cysticerci, the largest a little over 1"" in diameter. December 30. — Killed No. 109. It contained over one hundred small twniw, ranging from 5""" to 10"^'" in length; also a few small cysticerci, apparently of same age as in 107. January 8. — No. 108 died. It contained throe specimens of TwHia cxpansa ; one of these was adult ; many small T. fimhriata, varying l'"' to 7'"' long; also six cyi^tieerci, somewhat larger than tiio earlier found. April 20. — Killed No. 10(5. It contained many T. fimhriata, over twenty-live in all, which were over 7"" in length ; none were smaller. The duodenum and gall ducts were packed. None were adult. May 7. — Killed No. 110. It contained one adult T. fimhriata and several cysticerci. March 14. — Killed No. 103. It contained from lifty to sixty tunia from 7'"' to 10'"' in ongth ; four of those were in the gall ducts and were among the largest in size. l\v.- nia: immature to adult. March 29. — Killed No. 101. Found tivnid' in duodenum, gall ducts, and i)ancreatic ducts. The gall ducts were engorged; the liver smaller than normal. Thu twniie ranged in size from 7''" to 14''" ; three were adult. There were three cysticerci. April 28. — Killed No. 104. Found live taniia' from 2"" to 4"" in length, but no cysti. cerci. April 28. — Killed No. 102. Found Gfteen twnUv. The largest were not over 7"" in length, and immature. There were two csyticerci. Table C is made up from data obtained from the six lambs, .Nos. 105 to 110, inclusive, transported from the prairies to Washington. It shows the comparatively slow growth of the parasite; also the abun- dant infection of some of the animals so long as they were exposed to infection. It also presents either the ]>ossibility of infection after they were taken from the prairie or the retention of the embryo in the rumen through a considerable time. O. Date. Dec. 26 29 30 Jan. 8 Apr 20 May 7. No. A<;e in weeks. No. of Tceiiia Jimbri- ata. 105 107 109 108 106 110 32 33 . 33 34 49 51 4 19 100+.. Mauy . ?5 1 Weeks Weeks TcenicB after after size. October Decem- 15. ber 1. Centimeter. •> 10 11 4 4 + 1-4 0.5-10 11 4+ 1-7 12 G 7-15 27 20 Adult 29 23 Weeks after Uecein- ber 31. October 15, tbe date on whicb tho lambs wore taken from tlio prairie and coirallod. December I, tbe date on whicb the lambs were received in Wasbiugton. December 31, the date on which tlie adults, Nos. 101 to 104, were removed. Lambs K and I, Table B, sliow that the trvnia was developed to a length of 2"" in less than ten or twelve weeks, for the number of ttvuitv found shows a slight infection and some time may have elapsed after the birth of the lamb before its infection. Lambs A to [, Table B, show that in from twenty-tiiree to twenty- eight weeks the ticnitt, may develop to 8 or 10"" in length, and that the 107 infection is proportional to tlie time exposed. The infection is, how- ever, a variable quantity, and no definite statements can be deduced. As the lambs do not begin to nibble grass and drink water until some few days after their birth, the development of twnia in K and L prob- ably required not over two months. Lamb A, examined October 21, about twenty-three weeks after birth, gives, when compared with K aud L, an approximate rate of growth of the twuia of 2'"" a month, more or less. The rate of growth must so vary at different times that no definite rate can be determined at present. The keniw of No. 105, one of the same lot of Lambs as the foregoing, were no larger after thirty-two weeks than those of K and L after ten weeks. This points to a recent infection of No. 105, i. e., within ten weeks, or about the time the lambs were taken off the prairie and re- ceived into the corral. The twuicc of Nos. 107, 109, 108, and lOG coin- cide with this ; but the lambs No. 109 and 108 also poitit to a later in- fection, as nuiTiy very small tamicv were found in them. No. 108, which had td'niw 1"" long six weeks after its receipt in Washington, would lead us to suspect a recent infection ; but this is not necessarily the case, as the influence of the rumen of the sheep in detaining the para- site for a length of time has yet to be learned. The absence of young twnio} measuring less than 7<"" in No. 106 at sixteen weeks after its last association with an animal containing adult Uvnicv and twenty weeks after its arrival in Washington is also of interest in that it points to infection of the lamb from the adult sheep associated with it. No. 110 shows a very slight infection, and one, judging from the age of twnicv, that could have occurred in Colorado. The six cases show a slow growth of the parasite ; they also point to one of two things: That the twniw are, as embryos, retained in the rumen for some time after being swallowed, or that these tceniw are continually infecting their hosts by the direct method ; that is, the embryos passed by sheep, with little or no preparation, pass into other sheep and develop without the intervention of an intermediary host. So far nothing has been found to absolutely prove or disprove the latter statement. The infection, as shown by the various sizes found in these lambs and other sheep, points to a continuous infection nearly all the year. (See Tables A, B, and C.) Nos. 100 and 110 indicate a cessation of the infection for the length of time it required the smallest (7*^'") to attain their size. Lamb A in- dicates the time to be something less than twenty weeks, or at the period when they were received at Washington. Nos. 106, 107, 108, and 109, which had been confined eleven and twelve weeks, show as great infection as has been seen. This would happen with animals which were being infected in confinement, for the opportunities of infection, if the infection should prove to be direct, are greater. Various condi- tions, as the weather, food, water, etc., have so much to do with the problem of infection that far more data are necessary. 108 The fact of slow development atul continuous infection are the main points brou<;ht out in this experiment. Continuous infection is natu- rally one of the results where twniw are constantly developing and shedding ripe proglottides laden with embryos for the infection of other hosts. Continuous infection also leads me to suspect that no" interme- diary host is necessary for the contiiaiance of the life of the embryo. This proceeds from the fact that !io single species of mollusk, insect, or other animal is to be found at all seasons and places necessary to suit all the conditions under which we tind the host infected. Experiment No. 2. — A lamb dropped at a slaufrhter-houso in this city was kept witli its luotlier in an nninfected stall. Tlio 1 inib was fed on Jaunary 10, 1887, with a largo quantity of proglottides of Td'nia expausa from No. 108. The embryos were found to be alive and moving before feeding. On March 20 the same lamb was fed with proglottides of T. fimhr'mia from No. 10:?. These contained live embryos on the 18th instant. On March 21) fed the same lamb with proglottides coutainiugembryos of r._/(»i7>r(rt7rt from No. 101. On April 11) this lamb was killed and nothing was found except a few white spots iu and ou the liver. The experiment had uo results. AN EXPERIMENT TO INFEOT LAMBS WITH TiENIA FIMBRIATA. Experiment No. 3. — May 23, 1837, placed fifteen ewes with unborn lambs in three box-stalls. They were fed ou .alfalfa, haj^, corn, and bran. Their water was drawn from a hydrant near by. The ewes being thin in llesli, and taken from the prairie grass and placed upon dry feed, thrived but poorly. Between May 23 and May 29 eleven lambs were born, which lived until the close of the experiment. Five of the largest and oldest were placed with their mothers in stall No. 1. The remaining were divided between two stalls, Nos. 2 and 3. These animals were removed from all sources of infection through food and water, and the lambs had never been exposed to any source of infection. The ewes were susi)ected of being infected with T.Jini- hriafa. If the lambs became infected they would either take them of their mothers or from their feed. Between May 2G and June 15 the lambs were fed in stall A several times each with a number of ripe proglottides from adult Uvnuc. An interval was left between each feeding, and each lamb was fed at least three times. The other lambs were not fed. All but two of the ewes were found to contain adult ta'nia' when examined later. The lambs and ew^es were killed in nearly equal lots on June 25, July 15, and August 1. .Tune 25, killed one ewe and one lamb from pen No. 1, two ewes and one lamb from No. 2, and three dry ewes from No. 3. Lambs uninfected. One ewe had twnia^l'^"^ long. July 15, killed two owes and two lambs from No. 1, two ewes and two lambs from No. 2. Lambs uninfected. August 1, killed two ewes and two lambs from No. 1, and two ewes and two lambs from No. 2. Lambs uninfected. 109 The lambs were kept for two months, and were not infected in this time. This experiment shows that either a longer time is necessary for infection or that the embryo has to nudergo some develoi)mentor prep- aration that was not allowed and of which we are ignorant. The speci- mens fed were taken from slaughtered sheep, examined with a micro- scope, and fed by placing the proglottides which contained living embryos in the lambs' mouths and waiting until they had been swal- lowed. The lambs while living with their infected mothers should have been infected, providing infection by embryos fresh from the host be possible. As this was not the case, further preparation and development of the embryos outside of the ovine host seems necessary. 110 TAENIA FiMBUiATA, Diesiug. Plate XII. Fig. 1. Adult, uatiiral size. From coutiacted alcoUoUc specimen. Fig. 2. Head, edge view, XC Fig, 3. Head, side view, XO. Fig. 4. Head, top view, X6. Fig. 5. Portiou of segment : a, genital pore ; h, cirrbus i)oucli; c, seminal appara- tus; d, the efferent tube; e, the rudimentary uterine apparatus; /, vagina; ' disease in the young lambs. The Toch)nias, and a few Tiichocephahis. This lamb was one of the two that was drenched with eggs on May 16. He had pastured with the others, which it was subsequently learned had adult twnia, and which had been purchased supposing them to be infected. October 9. — A buck lamb was examined, one of the six purchased in May. Old cicatrices of Taenia marginata were found in the liver, six Cysticerci of this species, two adult and six young Twnia expansa, a quantity of young .and old Slroiujylus con- tortun, and a few specimens of Triclwcephalus. October l(i. — A buck lamb, another of thesix, was found to be infested by a quantity of very youug twnia, also by young and old SirongyJus contortus, Dochmius, au. There is another phase of the question which is still in doubt. Early 118 in the experiment sej>'inentsof tape-worms were placed in an iron troujifh ontof wliicli the sheep - ; and there might have been times when, for a day or two, a little puddle of water could have collected after a rain. In these, more especially the former, the development of ,the parasites could have proceeded nntil they were taken up by the huubs. The point in doubt is, whether the lambs got their embryos from the water or from the yard while grazing. I am inclined to believe the latter, for they acquired other species of worms which were not placed in the iron tank, and these were also in various stages of development. Still another feature inclines me to this view. If the lambs had been infected from the iron tank they would viry likely have been infected by a large number of twnicv^ all of nearly equal size; but they were not. Direct infection has been tried before, but only negative evidence obtained. The failures prob- ably arose not only from expecting results too soon, but also from not preparing the infecting material ])roperly. Since writing the above, two lambs have been examined, which give additional data : August 10, 1889. — A five nioiitlis old lamb wiis examined, wiiicU liad been born at the experimental station, and kept there nnder the same conditions as the other lambs, i. e., water supplied from a pump and pasturage from the yard and lane near the sheep pens. This lamb contained two adult Tiv.niae, and Slrotujuhis contortus, S. flicolUs, S. vcniricosus, Dochmius cenuius, Trieliocvphalun affiuis, and (Esophafjostoma Cohimbianum, in all stages of growth. The last species did not show adults. August 10. — Examined a lamb eleven weeks old, which had been bought with its mother from a neighljoring slaughter house when two days old. Tiie lamb had been kept under the same contlitions as above. There were found one adult Tivn'm (shed- ding proglottides carrying well-developed six-hooked embryos) and all the other species enumerated above, but not in the same abuudanc(\ Ea(;h of these lambs showed that the infection had been continuous. The elder of the two yielded a greater number of S. filicollis than any sheep hitherto killed, and led me to think that this species may have been productive of more trouble than had hitherto been suspected. The above experiments were planned with an aim to obtain infection within a limited area, and under conditions which could be controlled, deeming it better to obtain infection under such conditions, though there be a number of them to complicate the (piestioii, than to restrict the conditions and not get an infection. The presence of the adult f(vnia in the com[)aratively young lamb of eleven weeks shortens the limit of time of complete development of the t(V)iia. The td'uia was about two yards long, a-nd had developed inside of three months. A reason for the early infection of this lamb was that its mother died and left it to shift for itself. Tliese expei'iments con- clude theseries fordetermining whether sheep necessarily getthe worms from drinking water or from tlu^ i)asturage. {^iim)iu(r)/. — The life history seems fiom the above to be a compara- tively simple aifair. The embi-yos pass from sheep to shee]) and develop into adults, which reproduce young for infection of other animals. 119 Whatever cbauges the embryos may pass thronoli outsi(U> the sheep can have little to do with the case as far as a kuowledge of prevention of infection goes, for bnt very few of the conditions nnder which these sheep were kept can be improved by the flock-master. Disease.— ThQ tape- worm disease can be diagnosed by finding the lit- tle white oblong tape-worm segments which are voided from the sheep and stick to the moist pellets of dung. They may also be found adher- ino-to the wool and dirt around the tail. But this is only after the tape-worms have become adult and have begun to shed segments. Tho.K-h sheep often harbor tapeworms and give no evidence of their presence until after slaughter, there are other cases in which their pres- ence is oulv too evident to the flock-master. Tl.e first indications of the disease are usuallv nnobserved, because of the slow growth and ot the comparatively- small number of parasites that may be developing. The time of growth occupies about two or three months from infection. The number of individuals maybe from two or three to a hundred, but it is nnusual to find more than a half do/en adults together. As many as fourteen adults were found in a himb four months old. \\ hen young they occupy bnt small space, need little food, and cause few vermicular contractions. In the earlier stages it is plain that they cause but little trouble, bnt when they grow so large that they seem to till the whole of the small intestines they cause the serious disturbances ascribed to them. These disturbances mav be to a certain extent those arising from a re- flex irritation of the sympathetic and spinal nerves, but most ot them seem to be due to the indigestion which the worms produce. The worms obstruct the intestinal canal by their great mass, irritate it by their ver- micular contractions, cause excessive secretion of intestinal fluids, non- assimilation of food, and abstract nutriment from the intestinal con- tents for their own growth. The lambs become poor and hidebound; their flanks may either be distended by gas in the bowels or be tucked np from ganntness. Iti the nrogress of the disease the animals become evidently weaker, the mucous membranes paler, and the fleece dry and harsh from the loss of its yolk. The animals walk with a tottering gait. They often eat more and drink oftener than those less attected. In the severest cases the lambs grow extremely weak and poor, diarrhea becomes more and more pronounced, and at last they die through slieer exhaustion. While suflering from these worms tiiey are more susceptible to the at- tacks of other parasites, and other diseases supervene and hasten the death of the already weakened animals. Pro^,i0.sw.— Though the tape-worm disease in its mildest form is very destructive to lambs and yearlings, yet it would seem that if they are able to pass safely through a certain period they are very apt to re- cover. In 1887, in the examination of two wethers which two weeks before had been passing proglottides, or segments, in abmdance, and 12a from wliicli it was expected to seeuro specimens for illustration, only a small i)iece of the worm was found, all the rest having passed away. Occurrence of the disease. — The worm, though present throughout the year, is more abundant in the locality of Washington during May and June than at any other season. This fact was doubtless somewhat de- pendent on the age of the lambs examined, which were about three or four months old at that time. In Colorado an outbreak was heard ol in a flock of Merinos which occurred annually about July and August, after which time the lambs would improve. The disease is more prev- alent in the summer season, and causes the greatest damage in lambs less than six months old. If the young animals cm be carried beyond this age they seem to be cither better able to withstand the ravages of the parasite, or to have reached a season unfavorable for its develop- ment. Duration. — The broad tape-worms do not last long in theiradult slate, but after maturing nearly all their segments are shed at once. From the time that the segments are shed the afflicted lambs will begin to receive and rapidly lay on fat. The disease leaves no traces other than debility in the early stages of recov(;ry. Preventive treatment. — Treatment for the prevention of this disease is that suggested for general prevention of parasites and an observance of those measures which promote good health in the flock. Do not overstock pastures. Give good, pure water. When possible, put the lambs on new pastures. Feed some grain, put salt where the animals can take it daily, feed hay from racks, and grains, salt, and water from troughs. The medical treatment jiromises better results than that for Tccnia fitnhriata, since the T. expansa is never lound wedged into the gall duct or pancreatic duct, as is T. Jimbriata, but is found lower down in the small intestine, from whence it can be removed. Many of the popular tape-worm remedies are said to be efficacious, butas the disease is dif- ficult to diagnose until the worms begin to shed their segments much damage is done to the health of the lambs before treatujent begins. On those farms and ranches where it appears periodically the lambs should bo treated as soon as they begin to show symi)toms. Even then com- plete cure can not be attained, for the lambs will continue to pick up eggs as in the first instance. For safety all sheep in the flock should be dosed, especially if all are to occupy the same pastures as those afl'ected. Zurn {Die Schmarofzer, etc., p. 191, 1882), says that treatment is practical when the disease is recognized before the lambs and yearlings are reduced to a cachectic coiulition. Although those far reduced in strength may not survive a medication, still they should be dosed in order that the parasites may be expelled. Otherwise the si(!k not '^reated should be yarded by themselves or killed and buried, so that they may not scatter eggs for further infection. Before giving the sheep any 121 worm remedies they slioiild be prepared by witbboldiiif? food the night before and not watered on the morning of treatment. The dose should be administered at one time, allowing every animal to swallow it slowly if liuids are giv^en. They should not be turned out alter dosing, but should be watched during the day to see if the worms are voided. If the worms are not passed off the dose should be followed by a cathartic on the next day. If it is certain that the sheep have tape- worms and none appear, the animals should be redosed with increased quantities on the following day. Of course particular attention must be paid to the purity of the drug given. After the sheep have been driven out the yard should be cleansed by removing the surface earth. This dirt should be placed where it can not be washed on to the grass to which the sheep have access ; or, it may be thoroughly disinfected, burned, or buried. Cleansing the yard may save a reinfection. Ziirn (o. are the forms that escape from the snail, and are scattered by it in its wanderings. The cercaria, after a time of active life, loses its tail, which it has developed, and again en- cysts itself. (vSee Figs. 11 and 12 and Fig. 10.) The contents of the cyst still more resemble the future fluke, and it is at this stage that the sheep swallows it with grass. It then breaks from the cyst, arrives at thti stomach and duodenum, to finally make its way into the biliary canals and grow into another, adult hermaphrodite, capable of giving rise to other generations of young. According to Thomas the en'eysted embryo (Fig. 4) may give rise to daughter redi;e or to cercariiB, the former to develop in the summer and the latter during the cold season, The epitomized life history is first the egg ; second, the embryo^ which encysts in a snail j third, five te eig^t redise, developing from the cystic. 129 larva ; fouitli, fifteeu to twenty cercariiB, developiiij^- tioin each redia aud escapiug from the snail; tiftb, the encysted cercari;e, which after having been swallowed by a lamb develop into adult Hiikes. This life history is fully as wonderful as any occnring in nature. Ac. cording to it, at least seventy-live young flukes under favorable sur- roundings could develop from a single egg. As the proper conditions are scarcely ever fulfilled, there are but few of those which meet with all the requirements for development. The disease created by these peculiar parasites is known by many names, the most popular of which is Liver Rot, a term expressive of the chief pathologic symptom. Aqueous Cachexia, Rot, Rot Dropsy, Sheep- Rot, Liver-Disease, Liver Fluke, Jaundice, Yellows, Verminous Phthisis of the Liver and Ictero-Verminous Cachexia, are other names for the disease, each being expressive of some of its symptoms. The symptoms, according to Neumann (Maladies Parasitaires), to whom the writer is indebted for the greater part of this article, may be divided into four periods, viz : (1) Period of immigration.— This is the period in which the parasite invades the liver. In this stage the flukes are small aud do not cause excessive diisturbances. This period lasts from four to thirteen weeks. It is probable tUat it lasts as long as the weather remains fiivorable for the development of young flukes aud sheep are kept on infested pastures. (2) Period of anwmia.— This ordinarily coincides with the months of November ami January, or after the lapse of thirteen weeks from infec- tion. The sheep are less lively ; the mucous membranes about the eyes, the nose, and the gums, the internal surface of the ears aud the skin, are all paler than in well sheep. The appetite is still good, aud the animals have a teuden(;y to fatten, caused, according to Simouds, by a better assimilation of food from the increased flow of bile stimulated by the young flukes. This fattening stage has been taken advantage of in ■ England by a dealer (Bake well), who purposely exposed the lambs he wished to market early to the disease, that he might send fat lambs into the market five or six weeks ahead of his neighbors. Sometimes the appetite diminishes, thirst increases, and rumination is irregular. The conjunctiva, the mucous membranes of nose and mouth, and the skin are white, slightly tinged with yellow. There is a slight oodema (puf- finess); the skin is looser, feels pasty and soft to the touch where bare; the conjunctiva is infiltrated atul puffy and the eye partially closed ; the wool becomes dry and brittle, is easdy pufted oft", and sometimes falls ott" of itself. Weakness appears more and more marked. There is sometimes fever aiul quickened breathing. Palpation and percussion indicate ascites. The droppings are norm:d, but contain at the end of this period numerous fluke eggs, Death may result iu this stage from apoplexy. 23038 A p 9 130 (3) Period of loss of flesh. — The sheep begin to become leaner at the end of the third month after the immigration of the hirvae, or about the beginning of January. The malady is then at its height. The animal becomes gradually leaner; the mucous membranes and the skin are bleached, and lose the yellow tinge. The temperature is variable and is highest in either the morning or evening. Kespiration is feeble and frequent. The appetite keeps up, and the feces present nothing in particular except fluke eggs. The urine is nearly normal. The ani- mals are listless and dejected, carry their heads low, and give way when pressed on their backs. There are frequent abortions, isursing ewes have a clear, watery milk, very poor in nutritive elements. Their lambs are weak and thin, and usually die unless they are put to another nurse. The oedema becomes localized and increased in dependent parts. It is dispelled by walking and comes again in rest. The space under the jaws and along the trachea is a frequent seat of pufSness. This disap- pears during rest and comes on during feeding. It is often absent with adults in hot seasons. In the tliree weeks which follow the ani- mals become still poorer despite abundant feeding, and there is gener ally diarrhea, oedema, jaundice, and pain on pressure over the liver. Either death occurs at this period, or the animals imi^rove and enter the next period. (4) Period of emigration of theflnl-es. — This is the period of convales- cence and of spontaneous cure. All the symptoms grow less and finally disappear, but the cure is never complete, the changes which have taken place being irreparable. The recovery of affected sheep is exceptional. Duration of disease. — The flukes are said by some authors to remain nine months in the liver, by others fifteen months. After this time they make their way into the intestine and are evacuated with the excre- ments. Thomas says that he has seen the sickness last six years, and Neu- mann seems to coincide with Perronciro, that the flukes have little ten- dency to quit their hosts. The question of reinfection of the same ani- mal would leave it doubtful whether such long period of infection were all due to the same parasites or to renewed generations of them. The duration of the disease, which, as a rule, is variable, depends en- tirely on the degree of infection and the treatment, hygienic and me- dicinal, which they receive. It ordinarily lasts about six mouths, but excei)tionally may have an extremely rapid course of a few days, death being caused by an acute iuttainmatiou of the liver, set up by the para- sites, and occurring in from seven to nine days after the first appear- ance of the disease. Weakened by the fluke disease, the animals are more susceptible to other maladies, and these may destroy them before the primary disease has run its course. Diagnosis. — There is little difficulty in diagnosing liver-rot in the stages at which it is first noticed if the flock-master sacrifices one of the worst affected sheep. Although he may think that it hardly pays to 131 kill a sheep to find out what the trouble is, he will subsequently learn that, a little loss in the beginning leads to a great saving in theend, and therefore becomes an investment. In fluke disease not one or two lambs only are infected, but all the flock that have been feeding together. If the flock-master has a micro- scope he cau detect eggs of the fluke in the droppings, but this can only be found after the fluke has matured and the disease has well advanced. Besides, it requires some skill to make the required examination. So numerous are the eggs and so characteristic is the shell with its little cap, however, that this method forms an important element in diagno- sis. The droppings should be moistened with water and thoroughly picked to pieces, then spread evenly on a piece of glass and covered by another thin glass. The mass should be closely examined with the aid of a microscope magnifying from 70 to 80 diameters. This operation should be repeated a number of times if eggs are not found. The ex- amination of the liver is tlie best means of diagnosis. When the gall ducts are cut open the young flukes will be found in them. They usu- ally occur in smaller or larger nodular swellings. The structure of the liver is also characteristic, presenting a dark, soft, rotten ai)pearauce. Young flukes can be found by cutting into this organ and washing it in water. After allowing everything to settle, pour oil" the top and repeat the operation until the contents of the dish can be distinguislied. When spread out on aflat-bottouv ddish the flukes may be easily distinguished by the unaided eye, or, if very young, by tlie help of a small lens. If the sheep has been killed the flukes will be iseen to wriggle and curl, for they die slowly in water ordinarily warm. Pi-ofjnosk. — The disease is very tenacious, and when once on a farm is difficult to extirpate. Many farms in infected localities are rendered useless for sheep raising by these parasites. When a flock becomes infected it is uot to be expected that the disease will be stopped until it has caused extensive damage, and that only the most prompt anil effective measures will save any of the afllicted animals. Pathology.— Tha disease is seated in the liver, and all the symptoms and changes observed in other parts are directly dependent on those occurring in this most important organ. The different periods into which the various alterations have been divided are directly dependent on the [)eriods in the life history of the flukes. For our present purpose, however, it seems advisable to give but the most brief description of these pathologic changes. When the flukes first invade the liver they cause au inflammation, which is shown by a thickening of its mass. It becomes softer, and the surface, which should be smooth and glistening, becomes rough. These changes increase as the days go by, and the liver becomes softer and thicker. The surface becomes covered by thready fibers, as well as much rougher; the abdomen contains more or less dark-colored serous fluid; young flukes from one-tenth to one-fifth of au inch long 132 can either be found in serum-filled cavities of tbe liver or attached to the outside, or perhaps free in the cavity. Still later, the liver shows I^laces i)uckered up, which are caused by the reparative i)rocess and the contraction of the newly-formed tissue. There will be numerous chan- nels beneath the serous membrane visible to the unaided eye. The bil- iary canals will be found thickened and enlarged at places to the size of a hazel-nut, or even larger. In these dilatations are flukes of con- siderable size, surrounded by a greenish black, sticky mass. Some- times hard limy fragments are found in them. The substance of the liver becomes very rotten, and crackles under pressure by the finger. When the flukes migrate healing takes place to some degree, but tlie liver will never look healthy. It will grow considerably smaller and become much whiter, due to the connective tissue changes which take place. Preventive treatment, — Thomas has formulated rules of prevention against this parasite, which are founded on its life history and seesu to be eminently practical. He says : (1) All eggs of the liver fluke must be rigorously destroyed. Mauure of rotten sheep or other infected animals must not be put on wet ground. As the liver and intestines contain eggs, these, too, must be destroyed or put in the compost heap. The manure of affected aniuuils should not be stored where there is a drainage from it to the neighboring grass. It should be mixed with lime and salt before being spread on meadows or cultivated fields. (2.) If sheep are infected, let them be sent to the butcher at once, unless they are specinlly valuable and are not badly aflected. If kept, they must not be put onto wet ground. The above advice is preferable with all common stock; and the ex- ceptions, when medicine should be tried, are very few. Stock should be very valuable to repay the expense of care and treatment in face of the large percentage of death which occurs in this disease, and the ill condition of the remnant after recovery. (3.) Care must be taken to avoid introducing eggs of the fluke either with manure or fluked sheep, or in any other way. Rabbits and hares must not be allowed to in- troduce the eggs. The most prolific source of introducing parasites is in the introduc tion of infected sheep, and purchas<5rs should learn all thej" can of the history of the animals they buy, and not purchase from diseased flocks. (4.) All heavy and wet ground must be thoroughly drained. Draining is of advantage in many ways. It makes tillable land of what was before useless, either for pasturage (as shown by its infecting the flocks with a fatal disease) or for cultivation. (5.) Dressings of lime and salt (or both) should be spread over the ground at the proper season to destroy the embryos, the cysts of the fluke, and also the snail which acts as host. After draining, such fields should be cultivated and suitable crops raised on them. (6.) Sheej) must not be allowed to graze closely, for the more closely they graze the more fluke-germs will they pick up. 133 This rule is advisable wherever the sheep may pasture. Sheep on over-stocked pastures do not get enough grass, and become more in- fested with worms from having to eat close to the dirt. (7.) When sheep are allowed to graze ou daugerous grouud they should have a daily- allowance of salt and a little dry food. Exigencies can be conceived in which sheep may be allowed to pas- ture on infected ground, but, in view of the fatality attending the malady, it would seem more profitable to sell the animals while they are still in good condition than to expose them further to these parasites. Lime and salt are the two cheap i)reveutives against this parasite. The former, mixed with manure, increases its value as a fertilizer. A solution of three fourths of 1 per cent, of salt in water has been found by experiments in the laboratory to kill fluke embryos. This weak so- lution might prove too weak in tlie field, when the salt would be still further diluted by dew or rain. Perroncito has shown that the encysted cercaria) and the larvae encysted in Limncva palnsfris die in 2 per cent, salt solutions in five minutes; in 1 per cent, solutions they die after twenty or thirty-five minutes; 0.05 i)er cent, solutions kill in about the same time; in 0,25 per cent, solutions the worms live after twenty hours' immersion. The weakness of the brine necessary to kill the parasites in the labo- ratory points out that a snmll proportion of salt mixed with the lime would be very advisable. Salt was first advised from a knowledge of the fact that sheep never became infected with flukes on salt marshes. Stronger solutions of salt also kill the snails, which are the hosts of the embryonic fluke. The time of year for scattering the lime or salt on the fields is the first part of June, July^ and August. Neumann advises mixing two teaspoonfuls of salt for each sheep with the ground grain they eat. Perroncito advises the addition of one-half of 1 per cent, salt to the water they drink (about a heaping tablespoonful to each gallon of water). Although the flockmaster can never completely cure his sheep, he may, by judicious medication, so improve the condition of the con- valescent animals that they will take on considerable flesh. Many vegetable astringents and tonics have been tried, with more or less profit, but it is to the mineral astringents that we look for the best re- sults. Sulphate of iron and common salt, dissolved in the drink or mixed with the food, are among the best and cheaj)est. Medicinal treatment. — Some experimenters have endeavored to kill the flukes, and have met with varying success. The remedies tried have been extract of male-fern, given with turpentine or benzine, castor oil, etc. For proportions of these remedies see remedies for Twnia ex- pansa. Mojkowski, according to Neumann, has obtained encouraging results against the distomatosis (the fluke disease) of sheep with naph< 134 tlialiiie, given twice a day during a week, in from 10 to 15 grain doses, alone, orniixed with i)owdered gentian. The following recipes, to be used as licks, may be useful in small flocks : Take of sulphate of iron, 2 ounces ; calamus root, 1 pound ; of crushed oats and roasted barley malt, of each, 20 quarts. This quantity is sufllcient for one hundred sheep. Other mixed grain may be substi- tuted for the barley-malt and oats. Or, sulphate of iron, 1 ounce, and powdered juniper berries and gentian root, of each, 1 pound. Mix with 20 quarts of grits. A lick for fifty sheep. A very complicated but apparently good tonic remedy is known as Spinola's worm-cake, see page 121. Vieth recommends the following: Oak bark, calamus, gentian root, and juniper berries, of each 2 pounds. Pulverize and add pulverized sulphate of iron, 1 pound; pulverized cook- ing-salt, 10 pounds. Mix thoroughly, and give each sheep a teaspoonful every two or three days. The medicine is most easily administered mixed with meal, chops, bran, etc. Either of the vegetable ingredients of the above recipes can be omitted and substituted by some other well- known tonics, though each is thought to have its special virtues. The dietary treatment is the most valuable. Grain-feeding, mashes, strong meals, as flax seed meal cakes, or cotton-seed oil cakes, can be given in judicious quantities. The general treatment should embrace every means known to the flock-master to sustain the health of the flock. Police sanitation. — The meat of slieep aftected with liver-rot is safe to eat, but in advanced stages of the disease it is too watery, lean, and in- nutritious to be wholesome food, and is only an inferior article. When killed during the early stages of the disease it is more salable ami nutri- tious. Later on, it should not be put on the market or received by buyers. 13G DISTOMA HEPATIC UM, Liun. Plate XVI. Fijif. 1. Adult fluke, luatiiral size : la, young fluke, natural size, (Raillet.) Fig. 2. Eggs: a, egg with developing emWryo; b, egg with embryo; c, egg-shell. (Raillet.) Fig. :?. Ciliated and free embryo : «, perforating apparatus ;/>, ocular spot. (Leuck- art. ) Fig. 4. Encysted embryo found in suails. (A.P.Thomas.) Fig. 5. Diagram of digestive apparatus and nervous system : a, mouth sucker; b, pharynx; c, oesophagus; d, branches of intestine ; e, their brauchlets ; /, nerve ganglia ; g, ventral nerve. (Raillet.) Fig. 6. Limnrvns trimcatuluft, the principal snail which is the larval host of the fluke in Europe: a, natural size. (Raillet.) Fig. 7. Redia of ]>i8toma hcpadeum : a, mouth; h, pharynx; c, digestive tube; d, the so-called germinative cells destined to produce cercaria'. (Leucdiart.) Fig. 8. Redia coutaiuing cercari;e: o, mouth ; />, pharynx; c, digestive tube; d, d, cercaria^ (Leuckart.) Fig. 9. Cercaria dissected from its cyst: a, anterior sucker; ft, ventral sucker ; c, pharynx ; d d, branches of the intestine terminating in cieca. (Leuckart.) Fig. 10. Grass stalk with three encysted young flukes, a, a. (A. P. Thomas.) Fig. 11. Free-swimming cercaria just before it is about to encyst. (A. P. Thomas.) Fig. 12. A slightly older stage than Fig. 11. (A. P. Thomas.) Fig. 13. Genital apparatus of the liver fluke : a, digestive tube ; b, ventral sucker ; c, anterior testicle; d, its deferent canal ; e, posterior testicle; /, its def- erent canal; g, seminal veside ; /(, genital sinus; i, cirrhus pouch; /, ovary; A, oviduct; /, shell-gland; m, yolk glands; «, longitudinal and 0, transverse yolk-glaud canals ; p, uterus; g, vagina. (Raillet.) U" :xt^ 10 21 3t4 Haines, del. DISTONIA HEPATICUM (The Liver Fluke.) 137 DISTOMA LANOEOLATUM, Meblis. Plate XVII, Figs. 11 to 15. Description. — Body semi-transpareut, spotted with brown by the eggs, length from 4 to 9'"'", width 2.5""", lji,nceolate, obtuse behind, attenuate forward, and terminated by the oral sucker, which is nearly as large as the ventral. Integnment smooth, intestine with two branches, not further subdivided. Penis long, generally straight. Genital orifices very close to one another. Eggs ovoid, length from 0.037 to 0.040'"'". (Neumann.) The life history of this parasite seems to be as yet unknown, but it is believed to be analogous to that of Disfoma hepaficum. The embryo (Fig. 11) differs from that of D. hepafieum in being globular, armed with a cephalic spur, and in being ciliated only over the anterior third of the body. Its movements are said to be slower. Ercolani has shown that young embryos measuring 1'"™ first show traces of a digestive system (Fig. 14), and that the digestive system is preceded by groupings of cells, which first outline the testicles, then the penis, and lastly the ovaries. Two species of suails, Planorbis margi- nntns and Helix carthusina, which contained cercarire, have been pointed out, the former by WillemoesSuhm and the latter by Plana as the in- termediary hosts of the fluke. This species of fluke never produces symptoms or lesions as gra^e as D. hepnticum, and can only occasion aqueous cachexia or dropsy. This relative harmlessness is at- tributed by Leuckart to its small size and the absence of spines on the skiu. The two species are most often found together in the same host. By reason of its minute size, D. lanceolatum penetrates into the finest biliary cajials, where the young D. hepaiicum can not enter. Because the individuals of the former species escape observation on account of their small size they appear to be fewer in number. Friedberger has ex- tracted some thousands from the biliary passages by squeezing the liver. They are also found in great numbers in the gall bladder and in the intestine at the time of their emigration. (Neumann.) The means of prevention and treatment are the same for this as for Distoma hepaticum. Treatment is of more avail. PARASITES OF THE RUMEN. Amphistoma conicum, Zeder. Plate XVII, Figs. 7 to 10. Body of a rose tiut, irregular, and more or less dark. It is ovoid, narrowed in front^ and swells gradnally even to the posterior end; obtnse and slightly recurved on the ventral fiice. Length from 10 to 13""", width behind from 2 to 'A"'"'. (Nenmann.) This parasite has been found in sheep in India au(i Australia. The author has not observed it in this country. It oc3nrs scattered amongst the large villi of the rumen or first stomach, attached by its posterior sucker. It is said to cause but little digestive disturbance. Figures and description of this parasite are presented, as it is a representative of the genus, and may sometime serv^e for generic determination of allied parasites which may be found in this country. 138 • 140 LINGUATULA T^NIOIDES, Eiulolpbi. Platk XVII. Fig. 1. Male, natural size. (Cobbold.) Fig. 2. Female, natural size. (Cobbold.) Fig. 15. Egg with contained embryo. (Lenckart. ) Fig. 4. Embryo escjiped from egg-shell. (Lenckart.) Fig. 5. Pupa nine weeks old: «, anus ; fc, mouth. (Leuckart.) Fig. 6. Llngnatula deniU'ulatitm. (Leuckart.) AMPHISTOMA CONICUM, Rudolphi. Fig. 7. Piece of the rumen of a cow, showing the parasite attached between the papilla? by their large posterior sucker: a, au isolated individual, natural size. (Raillet.) Fig. 8. Dorsal view, X'2. ^Blauchard.) Fig. 9. Lateral view, X2. (Hlauchard.) Fig. 10. Egg of an amphistoma, XHO. (Cobbold.) DI8T0MA LANCEOLATUM, Mehlis. Fig. 11. Ciliated embryo. (Leuckart.) Fig. 12. Early stage of development, in which there is no digestive apparatus. (Ercolaui.) Fig. 13. Another stage : a, a, groups of cells representing the future testicles. (Erco- laui.) Fig. 14. Stage showing the testicles plainer, a, a ; h, the rudimentary cirrhus pouch, and c, the digestive system. (Ercolaui.) Fig. 15. Adult, natural size figure by its side: a, pharynx; />, o'sophagus; c, branches of iutestine ; d, ventral suckers ; e, e, testicles ; /,/, deferent canals ; g, cir- rhus pouch ; h, ovary; i, albuminous glands; k, uterus; I, vagina. PLKTE XYII Haines, del. LtNGdATHLA TAEXIOIDES. AMPHISTOMA CONICUM. DISTOMA LANOROLATUM. THE STOMACH ROUND WORMS. Strongylus CONTORTUS, Illld. Plate XVIII. Strongylm confortus, or the twisted strong.yle, is an inhabitant of the fourth stomach of sheep and goats. Though in the majority of flocks it produces but little if any disturbance, yet there are times when, in connection with other species, it causes disease which may carry otf numbers of lambs. In the southwestern States and Territories the disease has been called lombriz, a corruption of the Spanish word lombrici, meaning- worms. The later writers seem to be inclined to attach a si)ecific meaniug to this word, while the Mexicans, who used it, merely intended to say that the lambs died of worm disease. Description. — Female, 18 to :iO'"'" loug; male, 15 to *20'"'" long; body reddish; female luarked by a double spiral white line, thicker toward the caudal end. The «kiu shows eighteen lougitudinal Hues. The mouth is louud aud without visible lips or papilhe. The ueck has two barb-like side papilke; uuicellular glands scarcely visible. The male is about two-thirds as long as the adult female, and shows no spiral Hue. Bursa deeply bilobed, with a small dorsal lobe attached to one of the pair. The lobes are somewhat longer than broad. The ventral cost;ie are separated ; the lateral are double and separated ; the dorso-lateral is attached to the lateral group near its base; the dor-sal cost;o support the dorsal lobe and each branch is doable; the twofold character is indicated by a little notch. The lateral costiB are irregu- larly divided, many variations being observed. Spicula two, embracing a chitinous piece between them. They are short, cyliudrical, barbed on one side near the end, and have blunt tips. Female: Vnlva 3""" from the tail and covered by a nipple- like projection, 0.5'"™ long; the latter has thin borders, and is concavo-convex, to fit the body when pressed against it.. Uteri two, each opeuinginto the common vagina ; one is anteriorly directed and the other posteriorly, with a short loop between it and the vagina. The ovary of the posterior uterus is reflected anteriorly to rejoin its fel- low, and together they wind spirally around the dark-colored intestine. The ovoid eggs are laid in the gastrula form, or after they have passed through the segmenta- tion stage; length, 0.070 to 0.097"""; width, 0.043 to 0.054'°™. Occurrence. — This worm may be found in all stages in the fourth stomach or abomasum of sheep. When collected immediately' after death from a slaughtered sheep they may be detected adhering by their heads to the mucous membrane. They are then of a reddish color, which may be because they feed in part upon the blood of the victim. Tlie life history of Strongylus contorlus seems to be apparently simple. Among a number of lambs kept at the Experimental Station in 18S8 were two or three which had been raised thei-e. A post-mortem exami- 141 142 nation of one of these, with four other lambs which had been at the Station for the five previous mouths, revealed numbers of IStroiujylns eontortufi in all stages of growth, and of Dochmlus ccrnuus, Trichoceph- alns affinia and Tcenia expansa. These lambs were sup[)lied with well wa- t«"r, and were allowed to run iu a small, dry, grassy yard connected with a stable. The presence of these species of all sizes iu the former group of lambs showed that they acquired them on the place, and that their development was direct; that is, they did not pass through a secondary host in passing between the sheep and thelambs, for all of the conditions were uuder inspection. The grass iu the 3 ard became very short, and probably it was because the sheep ate it so close to t he ground that they became more infested with worms than sheep ordinarily do. The his- tory, therefore, is probably as follows : The eggs fall to the ground ; they are eaten by other sheep along with their feed, and they then ar- rive at the stomach and develop there. The disease they cause can not easily be distinguished from that pro- duced by other iutestinal parasites. In the worst cases, besides a gen- eral lack of tone aud good health, there is weakness, paleness, some fever, diarrhea, etc. In fatal cases death is said to occur within a very few days after the illness is observed ; but, as the parasites develop slowly, it is probable that no symptoms of illness are apparent until after the lambs have been ailing for some time. A positive diaguofeis is to be made only by i\, post-mortem examination. The little worms, if [)resent iu large numbers, will appear like masses of threads lying iu the stomach. If the sheep has been killed for examination, the worms will be seen wriggling and squirming in all directions. Treatment. — Various remedies are proposed, but of those available an emulsion of milk and tur[)eutiue, prepared by shaking the mass well, seems most practicable. Add 1 part of spirits of turpentine to 16 parts of milk, and give from 2 to 1 ounces of it to each animal, according to age of patient. Oue dose should be sufficient ; if not, repeat it in three or four days. Or, take of linseed oil, 1 ounce; turpentine, one-half ounce, shake well and give Jis one dose. Quantifies sufficieut for any number of sheep may be made upiu these proportions. The following recii)e is from Finlay Dun's Veterinary Medicine: Common salt, 3 pounds ; powdered ginger and niter, half a pound each ; dissolved iu 3 gallons of warm water ; add 21 ounces of turpentine when nearly cold. The dose for iambs between four and six months' old is 2 ounces. The entire quantity is sufficieut for one hundred and sixty lambs. For delicate landis, which are coughing and i»urging, the same writer recommends oil of turpentine, i)owdered gentian, and laudanum, 2 ounces each, all to be dissolved and stirred in 1 quart of linseed tea or lime water. This quantity is sufficient for ten or twelve doses. Ziirn recommends (after Rabe) the picrate of potash, because it is less irritating to the [)atients. The dose ior a lamb is from 2.^ to 5 grains; for an adult up to 20 graius. It can be given dissolved in water. 143 Dr. H. J. Detiners, in a report to the Commissioner of Agriculture, 1883,- on the diseases of slieep in Texas, fecommenils the use of tartar emetic as follows : A half pound of tartar emetic is to be dissolved iu 12 quarts of water, and from 1 to 2 ounces of the solution, containing from 5 to 10 grains of the remedy, is to be given each patient, depend- ing on its size. He recommends dosing out of a small 2-ounce vial, and in small swallows. Good, nourishing food, and a dry yard in summer, or a healthy, well- ventilated stable in fall and winter, are advisable. In giving medicine, drench from a horn, a spoon, or a stout glass bottle. Bottles are always liable to break. Let an assistant throw the sheep onto its haunches and hold it between his legs, back toward him. With the lower jaw seized in his left hand, from the left side, he can either seize the upper jaw or pull out the cheek-pouch with his right. The medicines are best administered while the sheep are thirsty. Small doses va-dy be diluted, but a dose of 4 or 6 ounces is more apt to run directly into the fourth stomach than larger doses ; otherwise, some of the latter might be diverted into the second stomach and fail of an immediate effect. The following recipe was recommended to the readers of Field and Farm, August 7, 1889, as a preventive remedy for worms in sheep. Mr. G. B. Both well, of Breckenridge, Mo,, who used it for fifteen years with success, is its author. Salt, 1 bushel ; air-slaked liuie, 1 peck ; sulphur, 1 gallon ; pulverized rosin, 2 <|uarts ; put iu trough with cover, where sheep can have free access. When sheep become thoroughly infested witii worms death is almost sure to follow, but the above, if kept before the sheep, will surely act as a preventive. A more complicated arsenical recipe for worms, the source of which is unknown, is as follows: Take of arsenic, washing soda, and carbonate of soda, each 1 ounce; put them into 2 quarts of hot water; boil, and stir for one-half hour, then add 10 quarts of cold water. The dose for a lamb, after weaning, is one-third of a gill. If the lamb is not very sick give but one dose, but if badly affected repeat iu nine days. 144 STRONGYLUS CONTORTUS, Rud. Plate XVIII. Fig. 1. Adult feraalo, X6: a, bead; b, ovaries wound arouud tlie intestines; c, c, uteri; d, a large papilhc, just iu front of and covering the vulva ; e, anus. Fig. 2. Adult male, xG. Fig. 3. Head : a, two barb-like papillio ; b, mouth ; c, lesophagus ; d, iutestine. Fig. 4. Eggs, highly maguilied: a, eggs before they have left the ovaries; b, egga showing nuclei ; v, eggs after they have passed through the oviduct ; d egg with one cell; e, with two; /, with four; tj, with eight; h, with many; i, egg as it is laid. Fig. 5. Skin, showing nine of the eighteen longitudinal lines. Fig. (i. Portion of female: a, the intestine; b, h, the ends of the ovaries. Fig. 7. Caudal eud of female : a, the anus ; b, the vulva ; c, vagina ; d, d, uteri tilled with eggs ; e, oviduct ; /, /, ovary ; (j, iutestine. Fig. 8. Spicula, enlarged. Fig. y. Bursa, expanded to show costic : a, ventral ;&, veutro-lateral ; t, lateral ; d, dorso-lateral ; e, dorsal ; /, sjiicula. Fig. lO.G roup of adult males and females, natural size. Fig. 11. Caudal end of male : a, bui"sa; i», spicula ; c, seminal reservoir ; d, iutestine. PL^iTE XVIII c/ -^W C Geo. Marx, dd. STRONGYLUS CONTORTUS, (Tne Twisted Stomach Worm.) INTESTINAL ROUND WORMS. Sheep in this country harbor at least six species of round worms, parasitic in the small and large intestines, which their ancestors brought with them from Europe. They are : IStroiigylusJilicolliSjRiul.', Stronfiy- lus ve/i^ncosMs, Rud., both found in the duodenum ; Dochmius cernuus, Creplin, found in the small intestine; Ascaris liimbricoides, Linn., also found in the small intestine; Trichocephalus affinis, End., found in the caecum; Sclerostotna hi/postomum, D'wsmg, found in the large intestine. A seventh species, (Esophagostoma Columbianum, Curtice, is found in the large intestine and is probably indigenous to this country. Of all these the last species produces by far the most injury. Dochmius cer- nuus is next in im[)ortance. The injury inflicted by the others may, at times, and in conjunction with other parasites, be considerable ; but disease which may be ascribed to either species alone has not yet been rej)orted. From personal observations it is believed that the number of individuals in each sheep are usually too few to ever cause extensive loss, and that their greatest harm is from the little discomforts which they may add to those produced by the more destructive parasites. At certain seasons of the year some of the above species are abun- dant, while at other times but few individuals may be found. Strongij- lus fiUcolUs and S. vcntricosus are usually found associated together, but are so small that they can easily be ove-rlooked, or if found may be re- garded as the young of other species. Dochmius cernuus is about an inch long, and being large is readily detected. Ascaris lumbricoides is rare, having been met with only a few times by helminthologistsin any country, and in but one lot of sheep by the author. Trichocephalus a.ffinis is usually found in young sheep, but is met with in comparatively small numbers. Sclerostoma hypostomum seems to be a rare species in the East, the single instance in which it was met with in these investi- gations being in examining an old sheep in Colorado. (Esophagostoma Columbianum seems to take the place of the last-named species in the East, and is found most abundantly in spring and summer in its adult state, although it is present throughout the year. The most favorable time for collecting mostot these species has been in late fall and win- ter. The quantities in which the various species may be found vary with the season and the flock examined, so much so that no accurate statements of percentage of occurrence or of distribution can be made. The symptoms which these worms produce are those of general debil- 23038 A p 10 145 146 ity and indigestion. They Are caused by the irritations set up in the intestines by the worms. It is found as a rule that a weakly shee[) is attacked by more than one species of parasite at a time, and, conse- quently, it is difficult to learn the symptoms produced by either of them acting alone. Then, too, it should be remembered that symptoms are sometimes incorrectly attributed to parasites when they really result from diseases due to entirely different causes. Even the fattest sheep harbor a few parasites, and some of them many more than one would suspect from their apparent good health. The treatment should be directed toward keeping animals in good health and in preventing them from acquiring parasites by providing them with pure water and pastures which are not overstocked. Medic- inal treatment will rarely be attempted for any single species of these parasites. A remedy which would prove effective for any one of them would d o for all. Their treatment will therefore be embraced under that for Dochmius cernuus. Strongylus filicollis, Eud. Plate XIX. Description. — Male, 8 to 15'"'" ; female, IG to 24""". Body very small ; cepbalic eud thread-like aud tortuous ; caudal end, especially of female, thick and straight. Skin marked by loiigitiuliiial lines stauding at about equal distances apart. Head very small, subspherical, continuous, with a swollen cylindrical neck;. the length of the iudated portion is about one-fourth that of the (esophagus. Four head papilhe visi- ble; the lateral papilUe are probably present, but can not easily be made out. Mouth terminal ; apparently without chitiuous armature. ffiesoi)hagus linear spatulate ; unicellular gland ducts present. • Position of ventral cleft not determined. Male: Filiform and uniform in size throughout its length ; bursa strongly bilobed ; the membrane being well filled ou the dorsum but absent on the veutrum ; can not be spread without tearing; cost;e generally symmetrically arranged, ventral slightly separated; ventro-lateral either joined to lateral or ventral ; lateral scarcely sej)a- rated; dorso-lateral joined to the dorsal, dorsal notched and with the dorso-lateral form a stem, the two pairs uniting to form the dorsal stem ; the lateral costre are the longest. Spicula 1..^)""" long, cylindrical, very slender and dark colored ; their points are tipped with an oval inflation of the membrane and are more or less firmly attached. Female: Tail obtuse; vulva situated about one-third of the entire length of the worm from the tail; body of the egg-bearing female enlarged in front of the vulva by the swollen and crowded uterus. Uteri directed each way from the vagina, and filled with comi^aratively few and large eggs in all stages of segmentation. Eggs 0.i7ium long, 0.08'"'" wide, ovoid ; laid in the morula or gastrula stages. Embryo not observed. This species occurs with Stromjylus ventricosus in the upper eud of the small intestine of sheep and lambs. It is often mistaken for the young of other si)ecies, and has been identified as a variety of Strongylus conlortus. It is needless to observe that it is specifically different from any other nematode found in sheep ; a glance at the plate illustrating the species is sufficient proof of this. It is quite abundant during fall 147 aud winter. European observers seem to find it rather infrequently. The species appears to be a comparatively harmless one. It is probably the young of this species which Wedl found associated with Ttvnia expansa, and named Tricho so ma papillosum. Wedl characterized it as having a double uterus aud the mouth furnished with four papillse. Neither of these characters is inconsistent with Strongylus Jilicollis, while the fact that Wedl's species, with a double uterus, was classified in a genus which has a single" uterus aud spicule indicates an error. 148 STRONGYLUS FILICOLLIS, Rud. Plate XIX. Fig. 1. Adult male, natural length iiulicateil byline: a, head; b. bnrsa and spieiila ; c, worm enlarged twice. Fig. 2. Adult female, natural length iudieated byline: a, head; b, vulva; c, anus; d, worm enlarged twiee. Fig. 3. Head: a, mouth surrouuded by four papilhe ; b, tcsophagus ; c, inflated skin surrounding head and neck. Fig. 4. Skin: shows nine of the eighteen longitudinal lines. Fig. 5. Cephalic end : a, the head ; b, the tcsophagus ; c, c, the unicellular gland ducts. Fig. 6. Bursa: a, the spicula ; b, their knobbed tips. Fig. 7. Portion of the spicula enlarged. Fig. S. Ovary of female with inclosed eggs showing segmentation. Fig. 9. Bursa spread out: «, ventral costai ; b, veutro-lateral ; c, lateral ; d, dorso- lateral ; (', dorsal. PLSTE XIX Haines, del. STRONGYLUS FILICOLLIS (The Thread-Necked Worm.) 149 Strongylus ventricosus, Ru(1. Plato XX. Deseripiion. — Male, G'"'" ; female, 13'"'". Body very small and comparatively stout. Males and young femalt^s usually si)irally coiled; body of old female straight, with cephalic end coiled. Slcin transversely striate, marked by fourteen longitudinal lines; the five larger standing at equal interspaces on the dorsal and ventral sur- faces, the two smaller standing close together on the sides. The crossings of the striiB and longitudinal lines make pits which are quite chai'acterislic. Head little larger than neck, but hemispherical and coutiimons with the cylindrical inflation of the neck. No head or neck papilLe visible. Mouth terminal, very small and round. The end of the head is furnished with a hemispherical cap-shaped chitinons piece. Other oral armature apparently absent. Inflated portion of head about one-fifth the length of oesophagus. Unicellular glands not apparent. Male about one-half the length of female ; bursa conical and bilobed, the ventral membrane being narrow, the dorsal wide; ventral costaj not separate, smaller than the ventro-lateral, which is stout; lateral widely separate and apparently formed of three nearly equal costte; dorso-lateral slender; dorsal notched at the end and giving oli' laterally a very short side branch. Spicula 0.35'"'" long, short and stout, and margined by a fringe-beari no- sinuous membrane. They are tipped by a soft pad-like expansion of the membrane. F(;male characterized by a swelling at the vulva, which gives the species its name. This character is more pronounced in older specimens. Vulva from two-ninths to one-third of the entire length of the female from the tail. Uteri directed anteriorly and posteriorly from the vagina. Ova 0.13'"'" long, 0.07'"'" wide, comparatively large, and found in all stages of segmentation. Embryo not observed. Tliis species is found in association with Strongijlus fiUcolUs iu tlie upper part of tlie small intestine of sheep. It can be separated by its smaller size, its spiral twist, and the markings of the skin. It is best found in fall and winter. The species was originally described from specimens taken from cattle, and so far as known has never before been noticed as being found in sheep. The female in its adult stage re- sembles the small specimens of 8. fiHcnUis. It is apparently the cause of little or no disturbance, altliougii from the appearance of its mouth parts it might seem to be more injurious than 8. filicolUs. 150 SrRONGYLUS VENTRICOSUS, Rud. Plate XX. Fig. I. Male, uatiiral size indicated by line audsiuill ii>^iiro of worm: a, head; h, bursa and spicnla. Fig. 2. Female, natural size indicated by line and small figure of worm: a, head; b, genital orifice. Fig. '^. Head: a, mouth; bb, chitinous cap surrounding it; c, (esophagus. Fig. 4. Portion of skin showing eight of tlie fourteen lines: a a, the two lateral lines: b b, the dorsal and ventral lines. The dots indicate depressions where the longitudinal and the latitudinal lines cross. Fig. f). Cephalic end: a, head; b, €eso])hagus. Fig. G. Spiculum: a, its chitinous portion; b, the protractor muscle; c, the fringe edging the membranous portion ; d, the distal end covered by membrane. Fig. 7. Female, natural size indicated by line: This female is more characteristic of the species than that of Fig. 2, but is not quite mature. Fig. 8. Bursa with spicnla. Fig. 9. Bui'sa spread out: a, ventral cost;© ; b, ventro-lateral ; c, lateral, of which there seems to be an accessory branch ; d, dorsal-lateral; e, dorsal, which also has an accessory branch. PLSTE XX i IMCL •5 liiilf « ; = :,' O >-:#/ ':« «.): If hK 'I A • \ V-e Haines, del. STRONGYLUS VENTRICOSUS (The Ventricose Worm.) THE LARGE ROUND WORM. ASCAEIS LUMBRICOIDES, Linn. Plate XXI. Description. — Male and female 150""" each ; in the specimens figured 120 each. Body- very large and thick, obtuse at each ead, of a yellowish color, skin marked by rings. The site of the vulva is marked by a smooth wide baud about one-third the entire length from the head. There are three longitudinal bauds ; the two wider are nearly lateral ; the third is ventral. The head end is abruptly terminated in three well- formed lips; the dorsal possesses two papilLe near its base and the two ventral one each. Each lip consists of a (ihitinous support covered by cuticular membrane. The tail of each is obtuse. The description after Schneider {Monographie d. Nematoden, p. 36) is as follows : " Lips nearly equal, their form changing from semi-circular to quadrangular. Teelh very tine. The lobes undivided. The azygoa lobe has a rounded point, and reaches with its anterior end to the front of the saddle. Cuticular rings longitudinally ribbed, Vulva 40 to 6.V"'" from the cephalic end. Vagina U""'" long. Tail of the male flat on the ventral side. Only behind the anus is the skin broadened into a bursa; sixty-nine to seventy-five papilhe on pach side ; the first seven pairs of these papill.B stand behind the anus ; the second pair stand nearer the ventral line than the first and third ; the fourth and fifth pairs and the sixth and seventh pairs are united into double papillic. (See Fig. 7.) The succeeding stand first in a single row, then in pairs forming a double row; and on the whole they are very irregular. An unpaired papilhe stands in front of the anus. Spicula two, each a single tube, with its point terminating bluntly and irregularly in front. "This parasite occurs in the small intestine in man and swine, and sometimes forces its way into the gall ducts, stomach, oesophagus, nose, and lungs." In one flock of sheep only has the author found this parasite. In this flock it occurred in six animals, a majority of those examined. That it is not a common parasite is attested by the writings of various Euro- pean helminthologists. A few of the latter have described a special species {Ascaris ovis), from the sheep, but as it is infrequently found it seems to be an inconstant parasite or an adventitious one, i. e., it is probably a constant parasite of some other domesticated animal, and occasionally only becomes parasitic on sheep. Besides, the specimens figured always seem to have been immature, and do not difier from Ascaris lumhricoides of the same size and age. In the single flock in which this worm was observed all the specimens found were immature. The vegetative organs of these specimens dift'er in no essential point from those of Ascaris lumhricoides as figured by various authorities. In addition, a close comparison of these specimens 151 152 with equally immature Ascaris taken from pigs gave no determinable difiterences. These remarks i)resiii)pose that A. lumbricoides of man and A. suilla of swine are identical species. The description seems to be incomplete, but as the species is neither peculiar to nor commonly found in sheep no attempt is made here to enlarge it. The species can easily be determined by a comparison with the figures. Sheep probably acquire this parasite while pasturing after swine. As few are infected, little harm is accomplished by the Ascaris. It is more abundant in summer and fall than at other seasons. 154 ASCARIS LUMBRICOIDES, Liuu. Plate XXI. Fifj. 1. Adult male, natural size. Fig. 2. Adult female, natural size. Fig. 3. Top view of head enlarged; a, dorsal lip with two papilUe ; h, h, ventral lips with one papillte each. Fig. 4. Head, ventral view. Fig. 5. Head, dorsal view. Fig. G. The lips greatly enlarged and flattened: a, a, papillie ; b,b, the serrated edge of chitinous support. Fig. 7. Tail of male, ventral vi6w : a, anus; 1, 2, 3, 4 and 5, 6 and 7, the post- anal papillir"; 8, the unpaired pre-anal ; 9, y, 9, other papilhe. Fig. 8. The two spatulate spicula: 8a, one of these enlarged. Fig. 9. Portion of female: a, the geuital opening; b, the ventral line; c, one of the two lateral lines. Fig. 10. Tail of female, lateral view. Fig. 11. The same, ventral view. PLHTE XXI Baines, del. ASCABIS LUMBRICOIDES, (The Common Round Worm.) t. To. l.ilh . R.-aiii 155 DocHMius CERNUUS, Creplin. Plate XXII. Description. — Female, 20 to 26""" ; male, 13 to 17""". Body very dark colored ivhen fresli ; whitened when preserved; attenuate towards the ends. Head cnrved, the mouth heing directed dorsally. Month round, smaller than the oral surface, and opens into an ovoid dark-colored capsule. About the opening stand four teeth, two on each side, their base being sunk into the capsule and their free edges projecting into the cavity. Tlie ventral are the larger, thiclcer, and more opaque ; their edges form an unbroken sinuous line. At the caudal opening of the capsule are one pair of ventral and a single dorsal tooth; the latter is conical, very large, and rises to near the mouth. In the pharyngeal opening are six very small club-shaped, spinous, chitinous appendages of the oesophageal supports or rods; they seem to be jointed. TIjere are six papillte — dorsal, lateral, and ventral pairs. The lateral may give off a branch on the dorsal side. There are two lateral neckpapilhe, nearly opposite the middle of the oesophagus; the ventral cleft is situated a little anterior to a line con- necting the latter. Unicellular neck glands quite plain. Male: Bursa funnel-shaped ; will not spread without tearing ; costo' unsymmetrical as to form; ventral pair not separated ; lateral, widely separated; dorsal notched ; dorso-lateral unequal in length and differently attached to the dorsal stem. Spicula O.G""" long, aculeate, fenestrated, and provided witli a narrow membranous margin. Female: Vulva about three-fifths of the entire length of the body from the end of the tail. Vagina opening at right angles to the side of the body. Uteri, lying one anterior, the other posterior ; each forms an S'^il^*^ loop; the anterior ovary is di- rected towards the tail, and, with the posterior, forms an intricate sinuous net-work surrounding the intestine. Eggs elliptical ; laid in the morula stage; length, 0.06™™; width, 0.03">">. Occurrence. — This species inhabits tlie small intestine of sheep, and attaches itself to the intestinal walls by its stout oral armature — the so-called teeth. It lives upon the blood of its victims. The life history of this S[)ecies of Dochiniiis has not been determined, but there is no reason for supposing it different from that of D. trigo- nocephalus, the alliecl species found in dogs. Tliis life history has been determined by Leuckart {Bic Memchlichcn Parasiten, Baud II, pp. j32- 134), and is essentially this: The eggs pass from the dog to the gi^onnd, where, in wet places, they undergo a development of the vegetative organs. If at this stage the young are swallowed by another dog they develop into adults. The development outside the dog may consume from three to six days. The worm may then continue living without further development for an indefinite time, depending on the conditions by which it is surrounded and the favorable opportunities for being eaten by the dog. Its development in the dog occupies about two weeks. The time consumed may be supposed to be that occupied by the development of Doehmius cernuns with approximate certainty. Leuckart states that though he saw some of the embryos enter snails while in their free living state, that this condition was an unnecessary one, and that the worms underwent no development while in the snails. It may be that if these parasites can enter the snails, their opportuni. 156 ties for safely passing the iiulefiuite time prior to finding tlieir way into their final host are increased. In my own experiments in keeping a nnmber of lambs in a circum- scribed space for five or six months after purchase, and in confining two others raised there with them, allowing them no water save such as was pumped for them, Doclimius ceniuus were found of various sizes in the lambs of each set. The two lambs raised on the place must neces- sarily have acquired them there. These parasites either developed to a certain extent in the iron watering trough or in little pools which could have collected and remained in the yard for a day or two after a rain, or the lambs were infected from the dry hill-side of the inclosure. The disease can only be diagnosed by the flock-master from a post- mortem examination. It has been recommended to diagnose these para- sitic diseases from the eggs of the worm found in examining the feces by the aid of a compound microscope. Such a plan is very tedious in its execution, and impractical save to one already skilled in the work. Tlie disease caused by Dochmius cernuus receives little attention in veterinary works. This is due, in all likelihood, to the fact that not more than two or three hundred of the parasites ever seem to be pres- ent in one sheep, and generally there are less than one hundred ; then, too, if other parasites are found present the illness would probably be ascribed to them. If, however, we may be allowed to infer tlie effects which would be caused in sheep from the effects which Dochmius duodenalls, a related species, produces in man,* in whom it has caused epidemics characterized by progressive anaemia, and if we may accu- mulate corroborative evidence from the disease which Dochmius trigo- nocephalus, a third species, j)roduces in dogs, we may fairly infer that the species causes more disease than has been suspected. Nor is its comparative paucity in individuals any contraevideuce, for in human patients affected with this disease the species is represented by usu- ally less than a hundred specimens, although as high as two or three hundred have been found in one patient. In dogs the author has found about the same number. The intestinal lesions are obscure to the unaided eye, except at those poiuts where the parasites have been attached. Here, if the worm has recently loosened its hold, there is a slight blood extravasation. The parasites maintain their hold by the chitinous cup with its projecting oral teeth, and in some way cause a hemorrhage, upon which they feed. The six pharyngeal spinose appendages may aid in wounding the deli- cate epithelial cells. It seems impossible that a dozen or twenty, or even fifty, specimens of Dochmius could, b^" creating such little injuries in withdrawing blood 157 from its host, cause the severe disease aud progressive auaeuiia ascribed to it in man, but such has beeu deteruiiued to be the fact from cliuical and post-mortem observalious. It may be that there is a reflex, sj'mpa- thetic action stimuhited by them of which we can take no account. The further changes observed in patients affected with Bochmius are much the same as in tliose aft'ccted with other parasites, except that anaimia with its attendant eifects seems to be the most prominent. The disease is one which begins in early lambhood and i^rogressively continues, the severity depending on the number of parasites entering the intestinal canal. The adult probably lasts through the winter aiul continually lays eggs which pass to the ground. The character of the season, of pasturage, and of tlie water, in being either favorable or unfavorable to the preservation of the young worms while on the ground, will therefore determine the amount of infection and sickness during the following season. The preventive treatment for the intestinal worms is the same as that advised for the lung worms — good care, pure water, i)lenty of grass, sufficient grain feeding, salt, anil separation of sick from the well. For the reason that the disease has not received the attention its impor- tance demands the medicinal treatment has not been worked out with the thoroughness that some of the other parasitic diseases have re- ceived. Medical treatment. — In man the most eflective remedy is extract of male fern, combined with powdered male fern, the remedy to be pre- ceded five or six hours by a dose of castor oil. This combination is also a good one to administer to dogs in the following proportions: Extract male fern, 40 grains ; powdered root of male fern, 75 grains. This mass must be made into ten pills with yellow wax, and all given at once. The dose of powder of male-fern root for sheep is from 1.^ to 3 ounces, and of the extract from 2 to 4 drams. As boluses are not only incon- venient to give to sheep, aud do uot pass directly into the fourth stomach, the administration should be by drenching. I should advise that the extract be mixed with from 2 to 4 ounces of castor oil. Other remedies advised for the round worms are wormseed, wormwood, and santouine. The latter is an alkaloid obtained from a species of Ar- temisia. As the lirairie lambs love to eat sage, of which there are a number of species belonging to the genus artemisia, it is likely that these plants may prove beneficial to theui through medicinal qualities. In my examinations of Western prairie sheep I do not now recollect hav- ing met with as many round worms as are found in Eastern sheep. The dose of santonine for sheep is from 1 to 3 grains, given in from 2 to 4 ounces castor oil. The preparations of taiusy, Tanacetum vnlgare, have long been used as vermicides. The dose of the oil is from 1 to 2 drams, given diluted by adding from 4 to 8 ounces of another oil. The receipt for Spinola's worm cake sufficient for one hundred sheep is : Take of 158 tiHisy root, calamus root, and tar, of each 2A poiiuds, of coiiiinon .salt 1;^ pounds, make iuto cakes with meal and water, and dry. The (h)se ofareca-niit powder, which is an effective reiiiedy for round worms as well as tape-worms, is from 1 to 3 drams for lambs. The oil of turpentine has proven of itself a valuable anthelmintic;, but should be used with care. For intestinal round worms in sheep from 1 to 4 fluid drams may be given, according to age. The turpentine should be mixed with from 2 to 4 ounces of castor oil. Sweet or linseed oil may be substituted, but their cathartic effects are untrustworthy. More than one dose should not be given until two or three days have elapsed, when, if it is deemed advisable to give a second dose, no untoward re- sults having been noticed from the first, the dose, slightly increased, may be rei)eated. Do not give more than the maximum dose. Tellor (Dis- eases of Live Stock) gives the following recipe: Linseed oil 2 ounces, oil of turpentine one-half ounce, for a drench. The French veterinari- ans advise, among other remedies, the use of emi)yreumatic oil, petro- leum, and chimney soot. Empyreumatic oil is animal oil, a by-product of distillation of animal matter for ammonia. Dippel's ethereal extract is a refined product, and the oil of Chabert consists of animal oil 1 part, turpentine 3 parts. The medicine should be administered as a liquid. The dose of animal oil, or oil of Chabert, is from 1 to 2 drams, to be given in 4 ounces of the chosen vehicle. The oils and alcohol dissolve animal oil, but if the vehicle is a watery mixture it must be well shaken. Bitter vermifuges made up into tea are excellent, as is also a decoction of chimney soot thickened by dextrine or the yellow of eggs. From the certain effect that petroleum has on insects externally we may infer that it should prove a valuable anthelmintic internally, if it may be given in sufficiently large doses. It has been used in man for Uvnia and round worms. The dose is 30 minims. The dose for sheep may be as large ; how much larger future experiments will determine. Until the toxic dose is learned it should be given with caution. It is proba- ble that 2 dram doses may be used. Give with from 2 to 4 ounces of sweet, linseed, or castor oil. Besides these there are many other remetlies proposed, as savin, sabadilla, spigelia or i^ink root, aloes, tartar emetic, asafetida, azeda- rach, kousso, kamala, and pumpkin seed. The greater part are of doubtful etiicacy; others are dear, and can be replaced by remedies equally as good and cheaper. Many of the bitter herbs may be pow- dered and given with grain, but the sheep will not get enough to have the best effects. Often the worst-affected lamb will not eat any, or very little, on account of loss of ap[)etite. This method of administration is, besides, wasteful. The uncertainty of sheep receiving a full dose is the chief argument against such a method. The effect of some of these plants on sheep is also modified by the fact that sheep are plant eaters and become more or less accustomed to the various medicinal principles found in them. 160 DOCHMIUS CERNUUS, Crepliu. Plato XXII. Fig. 1. Adult male, X 1' : 1", natural size. Fig. 2. Adult female, X 9 : 2(i, natural size ; b, vulva. Fig. 3. Cephalic eud of male, ventral view : a, head ; b, b, resoi^hagus ; c, c, neek papillai ; d, opposite ventral cleft out of which the unicellular gland ducts e,e, empty hy a common tuhe, /; """ long, linear aculeate, cioss-striated, and bordered by narrow margins which roll in towards each other. Two anal papilhe. Female stout and thick, and usually with a brown crust near the vulva. "Vulva very near the tail. Tail full to near the end, but ending in an acute mucronate point. Uteri directed toward the head; one, the caudal, makes a loop at the tail. The ovaries show loops near the tail. Eggs elliptical, O.!'""" long, 0.0(5'"™ broad, laid m the gastrula stage. Embryo not observed. Occurrence. — Sclerostoma hypostonmm is found iu the large intestine of raminaiits. It is present associated with (Esopliayostoma Colum- bianum in sheep iu this country, but not abundantly. It is closely re- lated to Sclcrostoma equimim of horses, a species said to make tumors iu the intestines. As S. hypostomum is rare, it has not yet been deter- mined whether it causes intestinal tumors in sheep. Since 8. tetracan- thum, whose embryos make tumors in the ctx^cnm of the horse, is more nearly related generically to Q<]sopha(jostoma than to Sclerostovia, I am inclined to believe, as I have proveu in regard to GiJsophaf/ostoma Colum- bianum iu sheep, that the species belonging to the genus (Esophayostoma are intestinal — tumor-making j)arasites rather than those of Scleros- toma. Life history. — M. Baillet {Nomean Diet, de Med. T. VIII, art. Hel- minthes., 188G) is aulliority for the following: The sclerostome of ruiuinauts is reproduced in the same way as that of solipeds. Its eggs, of which the vitcllus is segmented in t'.io uterus of the female, are laid in the large intestine and carried without by the fecal material. Tliey are hatched after 23038 A P 11 1G2 a few (lay.s, and l.lio eiiihryos iiro very similar in tlicir geucial form to tlmseof iSc/eros- toiiKi tclracitntham. Tlicy ar(} cyliiKlroid, ^slll)ul)^lI.sc at llic anterior ixtriMuily, and jiruvitk'd with a narrow tail much nIiorttM- tlian (hose of the yoiiiiii.sc/f /•«;»/omts of the liorM«\ Tliey move, be.sid<;.s, iu the ^sam(! manner a.s the latter. Tliey can live a lonj^ time, in the fecal material of ruminantn when they are not drieil, and in (Iiis condition they j;row. Some young Schrostotiux which, after hatching, were O.I{r)""" h>ng to 0.50""" have been found in the drop|iitig,s of .sheep. After having been kept damp two and a half mouths these were from O.CHJ to 0.78"'"' long. Their skin, which is folded on the surface of tho bod}', appears to indicate that, like the SvAerotftomcs of the horse, tht'v are jireparod to undergo a molt. The young Sclerostoma hy2)ostomHm can live a long time iu water after having reached a definite size iu the fecal material of rumi- nants. Wo have not yet observed cysts within tho mucous membrane of the large intes- tine of sheep.* But as the Sclerostoma hypostomum are in far less niirubers of ruminants than S. eqniniim or S. tetracauthitm in the horse, wo can not yet draw any conclusion from the negative result of our researches. Wo will not say then at present whether the Sclerostomcs of ruminants pass the second pllas(^ of their exist- ence in cysts, or whether they are developed in tho intestinal canal itself in tho midst of alimentary material which is found contained there. The eggs of the Svle- 70>ito)ncs of ruminants taken directly from the nterus of females and preserved in water at a temi)eraturo of from 12 to 20" C. (about 55 to 70^' Fah.) hatch at the end of four or live days after having undergone all the series of successive modifications which are alike observed in the eggs of Sclcrosfomes of 8olii»eds. The only possibility of error in Baillet's experiments is tlie intleiitifi- ciitiou of the species with which he was dealing', for he writes: It (5«e^')v<,s7o«(rt /(^/jw^/o/HHWi MS above all very frequent in sheep. There are often found individuals, probably younger, whoso month, entirely terminal, is less widely open, and provided with a single rank of teeth still loss numerous. These worms also lack a pharyngeal capsule, and often carry a membranous swelling on the sides of the head. The above describes (Esopha/jofitoma vemdosum quite well, and when the learned helminthologist did not experiment with eggs taken directlj' from the adult worm he may have had to do with the eggs of either. This would account for the similarities found between some of the young embryos experimented with and those of Sclerostoma tetracan- ill urn. (The author is of the opinion that the last named species should be classed with the CEaophagostoma instead of the Sclerostoma.) The life history of this species is, that the eggs are scattered by the sheej), that they then dexelop somewhat, and without the need of any^ secondary host are capable of further development in sheep when taken by them along with tlie food or drink, and that in the large intestine of the latter they may or they may not make tumors during their embry- onic stages. The prevention and treatment is the same as for other intestinal worms. * This indicates that (Enophatjoxtoma ('olumhianum has not been observed in France. — C. C. 164 SCLEROSTOMA HYPOSTOMUM. Plate XXIII. Fig. 1. Male, XH. Fig. la, uatural size. Fig. 2. Female, x8. Fig. 2a, uatural size. Fig. 3. Head, ventral view : a, the capsule ; ?>, the dorsal canal ; c, lateral ducts ; d, fBSopliagns. Fig. 4. Head, lateral view : a, c, d, as in Fig. 3; p, the three head-napilhe ;/, the coni- nion duct of the joined unicellular gland ducts is placed near the veutral cleft; g, the end of the wsophagus, showing three dependent lips; h, the cut-end of the skin. The drawing shows the longitudinal muscular band, separated into two groups l)y the lateral canals, i, i, and the three separa- tions of the muscular bundles between these canals which ai)pear on the surface as lines : k, k, k, cut end of the intestine. Fig. 5. Head, dorsal view: a, h, c, and d as in Fig. 3. Fig. G. Mouth end of lateral half of chitinous capsule: a, a, a, the ventral, lateral, and dorsal head papilhe; b, the dorsal canal which continues around the head in c, c; d, the mouth, arouud which is a circle of suuiU thorn-like teeth, about forty in all. Fig. (5a. Teeth enlarged. Fig. 7. Caudal end of capsule : o, the cut wall ; b, the dorsal canal ; c, the triangu- lar opening of cesophagus. Fig. 8. Section of esophagus: a, a, a, tlio chitinous sui)iiort; b, b, b, the walls, c, the orifice. Male bursa with spicula. Portion of epiculai : a, the chitinous cylinders; /), the membranous margins. 1)6. Diagram of anal jjapilhe. Bursa spread out: a, veutral costa^ ; /;, lateral ; c, d(U'sal ; d, the torn edge. Caudic superseded microscopic methods the discovery was easy. The method was not en- tirely macroscopic, for simple lenses of low power were used. The worms found in the largest tumors were never over 3 or 4""" in length, and presented only an embryonic development, the vegetative organs alone being present. Figs. 1, 2, and 4, in Plate XXV, were made from the largest specimens. As the adult worms of this class may difler materially from the embryos in the character of the mouth l)arts and in their appearance after the reproductive organs have de- veloi)ed, the difficulty was encouutercd of connecting the embryonic cystic form with an adult form existing in sheep or elsewhere. Determination of adult. — The most conclusive method of determining the adult would be to directly develop an embryo into an adult, but this proceeding was not attempted on account of its difficulties. A less satisfactory method remained of finding some adult worm whose em- bryo was unknown, and which not only corresponded in structure with the embryo, but whose life history was such that it was possible for it to be the parent of the embryo. It will not be profitable to detail theories advanced to aid in this investigation ; suffice it to say that while studying one day a group of wornis which came from the large intestines of sheep, I found among them an undescribed species. This species was immediately referred to the Sclera stomituv (Itaillet, Elements of Zoologie, p. 330), and later to Molin's genus (Esophafjos- toma. There may be an impropriety in accepting this name over others proposed at the same time for species of this genus, but as the same author proposed them, and as the genus is in general use, it is accepted in this classification. For reasons assigned hereafter in a description of the species I have called it a new one — (Ksopha(jostoma Golumhianum. The specific name is from the fact that the worm was first found in the District of Columbia. The adult worm is fouml in the large intestitie of sheep in considera- ble numbers, and iii the same animal may also be founarasite, and other wild animals which might be suspected as hosts are at the present time very rare. CESOPHAGOSTOMA COLUMBIANUM, n. sp. Description. — Mule, 12 to 15""" ; female, 14 to 18"'"'. Worm siinilar in ai)pearaiico to Docltmius cerniius, but liavinj; its head bout into tho form of a book. Head ter- minal, very short, somewhat thicker than tho neck, and separated from it by a con- striction. Papilhe six, of whicli two are dorsal, two ventral, and two lateral. The latter are more obtuse and are the openin<>s of the lateral canals of the body. Mouth terminal, supplied with a chitinous armature, consistinral a group; the lateral also slightly separated ; the dorso-latcral forms willi its frllow and the dorsal pair a 168 jri'oup; the dorsal rib is composed of two, which are widely separated only towards their free euds. Spiciihi two; awl-shaped, bordered by a very narrow meiubrane; the chitiuous cylinder is apparently fenestrated. At either side of ihi' ^iiiital orifice are two knobbed papilhe. Female relatively stouter; vulva just in front of anus, wliich is midway between it and the acutely pointed tail, usually covered by a hard brown patch ; reproductive organs in two sj'uunetrical sets anteriorly directed, ex- cept a small portion of one, which is at first posteriorly directed to form a loop in front of the anus. Uteri two, in the caudal end of the body. These may be traced up to the oviduct and ovaries, which coutiuue to the cephalic end of abdomen, where they are reflected to form a loop and thence coutinue to the caudal end to form still another loop. The ovary of the caudal uterus forms still another loop nearly oppo- site the uteri. Eggs laid with gastrula inclosed; length, 0.09'"""; width, O.Oo""". Embryos from 0.23""" upwards. The largest found in tumors were 4""" long; the smallest male found in intestiue was 7™"' long. The smallest embryos were without digestive ap- paratus. Thelargest possessed an intestine, unicellular glands, and a well-formed chitinous spherical cup in the head; also six cephalic papilhe, and at the neck two papil!;e and a well-defined fold. Occurrence. — The adults live iu the large intestine of sheep below the c.neciim; the embryos live in the intestinal walls in tumors, which, though more abundant iu the ciiecum, may be scattered from the duode- num to the anus. The species is distributed in the United States east of the Mississippi River as far north as Maryland, perhaps farther north. On comparing the species with others of the genus it was found that it corresponded more nearly with CEsophagDStomavenidosum^ a parasite of goats, than any other described in modern works, and that it cone sponded still more closely with 0. acutum, Molin. {LI sottordlne tliey may be very numerous (see Plate XXVI I, Fig. 1). Between the stage in which a few are scattered here and there over the cjecum ami lh:it in which the c:ecum has become a sf ifl" tube with walls from one fourth to one half inch in thickness (so thick and close have the tumors be- come) there are all varieties. The tumors may extend from the c;ecum to the anus. They may also be abundant along the small intestine. The cheesy material which the worms produce has been found in the lymphatics, on the omentum, and in the liver, but in these places it never seems to be sufiiciently abundant to show that the parasite lived long. 171 Microscopic serial sections made from aicobolic specimens show best the changes wliicli have taken phace in the surronuding tissue. On Plate XXVI, Fig. 2, there is figured an enhirged view of one of the worms still encysted and surrounded by the tumor of inflammation. From this section it is seen tliat the irritation setup in the adjoining con- nective tissue causes the cells to proliferate and crowd closer and closer together. It is also seen that there is a special cyst for the worm and a thickened adjoining jiortion of the tumor which is like a surround- ing membrane. As these two menibranes, the so-called cyst and the outer one, stain so nearly alike, it has occurred to me that they represent successive efforts of the adjoining tissue to protect itself against the parasite; but in view of the fact that the inner one is so easily enucle- ated, it is for the present considered asbelonging to the worm. At the foot of Plate XXV, Fig. 8, there is given an illustration of a small tumor in which the worm has es(;aped from the cyst and in which the surrounding matter has become cheesy, some of it even hard. Around the entire mass the tissue is slightly thickened and forms a capsule. From these two microscopic sections we can learn how these tumors grow. The worm penetrates to the submucous tissue and irritates it. The adjoining cells rapidly increase in number and crowd upon each other. So closely do they crowd and so numerous do they become, that the outer layers cut off the circulation from the inner cells and they die. Their degeneration gives rise to the cheesy mass. Now, if the worm remained in the center of the mass the new growth would event ually cease, but the worm makes its way to the outside and at that point keeps up this irritation and new growth. This is shown by and accounts for the dried older parts of the larger tumors and the fresh yellowish-green adjoining i)arts. As soon as the worm escapes the irri- tation ceases, the tumor shrinks, and absorption of the mass begins. The irritation produced by the worm provides it with food and favorable surroundings for development. Often the worm dies from weakness or other cause, and leaves behind those little hard incompletely-grown tumors which have been mentioned. Since writing the above life history two post-mortem examinations have been performed, which lead me to modify my views regarding the life history of certain other tumor-making parasites. On August 10, 1880, two lambs, one five months old, the other eleven weeks old, dier()bable that the adults of this species cause but little trouble; but the embryos, on the contrary, cause a groat deal. The disease is an insidi- ous one, for not only is the rate of infection gradual, increasing slowly in amount from week to week, but the rate of development of the tumors is very slow, npparentlj* requiring mouths. It is only when the disease is well advanced tliat its cumulative effects can be noticed. The disturbance of digestion caused by this parasite is mainly due to the derangements of the functionvS of the ccvcum. This derail ;4(Mnent is not seiions until the resulting tumors become exceedingly nuiiiiuons, well advanced in growth, and press upon the more essential mucous membrane, disturbing its functions. The most seriously affected sheep found in the abattoirs are notice- ably poorer, and one would be tempted to believe, were he to judge from the "knotty" viscera, as the butchers call them, that such animals shonld have died from the disease long before. These sheep usually have diarrhea, a disease which weakens the affected animals. Flock- masters who mistrust that their sheep are not doing well, and who know of no cause for it, should sacrifice one or two of the poorest to make a diagnosis. The meat of such sheep, though not quite as fat as other mutton, is suitable for food, and could not be distinguished in the market from other mutton. Prevention. — For the tumors caused by (Esophagostoina Columbianum there is no remedy except the removal and extermination of the adult worms. These adults are usually buried deeply in the mucous secre- tions and attached to the nie?nbraue of the large intestine. Tliey may be found in considerable numbers in older sheep. The medicinal rem- edy must therefore be one which will remove them from these i)laces. It is probable that such a one can eventually be found, but at present none can be recommended. It is probable that some one of the surer remedies advised for other intestinal parasites will do for these. In case medicinal remedies are tried each animal must be dosed. The killing of the adults will of course lessen the number of eggs with which the sheep become infested. As the eggs of this parasite pass to the ground the sheep may get them either while pasturing or drinking. The same care in changing pastures, in providing good drinking water and a plentiful supply of salt, should be observed as for other parasites. Judicious fall and winter marketing of infected sheep will also tend to lessen the chances of infection. If pastures are known to be perma- nently infected, theu they should be turned over to other stock for a year or two before being again grazed on by sheep. When it is prac- tical on the smaller farms the sheep lots should be plowed and either planted or left fallow. The object of change of pasture and of plowing is nearly the same ; in the one case, to wait until the parasites have died out; in the other, to bury them beneath several inches of soil, from which the sheep-owner may rest assured they will not emerge. 174 CESOPHA.GOSTOMA COLUMBIANUM, Curtice. Platk XXIV. Fig. 1. Adnlt male, x9, Fig. 1«, uatunil size. Fig. 2. Ailiilt female, x9, Fig. 2a, uatural size. Fig. 3. Cephalic eml of adult, ventral view: a, head; b, oesophagus; c, lateral canals opening ou head; d, unicellular glaiiicuia ; c, c, anal papilke. Fig. 11. Head, top view: o, mouth; b, b, lateral papilke; c, one of the four acute jiapillu). PLSTE XXIV Tl -^^^3 1,/ ten ] ci Q" Haines, del. CESOPHAGOSTOMA COLUMBIANUM (The Tumor-Making Uound Worm of Sheep.) 17G (ESOPHAGOSTOMA COLUMBIANIJM, Curtice. I'LATK XXV. Fig. 1. Worm in third stage, XHO: a, head, with chitiiious armatnri-; b, u'sojyh.ign.s ; c,iute8tiue; rf, unicellular glands ; e,auu8; /, line denotiug uutural length. Fig. 2. Cephalic end, lateral view, Xl50 : a, chitinons cnp; b, one of the six cephalic papilhe, (these are slightly distorted) ; c, side view of the nock-fold, under which the gland-ducts d, d, open on the ventral line ; e, a^sophagus ; /, intestine. Fig. 3. Worm in first stage when 0.23'"'". long. No internal organs were seen in this specimen. Fig. 4. Cephalic end, ventral view : a, head ; h, ueck-fuld, near, which are the neck papilhe g, {/; c, cesophagus; d, d, unicellular glands, which open under tho fold b; e, intestine; /,/, glands. Fig. 5. Worm inclosed in its cyst. Fig. (I. Tumor from which the cyst in Fig. 5 was talieu : a, surrounding tissue dis- sected from cjBCum ; &, fluid-filled space ; c, capsule with inclosed worm. Fig. 7. Older tumor. This dili'ers from tumor of F'ig. 6, in having a movahle cheesy mass. These tumors are distorted by compression, which makes them too flat. Figs. 6 and 7, and Fig. 3, Plate XXVI, present three stages in the dis- ease, as seen in fresh tissues under low magnifying powers. Fig. 8. Section of an advanced tumor: a, mucous membrane ; h, submucous; c, inner muscular layer; d, outer: e, serous membrane; /, the cheesy mass of the tumor in which is a small section of the worm. This presents a more ad- vanced stage of the disease than Fig. 2, Plate XXVI. PLSTE XXV m Haines, del. CESOPHAGOSTOMA ('OLUMBIANUM (Young Stages.) 178 (ESOPITAGOSTOMA COLUMBIANUM, Curtice. Plate XXVI. Fi.i;. 1. A pit'ct) of uiucoiis meiiibraue taken from tliy caeiiiii, surface view, natural size. The |>atcli of dots scattered uniformly over the surface reprcseutH intestinal glands; the irregularly scattered larger dots aud elevationn arc the youug worm tumors in their lirst stages. Fig. 'i. A section through a worm tumor in its younger stage : a, a, a, mucous inem- braue ; h, submucous connective tissue, in which are c arteries and d veins ; e, the tumor, which is made of connective tissue cells aud their nuclei, packed closely together; near its center is the worm cavity/, with a piet;e of the worm, which is surrounded by a section of a special capsule; out- side of this is 11 thick membrane, formed from the surrounding material. Fig. :J. Small tumor dissected from the ciccum: a, the outside capsule tilled with lluid, in which is b, a hard, cheesy mass : c, the worm in its capsule, which has been pressed out of the cavity in the mass h. This presents a more advanced stage ol the disease than lig. 7, Plate xxv. Fig. :?a. The ruptured capsule. Fig. 'ib. The worm near the end of its second stage about to moujt. f PLHTE XXVI ..-*.•*»' * So- .<#%^, r Haines, del. CESOPHAGOSTOMA COLUMBIANUM, (Small Tumors of Caecum.) A.Hoen & Co. lithocausticBaltiir 180 (ESOPIIAGOSTOMA COLUMBIANUM, Curtice. Plate XXVII. Fig. 1. Piece of c;t'cum exhibiting tumors caused hj tlio embryos of OLsophanostoma Colnmbianum, natural size. The various stages of growth are represented by the differeut sized tumois. The smallest are better shown in Plate XXVI, Fig. 1. Fig. 2. Cross-section of Fig. 1, at a a; b, mucous membrane; c, submucous; d, muscular and serous layers ; e e e, section through the cheesy masses. PLHTE XXVII \. di e «' Hai/nes, del. CESOPHAGOSTOMA COLUMBIANUM, (Large Tumors of Caecum.) A Hgen*Co,UthDC8UStic Bsir THE C^^CUM WORM. Trichocp:piialus affinis, Kud. Plate XXVIII. Descnption. — Male auil female about eiiual, 40 to 70'"™ 'oiig. Body whip-like, pos- sessing a short, stout caudal end, 12 to 18""" long, and a very thin liair-Iike cephalic end of twice this length. The latter contains the oesophagus and intestine; the fornuu' the reproductive organs and intestine. The head is very small and thin, without noticeable papilhe or chitinous armature. It is said to sometimes have two vesicular, transparent, wing-like intlatious. Skin of the neck transversely striate, and when highly magnified shows a serration of the sides indicating cuticular layers which overlap each other like shingles on a roof. CEsophj/gus and cephalic portion of intestine very minute ; its jiosterior end is large and dark, and empties at the caudal end of the body. On one side of the head there appears to be a canal filled with granules. Tlie male is to be distinguislied by its tightly-curled caudal end. The testicle, beginning near the cainlal end, continues anteriorly as a sinuous tube for about two- thirds the length of the thick portion of the worm ; it then becomes plaited to the end of the thick part, where it turns and continues posteriorly as an enlarged seminal duct for about half the length of the thickened body, where it is constricted; the remainder continues to the cloaca as a slightly enlarged tube. The intromitteut apparatus consists of two parts, an external membi'auous tube bristling with 8[)ine8 and an internal long, slim spiculum. It is always found exserted, and usually has one coil in it. The tube shows at its end that the external covering continues around the end into the tube to form a lining membrane, which may be retracted or protruded. There is considerable space between these membranes at the tip, and it assumes various forms, varying between a large sphere, as shown in the figures, and an elongate cylindrical body. The chitinous spiculum is terminated by an acute point. It is from 5 to G'"™ long, with a width of 0,025""". The tube is about three or four times as wide. The spiny points are turned away from the end. The female has a thick body, only slightly curved. Tail, obtuse; ovary begins at the caudal end, continues as a plaited canal to the cephalic end of the thick part of body, theu contracting returns to the caudal end where it enlarges, forms a fold, .and becomes the uterus, which empties through the sinuous vagina and the vulva at the cephalic end, where the body begins to enlarge. Eggs characterized by having re- frangeut polar bodies at each end. They measure 0.077""" in length, including these bodies, or 0.056""" excluding them (Raillet). Tbey are elliptical and dark brown. Occurrence. — This spftcies is found in tlie ciecuni of sheep, goats, and cattle. When the fresh intestine is examined the worm may be found with its slim, hair-like head firmly sewed into the raucous membranes. The serrated structure of the skin not only facilitates the progress of the head through the mucosa, but prevents ifs being i)ulled backward. The thick large end, which is wh;it one really sl'cs at first, appears to float free iu the intestinal contents. 181 182 The life history of this species has been determined by Leuckart, the distinguished helminthologist, who has added so much to this branch of biology. He succeeded in raising young embryos from the eggs to such a stage that there was no reasonable doubt that the next stage was passed in sheep. These he fed to a lamb, which he killed after sixteen days. In these he found numerous immature trichocephaU ahontl""" in length. He later verilied this experiment by another, with like results. {Die menschlichen Parasiien, Band II, 494:-4:99.) These experiments show that the eggs of Trichocejyhalns affinis, which pass from sheep to the ground, may develop there to some degree, and then, after being consumed with food or drink by a second sheep, con- tinue their development to their adult stages. Disease and treatment. — Unless the parasite should be ])resent in great abundance the species does not seem to be especially harmful. A few may be found in nearly all lambs and young sheep, especially in the all. The means of prevention is just the same as for other round worms. As they are attached so stoutly to the mucous membrane it is doubtful whether medicinal remedies would have the influence on them that they have on those worms situated in the small intestine. 184 TRICHOCEPHALUS AFFIMS, Rndolphi. Pl.ATK XXVI II. Fig. 1. Piece of cpecuin with tricltocephali attached, natural size: a, a, females; h,h, males. Fig. 2. Male, x7: rt, ca))illary cephalic end ; /^, coihul caudal end ; c, protriid«Hl inlm- mittent organ ; d, the convoluted, and e, the straight portion of the seminal apparatus; /, seminal reservoir; roduce a pneumonia, hence the disease has been termed verminous pneumonia. This pneumonia is limited to the neigh- borhood of the parasite and does not extend beyond. The patches are irom 1 to 2.5"" in width, but in those recently formed they rarely ex- tend more than 2 or 3""" deep. The injury seems to be mainly a me- chanical effect, due to the irritation set up by the parasites. When one of these patches is cut into \i frothy liquid exudes, bearing quanti- ties of eggs and embryos in all stages of development. They may be seen with a glass magnifying six diameters. In later stages of the disease the tubercles become little hard masses. These have been said to be calcareous, but they arc not soluble in acid, 189 aud seeni rather to be tlie contracted, hardened remains of the cheesy mass. There are sometimes found in certain lungs raised patches of a rather dry, emphysematous tissue, whicli seems to be due to the deeper lying parasites. In other lungs the patches which once showed the pneumonia have becoiued thickened, tirmer, denser, and a cut across them shows the thickening to extend to a considerable depth. The abundance of the nodules and patches of i)neumonia is very vari- able. There may be a dozen nodules of different sizes and two or three patches, or the nodules may be diffusely scattered over the whole pos- terior surfaces of the lung, or there may be associated with tliem numbers of patches due in part to the close proximity of the nodules and in part to the extension of the disease. In other cases there may be a few of the nodules with a series of patches ranged along the dorsum of the lung. Each lung seems to present a slightly different phase, dependent on the degree and the time of infection and possible reinfection. Source of infection. — That verminous pneumonia is caused by a worm (Strongylus ovis-piilmonaUs) and that sheep become infested while feed- ing or drinking has Already been enlarged upon. It is obvious, there- fore, that the best way to keep the sheep well is in some way to i)re- vent them from becoming infected with the parasite while feeding. Preventive treatment. ~\n giving rules for prevention the value of knowing the complete life history is fully illustrated. The unexplained gaps in this history are two, viz : there has been uo complete demonstra- tion of the manner and place in which the parasite spends its life be- tween the time of its escape from the lung of one animal and its recep. tion into that of another, nor has it been demonstrated that the worm must escape from the lung before it may complete its development. This latter item is an important one, for if the worms can continue multiplying indefinitely in the lung then there is little hope of freeing a sheep after it is once infected. On the other hand, if an infected sheep is to be regarded as incapable of continuing the infection within itself then the case is more hopeful. If the parasite must become para- sitic on a second host while external to the shee]>, as some claim, this is an important factor in its life history, for its continuance then depends on the presence, abundance, and seasonal appearance of this second host, and influences adverse to the life of the second host would be un- favorable to the parasite. As the parasites are present in the lungs of sheep throughout the year in all stages, this theory does not seem to hold good. The infec- tion of lambs is proof enough that the parasites are continually passing from one sheep to another, and whatever be the mode of living there are certain precautions which may be taken to keep the sheej) less in- fected if not to entirely exclude the worms. The older sheep, which seem to be more infected and which are the source of infection for young ones, should be marketed. Lambs should be weaned as early as they safely can be, separated froni the older sheep, pastured in fields where 190 there have been no sheep since the previous winter at least, and never allowed to pasture, water, or yard after infected animals. Sheep should be supplied with water from running streams or trou^Mis, and should not be allowed to contaminate the water in any way. Filthy drinking water is one of the most prolific sources of the parasite. There are two kinds of seasons which especially favor the production of parasitic diseases. The one is a very wet, warm season, during which the parasites seem to be able to live on the damp ground. The other is a very dry season, when the i)ools of water become diminished and (Stagnant, and whatever parasitic eggs or embryos there are in them are gathered into so small a volume of litpiid that sheep drinking of the water become more readilj' infected. Wet, hagiis; b, intestiue. Fig. 2. Head with papillji'. Fig. ;{. Caudal end of female: a, amis; b, vulva; c, vagiua; d, d, uteri ; e, e, ovi- ducts; /, /, ova; g, g, iutestine. Fig. 4. Middle of female with tail of male coiled around her. Fig. 5. Spiculum: a, cyliudrical part of the skeleton; 6, spatulate ribbed i)art ; c, wing of tube: d, membranous tip. Fig. 0. Spicula as they fit together. Fig. 7. Adult male and feuuile, Xfi. Fig. 8. Caudal eud of male: a, spicula. Fig. 9. Male bursa with apiuessed cost;e. Fig. 10. Male bursa with separated costa-. and sjticula in situ. Fig. ll. Caudal end of female, lettered as in Fig. ^5. PLSTE XXIX Haines, del A.Hoen & Co. Lifti. Baltiii STRONGYLUS OVIS-PULMQNALIS 'The Hair Lung Worm.) 194 STRONGYLUS OVIS-PULMONALIS, Diesiug. Plate XXX. Portion of left luug slightly affected by the stroiigyli. The purplish spots are those more recently invaded. The small gray spots are older. The large gray spots are caused by the worms and their young, which have produced an appearance of local pneumonia. PLATE XXX llalnea, del. SURFACE OF LUNG RECENTLY INVADED BY STRONGYLUS OVItJ-PULMONALIS. 196 STRONGYLUS OVIS-PULMONALIS, Diesing. Platk XXXI. Left Inng diseased by Slrongyhis ovis-puhnonalis, the hair lung-woriu. Natural size. Each dot is caused by the irritation set up by a young worm, aud its size cor- responds to the age of the worm. The larger patches consist at first of separate dots; as these enhirge they run together and finally become so fused that their identity is lost. The patches show the stage at which the worms become adult aud produce their young, which wander into the adjacent air cavities. PLKTE XXXI i" Haines, del. '■Is.. S SLTRKACK OF LUNG l)|SEASEI> BY STKONGYLUS OVIS-PULMONALIS. 198 STRONGYLUS OVIS-PULMONALIS, Diesing. Plate XXXII. Portion of right lung, oxhibitiug an advauced stage of the hair lung-worm disease. The small dark spots show the youngest stages, the large patches show the disease well advanced, while the largo light spots are the oldest. A section cut across one of these shows the depth at which the lung is atfected. PLSTE XXXII 1. % Haines, del. A.HaBriir.D.Lithocsiistiu.Baltin SURFACE OF LUNG DISEASED BY STR0NGYLU8 OVIS-PULMONALIS. 200 STRONGYLTIS OVIS-rULMONALIS, Diesing. Plate XXXIII. Fig. 1. Section of lung tissue through two small tumors caused by the worms X20: a, caseous degeneration of tissue in the center of the tumor ; b, the same in the pathway of the moving, growing worm; c, cut fragments of the worm (the pathway of the worm is interrupted between a and b, because the plane of the section did not include it) ; d, a bronchus into which the parasite has almost found its way; e, portion of a second tumor made by another worm; /, nearly normal tissue. Fig. 2. Section through an older tumor at the stage which has been likened to pneu- monia, X20: a, tumor with fragments of worms; b, fragments of an adult worm ; c, eggs in segmentation stage ; d, embryos somewhat developed ; e, young embryos; /, bronchi; g, nearly normal tissue. Fig. 3. An enlargement of b, Fig. 2, .showing fragments of adult worm in the bron- chi and alveola). Fig. 4. An enlargement of e, Fig. 2, showing young worms in the alveohc. Fig. 5. An enlargement of c, showing segmenting eggs in alveoli. Fig. 6. An enlargement of d, showingd eveloping embryos in alveoli. In Figs. 5 and G the outlines of the egg-shells are not shown. Figs. 3-6, X90. (These illustrations were made from specimens selected from a number of serial sections which were stained with alum-carmine; the dots represent the nuclei of the cells. All sections show the great multiplication of cells about the points of irritation, whether excited by the adults or embryos.) Fig. 7. o, embryo of Stronfinlus fdaria, and b embryo of S. ovis-puhnonaUs, each equally enlarged to show comparative differences in size and outline. PLSTE XXXIIl ^: -,a««--,<,;'\r , :m-.^ ;;^ Haines, del. m' SECTIONS OF LUNG DISEASED BY STRONGYLUS OVIS-PULMONALIS. THE THREAD LUNG-WORM-VERMINOUS BRONCHITIS- HUSK OR HOOSE-PAPER SKIN. Steongylus filakia, End. Plates XXXIV, XXXV, XXXVI. The thread liiuj? worm, or Strongylus Jilaria, is the best known of the sheep lung worms, for the reason that at times it causes exteusive epi- zootics in the iiocks, and that the worm is hirge enough to see when the bronchial tubes are slit and spread open. From personal observation it appears to be much rarer than Strongylus ovis-pulmonalis, and the disease it causes much less extensively distributed as to number of animals infected than that produced by the latter. In most of the American literature on this subject the disease caused by the hair lung- worm seems to be ascribed to the thread lung worm, and no mention is made of the former. Description.— M.a,\e, 33 to 54""" ; female, 55 to 80™". Worm filiform, white, with a dark hair line showing throughout its length; head obtuse, without notice- able papilhe or wings ; mouth circular, naked ; unicellular neck glands quite large ; cuticle longitudinally striate. Male : Bursa shallow, canipanulate, opening later- ally ; fiv-e sets of costie ; the dorsal are trifid, the lateral bifid, and the ventral sepa- rated. Spicula arcuate cylindrical ; 3.35""" long by 0.07.5""" wide ; short, very tliick, dark brown; chitinous portion a curved fenestrated conical tube; fleshy por- tion a membrane, which forms a bulb-like expansion toward their free end. Female : Vulva three-sevenths of her length from the head; uteri symmetrically directed anteriorly and posteriorly ; posterior oviduct becoming continuous with the uterus near its flexure at the tail; ovo-viviparous; eggs ellipsoid, 0.075 to 0.120™"" long; 0.045 to 0.082™™ wide. Embryo 0.25 to 3""". The life history of Strongylm filaria is in general that of other para- sites. In some way the young worms arrive in the bronchi, grow, de- velop, become adult, mate, and lay their eggs in the surrounding mucus. The eggs laid are not true eggs, for each egg-shell contains a j'^oung worm within, a feature which is described by calling the female ovo- viviparous. The inclosed young escape from the shell, and many of them are expelled from the lungs in the coughing fits along with other discharges. These young, which are scattered about watering-places, pastures, sheep-yards, or corrals serve as infecting and reinfecting ma- terial for a considerable length of time. Professor Leuckart {Entwickel ung d. Nematoden, Arch. d. w. MeilJcunde, 1865, p. 299), kept the young of this species alive for several weeks on damp earth, and observed them pass through a stage in which they molted or threw off their skins, 201 202 after which many died. Baillet {GoUn, 0., Bull deVAcad. dc Med., t. XXXI, 18G0, p. 874) preserved them alive in water for several mouths. Ercolani {Ncimiann, Traitc des Maladies parasitaires, p. 515) is author- ity for the statement that they can be resuscitated after being dried a year by putting them in water. The writer has kept them in stagnant water for weeks. Ercolani's statement is by far the most remarkable, and accounts for results obtained in an experiment in which the writer kept sheep for five months on a narrow dry pasture, supplying them with water from a pump only. When these sheep were examined they were found affected with Strongylus contortus, S.Jilicollis, iS. ventricosusy Dochmiuscermius, and Tcenia expansa in very young and old stages. The eggs of these were introduced on the pasture from two or three older sheep which were with the younger ones, or possibly by the young sheep themselves, some of which were between three and four months old at the time. Two of the lot were born and raised under experi- mental supervision, and these were also infected. Strongylus Jilaria was not present, but it was not discovered in any of the sheep from the same lot killed at the time of selection of the experimental animals, nor has any trace of this parasite been discovered in any of the older ones kept at the Experimental Station. Professor Raillet details experiments {Recueil de Med. V^terinaire An- ne.re, 7 Serie, Tome VI, No. 8, April 30, 1889, p. 173) in which he dried embryos of Strongylus Jilaria under different conditions, and found, after a few failures, that some could be revivified as late as sixty-three hours afterward by placing them in water. His success depended on the condition of the embryo at the time of drying. It may be accepted, therefore, that the young parasite may retain vi- tality indefinitely, depending on telluric and atmospheric conditions. From Leuckart's experiment it is to be inferred that though moist earth and damp places are favorable for the life of the young parasites, yet they are liable to molt and then may die from the loss of the older and tougher external skin. From Ercolani's and Raillet's experiments we may infer that the drying of the young parasite suspends its functions, which revive again when the surroundings are suitable, .and that the parasite is in this state the most dangerous to sheep. Preventive treatment. — The foregoing indicates that after a farm is once infected the prevention is not an easy matter, for dry embryos may be scattered everywhere. Although the parasite is more abundant at some seasons than at others, yet it may be found in limited numbers at all seasons, and animals aflected will distribute the eggs throughout the year, thus increasing the diflSculties of prevention. All animals wliich show the least appearance of being affected should be separated from the sound ones. The water supplied to the sheep should be pure, i.e., either taken from wells or led into troughs from sources which can not be contaminated. If the sheep are allowed to drink from running water, then all of the brook should be fenced out except where the 203 sheep drink. Dry pastures without bog-holes or sloughs are best for the animals. As the germs live for some time in a dried condition the old pastures should not be used for young sheep at least, nor should the latter bo allowed to graze after older sheep which have had the dis- ease during the previous year, nor should the pasture be overstocked so that the grass is eaten to its roots. Disease. — Verminous bronchitis attacks young animals, those under two years being the more susceptible. Animals poorly nourished and those already weak from other parasitic diseases are also more liable to become a prey to this worn. Damp, warm seasons are most favorable for the preservation of the parasite and the disease it produces. The disease is most prevalent in summer and autumn, becomes less in winter, and disappears in spring time. The symptoms of this disease, as in verminous pneumonia, are im- perceptible in the first stages. It is probable that, beyond the slight but deep cough produced in some of the worst cases, but little else can be noticed. The sheep may have difficulty in breathing when driven or be short-winded. They may be aucnemic, as shown by the harsh, dry skin, dry wool, and pale mucous membranes. In later stages the symptoms will be aggravated; difficulty in breathing, coughing, and general debility, associated with an anaimic condition, will be the most prominent symptoms. Occasionally shreddy masses will be coughed up, which, on close examination, will prove to be worms. This is a decisive test of the nature of the disease. The sheep has a fair appetite, but will gradually lose flesh. In the last stages the bronchial cartarrh is severe, the respiration very feeble and jerky, the cough deep, convulsive, and evidently painful, coming by fits and followed by suftbcation, which leaves the patient still more exhausted. The nasal discharge becomes more copious, and contains quantities of embryo and worm fragments. Owing to the diminished respiration productive of anaimia, the skin becomes dry and harsh, and resembles parchment ; hence the popular name " paper-skin." The wool is also affected and is easily ])ulled oft", exposing the white, bloodless skin underneath. Duration. — Death occurs in three or four months either by exhaus- tion of vital forces or by suffocation. As the first stages pass unnoticed the total time from infection to death is probably nearer five or six months. The duration of the disease depends on the amount of infec- tion, the previous health of the patient, the care it receives, and its vi- tality. Where the symptoms are very decided the patients rarely sur- vive. The disease is most intense in autumn, and if the sheep do not die, it becomes less intense in winter to more or less completely disap- pear in sirring. When the season has favored the development of the disease and the lambs show severe symptoms, the outlook for their re- covery is very unfavorable. A large percentage of those attacked die. 204 Others fall away in flesh to a serious extent and the growth of the fleece is retarded. Occurrence. — It is a usual thing to find lungs aft'ected with Strongylus ovis pulmonalis^ and more rare to And them aflected with IS. Jllaria. When the latter occurs it is ordinarily associated with the former, owing to its abundance, but it is easy to separate the two diseases. In the beginning of the S.filaria disease the very posterior tip of the lung is affected, turns dark red or grayish, and has a solid feeling and ap- pearance. From this the disease spreads anteriorly, lobe after lobe of the lung becoming involved as the bronchi choke up. These termi- nal patches are very sharply separated from the adjacent portion of the lung, which appears normal, except that it may be infected with S. ovis- pulmonalis, as indeed may be the part infected by S.Jilaria. The cause of this solidification or hepatization (so called because it becomes solid like liver) is the stoppage of the air tubes by the worms and the debris they produce. When they exclude the air from the part the air cells fill with debris and the part becomes solid. Portions of Jobes elsewhere may become involved, but more rarely. The anterior lobes often ap- pear red and solid, but it will generally be noticed that in these the red part is thin and not as spongy and resistant as the lobes in the poste- rior end. This state is due to the air being driven oat of the lobes and the walls coming together, producing a state of collapse (caruification or atelectasis). The solid lung produced by S.Jilariais often covered by a thickened whitish membrane, the inflamed serous membrane, which often grows fast to the chest or thoracic walls. After the worms disapi)ear, eitber having been killed by remedies or from some unknown reason, the heal- ing i)rocess begins, and the lamb recovers if not too much weakened. Treatment of this disease is far more hopeful than that of the pneu- monia due to Strongylus ovis-pnlmonalis. It may be dietetic, preventive, and medicinal. In an essay on this disease Mr. Stephen Powers {The American Merinp, O. Judd Co., 1887, p. 283) says : To sustain the strength and vitcality of a sheep already affected is exceedingly difli- cult, because the appetite is feeble and capricious. Tlio lamb can seldom be induced to eat enough even of the most nutritious food, to make any considerable impression on it in the way of betterment ; and the danger in giving it by force stimulating gruels, etc., is that, owing to its bloodless condition, the process of digestion will be HO illy performed that the food will do it more harm than good by causing scours. High feeding is of transcendent importance as a preventive measure; l)ut when tlie lamb has reached such a pass that vermifuges have to be employed, it is necessary to proceed with great caution in giving rich food. These remarks commend themselves to all who have had experience with afflicted sheep. Keep the lambs up to the highest point of ex- cellence and health by feeding and they will the better withstand the ravages of the parasites. Corn and oats, bran, chops, and oil-cake are all good fatteuers, and should be given in i)roper proportions. Salt should be placed where the sheep have free access, not only as a diet- 205 ary article, but for its medicinal iuflueuce. In addition they should have pure, fresh water once or twice a day. Wlieu the animals have become sick good diet should be supplied. As intimated by Mr. Powers, those animals which seem most in need of food take the least, and if they do eat i^.may even be of harm to them. However desirable it may be to feed animals well as a hygienic measure, still no amount of feed- ing will keep them from being infected when a season favorable to the parasite appears. There must therefore be a continual diligence exercised in keeping the pastures in good condition and the young sheep especially from becoming infected. As the parasites seem to thri ve best in water, it follows that dry pastures should be preferred. The danger of infection from pastures should be diminished by limiting the number of sheep, so that they will not have to eat the grass close to the roots, and by a judicious distribution of the young sheep on practi- cally virgin pastures. Should a pasture have become permanently in- fected from long use it should be plowed up and either cultivated a year or two or allowed to stand idle or surrendered to other stock. The effect of the cold upon the embryos of these parasites is not yet known, and it may be that the alternate freezing and thawing which they sustain is in the Northern States the cause of the destruction of large numbers of them. Leuckart's experiment of keeping the wo^ms in moist earth, during which time many molted and died, indicate that a pasture would be much safer w^hen thoroughly dried after a pro- longed rain than before, and also that such a wet time would be more dangerous for the sheep. A judicious selection of pasturage through- out the year, together with a shifting of the sheep from pasture to past- ure as the season and ages of the sheep seem to require, is the best that can be counseled at present. MeMcinal treatment may be productive of much good, but is usually resorted to so late that its best effects are lost. Medicines haye been administered with the food by drenching, by fumigations, and by tracheal injections. Salt and copperas in proportions of from 1 of cop- peras to 25 of salt, and of 1 of copperas to 4 of salt, the last mixture being given in wet weather, has been advised {The American Me- rino, by Powers, 1887, p. 285). The weaker mixtures maybe kept con- stantly bejfore the lambs for eighteen months. The stronger should be alternated every two or three weeks with clear salt. Powers kept it constantly before the lambs until after the second summer. I would deprecate the use of copperas for any continued length of time, for it not only harms the teeth, but if persisted in loses its force as a tonic remedy. In administering dry medicines in food much of their force is lost, for they are very apt to accumulate in the paunch or first stomach. Medicines given by drenching are more expensive in the dosing but more effective, for small quantities of fluids pass directly into the mani- folds or third stomach, and thence into the fourth stomach, especially if the sheep be thirsty. But few of the many remedies advised are in 206 the least effective except they be general tonics aud stimulants. Many advise the use of anthelmintics, but these are of vahie only in driving oft" the intestinal parasites. Turpentine seems to be an exception to this rule, as some of it is eliminated by the lungs and so reaches the worms. Powers {op. ciL, p. 283) advises turpentine and linseed oil mixed in equal parts, a tablespoonful at a dose. Mr. W. G. Berry saturates lumps of salt with turpentine, then crushes the salt, mixes with bran, and feeds as a preventive. Neumann {Maladies Farasitaires, p. 517) states that the following have been recommended : Picrate of potash, from 3 to G grains per dose, dissolved in oatmeal, water, or mucilage; a mixture of equal parts of turpentine and spirits of camphor, a teaspoouful daily in mucilaginous drink ; a mixture of creosote 120 parts, alcohol 500 parts, water 700 parts, dose a teaspoonful ; creosote GO parts, benzine 300 parts, water 2,000 parts, dose a teaspoonful for each patient daily for eight days* Hall {Veterinarian^ 18G8) says that he employed with success 10 drops prussic acid (to be diluted in water) for a dose morning and evening. Neumann adds, however, that experience shows there is little reliance on these methods of treatment, and the administration is, besides, more or less difficult. The same author states that success is less uncertain with fumiga- tions which penetrate directly to the worms, benumbs them, and pro- vokes a cough by which they are brought up and ejected. The shee[) to be treated should be driven into as nearly an air tight shed or stable as is practicable. Then rags, horns, feathers, hair, old leather, tar, asafetida, etc., should be placed on a red-hot shovel or in an iron pot filled with burning coals or in a tinner's fire-pot. The intensity, dura- tion, aud number of fumigations should be graduated according to the tolerance of the sheep. Either some person should subject themselves to the same fumigations, or a very close watch should be maintained in order to prevent the lambs suffocating. Tracheal injections. — The method of treatment by tracheal injections , l^romises much better results, but should only be practiced by a relia- ble veterinarian, who can oversee the results and take all necessary pre- cautions. The method has been detailed in the Second Annual Report of the Bureau of Animal Industry, 1885, page 284. It consists of intro- ducing remedies directly into the trachea by means of a hypodermic syringe which cause the death of the parasites. The medicines thus introduced have an opportunity of acting upon the parasites directly, before they are all absorbed by the mucous membrane ot the air pas- sages. There is no reason to doubt that they may have even a second- ary effect after their absorption if they are naturally thrown off by the mucous membrane of the air-passages and the epithelium of the alveoli, which is the case with most volatile substances. The method of tracheal iujectious waa first tried by Gohier in the early part of the present century, after learning experimentally that considerable quantities of liquid can be introduced into the trachea without producing suflfocation. Delafond some 207 years after conducted some experiments to determine the absorptive power of the air passages. He found that mucilaginous decoctions and solutions of sugar or honey are speedily absorbed when injected into the trachea, inducing slight symptoms of suftbcation for one or two hours. He also found that solutions of narcotic agents and stimulants manifest their physiological effects very soon after injection, and that oils and oily medicines produce a congestion of the lungs which is but slowly dis- sipated, and that even very dilute solutions of mineral and vegetable acids produce intlammatiou, with copious secretion of mucus, giving rise to symptoms of asphyxia and even leading to death. Dr. Levi, of the University of Pisa, has recently applied this method in the treat- ment of a number of diseases {Manuel praiique des injections tracheaJes dans le cheval, 1883). His experiments also tended to show that the mucous membrane absorbs very rapidly, and is tJicrofore less apt to suffer from the injection of irritating substances than if the absorption were less rapid. He also determined that the injection of small quantities of oily substances is not dangerous, the oil probably being emulsitiod and absorbed. Finally, there is always a slight reduction in the number of respirations, amounting to about three or four per minute, after the introduction of liquids, even when distilled water only is injected. Without entering into interesting questions concerning the administration of med. icines in this manner in other diseases, which are discussed at length in the work mentioned, we find that the author has experimented ou but one case of lung worms to test the eflicacj'^ of the method. Others, however, have reported cases in which their success justifies a detailed account of the method for future application. The instrument to be used is a simple hypodermic syringe holding from 1 toy fluid drams. The needle of the syringe must be provided with a removable solid rod or trocar, so as not to become plugged when it is pushed through the skin and walls of the trachea. As the needles are apt to break, a number of them should be kept on hand. After the operation the syriugo should be carefully washed in pure water, the piston supplied with a drop of olive oil, and the trocar replaced in the needle. It is best to disinfect by tilling the syringe and needle with a 5 per cent, solution of carbolic acid, or a 0.1 per cent, solution of mercuric chloride* before washing in pure water. The disinfection, however, is not absolutely necessary in this operation if the syringe and needle be kept thoroughly clean. To administer the medicine first fill the syringe and place at the side. Hold the sheep for drenching, and extend the head of the animal so as to fix and make promi- nent the trachea, which will be felt as a tense elastic tube along the middle line of the neck. The most convenient point for the introduction of the needle Is at about the middle of the length of the neck. It must be remembered that some care is to be observed, as the trachea is near some important structures on either side — the jugular vein, the carotid artery, and the pueumogastric nerve. Having fixed the trachea with the left hand, the needle with the trocar is inserted beneath the skin, and then an interannular space is sought so as not to pierce a cartilaginous ring. Or the needle may be pushed directly into the trachea without necessarily avoiding a cartilaginous ring. The unimpeded movement of the free end of the needle as if in an empty space is a sure sign that the needle is in its proper place. The trocar is no w removed, the syringe screwed upon the needle, and the contents very slowly forced into the trachea. Before the needle is finally, withdrawn Dr. Levi thluks best to wash it out with some pure water so as to remove the injecting fluid. lu withdraw- ing the needle this might accidentally be discharged in the wound made bj' the needle and set up inflammation if the substauces introduced be irritating. How this wash- ing out is to be done he does not state. It seems that a small pipette or medicine- * The former is prepared by adding 5 parts by weight of pure carbolic acid to 100 parts by weight of pure water previously heated ; the latter by adding 1 part of the corrosive sublimate (a violent poison) to 1,000 parts of water. 208 dropper filled with water and inserted into tlie end of the needle would suflice to wash it out, or drawing back the piston of the syringe WMuild leave the needle compara- tively empty. The need'e might also be washed out by removing the syringe, wash- ing it out, filling with water, and forcing a few drops into the trachea through this needle. This, however, would cause unnecessary delay before the animal is released, and is therefore not to be recommended. The simi>lest method, then, to empty the needle would be to drawback the piston, for the dischargeof anything but the purest water into the wound may produce more irritation than the medicinal substances themselves. The animal should be watched for some time, especially after the first operation, to observe how the injection has been borne, and whether any symptoms arise which indicate difficulty of breathing. If, as has been suggested, a slight incision be made in the skin before introducing the needle, and if a cartilaginous ring be avoided in piercing the trachea, the ordi- nary needle with beveled extremity will be suflicient, and the trocar may be dis- pensed with. When the needle has entered the trachea, a slight hissing noise, dne to the entrance and exit of air with each inspiration and expiration, indicates that the needle has reached its destination and is not plugged. The substances to be injected should have distinctly vermicide properties, with- out being at the same time too irritating or poisonous in their effects on the animal. Levi gives two formula' which he used with success upon a sheep. The worms were discharged in three days and the catarrh cured : Iodine, 2 parts ; iodide of potash, 10 parts ; distilled water, 100 parts, by weight. Begin with half a dram of this solution, add half a dram of water, and increase by half a dram of the above solution each day up to 5 drams. Another remedy is the following: Mis equal parts of turpentine and olive oil, and inject from 1 to 4 drams. In this case the writer probably intended to state that the dose should be increased from 1 to 4 drams on successive days. Eloire (Becueil de Med. Vet., 188'A, p. 683) gives the following formula : Ordinary oil of poppy and oil of turpentine, each 100 parts; carbolic acid and purified oil of cade, each 2 parts. The oil of poppy, being a bland oil, does not possess any medicinal proj)erties, and may be replaced by olive oil. Each sheep to receive about 2 drams a day for three days. Six animals treated in this way showed immediate improvement and were finally cured. Penhale { Velerinarian, 1885, p. 106) reports immediate relief and ultimate cure in two calves by injecting the following mixture : Oil of turpentine, 2 drams; carbolic acid, 20 drops ; chloroform, | dram. One-half of this amount may be given to a sheep and the dose subsequently in creased if necessary. Hutton (loc. cit., p. 62) reports favorable results in six out of eight cases by inject- ing the above liquid, in which 1 dram of the tincture of opium was used in place of chloroform. This completes the list of remedies thus far suggested and tried. The favorable testimony, though not abundant, is very eacouraging. There are many substances, no doubt, the use of which might be more beneficial than those mentioned, but nothing can be said of them until they have been tested. The dose for young sheep should be proportioned to the age and size of the animal. The preparations with turpentine seem to have given the best results. During treatment the patients should receive the best of care. The prevention of this disease is very desirable, though it may never 209 be completely attained. If a farm is completely free from it in the first place, then prevention simply lies in not allowing infected sbeep to be brought on the premises. All purchases of sheep should be from flocks which have shown no signs of the disease in preceding years. Brooks which run from pasture to pasture offer a chance of infection where the neighbors' flocks upstream are infected. Strange sheep should not be pastured unless they are known to be free from parasites. Feeding and care to keep up the general health are essential. Careful separa- tion of affected animals should be practiced, and the worst diseased ones may be slaughtered. Treatment should not be neglected. During treatment it is best to keep the sheep up, and after the course of treat- ment is concluded they should be turned into new pastures. 23038 A p 14 210 STKONGYLUS FILARIA, Rud. Plate XXXIV. Fig. 1. Adult female, x'-^: a, head; h, vulva. Fig. 2. Adult male, x3: a, head; b, bursa and epicula. The dark line in Figs. 1 and 2 is the intestine. Fig. 3. Cephalic end : a, mouth ; b, oesophagus ; c, intestine ; d, unicellular glands. Fig. 4. Middle portion of female : o, vulva ; b, vagina ; c, c, uteri with develoi^ing eggs- Fig. 5. Piece of skin showing striae. Fig. 6. Spicula: a, the fenestrated chitinous cylinders ; Z>, the bulb like enlargement of the surrounding membrane. Fig. 7. Caudal end of female : «, anus ; b, b, intestine ; c, loop of the caudal uterus. d, ovary. Fig. 8. Caudal end of male, ventral view : a, intestines ; i», seminal reservoii ; c, the torn edges of the spread bursa; d, ventral costai ; e, ventro-lateral ; /, lateral ; g, dorso-lateral ; h, dorsal ; i, spicula. Fig. 9. The same lateral view. Fig. 10. a, female, natural size ; b, male, natural size. Fig. 11. Eggs showing various stages of development of embryo in the foIlowiQg ordter : a,b,c,d; e, embryo escaped from shell. PLSTE XXXIV // 'P z^^- \^ n 'ii^'i A treatment 133 figures 130 legislation concerning 134 life history 128 occurrence 127 rare in United States 17 Diatoma lanceolatum 16 description 137 figures 140 Dochmiua cernuus 16,17,22,117,118,142,145,146 description 155 disease caused by 156 treatment 157 figures 160 life history 155 occurrence 155 Doclmiius trigonocephahts 156, 167 in dogs 155 life history 155 Dog, as a beast of prey 14 as a carrier of dangerous parasites 14 Dochmiits trigonocephaJus in 155 legislation concerning 78 parasites of, common to man 14 sheep 14 relation to sheep husbandry 13 Tcvnia ccenurus in 76,86 Tamia eucumerina in 76 Twnia marginata in ^. 76, 86 Taenia serrata in 76, 86 tape worms in 14, 75, 76 intestine 14 and in sheep 76, 86 treatment 77 preventive - 78 varieties of, liable to infection 14 Echinococcus (see Tania echinococcus). Embryos, conditions necessary for raising 11 External parasites If^ Feeding 1"^ Flukes 127,137 Foot scab 6^ Gadfly (see (Estrus ovis). Gid (see Tainia ccenurus). false 30,38 Goat lice (see Tiichodtcfex vUmax and T. limbattts). Grub in the head (see (Estrus oris). Head parasites (see GiHirus oris and Tmiia ccenurus). Head scab (see Sarcoptes scabiei). 217 Page. Hoose 185,201 Husk 185,201 Hydatids (see Twnia echinococcus). Illustrations 10 material for 10 purpose of 10 Infection, how secured in experiments 11 Injuries, how efl'ected by parasites 11 Intestines, nodular disease of 165 Itch 53 insects 53 Lime, parasiticide in manure , 13 Liiiguatula tivnioides 14, 16, 69 description 69 disease caused by 69 figures 140 life history 69 Lingnatnla rhinaria 69 List of parasites described , 16 external parasites 18 Liver, parasites in 127 Liver rot 127 Liver tluke (see Distoma hepaiieiim) 127 (see Distoma lanceolatum) 137 Lombriz (see Strongyhis contortus). Louse fly (see Melophagns oviniis). Lung worms 185,186,201 diagnosis 186 species of 185 parasites of the Old World 17 Lye water and whitewashing in scab 12 Mallophaga * 45 Man, parasites of, common to dog 14 sheep 16 tape worms in 14 and in sheep 87 Manure, destruction of embryos in 13 economic management of 12 mixture of, with lime • 13 source of parasitic infection 13 Measles, in mutton (see Twnia tenella). Measurements, tables 23 Medical treatment 15 Melophagua ovinua 16, 39 disease caused by 41 treatment 41 experiments with 41 figures 44 habits of 40 life history 40 occurrence 41 source 41 Muscle, parasites in 87 Nodular disease of intestines 165 Nose, parasites in 25 218 Page. (Esophagostoma acutum .., itjs CEsopJiagostoma cohmbianum 16, 17, 20, 21, 22, 118, 145, 161, 162 description 167 determination of adult 166 disease caused by 169 diagnosis 172 pathology 169 prevention 173 distribution 165 figures 174, 176, 178, 180 investigation concerning 165 life history 168 occurrence 168 (Estrusovis 16, 17, 19,20,25,85 description 25 of larvae 26 eifects on sheep 27 figures 34, 36, 38 occurrence 30 pathology 28 treatment 31 surgical , 33 Paper skin 185,201 Parasites, abundance 9 animal 17 common to sheep and dog 14 external, definition of 18 destructiveness 22 how sheep become, infested 19 length of time of development 20 location 18 of the skin 39 seasonal appearance 21 vegetable 17 Parasitic diseases the chief source of losses 9 Pastures, as a source of infection „ 13 care of 13 Pentastoma denticulatum 69 Pentastoma twnioides 69 Phthiriasis i 39,45 Pneumonia, verminous '. 185, 186 Psoroptes communis, var. oris 16, 17, 53, 56 disease caused by 56 diagnosis 57 differential 59 pathology 57 prognosis 58,59 source of contagion 58 symptoms of 56 treatment medicinal 60 preventive 56 figures , 66,68 legislation concerning 64 Purchasing sheep, examinations in 15 219 Eabbits, not infested by parasites of sheep . 14 Eangcs as a source of infection . 13 Salting 13 Scab - 53 general description of 53 insects 53 life history - 53 white-washing and lye water 12 Sarcoptesseahid var. ovis 53,54,56 description 54 disease caused by 54 diagnosis 56 prognosis 56 source of contagion 55 treatment 56 Schroatoma equinum 161, 162 Sclerostoma hyposiomum 16.145,167,168 description 161 figures 164 life history 161 occurrence 161 Sclerostoma tetracantlmm 161, 162 Sheep grub (see CEstrus ovis). Sbeep iudustry, value of 9 Sheep louse (see Trichodectes sphwrocephalua). rod headed 45 Skiu, parasites of 39,45,49 Sources of information, recognition of 23 Species abundant in United States 16 American and European compared 16 described 17 destructive 17 not in United States 16 of external parasites 16 rare in United States 16 Staggers (see Taenia cosnurus). Stomach round worms (see Strongylus contortus). Sirongijlus contortm 16,17,20,22,117,118,141,146,202 description 141. disease caused by 142 treatment 142 figures 144 life history 141 the lombriz disease 141 Strongylus filaria 16,17,20,21,185 description 201 disease caused by 203 duration 203 tracheal injections for 206 treatment, medical 205 preventive 202,208 figures 210,212,214 occurrence 204 220 Page. Sirongylus fdicoUis 16,22,118,145,146,149,202 description 146 figures 148 Sirongylus mivutisBimus in Algeria 17 Strongjjlus ovis-inamonaUs 16,17,20,22,185,186,201,204 description 186 disease caused by 187 diagnosis 187 pathology . 187 prognosis 187 source of infection 189 treatment medicinal 190 preventive 189 figures 192, 194, 196. 198,200 life history 186 Strongylus rtifescens a synonym 17 Strong ijlus ventricosus 17,22.118,145,149,202 description 149 figures 50 new parasite of sheep 17 Sturdy 83 Symptoms of sheep infested with parasites 11 Taenia aculeata 89 Tamiaalba 89 Tcenia Benedeni 8:^ Tain ia centripunctata 89 Tcenia coenurus -. 14,16,17,19,22,72,76,83 cystic stage 83 disease caused by 89 diagnosis 85 duration of development 84 treatment 85 figures 86 life history 83 method of infection 85 Tamia cucumerina 76 Tcenia echinococcus 14, IG, 17,72,86 figures 8S in man 14 life history 86 treatment 86 Twnia expansa 16,17,20,103,113,142,202 description 11'5 disease caused by 11-' diagnosis H'' duration 120 occurrence 120 prognosis -- H-' treatment 120 distribution 16,17,103,11:! experiments with 116 figures 124, 126 life history 116 221 Tcenia expansa life history summary , 118 occurreuce 1]5 Tcenia Jimiriata j^ 17 89 description , 91 disease caused by 95 treatment, medicinal 98 preventive 100 distribution 93 — experiments 103,105,108 figures 110,112 t investigations concerning 90 life history 94 objects of experiments 9I occurrence 93 2>os<-7>io/