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9090 013 413 196 V \a\ Cummlngs Scl^r '^^''^icms at Tufts University 200WostborQ,Raad ftf^.au r\^^£x. B II .1 /%^ rrtr* : — HORSES' TEETH A TREATISE ON THEIR MODE OF DEVELOPMENT, ANATOMY, MICROSCOPY, PATHOLOGY, AND DENTISTRY ; COMPARED WITH THE TEETH OF MANY OTHER LAND AND MARINE ANIMALS, BOTH LIVING AND EXTINCT ; WITH A VOCABULARY AND COPI- OUS EXTRACTS FROM THE WORKS OP ODONTOLOGISTS AND VETERINARIANS. WILLIAM H. CLARKE. SECOND EDITION, REVISED, Horses have very nearly the same diseases as men.—Pliny. We ought to make not merely books, but valuable collections, and to acknowledge the sources whence we derive assistance. Ibid. NEW YORK WILLIAM R. JENKINS, veterinary publisher and bookseller, 850 Sixth Avenue. 1884. Copyright, 1879, by William H. ClabkEo Smith & McDougal, Electrotypees, 82 Beekraan St., N. Y. PREFACE THE favorable reception of the first edition of this work by both press and public and my desire to encourage the study of Veterinary Science and Comparative Anatomy are the chief reasons for a Revised Edition. The improvements consist in an Ai^pendix, numerous Illustrations, a new Index, and the correction of errors in and the addition of fresh matter to the text and vocabulary. I am indebted to Mr. Jacob L. Wortman of Phil- adelphia for the able article on fossil horses in the Appendix, and to Prof. E. D. Cope, editor of The American Naturalist^ for a careful revision and im- provement of it. Some of the reference notes, how- ever, are my own. It was not my intention originally to make the book an exponent of the Doctrine of Evolution. The dis- cussion of the subject, however, is justifiable, for a work that does not embrace all the. facts science furnishes is unworthy of the age, and to shirk the re- sponsibility of the discussion because the subject is unpopular is cowardly. The fact that fossil horses' teeth are inseparably connected with those of the modern horse renders their consideration unavoidable. Further, in addition to being one of the most impor- tant factors Paleontology has thus far furnished in IV PREFACE. elucidating the subject of Evolution, they give in- creased scope and importance to the book itself. Truly the late Dr. John W. Draper was right when, at a mere glance, he said: ^'The subject (horses' teeth) is so suggestive !" So far as Evolution is concerned, I can only repeat what I said in the first Preface, namely, that it denotes improvement, and that Nature's laws are immutable, and to oppose them is as foolish as to beat the head against a stone wall. Again, as said in the first Preface, I think I can say now from experience that Special Works, on account of the thoroughness with which they are usually pre- pared, are growing in public favor (an opinion in which so able a journal as The Syracuse (N. Y.) Standard concurs), and that while General Works have their advantages, thoroughness of detail is not usually among them. W. H. C. New York, September, 1883. — CONTENTS FAGS INTRODUCTION.—Fundamental Principles of Dental Science 7 CHAPTER I. TOOTH-GERMS (ODONTOGENY). Periods at which the Germs are visible in the Fetus.—Dentine and Enamel Germs.—A Cement Germ in the Foal.—The Horse's Upper Grinders said to be developed from Five Germs, the Lower from Four.— Similar development of the Human Teeth.—Monsieur Mag- itot's Researches 31 CHAPTER n. THE TEMPORARY DENTITION, Twelve Incisors and Twelve Molars.—Why the Incisors are calle "Nippers."—The Treatment of Foals Affects Teething.— Roots of Milli Teeth Absorbed by the Permanent.-The Tushes 47 CHAPTER III. THE PERMANENT DENTITION. Distinction between Premolars and Molars. -The Bow-like Incisors.— Contrasts between the Ui)per and Lower Grinders, and the Rows formed by them. — The Incisors saved from Friction. —Horses' Teeth compared with those of other Animals.—Measurements.— Time's Changes. —Growth during Life 53 CHAPTER IV. THE CANINE TEETH OR TUSHES. Practically Useless.—Different in their Nature from the other Teeth.— Were "they formerly Weapons of Offense and Defense j—"Views of Messrs. Darwin. Hunter. Bell, Youatt, and Winter.—Their time of Cutting the most Critical Period of the Horse's Life 75 CHAPTER V. THE REilNANT TEETH. Usuallv regarded as Phenomenons.—The Name.—Traced to the Fossil Horses, in which (in the Pliocene Period) they "Cea-^ed tobeFnnc- tionaliy Developed.''—Nntnre's Metamorphoses —"The Agencies which "are at work in Modeling .\nimal and Vegetable Forms." Why Remnant Teeth are often as it were. Prematurely Lost.—Fos- sil Horses and a Fossil Toothed-Bird 94 Yl CONTENTS. CHAPTER VI. DENTAL CYSTS AND SUPERNUMERARY TEETH. page Teeth growiu": in various parts of the Bod3^ —Some Cysts more Prolific thau others, Producin-i; a Second, if not a Third, "Dentition/'— Reports and Theories of Scientiiic Men.— Cases ol Thud Dentition in Human Beings 115 CHAPTER Vn. horses' teeth under the microscope. The Dentinal Tabes, Enamel Fibers, and Cemental Canals Described and Contrasted 130 CHAPTER VUI. THE PATHOLOGY OP THE TEETH. Iraportancs of the Subject.—Caries caused by Inflamed Pulps, Blows, •\irus, and Morbid Diathesi:;.—Supernumerary Teeth and other Derangements.—Trephinrng the Sinuses. - Gutta Percha as a Fill- ing.—Cleaning the Teeth.—"A Diseased Fossil Tooth 136 CHAPTER IX. THE DENTISTRY OF THE TEETH. Reports of Cases Treated by Various Surgeons.— Gutta Percha. as a Filling for Trephined Sinuses.—Teeth Pressing against the Palate. —Pas.-ing a Probe through a Decayed Tooth.—Death of a Horse from S\\ allowing a Diseased Tooth ITS CHAPTER X. FRACTURED JAWS. How Caused, and how to Distinguish an Abrasion of the Gums from a Fracture of the Bone. —Replacing an Eye, Amputating part of a Lower Jaw, taking a Fractured Tooth and Bones out through the Nostril, &c ; 194 CHAPTER XI. THE TEETH AS INDICATORS OF AGE. Their various ways of Indicating Age.—The '• Mark's " Twofold Use.— The Dentinal Star.—MarivS with too much Cement.—Tricks of the Trade.— Crib-biting.—Signs of Ago Independent of the Teeth 203 CHAPTER XII. THE TRIGEMINUS OR FIFTH PAIR OF NERYES. Its Nature and the Relation it bears to the Teeth.—Its Course in the Horse and in Man 216 VOCABULARY 227 APPENDIX.—Rec(mt Discoveries of Fossil Horses.—Views of an Evo- lutionist.—Oriiriual Home of the Horse.—Elephant Tooth-Gernas.- Filling Children's Teeth 257 INDEX 279 PUBLIC OPINION 387 USTTEODUCTION". The following matter, which is designed to give at least a synopsis of the fundamental principles of dental science, is compiled from the works of the best known odontologists. It is somewliat heterogeneous in its make-up, and is, moreover, considering that it is an Introduction to a special work, anomalous, being rather an adjunct to than an ex2:>lanation of the work itself. Its lack of coherency and the few repetitions, the inevitable concomitants of all compilations, are offset by the interest of its historical records and the scope and clearness of its thoughts and deductions. While it does not treat specially of horses' teeth, it is just as applicable to them as to human teeth, or to those of any of the other animals mentioned. It is believed that the student of dental science will find the matter as useful as it is interesting:. In his work entitled "The Anatomy of Vertebrates" (vol. i, pp. 357-8), Prof. Richard Owen says: "A tooth is a hard body attached to the mouth or beginning of the alimentary canal, partially exposed, when developed. Calcified teeth are peculiar to the vertebrates, and may be defined as bodies primarily, if not permanently, distinct from the skeleton, consisting vm IXTRODUCTIOIS'. of a cellular and tubular basis of animal matter, con- taining earthy particles, a fluid, and a vascular pulp. '^In general, the earth is present in such quantity as to render the tooth harder than bone, in which case the animal basis is gelatinous, as in other hard parts where a great proportion of earth is combined with animal matter. In a very few instances, among the vertebrate animals, the hardening material exists in a much smaller proportion, and the animal basis is albu- minous ; the teeth here agree, in both chemical and physical qualities, with bone. "I propose to call the substance which forms the main part of all teeth dentine.* The second tissue, whicli is the most exterior in situation, is the cement. The third tissue, wliich, when present, is situated be- tween the dentine and cement, is the enamel. "Dentine consists of an organized animal basis and of earthy particles. The basis is disposed in the form *In a reference note in the Introduction to liis "Odontogra- phy," Prof. Owen says: "Besides the advantag-e of a substan- tive for an unquestionably distinct tissue under all its modifica- tions in tlie animal kingdom, the term dentine may be inflected adjectively, and the properties of this tissue described without the necessity of periphrasis. Thus we may.speak of the ' denti- Dal' pulp, 'dentinal' tubes or cells, as distinct from the corre- sponding properties of the other constituents of a tooth. The term 'dental' will retain its ordinary sense, as relating to the entire tooth or system of teeth." Wote.— The particular paraprraph to which the aVove note re- fers is from Prof. Owen's " Odontography." " The Anatomy of Vertebrates " having been written about twenty-five years sub- sequent to the "Odontography," and therefore reflecting the Professor's riper thon2:hts, the extracts made from, it were sub- Btituted for very similar matter in the " Odontography." TL'BES WITH XOrRISIIIXG, COIOKLLSS FLUID. IX of compartments or cells, and extremely minute tubes. The earthy particles have a twoibld arrangement, be- ing either blended with the animal matter of the in- terspaces and parietes of the tubes, or contained in a minute granular state in their cavities.
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  • The Oldest Known Bird Archaeopteryx Lithographica Lived During the Tithonian Stage of the Jurassic Some 150 Ma (Megannum = Million Years) Ago

    The Oldest Known Bird Archaeopteryx Lithographica Lived During the Tithonian Stage of the Jurassic Some 150 Ma (Megannum = Million Years) Ago

    T y r b e r g , T .: Cretaceous© Ornithologische Birds Gesellschaft Bayern, download unter www.biologiezentrum.at 249 Verh. orn. Ges. Bayern 24, 1986: 249—275 Cretaceous Birds - a short review of the first half of avian history By Tommy Tyrberg 1. Introduction The oldest known bird Archaeopteryx lithographica lived during the Tithonian stage of the Jurassic some 150 Ma (Megannum = million years) ago. The Cretaceous period which lasted from ca 144 Ma to 65 Ma therefore constitutes approximately one half of known avian history (table 1). During these 80 Ma birds evolved from the primitive Archaeopteryx — in many ways intermediate between birds and reptiles - to essentially modern forms which in some cases are recognizable as members of extant avian orders. Unfortunately this process is very poorly documented by fossils. Fossil birds as a general rule are not common. The lifestyle of birds and their fragile, often pneumatized, bones are not conducive to successful fossilization, and even when preserved avian bones are probably often overlooked or misidentified. Col- lectors investigating Mesozoic Continental deposits are likely to have their “search image” centered on either dinosaurs or mammals. It is symptomatic that of the five known specimens of Archaeopteryx two were originally misidentified, one as a ptero- saur and the other as a small dinosaur Compsognathus. Even when a fossil has been collected and identified as avian, problems are far from over. Avian skeletal elements are frequently badly preserved and rather undiagnostic, moreover birds (usually) lack teeth. This is a serious handicap since teeth are durable and frequently yield a remarkable amount of information about the lifestyle and taxo- nomic position of the former owners.