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 UNITED STATES OF AMERICA. 
 
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HORSES' TEETH: 
 
 A TBEATISB OX THEIB 
 
 Mode of Development. 
 
 PHYSIOLOGICAL RELATIONS, ANATOMY, MICIIOSCOPICAL CHAR- 
 ACTER, PATHOLOGY, AND DENTISTRY; 
 
 BASES ON THE WORKS OF WELL-KNOWN 
 
 Odontologists and Veterinary Surgeons; 
 
 TO WHICH IS ADDED A 
 
 U 
 
 a^^ 
 
 TOCABULARY OF THE MEDICAL AND TECHNICAL WORDS USED. 
 
 
 WILLI 
 
 NEW YORK: 
 PUBLISHED BY THE AUTHOR. 
 
 1880. 
 
Copyright, 1879, by William H. Clakke. 
 
 Smith & McDougai,, Electrotypers, 
 82 Btfekmaii St., N. Y. 
 
PREFACE. 
 
 LIKE all Special Works, the present volume will 
 i encounter more or less public prejudice. How- 
 ever, the thoroughness with which Special Works and 
 Articles are usually prepared has somewhat changed 
 public sentiment, and the tendency of the times ap- 
 pears to be in their favor. General Works have their 
 advantages, but thoroughness of detail is not usually 
 among them. It may also encounter prejudice on 
 account of the doctrine of Evolution which pervades 
 its pages; but this should not be, for it refers almost 
 exclusively to the Horse, and, besides, indicates Pro- 
 gress. Nature's laws are immutable, and to oppose 
 them is as foolish as to beat the head against a stone 
 wall. Whatever may be said of the original thoughts 
 in the book, the compiled matter is from the works of 
 well-known authors, some of which are also Special 
 Works. Further, many of the definitions in the Vo- 
 cabulary are from Special Cyclopedic Articles. 
 
 The w^ork is the result of less than twelve months 
 of research and study, which is some excuse for the 
 small proportion of original matter. While it is not 
 exhaustive, it is believed that a good foundation has 
 been laid whereon to build, and that it will meet the 
 present requirements of the Veterinary Profession, and 
 may also be useful to both Horsemen and Farmers. 
 
ly PKEFACE. 
 
 In order to make the work acceptable to all classes 
 of readers, much of the selected matter has been edited 
 and more or less condensed, a vocabulary of most of 
 the technical words used and parenthetical explana- 
 tions have been made, and an attempt has been made 
 to relieve the monotony of dry anatomy by inserting 
 reference notes and headings that are at least apropos. 
 
 As I neither understand Veterinary nor Human Sur- 
 gery, an explanation, if not an apology, is required, for 
 as a rule the trained surgeon only should exercise the 
 prerogative of an Instructor. 
 
 At the request of Stephen J. Cox, Esq., I consented 
 to become the Editor of a book whereof Mr. Charles D. 
 House was to have been author. Mr. House furnished 
 the facts for which he has received credit, and then 
 abandoned the project. Whether I acted wisely or not 
 in completing the work myself, and whether Mr. Cox 
 does or does not deserve thanks for inducing me to 
 begin it, is for the reader to decide. 
 
 I am indebted to the Astor Library for the use of 
 many books ; also to the Cooper Union ; to Prof. J. M. 
 Heard, of the New York College of Veterinary Sur- 
 geons, for the use of books and for valuable sugges- 
 tions; also to Prof. F. G. Fairfield of the same College 
 for the interest he took in the parts relating to micros- 
 copy, and to Surgeons J. S. and C. C. Cattanach for 
 the use of books and anatomical specimens. To Prof. 
 John W. Draper, of the University of the City of New 
 York, wlio perceived at a glance that the subject is 
 "so sugg-estive;" Dr. George Thurber, of the Orange 
 Judd Company, and W. B. Smith, Esq., of the Authors' 
 Publishing Co., I am under obligation for encourage- 
 ment to persevere in my labors. 
 
 W. H. C. 
 
CONTENTS. 
 
 PAGE 
 
 INTRODUCTION '^ 
 
 CHAPTER I. 
 
 TOOTH-GERMS (ODONTOGENY). 
 
 Periods at wliicli the Germs are visible in the Fetus.— Den- , 
 tine and Enamel Germs.— A Cement Germ in the Foal. | 
 —The Horse's Upper Grinders said to be developed 
 from Five Germs, th3 Lower from Four. -Similar de- 
 velopment of the Human Teeth 31 
 
 CHAPTER II. 
 
 THE TEMPORARY DENTITION. 
 Twelve Incisors and Twelve Molars.— Why the Incisors 
 are called " Nippers."— The Treatment of Foals Affects 
 Teething.— Temporary Teeth Absorbed by Permanent. 47 
 
 CHAPTER III. 
 
 THE PERMANENT DENTITION. 
 Distinction between Premolars and Molars.--The Bow-like 
 Incisors.— Contrasts between Upper and Lower Grmd- 
 ers and Rows formed bv them.— The Incisors saved 
 from Friction.— Hors3s' teeth compared with those of 
 other Animals.— Measaremeuts.— Time's Changes, &c. 53 
 
 CHAPTER IV. 
 
 THE CANINE TEETH OR TUSHES. 
 Practically Useless.— Diff 3 rent in their Nature from other 
 Teeth — Wers they formerly Weapons of Offense and 
 Defense?— Views of Profs. Darwin, Hanter, Bell, You- 
 att, and Winter.— Time of Cutting a Critical Period. . 75 
 
 CHAPTER Y. 
 
 THE REMNANT TEETH. • 
 
 Usually rea:arded as Phenomenons.— The Name.— Traced 
 to Fossil Hors-s. in which (in the Pliocene Period) they 
 Ceased to be Fnnt^tionally Developed.— Nature's Meta- 
 morphoses.—" The Agencies which are at work in Mod- 
 eling- Animal and Veqretable Forms."- Why they are 
 often, as it were, Prematurely Lost.— Fossil Horses. . . 94 
 
Vi COjnTENTS. 
 
 PAGE 
 
 CHAPTER VI. 
 
 DENTAL- CYSTS AND SUPERNUMERAKY TEETH. 
 
 Teeth jrrowing in various parts of the Body. — Some very- 
 Prolific Cysts, Froduciiig a Second, it not a Third, 
 •'Dentition." — Rexjorts and Theories oi Scientific Men. 115 
 
 CHAPTER VIL 
 
 HORSES' TEETH UNDER THE MICROSCOPE. 
 
 The Dentinal Tubes, Enamel Fibers, and Cemental Canals 
 
 Descriijed and Contrasted 130 
 
 CHAPTER Vni. 
 
 THE PATHOLOGY OF THE TEETH. , 
 
 Importance of the Subject. — ^Caries caused by Inflamed 1 
 
 Pulps, Blov/s, Virus, and Morbid Diathesis. — Supernu- 
 merary Teeth and other Derangements. — Trephining 
 the Sinuses. — Gutta-Percha as a Filling. — Cleaning the 
 Teeth.— A Diseased Fossil Tooth 136 
 
 CHAPTER IX. 
 
 THE DENTISTRY OF THE TEETH. 
 
 Eeports of Oases Treated by Various Surgeons. — Gutta- 
 percha as a Filling for Trephined Sinuses. — Teeth 
 Pressing against the Palate. — Death of a Horse from 
 Swallo^ving a Diseased Tooth 175 
 
 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 Fractur£d 
 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.— Marks with too 
 much Cement. — Tricks of the Trade.— Crib-biting. — 
 \ Signs of Age Independent of the Teeth. T. . . 203 
 
 CHAPTER XIL 
 
 THE TRIGEMINUS OR FIFTH PAIR OF NERVES. 
 
 Its Nature and thn Relation it bears to the Teeth. — Its 
 
 Course in the Horse and in Man 216 
 
 VOCABULARY 227 
 
 INDEX 257 
 
INTRODUOTIOF. 
 
 The following matter, which is designed to give at 
 least a s3aiopsis of the fundamental principles of dental 
 science, is compiled from the works of the best known 
 odontologists. It is somewhat 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 explanation 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 
 
Viii INTRODUCTION'. 
 
 oi' 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, 
 which is the most exterior in situation, is the cement. 
 The third tissue, which, 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 advantage of a substan- 
 tive for an unquestionably distinct tissue under all its modifica- 
 tions in the 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- 
 nal' pulp, 'dentinal' tubes or cells, as distinct from the corre- 
 sponding properties of the other constitueiits of a tooth. The 
 term 'dental' will retain its ordinary sense, as relating to the 
 entire tooth or system of teeth." 
 
 Wote.— The particular paragraph to which the above 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 thoughts, the extracts made from it were sub- 
 stituted for very similar matter in the " Odontography." 
 
II^TRODUCTIOK. IX 
 
 of compartments or cells, and extremely minute tubes. 
 The earthy particles have a twofold 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. The density 
 of the dentine arises principally from the proportion 
 of earth in the first of these states of combination. 
 The tubes contain, near the formative pulp, filament- 
 ary processes of that part, and convey a colorless fluid, 
 probably transuded 'plasma.' They thus relate not 
 only to the mechanical conditions of the tooth, but to 
 the vitality and nutrition of the dentine. This tissue 
 has few or no canals large enough to admit capillary 
 vessels with the red particles of blood, and it has been 
 therefore called * unvascular dentine.' 
 
 " Cement always closely corresponds in texture with 
 the osseous tissue of the same animal ; and whenever 
 it occurs of different thickness, as upon the teeth of 
 the horse, sloth, or ruminant, it is also traversed, like 
 bone, by vascular canals. When the osseous tissue is 
 excavated, as in dentigerous vertebrates above fishes, 
 by minute radiated cells, forming, with their contents, 
 the ' corpuscles of Purkinje,' these are likewise present, 
 of similar size and form, in the cement, and are its 
 chief characteristic as a constituent of the tooth. The 
 hardening material of the cement is partly segregated 
 and combined with the parietes of the radiated cells 
 and canals, and is partly contained in disgregated 
 granules in the cells, which are thus rendered white 
 and opaque, viewed by reflected light. The relative 
 density of the dentine and cement varies according to 
 the proportion of the earthy material, and chiefly of 
 that part which is combined with the animal matter 
 in the walls of the cavities, as compared with the size 
 
X IKTHODUCTIOK. 
 
 and number of the cavities themselves. In the complex 
 grinders of the elei^hant, the masked boar, and the 
 copybara, the cement, which forms nearly half the 
 mass of the tooth, wears dov>m sooner than the dentine. 
 " The enamel is the hardest constitnent of a tooth, 
 and, consequently, the hardest of animal tissues; but 
 it consists, Uke the other dental substances, of earthy 
 matter arrans^ed by organic forces in an animal matrix. 
 Here, however, the earth is mainly contained in the 
 canals of the animal membrane, and, in mammals and 
 reptiles, completely fills those canals, which are com- 
 paratively wide, whilst their parietes are of extreme 
 tenuity. The hardening salts of the enamel are not 
 only present in far greater proportion than in the den- 
 tine and cement, but, in some animals, are peculiarly 
 distinguished by the presence of the fluate of lime." 
 
 Again Prof. Owen says ("Anat. of Vert." vol. i, pp. 
 359-60) : 
 
 *"' Teeth vary in num'ber, size, form, structure, modi- 
 fications of tissue, position, and mode of attachment 
 in different animals. They are principally adapted for 
 seizing, tearing, dividing, pounding, or grinding the 
 food. In some animals they are modified to serve as 
 weapons of offense and defense; in others, as aids in 
 locomotion, means of anchorage, instruments for up- 
 rooting or cutting down trees, or for transport and 
 working of building materials. They are characteristic 
 of age and sex, and in man they have secondary rela- 
 tions subservient to beauty and to speech, 
 
 "Teeth are always most intimately related to the 
 food and habits of the animal, and are therefore highly 
 
INTRODUCTIOiT. Xl 
 
 interesting to the ph3^siologist. They form for the 
 same reason most important guides for tlie naturalist 
 .in the classilication of animals; and their A'alue, as 
 zoological characters, is enhanced by the facihty with 
 which, from their position, they can be examined in 
 living or recent animals. The durability of their tis- 
 sues renders them not less available to the paleontolo- 
 gist in the determination of the nature and affinities 
 of extinct species, of whose organization they are often 
 the sole remains discoverable in the deposits of former 
 periods of the earth's history." 
 
 Prof. A. Chauveau says (" Comparative Anatomy of 
 theT)omesticated xinimals") : 
 
 "Identical inxill our domesticated animals by their 
 general disposition, mode of development, and struc- 
 ture, in their external conformation the teetli present 
 notable diffarences, the study of which offers the 
 greatest interest to the naturalist. For it is on the 
 form of its teeth that an animal depends for its mode 
 of alimentation; it is the regime, in its turn, which 
 dominates the instincts, and commands the diverse 
 modifications in the apparatus of the economy; and 
 there results from this law of harmony so striking a 
 correlation between the arrangement of the teeth and 
 the conformation of the other organs, that an anato- 
 mist may truly say, 'Give me the tooth of an animal, 
 and I will tell you its habits and structure.'" 
 
 In a letter which I wrote to Prof. Theodore Gill, of 
 the Smithsonian Institution, Washington, D. C, I 
 asked what there was about teeth that enabled natu- 
 ralists to tell so much by them. In reply he said : 
 
Xii INTRODUCTION'. 
 
 *' The teeth are quite constant in the same type, are 
 generally appreciably modified according to family, are 
 the most readily preserved in a fossil state, and are in 
 direct relation with the economy of the animal. Hence 
 they furnish the best indications of the relations of 
 the animal to which they belonged, especially in cases 
 where the type was not very different from an existing 
 one. In the case of the older and more aberrant types, 
 liowever, the indications furnished by the dentition 
 should be accepted with great caution." 
 
 In the Introduction to his " Odontography '^ Prof. 
 Owen gives, besides his own and other men's views, a 
 history "of the leading steps to the present knowl- 
 edge" of dental science (that is, up to 1844), of which 
 the following are extracts : 
 
 " As regards the teeth, the principle of cbief import 
 to the physiologist arises out of the fact, which has 
 been established by microscopic investigations, that the 
 earthy particles of dentine are not confusedly blended 
 with the animal basis,' and the substance arranged in 
 superimposed layers, but that these particles are built 
 up with the animal basis as a cement, in the form of 
 tubes or hollow columns, in the predetermined arrange- 
 ment of which there may be discerned the same rela- 
 tion to the acquisition of strength and power of resist- 
 ance in the due direction, as in the disposition of the 
 columns and beams of a work of human architecture. 
 
 " Whoever attentively observes a polished section or 
 a fractured surface of a human tooth may learn, even 
 Vv^ith the naked eye, that the silky and iridescent luster 
 reflected from it in certain directions is due to the 
 presence of a fine fibrous structure. 
 
INTR0DUCTI05T. xiii 
 
 " Malpighi,* in whose works may be detected the 
 gei'ins of many important anatomical truths that have 
 subsequently been matured and established, says the 
 teeth consist of two parts, of which the internal bony 
 layers (dentine) seem to be composed of fibrous and, as 
 it were, tendinous capillaments reticularly interwoven. 
 
 "LeeuwTnhoek,t having applied his microscopical 
 observations to the structure of the teeth, discovered 
 that the apparent fibers were really tubes, and he com- 
 municated a brief but succinct account of his discovery 
 to the Royal Society of London, which was published, 
 together with a figure of tlie tubes, in No. 140 of their 
 Transactions. This figure of the dentinal tubes, with 
 additional observations, again appeared in the Latin 
 edition of Leeuwenhoek's works, published at Leyden 
 in 1730. The dentine of the human teeth, and also 
 that of yonng hogs, is described as being * formed of 
 tubuli spreading from the cavity in the center to the 
 circumference.' He computed that he saw a hundred 
 and twenty of the tubuli within tlie forty-fifth part of 
 an inch. He was awara also of the peculiar substance 
 now termed the cement, or crusta jwtrosa, which enters 
 mto the composition of the teeth of the horse and the 
 ox. 
 
 "These discoveries may be said to have appeared 
 before their time. The •contemporaries of Leeuwen- 
 
 * An Italian physician ; born in 1628 ; died in 1604. He was 
 the first to apply the newly -invented microscope in the study of 
 anatomy. 
 
 X A Dutch naturalist and manufacturer of optical instruments. 
 His microscopes were said to be the best in Europe. Besides 
 his dental discoveries, he discovered the red globules of the 
 blood, the infusorial animalcules, and that of the spermatozoa. 
 Born in Delft October 34, 1632 ; died there Au^st 26, 1723. 
 
Xiv IHTRODtJCTIOK. 
 
 hoek were not prepared to appreciate them ; besides 
 they could neither repeat nor confirm them, for his 
 means of observation were pccuHarly his own; and 
 hence it has happened that, with tlie exception of the 
 learned Portal,* they have either escaped notice, or 
 have been designedly rejected by all anatomists until 
 the time of the confirmation of their exactness and 
 truth by Purkinje in 1835." 
 
 Continuing the subject. Prof. Owen further says of 
 the three constituent parts of teeth — dentine, enamel, 
 and cement — beginning with 
 
 THE DENTIIy^E. 
 
 '•'Purkinje states that the dentine consists, not of 
 superimposed layers, but of fibers arranged in a homo- 
 geneous intermediate tissue, parallel with one another, 
 and perpendicular to the surface of the tooth, running 
 in a somewhat wavy course from the internal to the 
 external surface, and he believed these fibers to be 
 really tubular, because on bringing ink into contact 
 with them, it was drawn in as if by capillary attraction. 
 
 " On the publication of this discovery, it was imme- 
 diately put to the test by Prof. Miiller, by whom the 
 tubular structure of the denthie was not only con- 
 firmed, but the nature and one of the offices of the 
 tubes were determined. He observed that the white 
 color of a tooth was confined to these tubes, which were 
 imbedded in a semitransparent substance, and he found 
 that the whiteness and opacity of the tubes were re- 
 moved by acids. On breaking a thin lamella of a tooth 
 transversely with regard to its fibers, and examining 
 the edge of the fracture, Miiller perceived tubes pro- 
 
 * " Histoire de I'Anatomie ct de la Cliirurgie,-' Paris, 1770. 
 
INTRODUCTION". XV 
 
 jecting here and there from the surfaces. They were 
 white and opaque, stiff, straight, and apparently not 
 flexible. Tliis appearance is well represented in the 
 old figure by Leeuwenhock. If the lamellae had been 
 previously acted upon by acid, the projecting tubes 
 were flexible and transparent, and often very long. 
 Hence Miiller inferred that the tubes have distinct 
 walls, consisting of an animal tissue, and that, besides 
 containing earthy matter in their interior, their tissue 
 is, in the natural state, impregnated with calcareous 
 salts."* 
 
 THE CEMENT. 
 
 « The organized structure and microscopic character 
 of the cem!ent were first determined by Purkinje and 
 Faenkel, and the acquisition of these facts led to the 
 detection of the tissue in the simple teeth of man and 
 carnivorous animals. The cemen fc is most conspicuous 
 where it invests the fang of the tooth, and increases m 
 thickness as it approaches the apex of the fang. The 
 animal constituent of this part of the cement had been 
 recognized by Berzelius as a distinct investment of the 
 dentine long before the tissue of which it formed the 
 basis was clearly recognized in simple teeth. Berzelius 
 describes the cemen tal membrane as being less consist- 
 ent than the animal basis of the dentine, but resistmg 
 
 * If Lord Bacon's theory is correct, the probability is that these 
 tubes contain something besides earthy matter and calcareous 
 saltr,, to wit, spirit. In " Novum Organum " lie says (B. Mon- 
 tagu, vol.xiv, p. 417): "All things abhor a solution ot their 
 continuity, but vet in proportion to their rarity. The more rare 
 the bodies be, the more they suffer themselves to be thrust into 
 small and narrow passatjes; for water will go into a passage 
 which dust will not ^o into, air whix^h water vAM not go into, 
 and flams and spirit which air will not go into." 
 
Xvi IKTRODUCTIOK". 
 
 longer the solvent action of boiling water, and retain- 
 ing some fine particles of the earthy phosphates when 
 all such earth liad been extracted from the dentinal 
 tissue. Cuvier also states that the cement is dissolved 
 with more difficulty in acid than the other dental tis- 
 sues. Retzius,* however, states that the earth is 
 sooner extracted by acid from the cement than from 
 the dentine of the teeth of the horse. 
 
 *''In recent mammalian cement the radiated cells, like 
 the dentinal tubes, owe their whiteness and opacity to 
 the earth which they contain. According to Eetzius, 
 * numerous tubes radiate from the cells, which, being 
 dilated at their point of beginning, give the cells the 
 appearance of an irregular star. These tubes form 
 numerous combinations with each other, partly direct 
 and partly by means of fine branches of t¥o"oo"^^^ ^^ 
 -g-g-i-oo-th of an inch in diameter. The cells vary in 
 size. The average size of the Purkinjean cells in hu- 
 man cement is jeVo^^^ c>f an inch. In sections made 
 transversely to the axis of the tooth, it is clearly seen 
 that tiiese cells are arranged in parallel or concentric 
 striae, of which some are more clearly and others more 
 faintly visible, as if the cement were deposited in fine 
 and coherent layers.' The layer of cement is found in 
 
 *Prof. Retzius, of tlie University of Stockholm, informs us 
 that he had heen led by the iridescence of the fractured surface 
 of the substanco of a tontli to conceive that that appearance was 
 du3, as in the crystalline lens, to a fine fibrous structure, and that 
 he communicated his opinions as to the ren^ular arranofement of 
 these fibers to some of his colleagues in 1834, In 1835, having 
 obtained a powerful microscope, he began a series of more exact 
 researches on the intimate structure of the teeth in man and 
 the lower animals, which he communicated to the Royal Acad- 
 emy of Sciences at Stockholm on January 13, 1836, being then 
 unacquainted with the discoveries of Purkinje. — Owen. 
 
INTRODUCTION". Xvii 
 
 the deciduous teeth, but is relatively thinner, and the 
 Purkinjeiin cells are more irregular. 
 
 '-'In growing teeth, with fangs not fully formed, the 
 cement is so thin that the Purkinjean cells are not 
 visible. It looks like a fine membrane, and has been 
 described as the periosteum of the fangs; but it in- 
 creases in thickness with the age of the tooih, and is 
 the seat and origin of what are called exostoses of the 
 fang, which are wholly composed of it.' These growths 
 are subject to the formation of abscesses, and all the 
 morbid actions of true bone. 
 
 "It is the presence of this osseous substance which 
 renders intelligible many well-known experiments of 
 which human teeth have been the subjects, such as 
 their transplantation and adhesion into the combs of 
 cocks, and the establishment of a vascular connection 
 between the tooth and the comb. 
 
 "Under every modification the cement is the most 
 highly organized and most vascular of the dental tis- 
 sues, aud its chief use is to form the bond of vital 
 union between the denser and commonly unvascular 
 constituents of the tooth and the bone in which the 
 tooth is implanted. In a few reptiles (now extinct), 
 and in the herbivorous mammalia, the cement not only 
 invests the exterior of the teeth, but penetrates their 
 substance in vertical folds, varying in number, form, 
 extent, thickness, and degree of complexity, and con- 
 tributing to maintain that inequality of the grinding 
 surface of the tooth whicli is essential to its function 
 as an instrument for the comminution of vegetable 
 substances." * 
 
 * Cement Mistaken fou Taetah (ODONTOT/iTnosV — Sur- 
 geon E. Mayliew says ("The Horse's Mouth," &c.): "Within 
 the alveolar cavity, the ci'usla petrosa, which becomes of cou* 
 
Xvm IKTRODUCTIOIT. 
 
 THE EK"AMEL. 
 
 "The higlier an animal is placed in the scale of or- 
 ganization, tiie more distinct and characteristic are not 
 only the various organs of the body, but the different 
 tissues which enter into their composition. This law 
 is well exemplified in the teeth, although in the com- 
 parison of these organs we are necessarily limited to 
 the range of a single primary group of animals. We 
 have seen, for example, that the dentine is scarcely 
 distinguisha])le from the tissue of the skeleton in the 
 majority of fishes; but that its peculiarly dense, un- 
 vascular, and resisting structure, which is the excep- 
 tionable condition in fishes, is its prevalent character 
 in the teeth of the higher vertebrates. 
 
 "So likewise with the enamel. This substance, 
 which under all its conditions bears a close analogy 
 with the dentine, is hardly distinguishable from that 
 tissue in the teeth of many fishes. The fine calciger- 
 ous* tubes are present in both substances, and undergo 
 similar subdivisions, the directions only of the trunks 
 
 siderable thickness ftround the fang", is of a yellowish-white 
 color ; but where, as on the crown of the tooth, it is exposed to 
 the chemical action of food and air, it presents a darker aspect, 
 and resembles an accmnulation of tartar, for which indeed it 
 has been mistaken. It fills up the infimdibula of the grinders 
 and lines those of the incisors. It is pierced by all the vessels 
 wliich nourish the teeth." 
 ! The editor of ''The Veterinrtrian " (18i9), in a "review" of 
 Mr, Mayhew's work, says: "Both English and French veteri- 
 nary writers have mistaken the crusta petrosa for tartar, not be- 
 ing aware of its existence inside as well as outside of the tooth." 
 
 * This word is peculiar to if not originated by Prof. Owen. It 
 is synonymous with the word Ccdciferous (limy). 
 
INTRODUCTION". XIX 
 
 and branches being reversed, agreeably with the con- 
 trary course of their respective developments. The 
 proportion of animal matter is also greater in the 
 enamel of the teeth of nshes than in the higher verte- 
 brala, and the proportion of tlie calcareous salts incor- 
 porated with the animal constituent of the walls of 
 the tubes is greater as compared with the subcrystal- 
 line part deposited in the tubular cavities. 
 
 "The enamel may be distinguished, independently 
 of its microscopic and structural characters, by its 
 ghstening, subtransparent substance, which is white 
 or bluish-white by reflected light, but of a gray-brown 
 color when viewed, under the microscope, by trans- 
 mitted light. * ^ * The enamel of the molar 
 tooth of a calf, which has just begun to appear above 
 the gum, and which can readily be detached from the 
 dentine, especially near the beginning of the fangs, is 
 resolvable into apparently fine prismatic fibers. If 
 these fibers be separately treated with dilute muriatic 
 acid, and the residue examined with a moderate mag- 
 nifying power, in distilled water, or, better, in dilute 
 alcOliol, portions of more or less perfect membranous 
 sheaths or tubes will be discerned, which inclosed the 
 earthy matter of the minute prism, and served as the 
 mold in which it was deposited. 
 
 "Prof. Ketzius, who obtained a small portion of 
 organic or animal substance from the enamel-fibers of 
 an incompletely-formed tooth of a horse, conjectured 
 that it was a deposition of that fluid whicli originally 
 surrounds the loose enamel-fibers, and that ^in pro- 
 portion as these fibers are pressed tighter together, and 
 additional fibers are wedged between them, the organic 
 deposition is forced away.' 
 
 *'Retzius accurately describes the enamel-fibers of 
 
XX INTRODUCTION". 
 
 the horse as presenting the form of angular needles, 
 about ^i^Vo^^^ <^f ^^^ ii^ch in diameter, which are trav- 
 ersed by minute and close-set transverse striae over 
 the whole or a part of the fiber; and he conjectures 
 that if the enamel-fiber be a mass of the calcareous 
 salts, surrounded by an organic capsule, that the stride 
 may then belong to the capsule, and not to the enamel- 
 fiber. The later researches of Dr. Schwann add to the 
 probability of this conjecture; and the absence of the 
 minute striae in the enamel of fossil mammalian teeth, 
 at least in the examples which I have submitted to 
 microscopic investigation, may depend upon the de- 
 struction of the original organic constituent of the 
 enamel. 
 
 "The enamel-fibers are directed at nearly right 
 ansfles to the surface of the dentine, and their central 
 or inner extremities rest in slight but regular depres- 
 sions on the periphery of the coronal dentine. Thus 
 in the human tooth, the fibers which constitute the 
 masticating surface are perpendicular, or nearly so, to 
 that surface, while those at the lower part of the crown 
 are transverse, and consequently have a position best 
 adapted for resisting the pressure of the contiguous 
 teeth, and for meeting the direction in which external 
 forces are most likely to impinge upon the exposed 
 crown of the tooth. The strength of the enamel-fibers 
 is further increased by the graceful, wavy curves in 
 which they are disposed. These curves are in some 
 places parallel, in others opposed. Their concavities 
 are commonly turned toward each other, where the 
 shorter fibers, which do not reach the exterior of the 
 enamel, abut by their gradually attenuated peripheral 
 extremities upon the longer fibers. Other shorter fibers 
 extend from the outer surface of the enamel toward 
 
II^TRODUCTION". XXI 
 
 the dentine, and are wedged into the interspaces of 
 the longer fibers. In the teeth of fishes, the calciger- 
 ous tubes or fibers of the enamel, which ramify and 
 subdivide like those of the dentine, have their trunks 
 turned in the opposite direction, or toward the periph- 
 ery of the tooth. So likewise in human teeth the 
 analogous condition may be discerned in the slightly 
 augmented diameter of the enamel-fibers at their pe- 
 ripheral as compared with their central extremities. 
 AVhen the extremities of the human enamel-fibers are 
 examined with a magnifying power of 300 linear 
 dimensions, by reflected light, they are seen to be co- 
 adapted, like the cells of a honey-comb, and, like these, 
 to be, for the most part, hexagonal. 
 
 "The internal surface of the enamel is marked hy 
 fine transverse fines or ridges, of which Retzius counted 
 twenty-four in tlie vertical extent of one-tenth of an 
 English inch of the crown of a human incisor. These 
 lines are parallel and wavy, and, like the analogous 
 markings on the surface of shells, indicate the succes- 
 sive formation of the belts of enamel-fibers that encircle 
 the crown of the tooth. They may be traced around 
 the whole crown, but are very faint upon its inner or 
 posterior surface. Retzius cites Leeuwenhoek as the 
 discoverer of these superficial transverse lines of the 
 enamel, but the older observer supposed them to be 
 indicative of the intervals between the successive move- 
 ments in the cutting of the tooth through the gum. 
 
 " The enamel, by virtue of its physical qualities of 
 density and durability, forms the chief mechanical 
 defense of the tooth, and is consequently limited in 
 most simple teeth to tlie exterior surface of the exposed 
 portion of the dentine, forming the crown of the tooth. 
 * * ''^ In the herbivorous mammalia, with the 
 
Xxii INTRODUCTION. 
 
 exception of the Edentata, vertical folds or processes 
 of the enamel are continued into the substance of the 
 tooth, varying in numher, form, extent, and direction, 
 and producing, by their superior density aud resistance, 
 the ridged inequalities of the grinding surface on which 
 its efficacy in the trituration of vegetable substances 
 depends." 
 
 Dr. Boon Hayes's thoughts are thus recorded in a 
 "Medical Circular," extracts from which appear in 
 "The Veterinarian" for 1853 (pp. 535-G) : 
 
 " In the first place, observe the pulpal cavity, which 
 is to the tooth what the medullary cavity is to bone. 
 Both originate in the same way. Into it passes an 
 artery, a vein, and a nerve. These ramify upon the 
 pulpal surface, the artery carrying blood to the denti- 
 nal tubuli, whence the liquor sanguinis (not blood 
 corpuscles), proceeds to the nourishment of this ap- 
 parently inorganic mass. 
 
 "In the teeth of some animals this cavity seems to 
 send off diverticula between tlie dentinal tubuli, as if 
 for the purpose of supplying them with more vascu- 
 larity. The dentinal tubes open on the walls of the 
 pulpal cavity, and thence radiate to the enamel supe- 
 riorly and the crusta petrosa interiorly. I think it 
 would not be difficult to prove that caries of the teeth 
 more frequently proceeds from inflammation begin- 
 ning in this cavity than from any other cause. 
 
 "When the tubes of the dentine are examined with a 
 high magnifying power, and by transmitted light, they 
 appear dark. They are much more minute in diameter 
 than the blood globules; hence the liquor sanguinis 
 alone cm penetrate them for their nourishment; so 
 
INTRODUCTION. XXUl 
 
 that the teeth are in the same condition as bone in this 
 respect. 
 
 "The dentinal tubes, as before said, appear dark; 
 the hghter and apparently broader masses are the real 
 substance of the dentine. In this, and especially near 
 the layer closest to the enamel, dentinal cells are some- 
 times seen, which may probably be analogous to the 
 lacunae of bone. 
 
 "If the dentinal curvatures are examined, it will be 
 seen that they are of two kinds. One set is in bold 
 and evident curves; the other is not so e^^dent, but it 
 exists, nevertheless, and a little patience and a high 
 magnifying power will demonstrate the fact that its 
 curves are upon the curves of the first set. The former 
 are called the primary, the latter the secondary curves 
 of the dentinal tubuli (in botanical description, a 
 biserrated leaf). From the tubuli minute bracelets 
 are given off on the sides, and toward the end the tubes 
 terminate, either in cells, by anastomosis, or by looping 
 back upon themselves. 
 
 "The cement at first envelops the whole tooth, but 
 soon wears off the crown and as far down as the neck. 
 Compared with the dentine and enamel, it is very soft, 
 and more closely resembles bone ; in fact in some ani- 
 mals it is continuous with the bone of the jaw, thus 
 proving its identity. It contains lacunae and canalic- 
 uli, and, when there is a large mass of it, something 
 like Haversian canals. 
 
 " There is a a^reat analoory between tooth and bone. 
 In the cement there is absolute likeness, and in the 
 dentine analogies too striking to be overlooked, viz., 
 the tubuli, analogous to tlie canaliculi, the intertubular 
 cells, analogous to the lacunre, and the intertubular 
 substance, analogous to the lamina? of bone. In the 
 
XXIV INTRODUCTION". 
 
 enamel the greatest departure is observable, but not 
 wider than its peculiar function suggests; and it must" 
 be remembered, first, that it is the least constant tissue 
 of the teeth; secondly, that its chemical composition 
 is very much the same as that of the dentine and 
 cement, both of which resemble bone. Lastly, the 
 analogy is completed in a review of the mode of tooth 
 development. Thus, upon a mucous papilla a large 
 quantity of gelatinous matter is observable, in which 
 certain cells appear. The gelatinous matter resembles 
 the incipient cartilage in which ossification begins. 
 This papilla is supplied with an artery, which nour- 
 ishes its cells, and the cells gradually so develop that 
 the older ones are pushed outward and form the 
 dentine." 
 
 HOW MADDER AFFECTS THE TEETH. 
 
 John Hunter, one of the most celebrated physiolo- 
 gists of the eighteenth century, made many experi- 
 ments on, the teeth of different animals, one object 
 being to determine whether they were vascular or not. 
 His conclusion was that they were not vascular, and 
 he founded his belief partly upon the following experi- 
 ment (" The Human Teeth," pp. 23-4) : 
 
 " Take, for example, any young animal, as a pig, and 
 feed it with madder for three or four weeks; then kill 
 it. On examination you will find the following ap- 
 pearances: First, if the animal had some parts of its 
 teeth formed before the feeding with madder, they 
 will be known by their remaining of the natural color; 
 but such parts of the teeth as were formed while the 
 animal was taking the madder will be of a red color. 
 This shows that it is only those parts that were formed 
 while the animal was taking the madder that are dyed; 
 
INTR0DUCTI02^. XXT 
 
 for what were already formed will not be in the least 
 tinged. Tills is different in all other bones; for we 
 know that any part of a bone which is already formed 
 is capable of being dyed with madder, though not so 
 fast as th e part that is forming. Therefore, as we know 
 that all other bones are vascular, and are thence sus- 
 ceptible of the dye, v/e may readily suppose that the 
 teeth are not susceptible of it after being once formed. 
 But we shall carry this a step further: If you feed a 
 pig with madder for some time, and then leave it off 
 for a time before killing it, you will find the appear- 
 ances as above, with this addition, that all the parts of 
 the teeth which were formed after leaving off feeding 
 with the madder will be white. Here, then, in some 
 teeth we sliall have white, then red, and then white 
 again ; and so we shall have the red and white colors 
 alternately through the whole tooth.* 
 
 "This experiment shows that a tooth, once tinged, 
 does not lose its color. Now, as all other bones that 
 
 *In the concluding part of Moore's " Lalla Rookh" ("The 
 Light of the Harem"), the Enchantress says of an herb with the 
 unmusical name of " Haschischat ed dab:" 
 
 *' The visions, that oft to worldly eyes 
 The glitter of mines mifold, 
 Inhabit the mountain -herb, that dyes 
 The tooth of the fawn like gold." 
 
 A reference note to the above is as follows : "An herb on 
 Mount Libanus, which is said to communicate a yellow golden 
 hue to the teeth of the goats and other animals that graze upon 
 it. Niebuhr thinks this may be the herb which the Eastern 
 alchemists look to as a means of making gold. 'Most of those 
 alchemical enthusiasts think themselves sure of success if they 
 could but find out the herb which gilds the teeth and gives a yel- 
 low color to the flesh of the shcsp that cat it. Even the oil of this 
 plant must be of a golden color. It is called HcLSchischat ed dab* 
 Father Jerome Dandini, however, asserts that the teeth of the 
 
XXvi IKTKODUCTIOI^. 
 
 have been tinged lose their color in time, when the 
 animal leaves off feeding with the madder (though 
 very slowly), and as that dye must be taken into the 
 constitution by the absorbents, it seems that the teeth 
 are without absorbents as well as other vessels." 
 
 The editor of Hunter's " Treatise," Thomas Bell, 
 F.K.S., differed with Hunter about the vascularity of 
 the teeth. He thus concludes a note on the above 
 quotation : 
 
 " The truth appears to be that the teeth are organ- 
 ized bodies, having nerves and absorbent and circula- 
 ting vessels, but possessing a low degree of living 
 power, and so dense a structure as to exhibit phenom- 
 ena, both in their healthy and diseased condition, 
 which are very dissimilar from those which are ob- 
 served in true osseous structures." ^ 
 
 TRAN'SPLAKTIN'G TEETH. 
 
 The transplanting of teeth, which Dr. Hunter says 
 is " similar to the ingrafting of trees," is expatiated 
 upon at some length. He then gives an account of a 
 case of transplanting which he admits "is not gener- 
 ally attended with success," he having " succeeded but 
 once out of a great number of trials." It is as follows 
 (" The Human Teeth," pp. 100-101) : 
 
 *^ I took a sound tooth from a person's head ; then 
 
 g-oats at Mount Libanus are of a siher color, and adds: 'This 
 confirms to me that which I observed in Candia, to wit, that 
 the animals that live on Mount Ida eat a certain herb which 
 renders their teeth of a golden color, which, according to my 
 judgment cannot otherwise proceed than from the mines which 
 are under ground.' — Dandlni, Voya'je to Mount Libanus." 
 
INTRODUCTION". XXMl 
 
 made a wound in a cock's comb, pressed the fang into 
 it, and fostcned it with threads. The cock was killed 
 some months after, and I injected the head with a very 
 minute injection. I then put the coml^ into a weak 
 acid. The tooth was softened, and I divided it longi- 
 tudinally. Its vessels were well injected, the external 
 surface adhering to the comb by vessels similar to the 
 union of a tooth with the gum and sockets."* 
 
 * MM. E. Magitot, C. Logros, and C. Robin, have experimented 
 in transplanting- the follicles or germs of dogs' teeth, an account 
 of which appears in " Comptes Rendus" for 1874. They say : 
 
 " Our experiments comprised 88 grafts, mostly from newly-born 
 dogs, but some were 22 and even 58 days old. The animals 
 were invariably sacrificed by the pricking of the bulbs, and 
 the jaws were opened at once, to lay the follicles bare. One-half 
 -of both jaws thus served to supply the grafts, while the other 
 was kept for a standard of comparison. The doors on which the 
 grafts were applied were usually adults, but sometimes of the 
 same age and bearing as those that supplied them. The germs 
 were rapidly isolated from the dental gutters, and introduced at 
 once. In some instances they were dipped for a few minutes in 
 the blood's serum of the sacrificed animal, which was kept by 
 the bath (bain-marie) at a temperature of from 30" to 35° C. 
 They were introduced under the skin of the nape of the neck, 
 the top of the head, and the dorsal and lumbar regions. In 36 
 cases the process of application consisted of a simple incision and 
 the introduction of the graft 2 or 3 centimeters from the open- 
 ing, which was closed by two sutural stitches. In the other 52 
 cases a special trocar of an interior diameter of 7 millimeters was 
 used, which allowed a swifter and surer transplantation, but it 
 did not appear to exert an appreciable influence on the results. 
 
 " Ten grafts were made from newly-born dogs on adult guinea- 
 pigs, divided as follows : Whole follicles, 6 ; isolated enamel- 
 organs, 3 ; bulb alone, 1. The results were all negative— caused 
 by resorption and suppuration— corroborating M. Bert's experi- 
 ences in grafis between animals of different zoological orders. 
 
 " The 78 other grafts were made on newly-born, young, and 
 adult dogs, and were maintained from 13 to 54 days. The 25 
 grafts that remained 54 days resorbed themselves. The experi- 
 ments in detail were as follows : 1. Isolated whole follicles, 26. 
 2, Follicles with a portion of the maxillary bone, 5. 3. Isolated 
 
xxviii IKTRODUCTIOI^. 
 
 This appears to prove that Dr. Hunter was right 
 when he said that teeth "are capable of uniting with 
 
 bulbs, IG. 4. Bulbs witli a cap of rudimentary dentine, 7. 5. 
 Isolated caps of dentine, 4. 6. Isolated enamel-organs, with a 
 slired of buccal mucous membrane, 19. 7. Enamel organs, with 
 a cap of dentine adhering, 1. The results were : Of the first, 7 
 kept alive and grew steadily, except in one instance, in whicli a 
 disturbed nutrition brought on tlie formation of globulary den- 
 tine and irregular stacks of enamel prisms. The second gave 3 
 suppurations and 2 resorptions, again corroborating Mons. Bert's 
 experiments. The third gave 3 positive results, in two of wliich 
 a new cap of dentine was produced, quite regular, but globulous 
 and somewhat altered in its nutrition. The other was without 
 enamel. In the fourth experiment the bulbs could not be found ; 
 they underwent resorption. When compared with the preced- 
 ing experiment, this result is astonishing ; but it should be un- 
 derstood that these grafts were maintained from 43 to 54 days. 
 Of the fifth a single one kept alive, but without showing any 
 growth. It remained stationary 43 days. The sixth invariably 
 ended in resorption, notwithstanding we were careful to graft 
 the shred of mucous membrane, which supplies the organ with 
 nutritive vessels. This result is not surprising when the exces- 
 sive frailty of this tissue and its lack of vascularity are consid- 
 ered. Some of the negative grafts were either reduced in size, 
 being evidently in process of resorption, or underwent the oily 
 transformation. Others caused abscesses, and were eliminated. 
 "Conclusions. — 1. The grafts gave favorable results only be- 
 tween animals of the same zoological order. 2. The isolated 
 whole follicles and bulbs may live and develop themselves. 3. 
 The transplanting of more or less voluminous portions of jaws 
 with the follicles failed through suppuration or resorption. 4. 
 The grafts of the enamel-organ, isolated, seem invariably given 
 up to resorption. 5. Under certain circumstances the growth is 
 regular, with no other difference from that in the normal state 
 than a noticeable slowness in the phenomena of evolution. 6. 
 Under other circumstances there is trouble in the formation of 
 the dentine and enamel, the study of which, however, may be ap- 
 plied to the elucidation of the phenomena, still so dark, of tooth 
 development. 7. The experiments are an acquisition to the lit- 
 erature of and may be compared with other surgical grafts." * 
 
 * For the translation of the above interesting article (from the Reports of 
 the French Academy) I am indebted to Monsieur C. Raoux, of New York. 
 
INTRODUCTIOiq". XXIX 
 
 any part of a living body." Mr. Bell thus concludes 
 a note on the above case of transplanting: 
 
 " The experiment has an interest attached to it far 
 more important than its having given rise to the tem- 
 porary adoption of an objectionable operation. In the 
 result of tbis experiment may be found an interesting 
 collateral argument in favor of the organized structure 
 of the teeth, and their actual living connection with 
 the body. The vessels of the tooth, we are told, were 
 well injected, and the external surface adhered every- 
 where to the comb by vessels. To what purpose are 
 these vessels formed, what object can be possibly ful- 
 filled by the existence of a vascular pulp in the internal 
 cavity, and a vascular periosteum covering the external 
 surface — so obviously vascular that it was tcell injected 
 from the vessels of a cock's comb, into which it had 
 been transplanted— unless they are intended to nourish 
 the bony substance of which the tooth consists, and to 
 form the medium of its connection with the general 
 system ?'' 
 
 Prof. Eichard Owen says (" Odontography," vol. i, 
 p. 470) : 
 
 " The saving of material is the least of the benefits 
 gained by this tubular structure of the dentine. The 
 vitality of the tissue, which Hunter recognized so 
 forcibly, but which, being equally convinced of the 
 non-vascularity of the tissue, he was unable to explain 
 
 « willing rather to enunciate an apparent paradox or 
 
 be taunted with dilemma, than yield one iota of either 
 of his convictions'* — is exphcable by the possible and 
 
 *Prof. Owen quotes from Bell's " notes" in Hunter's "Human 
 Teeth." 
 
XXX INTRODUCTION". 
 
 highly probable fact of a circulation of the colorless 
 plasma of the blood through the dentinal tubes. That 
 some elementary prolongations of nerve may also be 
 continued into these tubes, who can confidently deny ?'' 
 
 As Prof. Owen says the " teeth are always most 
 intimately related to the food and habits of the ani- 
 mal," it would be interesting and perhaps useful to 
 ascertain what effect sugar and other unusual articles 
 of diet would have on horses' teeth. In the interest 
 of science, experiments appear to be in order. In this 
 connection the following paragraph, a part of whicli 
 may be found in Prof. William Youatt's work, " The 
 Horse " (p. 135), the remainder in '' The Veterinarian," 
 is interesting: 
 
 " Surgeon Black, of the Fourteenth Dragoons, says 
 til at suo'ar was tried as an article of food durins: the 
 Peninsular AVar. Ten horses were selected, each of 
 which got eight pounds a day. They took it very 
 readily, and their coats became fine, smooth, and 
 glossy. They got no corn, and only seven pounds of 
 hay instead of twelve, the ordinary allowance. The 
 sugar supplied the place of corn so well, that it would 
 probably have been given abroad ; but peace came, and 
 Avith it corn. The horses returned to their usual diet, 
 but several of them became crib-biters. The experi- 
 ment was made at tlie Brighton depot, during a period 
 of three months. To prevent the sugar from being 
 used for other purposes, it was scented with assafetida, 
 but the latter did not produce any apparent effect on 
 the horses." 
 
HORSES' TEETH. 
 
 CHAPTER I. 
 
 TOOTH-GERMS (ODONTOGEI^Y). 
 
 Periods at wliicli 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 dcA^eloped. from Five 
 Germs, the Lower from Four. — Similar development of the 
 Human Teeth.— Monsieur Magitot's Researches. 
 
 4 
 
 Furrows in what is subsequently transformed into 
 jawbones, in which tooth-germs are, as it were, planted, 
 are Nature's first visible preparation for the develop- 
 ment of the teeth. According to Prof. William You- 
 att, the germs of the temporary teeth are visible seven 
 or eight months before the foal is born. Three months 
 before its birth the germs of the permanent teeth are 
 also visible, a distinct partition separating them from 
 the temporary. At this time, according to Veterinary 
 Dentist C. D. House, the capsules or bags (also called 
 follicles, sacs, &c.), containing the tooth-pnlps* of the 
 
 * Tlie puh^s from which the teeth are developed should not he 
 confounded witli tliose of the teeth themselves. Tiie latter, com- 
 monly called nerves, on the exposed and pulsating: tops of which 
 some human dentists are so inhuman as to put fillings, occupy 
 "the central cavity of each tooth, and is a delicate mass of 
 connective tissue, cuntuiuing both blood-vessels and nerves." 
 
33 TOOTH-GERMS. 
 
 future temporary teeth are about the size of small peas. 
 They will bear some pressure between the iSngers, the 
 indentions spriuging back like those of an India rub- 
 ber ball. 
 
 The nature of tooth-germs and the development of 
 teeth have been studied with some diligence by scien- 
 tific men — Dr. John Hunter, it is said, making the first 
 important discoveries in connection with the science. 
 The discussion of this interesting and, to students, 
 useful subject is left to these men. There is some 
 conflict in their views, but it should be remembered 
 that the extracts reflect the opinions of men from 
 Hunter's time (over a century ago), to 1876. The de- 
 velopment of tooth-germs being the same in principle 
 (though different in detail) in all m-ammals, the matter 
 which follows (as has been said of that in the "Intro- 
 duction"), is as applicable to the horse as to man. 
 
 In the Introduction to his " Odontography " (Lon- 
 don, 1844), Prof. Eichard Owen says: 
 
 " In the development of a tooth a matrix of equal 
 complexity v/as first recognized to be concerned by 
 John Hunter, the several parts of this matrix being 
 first distinctly indicated in the ^Natural History of 
 the Human Teeth.' * * * Hunter has been gen- 
 erally regarded by physiologists as being the author of 
 tiie theory that the pulp stood to the tooth-bone in the 
 relation of a gland to its secretion ; that the formative 
 virtue of the pulp resided in its surface ; that the den- 
 tine was deposited upon and by the formative or secre- 
 tive surface in successive layers, and that the pulp, 
 exhausted, as it were, by its secretive aetivit}', dimin- 
 ished in size as the formation of the tooth proceeded, 
 excepc in certain species, in which it was persistent, 
 
JOHN HUi^^TER's DISCOVERY. 33 
 
 and maintained an equable secretion of the dentine 
 tlirougbout tiie lifetime of the animal This idea of 
 the pulp's function has predominated in the minds of 
 most subsequent writers on the development of the 
 tec til. * ••' * * 
 
 " Three formative organs are developed for the three 
 principal or normal deutal tissues, the 'dentinal-pulp/ 
 or pulp proper, for the dentine, the 'capsule' for the 
 cement, and the 'enamel-pulp' for the enamel. The 
 essential fundamental structure of each form.ative 
 organ is cellular, but tlie cells differ m each organ, 
 and derive their specific characters from the properties 
 and metamorphoses of their nucleus, upon which the 
 specific microscopical characters of the resulting calci- 
 fied substances depend. 
 
 "In the cells of the dcntinal-pulp the nucleus fills 
 the parent cell v/ith a progeny of nucleoli before the 
 work of calcification begins. In the enamel-pulp the 
 nucleus of the cell disappears, like the cytoblast of the 
 embryo plant m the formation of most vegetable tis- 
 sues. In the cells of the capsule the nucleus neither 
 perishes nor propagates, but retains its individuality, 
 and gives origin to the mos^; characteristic feature of 
 the cement, viz., the radiated cells. 
 
 ''The primordial material of each constituent of the 
 tooth-matrix is derived from the blood, and special 
 arrangements of the blood-vessels preexist to the devel- 
 opment and growth of the constituent substances. A 
 pencil of capillaries is directed to a particular spot in 
 the primitive dentiparous groove, and terminates there 
 by a looped network, from which spot a group of nu- 
 cleated cells begins to arise in the form of a papilla. 
 
 T^ ^ ^ n* *i* 
 
 "The primary dentinal papilla and its capsule rap- 
 
34 TOOTH-GEPtMS. 
 
 idly increase by successive additions of nucleated cellSp 
 apparently derived from material supplied by the cap- 
 illary plexus at the base. The capillaries now begin 
 to penetrate the substance of the pulp itself, where 
 they present a subparallel or slightly diverging pencil- 
 late arrangement, but preserve their looped and retic- 
 ulate termination near the apex of the pulp. Fine 
 branches of nerves accompany the capillaries, and ter- 
 minate also in loops. * * '^ The primary cells and 
 the capillary vessels and nerves are imbedded in and 
 supported by a homogeneous, minutely subgranular, 
 mucilaginous substance, the ' blastema/ * * * The 
 vascularity of the dentinal-pulp, and especially the 
 rich network of looped capillaries that adorns the 
 formative peripheral layer at the period of its func- 
 tional activity, have attracted general notice, and have 
 been described by Hunter and subsequent authors. By 
 most this phenomenon has been regarded as evidence 
 of the secreting function of the surface of the pulp, 
 and the dentine as an outpouring from that vascular 
 surface which was supposed to shrink or withdraw 
 from the matter excreted. * * ''' 
 
 " The enamel-pulp differs from the dentinal-pulp at 
 its first formation by the more fluid state of its blas- 
 tema, and by the fewer and more minute cells which 
 it contains. The source of this fluid blastema appears 
 to be the free inner vascular surface of the capsule. 
 As it approaches the dentinal-pulp the blastema ac- 
 quires more consistence by an increased number of its 
 granules, and it contains more numerous and larger 
 cells. Many of these show a nuclear spot, others a 
 nucleus and nucleolus. The spherical nucleolar cells 
 in the part of the blastema further from the capsule 
 are so numerous as to form an aggregate mass, with a 
 
DEFII^TING THE BLASTEMA. 35 
 
 small quantity of the condensed blastema in tlie 
 minute interspaces left between the cells, which are 
 pressed together into hexagonal or polygonal forms. 
 * * * The field of the tinal metamorphosis of the 
 cells into the molds for the reception of the solidifying 
 salts is confined to close contiguity with the surface of 
 the dentinal-pulp. Here the cells increase in length, 
 lose all trace of their nucleus, and become converted 
 into long and slender cylinders, usually pointed at both 
 ends, and pressed by mutual contact into a prismatic 
 form. These cylinders have the property of imbibing 
 the calcareous salts of the enamel from the plasmatic 
 fluid, and of comp'icting them in a clear and almost 
 crystalline state in their interior. * * * 
 
 "The blastema or fundamental tissue of the capsule 
 is, at first, semitransparent and of a pearly or opaline 
 color, but IS soon richly ornamented by the plexiform 
 distribution of the blood-vessels. As the period of its 
 calcification approaches, which is later than that of 
 the dentinal-pulp, it becomes denser, and exhibits nu- 
 merous nucleated cells. The blastema itself presents 
 more evidently a fine cellular or granular structure, in 
 which the calcareous salts are impacted in a compara- 
 tively clear state, constituting the framework of the 
 cemental tissue. The characteristic features of this 
 tissue are due to the action of the proper nucleated 
 cells upon the salts of the plasma diffused through the 
 blastema in which those cells are imbedded, the cells 
 being characterized by a single, large, granular nu- 
 cleus, which almost fills the clear area of the cell itself. 
 If, when the formation of the cement has begun m the 
 incisor or molar of a colt, one of the detached specks 
 of that substance, with the surrounding and adhering 
 part of the inner surface of the capsule in which it is 
 
26 T00TH-GER3fS. 
 
 imbedded, be examined, the nucleated cells are seen, 
 closely aggregated around the calciiied part, in con- 
 centric rows, the cells of which are farther apart as 
 the rows recede from the field of calcilication. Those 
 next the cement rest In cup-shaped cavities in the 
 periphery of the calcified part, just as the first calcified 
 cells of the thiick cement which covers the crown of a 
 complex molar are lodged io cavities on the exterior of 
 the enamel. Tliese exterior cavities of the cement are 
 formed by centrifugal extension of the calcifying pro- 
 cess in the blastema in which the cells are imbedded. 
 The calcareous salts penetrate in a clearer and more 
 compact state the cavity of the cell, but their progress 
 is arrested apparently by the nucleus, whicli maintains 
 an irregular area, partly occupied by the salts m a sub- 
 granular, opake condition, but chiefly concerned in 
 the reception and transit of the plasmatic fluid, which 
 enters and escapes by the minute tubes that are sub- 
 sequently developed from the nucleolar cavity as calci- 
 fication proceeds. 
 
 '' The radiated cells or cavities thus formed are the 
 most common characteristic of the cement, but not the 
 constant one. The layer of the capsule which sur- 
 rounds the crown of the human teeth and of the 
 simple teeth of quadrnmana and carnivora, consists 
 simply of the granular blastema, y/ithont nucleated 
 cells, and the radiated corpuscles are, consequently, not 
 developed m the cement which results from its calci- 
 fication. In the thicker part of the inflected folds of 
 the capsule of the complex teeth of the herbivora, 
 traces of the vascularity of that part of the matrix are 
 persistent, the blastema calcifying around certain of 
 the capillaries, and forming the medullary canals. 
 The varieties of these canals are traversed by minute 
 
PROF. TOMES'S THEORY. 37 
 
 tubules, continued from or communicating with the 
 radiated cells. Those tubules, and the more parallel 
 ones which traverse the thickness of the cement in 
 many mammalia, are the remains of linear series of 
 , the minute granules of the blastema. * * '^ 
 
 *•' The general form of the dental matrix and its rela- 
 tion w^ith its calcified product, bear a close analogy 
 with those of the formative organ of hairs, bristles, and 
 other productions of the epidermal system. In these 
 the papilla, or pulp, is developed from the external 
 skin; in the teeth, from tlie mucous membrane, or 
 internal skin." * * * * 
 
 Prof. Charles S. Tomes differs from the views of 
 Messrs. Hunter and Owen as to the pulp's secretive 
 office, claiming that a tooth is formed by a meta- 
 morphosis of its pulp. He says ("Manual of Dental 
 Anatoni}^, Human and Comparative/' London, 187G, 
 pp. 104-5-G) : 
 
 "' Prior to the beginning of any calcification, there 
 is always a special disposition of the soft tissues at the 
 spot wliere a tooth is destined to be' formed, and the 
 name of ' tooth-germ' is given to those portions of the 
 soft tissue which are thus specially arranged. All, or 
 a part only, of the soft structures making up a tooth- 
 germ become converted into the dental tissue by a 
 deposition of salts of lime within their own substance, 
 so that an actual conversion of at least some portions 
 of the germ into tooth takes place. The tooth is not 
 secreted or excreted by the germ, but an actual meta- 
 morphosis of the latter takes jolace. 
 
 " The principal tissues, namely, dentine, enamel, and 
 cement, are formed from different parts of the tooth- 
 germ; hence we are accustomed to speak of the enamel- 
 
38 TOOTH-GERMS. 
 
 germ and tlie dentine-germ. The existence of a spe- 
 cial cement-germ is very doubtful, some writers assert- 
 ing, others denying its existence. ^k * * 
 
 " Tootli-gernis are never formed upon the surface, 
 but are situated a little distance beneath it, lying in 
 some animals at a considerable depth. Every known 
 tooth-germ consists in the llrst instance of two por- 
 tions, and two only, the enamel and dentine germs. 
 These are derived from distinct sources, the former 
 being a special development from the epithelium of 
 the mouth, the latter from the more deeply lying parts 
 of the mucous membrane. Other things, such as a 
 tooth-capsule, may be subsequently and secondarily 
 formed. The existence of an enamel-organ in an early 
 stage is independent of any subsequent formation of 
 enamel by its own conversion into a calcified tissue, for 
 I have shown it to be found in the germs of teeth 
 whicii have no enamel; in fact, in all tooth-germs 
 whatever. 
 
 "That part of the tooth-germ destined to become 
 dentine is often called the dentine papilla, having 
 acquired this name from its papilliform shape; and in 
 a certain sense it is true that the enamel-organ is the 
 epithelium of the dentine papilla. Yet, although not 
 absolutely untrue, such an expression might mislead 
 by implying that the enamel organ is a secondary de- 
 velopment, whereas its appearance is contemporaneous 
 with, if not antecedent to, that of the dentine-germ. 
 The most general account that I am able to give of the 
 process is, that the deeper layer of the oral epithelium 
 sends dow^n into the subjacent tissue a process, the 
 shape and structure of whicli is, in most animals, dis- 
 tinguishable and characteristic before the dentine- 
 germ has taken any definite form. This process en- 
 
THE ORAL EPITHELIUM. . 39 
 
 larges at its end, and, as seen in section, becomes 
 divaricated, so that it bears some resemblance to an 
 inverted letter Y ; or it might be better compared to a 
 bell-jar with a handle. This constitutes the early stage 
 of an enamel-germ, while beneath it, in the mucous 
 tissue, the dentmc-germ assumes its papilliform shape. 
 The details of the process varying in different animals, 
 I will at once proceed to the description of tlie devel- 
 opment of teeth in the various groups." 
 
 Prof. Tomes's views of the development of tooth- 
 germs in mammals are thus summarized by himself 
 (" Philosoi)hical Transactions Eoyal Societ}^' 1875, 
 part i, p. 285) : 
 
 "1. There is never, at any stage, an open groove 
 from the bottom of which papilia3 rise up. 
 
 "2. That the first recognizable change in the region 
 of a forming tooth-germ is a dipping down of a process 
 of the oral epithelium, looking, m section transverse 
 to the jaw, like a deep simple tubular gland, which 
 descends into the submucous tissue, and ultimately 
 forms the enamel-organ. 
 
 " 3. That subsequently to the descent of the so-called 
 enamel-germ, the changes in the subjacent tissue re- 
 sulting in the formation of the dentine papilla take 
 place opposite to its end, and not at its surface. I 
 
 "4. That the permanent tooth-germs first appear as 
 offshoots from the epithelial process concerned in the 
 formation of the deciduous tooth-germ (Kolliker), the 
 first permanent molar being derived from a primary 
 dipping down (like a deciduous tooth), the second de- 
 riving its enamel-germ from the epithelial neck of the 
 first, and the third from that of the second (Legros 
 and Magi tot)." 
 
40 TOOTH-GEIIMS. 
 
 Again, in the Society's Transactions for 1876 (p. 2G5), 
 Prof. Tomes says: 
 
 '•1. It is desinible to abandon tiie terms * papillary/ 
 *i'oliicular,' and 'eruptive' stages, inasmuch as they 
 are hypothetical and arbitrary, and correspond to no 
 serial conditions verified by observation. 
 
 "3. In all animals a tooth-germ consists primarily 
 of two strnctures, and. only two — the dentine-germ 
 and the enamel-germ. The simplest tooth-germ never 
 comprises anything more. When a capsnTe is devel- 
 023ed, it is derived partly from a secondary upgrowth 
 of the tissue at the base of the dentine germ, and partly 
 from an accidental condensation of the surrounding 
 connective tissue. 
 
 '•'3. The existence of an enamel-organ is quite uni- 
 versal, and is in no vray dependent on the presence or 
 absence of enamel on the completed tooth, although 
 the degree to which it is developed has distinct relation 
 to the thickness of tlie future enamel. 
 
 "4. So far as my researches go, a stellate reticulum, 
 constituting a large bulk of the enamel-organ, is a 
 structure confined to the mammalia. (It is absent in 
 the armadillo, and I should infer from Mr. Turner's 
 description, in the narwhal also). 
 
 "5. As laid down by Profs. Huxley and Kolliker, 
 tlie dentine-papilla is beyond all question a dermal 
 structure, tlie enamel-organ an epithelial or epidermic 
 structure. As I believe it can be shown that the enamel 
 is formed by an actual conversion of the cells of the 
 enamel-organ, this makes the dentine a dermal and 
 the enamel an epidermic structure. 
 
 "6. In teleosts the new enamel-germs are formed 
 directly from tlie oral epithelium. They are new for- 
 mations, and arise quite independently of any portion 
 
MONSIEUR CHAUVEAU'S THEORY. 41 
 
 of the germs of the teeth which preceded them. In 
 mammals and reptiles, and in some of the batrachia, 
 new tooth-germs are developed from portions of their 
 predecessors. 
 
 *' 7. In all animals examined the phenomena arc very 
 uniform. A process dips in from the oral epithelium, 
 often to a great depth, its end becoming transformed 
 into an enamel-organ coincidentall}^ with the formation 
 of a dentine-papilla beneath it. The differences lie 
 rather in such minor details as the extent to" which a 
 capsule is developed, and tlierefore no such generali- 
 zation as that the teeth of fish in their development 
 represent only an earlier stage of the development of 
 the teeth of mammalia can be drawn." 
 
 Monsieur A. Chauvean's theory of the development 
 of tooth -germs is as follows (" Comparative Anatomy 
 of the Domesticated Animals," p. 921) : 
 
 '' The teeth are developed in the interior of a cavity, 
 named the dental follicle or sac, by means of tlie ele- 
 ments of three germs, one belonging to the dentine, 
 another to the enamel, and a third to the cement. The 
 dental follicle is an oval cavitj^, with walls composed of 
 two layers. The external is fibrous and complete; the 
 internal, soft and gelatinous, is allied at the bottom to 
 the dentine-germ. The latter is a prominence, which 
 is detached from the bottom of the follicle, and has 
 the exact shape of the tooth. Its structure comprises, 
 in the center, delicate connective tissue, provided with 
 vessels and nerves, and on the surface a layer of elon- 
 gated cells. At the summit of the follicle, facing the 
 dentine-germ, is the enamel-germ. It is exactly ap- 
 plied to the dentin al-pulp, which it invests like a caj). 
 
42 TOOTH-GERMS. 
 
 and is composed of a small mass of mucous connec- 
 tive tissue, covered by a layer of cylindrical cells, and 
 joined to the buccal epithelium by the guhernaculum 
 dentis.'^' According to Monsieur Magitot, the cement- 
 organ manifestly exists in the foal. The base of the 
 dentine-germ has been found, but it disappears rapidly 
 after having performed its function. 
 
 ' ^'Developinent of the Dental Follicle. — On the free 
 borders of the maxillae, the epithelium of the buccal 
 mucous membrane forms an elongated eminence — the 
 dental ridge. Below this ridge the epithelium consti- 
 tutes a bad, which develops in size, and is sunk in the 
 mucous membrane. This is the enamel-germ. It has 
 a layer of cylindrical cells on its deep surface, and in 
 its center are round cells. After a certain time it is 
 only joined to the epithelium, as already said, by a very 
 thin line of cells, the guber?iaculum dentis. While this 
 enamel-germ grows downward, it covers, by its base, a 
 connective bud which rises from the mucous derma. 
 The two buds are reciprocally adapted to each other, 
 
 * Concerning the gubernaculum dentis Prof. C. S. Tomes says 
 (" Dental Anatomy," p. 135) : " Another structure, once thought 
 to be important, but now known to be a mere bundle of dense 
 fibrous tissue, is the ' gubernaculum.' The permanent tooth 
 sacs, durinor their growth, have become invested by a bony shell, 
 which is complete, save at a point near their apices, where there 
 is a fora''men. Through this foramen passes a thin fibrous cord, 
 very conspicuous when the surrounding bone is broken away, 
 which is called the c^ubernaculum, from the notion entertained 
 by the older anatomists tliat it was concerned in directing or 
 effecting the eruption of the tooth. The j2fubornacula of the 
 front y)ormanent tooth sacs perforate the alvolus ana [:)lend with 
 the gum behind tlie nocks of the co^vesponamg milk teeth, 
 those of the bicuspids uniting wi+h the pcrj^ste^iri o^ ■th«' !»/"«et'lj 
 of thoir deciduous predecessors." 
 
THE DENTIJ^E-GERM TOOTH-SHAPED. 43 
 
 and around them the connective tissue condenses and 
 gives rise to the walls of the follicle. It will therefore 
 be seen that the enamel-organ is a dependenc}^ of the 
 epithelium, and the dentine-organ a production of the 
 mncous derma. 
 
 '^Formation of the Dentine, Enamel, and Cement, — 
 As before said, the germ of the dentine has exactly the 
 form of the fature tooth; consequently the dentine 
 which arises from its periphery presents the shape of 
 a tooth also. The dentine and enamel are developed 
 by the modification of the elements situated at the 
 surface of their germs. The dentine is constituted of 
 the cells of the germ, which send out ramifying and 
 commanicating prolongations — the dentinal fibers — 
 and by an intercellular substance, which is impreg- 
 nated with calcareous matter, and which, being molded 
 around the fibers, forms canaliculi. The enamel is 
 derived from the deep cells of its germ, which are 
 elongated and prism-shaped, and are calcified in be- 
 coming applied to the surface of the dentine. Tlie 
 cement is developed at the expense of the walls of the 
 follicle, according to the mode of ossification of the 
 connective tissue. 
 
 ^'Eruption. — As the dentine is formed, the, tooth 
 increases in length and presses the enamel-germ up- 
 w^ard. The latter, constantly compressed, becomes 
 atrophied, and finally disappears wdien the tooth has 
 reached the summit of the follicle. In the same way 
 the young organ pierces the dental follicle and gum 
 and makes its eruption externally. 
 
 "Such is the mode of the development of the tem- 
 porary teeth, and the perminent ones are formed in the 
 same manner. During the development of the germ 
 of the temporary tooth, a bud is seen detaching itself 
 
44 TOOTH-GERMS. 
 
 from this germ and passing backward, to serve, at a 
 later period, in forming the permanent tooth." 
 
 In another part of his work Prof Chauveau says: 
 
 "The follicle in v/hich the incisor teeth are devel- 
 oped shows only two papillis. One, for the secretion 
 of the dentine, is lodged in the internal cavity of the 
 tootli, and is hollowed into a cup-shape at its free ex- 
 tremity; the other is contained in the external cul-de- 
 sac." 
 
 •^- 
 
 In describing the simplicity of the structure of the 
 horse's canine teeth (tushes). Prof. Lecoq says: 
 
 ^'The disposition of tlie developing follicle is in har- 
 mony v/ith the simplicity of their structure. At the 
 bottom there is a simple and conical papilla for the 
 internal cavity; on the inner vv'all, a double longitu- 
 dinal ridge, on which are molded the ridge and grooves 
 on the inner f ice of the tooth." 
 
 Prof William Youatt's theory of the development 
 of horses' teeth is unique. He is probably correct 
 about the bones or processes being separate, and his 
 claim that they are solidified by the cement is certainly 
 philosophical ; but he differs from all other authorities 
 about the enamel completing the formation of the 
 tooth, for it is a well-known fact that a virgin tooth 
 is enveloped by cement (its protecting varnish), which 
 wears off as soon as the tooth is brought into use. He 
 says ("The- Horse," p. 223): 
 
 "A delicate membranous bag, containing a ielly-like 
 substance, is fonnd in a little cell withm the jawbone 
 of the unborn animal. It assumes by degrees the 
 shape of the tooth, and then the jelly begins to change 
 
GREAT USE OF THE CEMEKT. 
 
 45 
 
 to bony matter. A hard and beautiful crystallization 
 is formed on the membrane without, and so we have 
 the cutting tooth covered by its enamel. 
 
 '• In the formation of the grinders there are origin- 
 ally five membranous bags m the upper jaw and four 
 in the lower. The jelly in them 
 gives place to bony matter, 
 which is supplied by little ves- 
 sels, and which is represented 
 by the darker portions of the 
 cut with central black spots. 
 The crystallization of enamel 
 may be traced around each of the bags, and there 
 would be five distinct bones or teeth but for the fact 
 that a third substance is now secreted. (It is repre- 
 sented by the white spaces). It is a powerful cement, 
 and through its agency the bones are united into one 
 .body, thus making one tooth of the five. This being 
 done, another coat of enamel spreads over the sides, 
 but not the top, and the tooth is completed.'' 
 
 Dr. Robley Dunglison's theory of the development 
 of the human teeth is in principle the same as Prof. 
 Youatt's tlieory regarding those of the horse. In his 
 "Medical Dictionary," article "teeth," he says: 
 
 "The incisor and canine teeth are developed by a 
 single point of ossification, the lesser molars by two, 
 and the larger by four or five." 
 
 Surgeons M. II. Bouley and P. B. Ferguson believe 
 that the teeth are the combined product of the secre- 
 tion of the pulp and of the membrane which linos the 
 alveolar cavities. They say that the question as to 
 whether the sensibility of the teeth is inherent in the 
 dental substance itself, or resides exclusively in the 
 
46 TOOTH-GERMS. 
 
 pulp, is a pliyslological point of which a satisfactory 
 solution remains to be given.* 
 
 * Of tlie development of teetli ia the human fetus Monsieur 
 E. Magitot says ("Comtes Rendus," 1874): "Seventh Week— 
 The epitlielial eminence and epithelial intiecLion of Kolliker 
 only may be seen at the edge of the jaw. The superior maxil- 
 lary and intermaxillary bones are not united, and the inferior 
 maxillary arch contains Meckel's cartilage only, without any 
 trace of bone. The epithelial bands (enamel-organs) are succes- 
 sively formed in the order of their designation. Ninth — The 
 dentine bulb appears in juxtaposition with the downward ex- 
 tremity of the enamel -organ. This stage occurs nearly simul- 
 taneously for the whole series of temporaiy follicles. Tenth — 
 The wall of the follicle detaches itself from the base of the bulb 
 and rises up its sides. Fifteenth — The exjithelial band begins 
 its transformation into an enamel-organ. The enamel-germ of 
 the first -permanent molar may now be seen springing from the 
 ej^ithelial inflection. Si-xteenth — The wall of the follicle is 
 closed. The epithelial band is broken, and the follicle thencefor- 
 ward has no connection with the surface epithelium. The epi- 
 thelial bands of the permanent teeth, which are derived from the 
 necks of the enamel-organ of tiie corresponding deciduous teeth, 
 appear. Svveideenth — Appearance of the cap of dentine of the 
 central and lateral incisors ; also the bulb of the first permanent 
 molar. Eii/hteenth — Appearance of the dentine caps of the first 
 and second molars ; also the wall of the follicle of the perma- 
 nent molar. Twentieth — Hight of the dentine caps of the cen- 
 tral incisor, lateral incisor, and canine, .059; first and second 
 molars, .039. Appearance of dentine organ of permanent teeth, 
 and iuclosure of wall and rupture of band of first molar. Twenty- 
 fifth — Dentine caps, .07, .054. The permanent follicle walls, 
 which ayipeured after the twenty-first week, have acquired a cer- 
 tain distincmess. Twenty-eighth — Dentine caps, .093, .078. The 
 epithelial germs of the permanent follicles begin their transfor- 
 mation into enamel-organs; dentine cap first molar, .003 to .007. 
 Tldriy-scconel — Dentine caps, .113, .093. The first permanent 
 molar cusps, which form upon the several apices of the dentine 
 organ, have coalesced. Thirty -sixth — Dentine caps, .118, .109; 
 permanent molar, .004 to .039. Thirty-ninth — Dentine caps, 
 .136, .118 ; permanent molar, .039 to .078. The permanent follicle 
 walls close. The dentine caps appear one month after birth." 
 
CHAPTER II. 
 
 THE TEMPORAEY DENTITIOIS". 
 
 Twelve Incisors and Twelve Molars. — Why the Incisors are 
 called " Nippers." — The Treatment of Foals Affects Teeth- 
 ing.— The Temporary Teeth Absorbed by the Permanent. 
 —The Tushes. 
 
 The foaFs temporary teeth (known also as milk or 
 deciduous teeth), ure adapted in size and number to 
 the capacity of the jaws and the amount and nature 
 of the mastication required for its sustenance. There 
 are only twenty-four temporary teeth functionally de- 
 veloped. They consist of twelve incisors or nippers * 
 and twelve molars or grinders, six above and six below 
 of each kind. The dental formula is expressed thus: 
 
 Incisors, f — |; molars, f — f =24. 
 
 According to Veterinary Dentist C. D. House, who 
 says the care and treatment of foals will affect the 
 growth of their 1;eeth as much as they will their gen- 
 
 * Horsemen call the incisor teeth "Nippers." The word ex- 
 presses the office they perform, to wit, nipping grass, as well as 
 the word "grinder" does in the case of the molars — grinding 
 corn. They call the first pair of incisors "central nipi^ers," or 
 " centrals," one being on either side of the median line ; the 
 second pair are the "dividers," for they stand between the first 
 and third pairs; the third pair are called the "corners," from 
 their forming the points of the crescent-like figure. 
 
48 THE TEMPORARY DENTITIOJir. 
 
 enil deyelopment, the foal has no teeth at birth, Na- 
 ture providing a thin, membrane-like covering for the 
 central incisors as well as the hoofs. In two or three 
 days, however, the molars are all cnt. The incisors 
 are cnt in pairs, two above and two below. The first 
 pair ("^central nippers ") protrude in from three to eight 
 days, and attain their growth in about two months. 
 The second pair ('-'divider nippers") are cut when the 
 foal is five or six weeks old. They also attain their 
 growth in about two months. The time of cutting 
 the third pair ('-corner nippers") varies. In some 
 foals they appear as early ^s the sixth month ; in 
 others as late as the ninth. They attain their growth 
 in about three months."^ 
 
 The temporary teeth are smaller and whiter and 
 have more distinct necks tlian the permanent. Their 
 "shining, milky-white color," Monsieur Chauveau 
 says, is "due to the thinness or absence of the crusta 
 petrosa" (cement). "Their crowns," he says, "are 
 finely striated, and not cannular, on the anterior face." 
 He also says that " they are not constantly pushed out- 
 ward from their cavities, their growth ceasing when 
 they begin to be used." This is probably accounted 
 for by the fact that the temporary teeth are absorbed 
 by the permanent, the proper development of the latter 
 apparently requiring the tooth material of the former. 
 
 ^ Prof. Owen says : " Monsieur Rousseau, who describes the 
 first dentition as b^ing terminated by tlie appearance of (lie lat- 
 eral incisors, assigns from the seventh to the tenth month as the 
 period of its completion. The appearance of the third deciduous 
 incisors, or 'corner nippers,' completes the stage of dentition 
 called the ' coil's mouth ' by veterinary authors. The deciduous 
 incisors have thinner and more trenchant, normally-shaped 
 crowns than those of their permanent succgssoj's." 
 
SHED OR ABSORBED. 49 
 
 The incisors, which stand in an almost npriglit 
 position, are smooth and ronnded on the outer sur- 
 face, but grooved on the inner. Their average length, 
 including the root, is about an inch, their width 
 about half an inch. The molars are about an inch 
 and a quarter in length, and nearly an inch in long 
 (antero-posterior) diameter. The short (transverse) 
 diameter of the upper molars, which is about three- 
 fourths of an inch, exceeds that of the lower nearly a 
 half. Surgeon John Hughes says that in proportion 
 to their length the breadth * of the temporary teeth is 
 greater than the permanent. When first cut the in- 
 cisor teeth are very sharp ; the outer edges are higher 
 than the inner, tlie slant resembling that of a chisel. 
 A little wear, however, dulls the teeth, and brings the 
 edges to a common level. The contrast between the 
 edges of the corner incisors, however, is distinct for 
 some time, the outer edge wearing off slowly. 
 
 There is a marked contrast in the appearance of the 
 incisors at the age of one year and about the close of 
 the second. At the former period they look new and 
 fresh, standing close together, while at the latter they 
 not only look old and worn, but the development of 
 the jaws has caused them to stand apart. Their nar- 
 row necks are also conspicuous at two years of age. 
 
 The incisors are shed in the order in which they are 
 cut. Nature provides them as they are needed, and 
 takes them away so as to cause the least inconvenience 
 to the foal. During the shedding of the central inci- 
 sors foals have the use of the dividers and corners. 
 The permanent centrals are ready for use before the 
 dividers arc shed, and the permanent dividers are 
 
 *" Broad til is antcro-posterior diameter; thickness is trans- 
 verse diameter." — R. Owen 
 
50 THE TEMrORARY LE^'TITIO^. 
 
 ready before tlie corners are shed. However, during 
 the shedding periods, particularly that of the central 
 teeth, foals experience more or less diScnlty in graz- 
 ing ; but if they are given a moderate quantity of soft, 
 green food, their health will not be impaired, nor will 
 they lose much flesh. 
 
 The central incisors are shed when the foal is about 
 two years and a half old, the dividers at three and 
 a half or four, and the corners afc four and a half or 
 five. 
 
 The molars, which Prof. Eichard Ow^en says sooner 
 begin to develop roots than the permanent, are shed 
 with even less inconvenience to the foal than the in- 
 cisors. The fourth grinder, the first permanent tooth 
 cut, is ready for use before the first temporary molar 
 is shed, and the fi.fth and sixth are ready before the 
 second and third are shed. The time of shedding the 
 twelve teeth varies somewhat, and the falling off of 
 the "caps" of the uppers v/ill pi-ecede those of the 
 lower teeth several weeks. Tiie thin shells (caps) that 
 fall oil are all that is left of the temporary molars, 
 their roots and bodies having been absorbed by the 
 permanent teeth, except of course that part which has 
 been W'Orn from the crown by attrition. Thus, when 
 Nature is let alone, the temporary teeth are absorbed 
 rather than shed; but when a shell is loose and in the 
 way, it does no harm to remove it. The first molar is 
 shed about the end of the second year, the second 
 about the end of the third, and the third about the 
 end of the fourth. 
 
 Surgeon W. A. Cherry says that the shedding of the 
 teeth usually occurs in the Spring. Tiiere is, he says, 
 a sufficient interval of time between the shedding of 
 the upper and lower molars for the nev/ teeth in tho 
 
UNFUNCTIOKALLY DEVELOPED CAXINES. 51 
 
 upper jaw to meet the old ones in the lower; sometimes 
 tlio respective teeth, when the caps fall olf, are not more 
 than the sixteenth of an inch apart. He also says that 
 as the temporary teeth wear down they become less 
 and less dense. 
 
 While, as before said, it does no harm to remove 
 loose shells, the punching out of a pair of incisors, 
 Wiiich is sometimes done for the purpose of deception, 
 frequently causes serious injury to the permanent 
 pair (which should absorb the temporary, and fill the 
 space that has become too large for it), not to mention 
 the interference with grazing. The temporary teetli are 
 often broken oR at the neck and the sockets injured; 
 tliis sometimes causes the permanent to grow irregu- 
 larly, which in the case of the liorse is a very serious 
 matter, for if the permanent teeth do not meet, and are 
 consequently not worn off by attrition, their growth, 
 which continues throughout life, will cause trouble. 
 There are cases, however, suck as abnormal groAvths, 
 accidents, &c., in which it is necessary to remove the 
 temporary tooth, but the forceps only should be used. 
 When the teeth have been removed for the purpose of 
 deception, the object is to make it appear that tliey 
 Jiave been slied, and that the animal is older than it 
 reallv is. 
 
 Veterinary authors, as a rule, do not mention the 
 temporary tushes. A few odontologists, however, liave 
 described them. Prof. Owen ('•'Odontography," vol. i, 
 p. 580) says "^the small deciduous canine^ is cut about 
 the sixth month, at the time the third or cnmer inci- 
 sors are cut. Tlie lower tush, owing to its diminutive 
 size, and its being so close to the incisor, "is shed 
 almost as soon as tlie crown of the contiguous incisor 
 is in full place, being carried out by the same move- 
 
52 THE TEMPORARY DEKTITIOIT. 
 
 ment." Bojanns,* Prof. Owen says, first "drew the 
 attention of vetorinary authors to it by his memoir 
 * De Dentibus Caninis Caclucis/ &c. Bojiinus never 
 found the lower deciduous canine retained beyond the 
 first year. The deciduous canine of the u[)per jaw, 
 being- developed at a short distance behind the incisors, 
 is less disturbed by the eruption of the outer incisor, 
 but is nevertheless shed in the course of the second 
 year. The deciduous canines appear from Camper's f 
 observations to retain their place longer in the zebra 
 than in the horse." 
 
 Monsieur Lecoq says: 
 
 " The canine teeth are not shed, and grow but once. 
 Some veterinarians, and among them Forthomme and 
 Rigot, witnessed instances in which they were replaced ; 
 but the very rare exceptions cannot make us look upon 
 these teeth as liable to be renewed. We must not, 
 however, confound with these exceptionable cases the 
 shedding of a small sp*icula or point, which, in the 
 majority of horses, precedes the eruption of the real 
 tusks." 
 
 Prof. C. S. Tomes says: 
 
 " The milk teeth of all the ungulata are very com- 
 plete, and are retained late. They resemble the per- 
 manent teeth in general character, but the canines of 
 the horse, as might have been expected — their greater 
 development in the male being a sexual character — are 
 rudimentary in the milk dentition." 
 
 * " Nova Acta Nat. Curios., torn, xii, part ii, p. 697. 1825." 
 f " CEuvres de Pierre Camper. Paris, 1805." 
 
CHAPTER III. 
 
 THE PERMANENT DENTITION. 
 
 Distinction between Premolars and Molars. — The Bow-like In- 
 cisors. — Contrasts between tlie Upper and Lower Grinders, 
 and the Rows formed by them. — The Incisors saved from 
 Friction. — Horses' Teeth compared with those of other An- 
 imals. — Measurements. — Time's Changes. — Growth during 
 Life. 
 
 The Permanent Teeth, owing to their increased size 
 and number, are as well adapted to the needs of the 
 horse as the temporary are to the foal. In the males 
 forty teeth are functionally develoj^ed ;* in the feaiales 
 thirty-six, the latter, as a rule, having no canine teeth. 
 However, their rudiments exist in the jaw\s, and some- 
 times, especially in old age, protrude. Of the forty 
 teeth in the male horse there are twelve incisors, four 
 canines or tushes (also called cannon or bridle teeth), 
 twelve premolars,! and twelve molars. The dental 
 formula is expressed thus : 
 
 -^•J 3 3 ^ '^v 1 1) ^' -w^v 3^ — 3^7 ^^^-} ^ — 3 — '*^* 
 
 * The teeth that are not functionally developed are treated of 
 in tlie chai)ter entitled " Remnant Teeth." 
 
 f "Premolars are teeth in front of the molars ; they usually 
 differ from them by beinjr smaller and more simple in form, and 
 in most animals have displaced deciduous predecessors. But 
 they are not always smaller nor simpler in form (e. g., the 
 
54 THE PERMANENT DElls'TITIOl^r. 
 
 The incisors and premolars absorb and replace the 
 entire temporary dentition, except the shells or caps 
 described in the preceding chapter, but tbe canines 
 and molars are cut through the gums. 
 
 In Yeterinary works, as a rule, no distinction is made 
 between a premolar and a molar, the twenty-four back 
 teeth being called either molars or grinders. Prof. 
 0. S. Tomes says the premolars and mofers "are very 
 similar to one another in shape, size, and in the pat- 
 tern of their grinding surface." There is a difference, 
 however, between the respective teeth, and naturalists 
 make a distinction. The premolars (the three first 
 back teeth), whicli replace the temporary molars, are 
 slightly larger than the molars (the three last back 
 teeth). They have besides a backward inclination, 
 v/hile the molars incline forward ; the respective teeth 
 are thus set toivard one another. Both kinds are 
 properly called grinders. 
 
 The permanent teeth arc cut in pairs, two in either 
 jaw, the upper teeth preceding the lower from one to 
 two weeks. In the cutting of the canines, however, 
 the reverse is the rule, for the lovvTr teeth precede the 
 upper. About a year's time elapses betv/een the cut- 
 ting of the respective pairs of teeth ; that is, when the 
 central incisors are cut, it v/ill be about a year before 
 the dividers will emerge. The rule is applicable to 
 the premolars and molars also, but the case is different, 
 for tvv^enty-four of these teeth have to be cut during 
 
 horse) ; nor do tliey always displace deciduous predecessors 
 {e. g., til oy do not all do so in the marsupials) ; so that this defi- 
 nition is not absolutely precise. Still, as a matter of practice, 
 it is usually easy to dJstin^Tiish tiie premolars, and tlie division 
 into premolars and molars is useful." — C 8, Tomes, "Dental 
 Anatomy," &c., p. S5S. 
 
TIME 0? CUTTIJTG. 55 
 
 the same period of time that the twelve incisors are 
 cut. A permanent tootli attains its growth in about a 
 year. 
 
 Accordhig to the best authorities, the molar and 
 canine teeth are cut at tlie following periods: The 
 first molars (in veterinary works they are called the 
 fourth, because the three premolars come in front of 
 them) are the first permanent teeth cut. The time of 
 their cutting varies, for the foal's jaws must be suffi- 
 ciently developed to afford fliem room, notwitiistand- 
 ing they are usually the smallest of the six back teeth. 
 They are cut about the beginning of the second year, 
 and are generally ready for use by the time the foal is 
 two years old. The second molars are cut at about 
 tlie age of two years, and are therefore fully developed 
 by the end of the third year. The third pairs, the last 
 of the molars, and consequently the most posterior of 
 all the teeth, are sometimes cut as early as the third 
 year, in which case they would be developed by the end 
 of the third or the beginning of the fourth year. The 
 time, however, may be prolonged six months or more. 
 The canine teeth (tushes) emerge at or near the be- 
 ginning of the fourth year.^- 
 
 The time of the appearance of the incisors and pre- 
 molars has already been indicated in the preceding 
 ch.apter. However, the following extract from Prof 
 Owen's "Odontography" is appropriate in this place, 
 a=' it throws further light on the subject, and to some 
 extent agrees with the dates already given: 
 
 '■The fir>t true permanent molar appears between 
 the ebvcnth and thirbcenth months. The second fol- 
 
 •■• For further particulars concornin<T tlio tuslies the reader iB 
 referreJ to the succeeding chapto;-. 
 
56 THE PEBMAJS'Eiq-T DEJ^TITIOJ^. 
 
 lows between tlie fourteenth and twentieth months. 
 The crowns of the premolar and the last true molar 
 are now advancing in the closed sockets of reserve. 
 The first premolar displaces the second,* and nsually 
 at the same time the very small deciduous molar, at 
 from two years to two years and a half old. The first 
 permanent incisor rises above the gum between two 
 years and a half and three years. At the same period 
 the second premolar pushes out the third deciduous 
 molar. The last premolar displaces the last deciduous 
 molar about the completion of the fourth year, and 
 the appearance above the gum of the last true molar 
 is usually anterior to this. The second incisor pushes 
 out its predecessor between three and a half and four 
 years. The small persistent canine or tusk, contrary 
 to the usual rule, next follows, its development having 
 received no cheek by the retention of its rudimental 
 predecessor. Its appearance indicates the age of four 
 years ; but it sometimes appears earlier, rarely later. 
 The third incisor pushes out the deciduous one about 
 the fifth year, but is seldom completely in place before 
 the horse is five years and a half old. The third j^re- 
 molars are then usually on a level with the other 
 grinders." 
 
 On the completion of the fifth year a male foal is 
 called a horse, a female or filly foal a mare. The teeth, 
 however, are not all fully developed before the sixth 
 year, and the roots of the grinders do not begin to 
 
 * To prevent confusion, it sliould "be understood that Prof. 
 OAven calls tlie "very small deciduous molar" liere referred to 
 the first deciduous molar, notwithstanding it is not functionally 
 developed. Hence, as it has no successor, the first premolar dis- 
 places the second deciduous molar, the s3cond premohir the third 
 deciduous mola.r, and the third, the fouxtK 
 
THE INCISORS ADAPTED FOR GRAZING. 
 
 57 
 
 grow till about the seventh year, being, to use Prof. 
 Owen's words, "implanted, in the. socket by an undi- 
 vided base." 
 
 The incisor teeth, which will average about two 
 inches and a quarter in length, are characterized by 
 distinct curvatures, the outer sur- 
 fiice, according to Surgeon John 
 Hughes, forming a third of a cir- 
 cle, the inner a fifth. Were a string 
 drawn from the crown of one of 
 these teeth to the apex of the 
 root, the figure would resemble a 
 bow. The upper teeth are larger 
 than the lower, and there is a dif- 
 ference in^size of the respective 
 teeth in both jaws, the centrals 
 being larger than the dividers, 
 and the dividers larger than the 
 corners. 
 
 The incisors meet edge to edge, 
 being thus admirably adapted for 
 the purposes of grazing, and at ^ ^i,gi„ i„eisor tooth -. pos. 
 the age of six years the bodies are tenor face.-c^«.e««. 
 nearly perpendicular one to the other. They form 
 nearly semicircular figures, and, when the mouth is 
 closed, present a rounded outer surface. 
 
 " The incisors," says Prof. Owen, "if found detached, 
 recent or fossil, are distinguishable from those of the 
 ruminants by their greater curvature, and from those 
 of all other animals by the fold of enamel which pen- 
 etrates the body of the crown, from its broad, flat sum- 
 mit, like the inverted finger of a glove." 
 
 The fold of enamel, which is commonly called the 
 <«mark," but which is also known as the infundibulum, 
 
58 THE PERMANENT DEKTITlON. 
 
 central enamel, &c., according to Surgeon J. Hughes's 
 mGasurements, penetrates the lower centrals to the 
 depth of from three-iifths to seven-tenths of an inch ; 
 the dividers from seven-tenths to four-fifths, and the 
 corners from one-half to three-fifths. It penetrates 
 the upper centrals from one inch and a tenth to one 
 and a fifth ; the dividers from one and a fifth to one 
 and a fourth, and the corners from four-fifths to nearly 
 an inch. Prof. Youatt says the grinder teeth have 
 each two iniundibula, v/hich penetrate to their roots. 
 
 The followhig is Prof. A. Chauveau's description of 
 the incisor teeth ("The Comparative Anatomy of the 
 Domesticated Animals/' Fleming's trans., p. 349) : 
 
 " The general form of the incisors is that of a tri- 
 faced pyramid, presenting an incurvation f^diose con- 
 cavity is toward the mouth. Tiie base of this pyra- 
 mid, the crown of the tooth, is flattened before and 
 behind. The summit or extremity of the fang, is, on 
 the contrary, depressed on both sides. The shaft of 
 the pyramid presents at diiierent points of its hight, a 
 series of intermediate conformations, which are utilized 
 as indications of age, tlie continual growth of the teeth 
 bringing each of them in succession to the frictional 
 surface of the crown. 
 
 " Examined in a young tooth, but one that has com- 
 pleted its evolution, the free portion presents the fol- 
 lowing characteristics : An anterior face, indented by 
 a slight longitudinal groove, v^^hich is prolonged to 
 the root ; a posterior face, rounded from side to side; 
 two borders, of which the internal is always thicker 
 than the external ; and, lastly, the surface of friction. 
 The latter does not exist in a tooth that has not been 
 used, but in its stead are two sharp margins, circum- 
 
THE TWO mXGS OP E]SrAMEL. 59 
 
 scribing a cavitj^ named the external de?ital cavity, or, 
 better, infundiljulum. This cavity terminates by a 
 conical cul-de sac, which descends more or less deeply 
 into the snbstance of the tooth. The margins are 
 designated the anterior and posterior. The latter, less 
 elevated than the former, is cut by one or more 
 notches, which arc always deepest in the corner teeth. 
 It is by the wear of these margins that the surface of 
 fi'iction is formed, and in the center of which the in- 
 i'undibulum persists during a certain period of time. 
 
 *•' The fang is perforated l)y a single aperture, through 
 w^hich the pulp of the tooth penetrates into the inter- 
 nal cavity. 
 
 "In the composition of the incisor teeth are found 
 tlie three fundamental substances of the dental organ. 
 The dentine envelops the pulp cavity. Dentine is de- 
 posited in this cavity after the complete evolution of 
 the tooth to replace the atrophied pulp, the yellow tint 
 of which distinguishes it from the dentine of the first 
 Ibrmation. It forms on the table of the tooth the 
 mark designated by Girard the dentinal star. 
 
 " The enamel covers the dentine, not only on its free 
 portion, but also on the roots; it does not extend, 
 liowever, to their extremities. It is doubled into the 
 external dental cavity, lining it throughout; and when 
 the surface of friction is established, a ring of enamel 
 may be seen surrounding it, and an internal ring cir- 
 cumscribing the infundibulum. The first circle is 
 called the encircling enameU the second the centred 
 enamel. In the virgin tooth the central enamel is 
 continuous with the external enamel, and passes over 
 the border wliich circumscribes the entrance to the 
 infundibulum. 
 
 '•The cement is applied over the enamel like a pro- 
 
CO TtlE PEEMAI^EKT DENTITION. 
 
 tecting varnish, but is not everywhere of the same 
 thickness. On the salient portions it is extremely 
 thin, and the friction caused by the tbod, the lips, and 
 the tongne soon wears it away altogether. It is more 
 abundant in depressed situations, as in the longitudi- 
 nal groove on the anterior f?ice of the tooth, and par- 
 ticularly at the bottom of the infundibulum. The 
 quantity accumulated in this cul-de-sac is not, how- 
 ever, always the same. We have seen it almost null, 
 and on the other hand, we possess an incisor unworn, 
 or nearly so, in which the cavity is almost entirely 
 obstructed by it. We are not aware that, up to the 
 present time, any account has been taken of these dif- 
 ferences in calculating the progress of wear ; but it is 
 manifest that they shorten or prolong the time re- 
 quired for the effacement of the infundibulum." 
 
 The grinder teetli, the horse's millstones, present 
 various and interesting contrasts. They are sepa- 
 rated from the incisors by a space that will average 
 about four inches in extent, the sharp-pointed tushes 
 (in males) only intervening. The space between the 
 grinders and tushes is called the diastema (place for 
 the bit). The upper grinders, except the first and 
 last, are nearly quadrangular in form. The first and 
 last, which exceed the others about a third of an inch 
 in antero-posterior (front to rear) diameter, terminate 
 in obtuse angles, which are far more pronounced on 
 the inner than on the outer surface, thus affording the 
 tongue fuller and freer pla}', without the danger of its 
 being lacerated, as would be the case wxre the angles 
 sharp. The form of the lower grinders, with the same 
 exceptions in the case of the first and last, is nearly 
 rectangular; their antero-posterior diameter is the 
 
THE HORSE'S DIIlTlN'ER TABLES. Gl 
 
 same as that of tlic upper teeth, but their transverse 
 diameter is nearly a half less. . 
 
 The broad crowns of the upper teeth form what are 
 called by veterinarians " tables," wdaereon the food is 
 ground or kneaded by the narrow-crowned opposite 
 grinders, the lateral movement of the lower jaw ena- 
 bling the latter teeth to pass over the entire extent of 
 the former. 
 
 Tlie crown surfVices of the upper and lower rows are 
 slanting instead of level, the former slanting inward, 
 the latter outward. The inclined-planes are thus in 
 perfect opposition, and yet in perfect harmony, for they 
 facilitate the lateral and semicircular movement of the 
 lower jaw during mastication. 
 
 The tigures formed by the upper and lower rows of 
 grinders, aside from the difference in their thickness, 
 are very dissimilar. The upper rows are slightly con- 
 cave, and converge in conformity to the narrowing of 
 the jaws; the space between the sixth grinders averag-es 
 about two inches and four-fifths, while that between 
 the first is about two inches. The lower rows form 
 regular but oblique lines, which also converge, like the 
 sides of a hopper, in conformity to the narrowing of 
 the jaw^s, the space between tlie two sixth grinders and 
 the two first averaging respectively two inches and a 
 half and one inch and a half. Thus, when the mouth 
 is closed, the lower teeth in the region of the sixth 
 grinders scarcely cover a third of the crown surface of 
 the upper teeth, while those in the region of the first 
 barely lap their inner edges. This apparent structural 
 defect is overcome by the lateral movement of the 
 lower jaw, which, owing to the fact that it increases 
 in proportion to the distance from its hinge-like joint 
 in the region of the temporal bone and zygomatic 
 
62 THE PERMANENT DENTITION. 
 
 arch,* is greater in the region of the first grinders 
 than in that of the sixth. Therefore it will be per- 
 ceived that it is only alternately that the rows are used 
 in the performance of the masticatory function, and 
 that v/ere the grinders in exact apposition (edge to 
 edge), the lateral and semicircular movement of the 
 lower jaw would be as awkward and unnatural in the 
 case of the horse as the same movement would be in a 
 human being. 
 
 There are still other contrasts between the grinders. 
 According to Surgeons M. H. Bouley and P. B. Fergu- 
 son, the upper teeth are slightly convex, the lower 
 slightly concave. Again, according to Charles D. 
 House, the outer surface of the upper grinders is pro- 
 vided with a coat of enamel twice as thick as that of 
 the inner, "while the reverse is the case with the lower 
 teeth. There is design in this provision of Nature 
 (notwithstanding Mr. House says it is inexplicable), 
 for the projecting edges receive that which they re- 
 quire, to wit, strength in proportion to their hight; 
 otlierwi^e they w^ould be easily broken off. As the 
 
 * Prof. Youatt says ; " The branclies of tlie lower jaw termi- 
 nate in two processes, the coracoid (beak-like), and the condy- 
 loid (rounded). The coracoid passes under the zy<Tomatic arch, 
 the temporal muscle being inserted into it and wrapped round 
 it. The condyloid is receiv^ed into the glenoid (shallow) cavity 
 of tlie temporal bone, at the base of the zygomatic arch, and 
 forms the joint on which the lower jaw moves. The joint ad- 
 mits of a hinge-like motion, which is the action of the jaw in 
 nipping the herbage and seizing the corn. The corn, however, 
 must be ground ; bruising and champing it are not sufficient for 
 the purposes of digestion. It must be put into a mill. It is put 
 into a mill, and as perfect a one as imagination can conceive. 
 The construction of the glenoid cavity gives the required lateral 
 or o rinding motion." 
 
THE GRINDERS THEIR OWN WHETSTONES. 63 
 
 lower edges have only about lialf the hight of the up- 
 per, they do not require more tlian half the quantity 
 of enamel to strengthen them. Another use of this 
 unequal disposition of enamel is its tendency, by its 
 wear, to preserve the slant of the respective crown sur- 
 faces. Further, the dentine, which hlls tlie interspaces 
 between the folds or ridges of enamel, being softer 
 than the enamel, wears out faster, thus keeping the 
 ridges sharp.* The grinders are therefore, owing to 
 this "interblending of the dental tissues," their own 
 whetstones as well as the horse's millstones. 
 
 Some writers, even of the present day, deny that the 
 enamel penetrates to the interior of the grinders; but 
 the fact that it does was established by John Hunter 
 over a century ago, and a cut of a section of a horse's 
 grinder (slightly magnified) showing the enamel folds, 
 
 * Pr.^f. R. Owon illustrates the above principlo in the Intro- 
 duction to his " Odontography," paj^e 26. He sa3'S: "It(tliG 
 enamel) sometimes forms only a partial investment of tlie crown, 
 as in the molar teeth of the iguanodon, the canine teeth of the 
 hog and liippoi^otamus, and the incisor3 of the Rodentia. In 
 these the enamel is placed only on the front of the tooth, but is 
 continued along a great part of the invested base, which is never 
 contracted into one or divided into more fangs, so that the char- 
 acter of the crown of tlie tootli is maintained throughout its 
 extent as rej^ards both its shape and structure. The partial 
 application of the enamel operates in maintaining a sharp edge 
 upon the exposed and worn end of the tootli precisely as the 
 hard steel keeps up the outer cutting edge of tlie chisel by being 
 welded a<Tainst an inner plate of softer iron." 
 
 Prof. C. S. Tomes, speaking of the grinder teeth of the horse, 
 says : " As each ridge and pillar of the tooth consists of dentine 
 bordered by enamel, and the arrangement of the ridges and pil- 
 lars is complex, and as, moreover, cementum fJlrJ up the inter- 
 spaces, it is obvious that an efficient rough griiuiing surface will 
 bo preserved by tlie unequal wear of the several tissues." 
 
64 THE PERMANEN"T DEJ^TTITIO^q". 
 
 may be found in his "I^atnral History of the Human 
 Teeth." 
 
 The formation of the enamel is thus described by 
 Prof. Bouley and Surgeon Ferguson ("Veterinarian," 
 1844) : 
 
 "In the grinder teeth the enamel may be said to 
 resemble a little ribbon, which forms, in refolding 
 many times upon itself in the interior of the tootli, a 
 succession of undulating planes, and constitutes the 
 hard external envelop of the cubic mass of the organ. 
 An idea of this disposition may be formed on examin- 
 ing a tooth which is not yet cut, but which is ready to 
 be cut. Those that have been worn, present on their 
 crowns, besides the undulating lines of the enamel 
 envelop, a sucaession of reliefs, salient and sinuous, of 
 the substance of the enamel, which are nothing else 
 than the free borders of this folded ribbon. It is in 
 the intervals of the folds of euLimel that is deposited 
 the ivory-colored substance (dentine), which renders 
 the tooth a solid mass when it has attained its full 
 growth." 
 
 Prof. Eichard Owen, one of the first odontologists 
 of the age, in whose numerous works descriptions of 
 many kinds of teeth may be found, has paid a fair 
 share of attention to the study of horses' teeth, both 
 recent and fossil. His description of the grinders and 
 comparisons with the teeth of other animals are too 
 interesting to be omitted here, and render any apology 
 for the few repetitions of facts already given unneces- 
 sary. He sa3^s (-'^ Odontograph}^/' vol. i, p. 572): 
 
 "The horse will yield us the first example of the 
 dentition of the hoofed quadrupeds with toes in un- 
 
ANOPLOTIIERES, TLUMII^'AXTS, AXD TAPIRS. 05 
 
 even number, because it offers in tliis part of its organ- 
 ization some transitional features between the dental 
 cbaracters of the ty[)ical members of the isodactyle 
 and of those of tlie anisodactyle unguhita. 
 
 "All the kinds of teeth are retained and in almost 
 normal numbers in both jaws, with as little unequal 
 or excessive development as in the anoplothere,* but 
 the prolongation of the slender jaws carries the canines 
 and incisors to some distance from the grinders, and cre- 
 ates a long diastema, as in the ruminants f and tapirs. J 
 
 * " The anoplothere was one of the earliest forms of hoofed 
 quadrupeds introduced upon the surface of this earth, and it is 
 cliaracterized by the most complete system of dentition. It not 
 only possessed incisors and canines in both jaws, but they were 
 so equally developed that they formed one unbroken series with 
 the premolars and molars, which character is now found only 
 in the human ftpccies. The dental formula is : I.. 3—8, 3—3 ; 
 C, 1-1, 1-1 ; P. M., 4-4, 4-4; M., 3-3, 3-3=:44. The An- 
 oplothere Commune was the size of an ass, and, with the other 
 species of the extinct genus, had a cloven hoof, like the Rumi- 
 nants, but the division extended throuofh the metacarpus and 
 metatarsus. The anoplothere Avas an animal of aquatic habits, 
 and had a very long- and strong tail, which Cuvier conjectures 
 to have been used like that of the otter in swimming." — Owen. 
 
 f " The ordinary dental formula of the Ruminantia is : I. 
 (upper jaw), 0-0, (lower jaw), 3-3 ; C, 0-0, 1-1 ; P. M., 3-3, 
 3—3 ; M., 3-3, 3—3=32. The antelopes, the sheep, and the 
 ox, which are collectively designated the 'hollow-horned ' rumi- 
 nants, present this formula. It likewise characterizes many of 
 the ' solid-horned ' ruminants, or the deer tribe, the exceptions 
 having canine teeth in the upper jaw in the male sex, and some- 
 times also in the female, though they are always smaller in the 
 latter." — Oicen. 
 
 X " The dental formula of the tapir is : I., 3-3. 3-3 ; C, 1-1, 
 1-1 ; P. M., 4-3, 4-3 ; M., 3-3, Z-^^A%"—Owcn. 
 
 It is noteworthy that the dentition of the tapir corresponds 
 precisely in number with that of the horse, providM the latter's 
 
G6 THE PEEMAXEXT DEXTITIO:^'. 
 
 " The upper grinder teeth present a modification of 
 the complex structure intermediate between the aoo- 
 X>iotlierian and ruminant patterns. The crown is 
 cubical, but is impressed on the outer surface by two 
 wide and deep longitudinal channels. It is penetrated 
 from within by a valley, v/liicli enters obliquely from 
 behind forward. This is crt.issed by two crescentic 
 Talleys, which soon become insulated, as in the camel ;^' 
 but a large internal lobe, at the end of the oblique val- 
 ley, presents more of the anoplotherian proportions 
 than is shown by any ruminant. It is at first distinct ; 
 but althongh it soou becomes confluent with the ante- 
 rior lobe iu the existing species of the horse, it con- 
 tinued distinct much longer., and with more of the con- 
 ical or columnar form, in the primigenial horse of the 
 miocene tertiary period. 
 
 ''The grinder teeth of the horsc^, Ouvierf remarks, 
 
 Remnant teeth are counted ; and, besides, the odd teetli in both 
 animals appear in the upper jaw. Prof. T. H. Huxley says : 
 " Deepen the valley, Increase the curvature of the (outer) wall 
 and lam'inoe (transverse ridg-es); give the latter a more directly 
 backward slope; cause them to develop accessory ridges and 
 l)illars, and the upper molars of the tapir will pass through the 
 structure of that of the rhinoceros to that of the horse." 
 
 *"The dental formula of the camel is: I, 1-3, 1-3; M., 
 Q—Q, 6—6=32. The anterior molars are conical. They are 
 separated from the posterior molars, and are sometimes regarded 
 as canines. The upper incisors are also conical, compressed, 
 somewhat curved, resembling canines, and are used for tearing 
 up the hard and strong plants of Ihe desert, on which the ani- 
 mal usually feeds." — Amc^^'can Cyclopedia. 
 
 f A French naturalist. Died May 13, 1883. " He is regarded 
 as the founder of the science of comparative anatomy, and his 
 knowledge of the science was such tliat a bone or a small frag- 
 ment of a fossil animal enabled him to determine the order, and 
 
THE HORSE AN"D THE RHINOCEROS. 67 
 
 have a closer analogy with those of the rhinoceros* 
 than might at first be. supposed. The anterior cres- 
 centic enamel represents the termination of the prin- 
 cipal or obli(|ue valley, which is cut olf by a bridge of 
 dentine analogous to that in the leptorhine rhinoceros. 
 The posterior crescentic island is a further develop- 
 ment of the fclds in the rhinoceros' molar, but is much 
 earlier insulated in the horse. 
 
 *'In the lower jaw the same analogies maybe traced. 
 The teeth, on the outer side, are divided into two 
 convex lobes by a median longitudinal fissure; on the 
 inner side they present three principal unequal convex 
 ridges, and an anterior and posterior narrower ridge. 
 The crown of the grinder is penetrated from the inner 
 side by deeper and more complex folds than in the 
 anoplothere, and still more so than in the rhinoceros 
 
 even genus, to which it belonged. The time of Cuvier marks 
 the opening of a new epoch in comparative anatomy. He ap- 
 plied this science to natural history, physiology, and to the study 
 of fossils The first edition of "Lccons d'Anatomie Comparee" 
 appeared about the beginning of the i^resent century, and the 
 second was the last work upon v/hich Cuvier labored. For 
 more than thirty years he had collected an immense amount of 
 facts and materials, which are partly embodied in this book. It 
 is a monument of patient industry, a model in arrangement, and 
 a mine of knowledge, of whicli all observers since have availed 
 themselves. " — American Cyclopedia. 
 
 " " The essential characteristics of the dentition of the genua 
 rhinoceros are to be found in the form and structure of the 
 molar teeth. They diifer essentially from those of the horse by 
 being implanted by distinct roo*p. The normal dental formula 
 of the molar series is: P. M.. 4-4, 4-4; M.. 3-3, 3-3:=28. 
 There are no canines. As to the incisors, the species vary, not 
 only in regard to their form and proportions, but also their ex- 
 istence." — Oioen. 
 
68 THE PERMAKEXT DENTITION". 
 
 and iDixleothere. * The anterior valley between the nar- 
 row ridge and the first principal internal column ex- 
 pands into a snbcrescentic fold. The second is a short, 
 simple fold, and terminates opposite that which pene- 
 trates tlie tooth from the outer side. The third inner 
 fold expands in the posterior lobe of the tooth like the 
 first, and two short folds partially detach a small ac- 
 cessory lobe at the posterior part of the crown. All 
 the valleys, fissures, or folds, in both the npper and the 
 lower grinders, are lined by enamel, which also coats 
 the whole exterior surface of the crown. 
 
 "The character by which horses' grinders may best 
 be distino-uished from the teeth of other herbivora cor- 
 responding with thom in size, is the great length of 
 the tooth before it divides into fangs. This division, 
 indeed, does not begin to take place nntil much of 
 tlie crown has been worn away. Thus, except in old 
 horses, a considerable proportion of the whole of the 
 tooth is implanted in the socket by an nndivided base. 
 This is slightly curved in the upper grinders. 
 
 "The deciduous molars have shorter bodies than the 
 permanent, and sooner begin to develop roots. They 
 may be distinguished from the rooted molar of a rumi- 
 nant, as may also their permanent successors with 
 roots, by their form and the pattern of their grinding 
 surface. The latter may be a little changed by tiie 
 partial obliteration of its enamel folds, but it gen- 
 erally retains enough of its character to show the 
 distinction." 
 
 * " The species of paleotlierium, wlucli appear to have accom- 
 panied the anoplotheres in the first introduction of hoofed quad- 
 rupeds upon this planet, v/ere characterized by the same com- 
 plete dental formula, namely, forty-four functionally developed 
 teeth." — Owen. 
 
AKISTOTLE'S MISTAKE. 69 
 
 Monsieur Lecoq's description of the grinder teeth, 
 like the one just quoted, is a contribution to dental 
 science. The repetition of facts ah'eady given is off- 
 set by its additional facts, and its historical informa- 
 tion is as interesting as are Prof. Owen's comparisons. 
 It is as follows ('' Traite de I'Extcrieur du Cheval et des 
 Princii^aux Animaux Domestiques'') : 
 
 " It w^as believed for a long time that the grinders of 
 Solipeds were all persistent teeth. This error, founded 
 on the authority of Aristotle, w^as so deeply rooted that, 
 although Ruini, toward the end of the Sixteentli cen- 
 tury, had discovered the existence of two temporary 
 molars, Bourgelat did not believe it when he founded 
 the French veterinary schools, and was only convinced 
 when Tenon proved hy specimens, in 1770, that the 
 first three are deciduous. 
 
 " Generally considered, the grinder arcades have not 
 the same disposition in both jaws. Wider apart in the 
 superior one, they form a slight curve, whose convexity 
 is outward. In the inferior jaw, on the contrary, the 
 two arcades separate in the form of a Y toward the back 
 of the mouth. Instead of coming in contact by level 
 surfaces, the grinders meet by inclined-planes. In the 
 lower jaw the internal border is higher than the exter- 
 nal, while the reverse is the rule in the upper. This 
 circumstance prevents the lateral movement of the 
 lower jaw taking place without separation of the inci- 
 sors, and thus saves them from friction. 
 
 " Like the incisors, each grinder presents for study 
 a free and a fixed portion. The free portion (the body), 
 nearly square in the upper grinders, broader than 
 thick in the hnver, sliows at the external surface of the 
 former two longitudinal grooves, the anterior of which 
 
70 THE PERMAKEKT DENTITIOIS". 
 
 is the deeper, both being continued on the incased 
 poi'tion. This is not the case with the lower grinders, 
 "which have but one narrow and frequently indistinct 
 groove. The internal surfiice, in both javv\s, presents 
 only one groove, and that but lirtlj marked. It is 
 placed backward in tlie upper teeth, and is most ap- 
 parent toward the rout. The anterior and posterior 
 faces of the respective teeth, wliieh are in coniaet with 
 each other, are nearly level, but at the extremities of 
 the arcades the isolated faces are converted into a nar- 
 ro^v border. 
 
 " The grinders are separated from each other by their 
 imbedded portion, particularly at the extremities of 
 the arcades, an arrangement v/hich strengthens them 
 by tlirow^ing the strain put upon the terminal teeth 
 toward the riiiddle of the line. They exhibit a variety 
 of roots. In the first and last, either above or below% 
 there are three, while the intermediate teeth have four 
 in the upper jaw, and only two in- the lower. The 
 root, if examined a short time after the eruption of 
 the free portion, looks only like the shaft of the latter, 
 without any appoarancc of fangs, and has internally 
 a wide cavity. It is not until the tooth begins to be 
 l^ushed from the alveolus and its crown has become 
 worn, tiiat its fano-s are formed. These are at first 
 hollow, and afterward filled, as v/ell as the cavity of 
 the tooth, ])y the formation of new dentine. Erom 
 this time tlie fangs cease to gro^v, but the tooth, con- 
 stantly projected beyond the alveolar cavity, allows the 
 walls which inclose it to contract; so that in extreme 
 old age the sliaft, completely v/orn away, instead of the 
 tooth, leaves several stumps formed by the fangs. 
 
 "The replacement of the twelve molars is not at all 
 like Vvdiat happens with the incisors. They grow im- 
 
KELATEVE SIZE OF THE GPvIINDERS. 71 
 
 mediately below the temporary teeth, aud diNride their 
 two fangs into four, the uhsorbing process continuing 
 until the bodies are reduced to simple plates and fall 
 off.'' 
 
 In measuring the tceih in a large-sized head the 
 following facts and figures were elicited: Length of 
 grinder rows, 7 inches. Space between the sixth 
 grinders, upper rows, measuring from the inner sur- 
 faces, but not including the angles, 3 inches; center of 
 rows, 2}f ; first grinders, not including the space of 
 the angles, 2^. Lower rows: Between the sixth 
 grinders, 2|-; center of rows, 1{-^; first grinders, 1-|-. 
 Upper tush from first grinder, 2-J ; from third incisor, 
 1^. Lower tush from grinder, 3-|; from incisor, |. 
 Space between the upper tushes, 2 ; between the lower, 
 If. Space between the upper corner incisors, measur- 
 ing from center of teeth, 2; lower, 1||; between the 
 upper dividers, II- ; lower. If. Distance around semi- 
 circle of upper incisors, 4-fg-; around lower, 3|f. 
 
 As a supplement to tlie above, the following extract 
 is made from ''An Essay on the Teeth" by Surgeon 
 John Hughes ("Veterinarian," 1841, "Proceedings 
 Vet. Med. Ass.," p. 22) : 
 
 " The upper and lower grinders will measure from 
 2| to 3 inches in length. In transverse diameter the 
 former exceed the latter in tlie proportion of 7 to 4. 
 The aggregate measurement of the sockets of the up- 
 per grinders is about 7 inches. The first tooth occu- 
 pies one inch and a half of this space, the second 1|-, 
 the tliirdl-i", the fourth 1, the fifth 1, and the sixth 1-J-. 
 The breadth of the corresponding lowTr teeth is about 
 the same as that of the upper." 
 
72 THE PERMAIs^EiTT DENTITION". 
 
 There is a difference in the structure of all the teeth, 
 and an expert can tell to which socket each belongs. 
 They lit their sockets accurately/'^' are braced all round 
 by the jawbone processes, and receive besides support 
 and protection from the gums, which adhere to them 
 tenaciously and are almost as hard as cartilage. Use 
 and time, however, work changes, the teeth all wearing 
 down, the incisors in particular changing shape and 
 projecting outward. At the age of twelve years the 
 gums begin to slacken, causing the teeth to look 
 longer. The change from the upright position of the 
 incisors, and the increased space between them and 
 the canines, is caused by the elongation of the jaws, 
 which carries the incisors outward. The canines do 
 not change their position, but they become mere stubs. 
 
 * " The manner of attachment of the human teeth is that 
 termed ' gomphosis,' i. e., an attachment comparable to the fit- 
 ting of a peg into a hole. The bony sockets, however, allow of 
 a considerable degree of motion, as may be seen by examining 
 the teeth in a dried skull, the fitting being in the fresh state 
 completed by the interposition of the dense periosteum of the 
 socket. This latter, by its elasticity, allows of a small degree 
 of motion in the tooth, and so doubtless diminishes the shock 
 which would be occasioned by m.astication were the teeth per- 
 fectly immovable and without a yielding lining within their 
 sockets." — C. S. Tomes, "Dental Anatomy" d-c, p. SS. 
 
 John Hunter says (" Human Teeth ") : " The fangs of the 
 teeth are fixed in the gum and alveolar processes by that species 
 of articulation called goonphosis, which in some measure resem- 
 bles a nail driven into a piece of wood. They are not, however, 
 firmly united with the processes, for every tooth has some de- 
 gree of motion; and in heads which have been boiled or macer- 
 ated in water, so as to destroy the periosteum and adhesion of 
 the teeth, we find them so loosely connected with their sockets 
 that the incisors are ready to drop out, the grinders remaining, 
 as it were, hooked, from the number and shape of their fangs/' 
 
THE HORSE AS A MILLER. 73 
 
 Notwithstanding all these changes it is a rare thing to 
 see a missing incisor or grinder. The canines, how- 
 ever, owing perhaps to their sharp points, not only 
 wear out, but now and then, in extreme old age, fall 
 out. 
 
 The permanent teeth agree with the temporary in 
 but few respects, though the general appearance of the 
 respective teeth is nearly the same. They differ in 
 many respects. Their bodies are larger and denser, 
 and their roots longer and stronger. The grooving of 
 the incisors is the reverse ; the outer surface is usually 
 double grooved, the inner smooth, both being slightly 
 rounded. They are less upright in position, and less 
 sharp, but are more discolored, and the "marks" (in- 
 fundibula) are wider and deeper and wear out more 
 slowly. They attain tlieir growth more slowly, and a 
 healthy tooth continues to grow throughout life. 
 
 In proof of the last assertion many authorities could 
 be cited, but those that follow must suffice. It is a 
 wise provision of Nature, as but for it a horse's teeth, 
 particularly the grinders, would be worn to stubs in 
 two or three years after tlieir development. Prof. 
 M. H. Bouley and Surgeon P. B. Ferguson say (" Vet- 
 erinarian," 18-14) : 
 
 "The growth throughout life is a compensation for 
 the enormous w^ear of the teeth, the liorse having to 
 perform for himself that which the miller performs for 
 man ; and thus during a very long time the teeth pre- 
 serve, if not their form, at least their length." 
 
 Prof. A. Chauveau, referring to the horse, says: 
 
 " The permanent teeth present in their development 
 a common but very remarkable characteristic, rarely 
 4 
 
74 THE PEEMAI^EXT DEKTITIOI^. 
 
 met with in other animals. Th^y are thrust up from 
 the alveoh during the entire life of the animal to re- 
 place the surface worn by friction ; so tliat the crown 
 is formed successively by the various portions of the 
 fang, each of which issues in its turn from the alveolar 
 cavity." 
 
 Prof. 0. S. Tomes says " the elevation of the tooth 
 takes place quite independently of growth from a per- 
 sistent pulp, and ni fact happens after the formation 
 of its roots." 
 
CHAPTER IV. 
 
 THE CANINE TEETH OR TUSHES. 
 
 Practically Useless.— Different in their Nature from the other 
 Teeth.— Were they formerly Weapons of Offense and De- 
 fense?— Views of Messrs. Darwin, Himter, Bell, Youatt, and 
 Winter.— Their time of Cutting the most Critical Period of 
 the Horse's Life. 
 
 The Canine Teeth {laniarii denies), comparatively 
 speaking, are of little practical use; at least tliey are 
 of little use to the modern horse. They have heeu 
 much reduced in size during the evolution of the horse, 
 and, if Mr. C, 11. Darwin's theory is correct, are prob- 
 'al)ly "in the course of ultimate extinction." They 
 distinguish the sex, it is true, but their loss would not 
 be felt on that account. The horse sometimes uses 
 them in tearing bark from trees, for he is by instinct 
 his own (botanical) doctor, and the bark is his medi- 
 cine. The sharp points of the tushes penetrate the 
 bark more readily than the incisors, and apparently 
 the horse wishes to save his incisors, thus showing his 
 horse-sense. Their nature is different from that of 
 the other teeth, for the incisors and grinders grow till 
 old age. This is not the case Avith the tushes, and, 
 farther, they are never in apposition (superposed), and 
 consequent! V do not wear one another. 
 
 The lower tushes, as before said, are about three- 
 f^uirths of an inch from the corner incisors, and about 
 three inches and a half from the first grinders. The 
 
76 THE CAKIJTE TEETH. 
 
 space between the upper tushes and the corner incisors 
 is doable that of the lower, and they are consequently 
 three-fourths of an inch nearer the grinders. The dis- 
 tances may vary a half an inch or more. The space 
 between the tushes and grinders 2S> as already said, 
 called the diastema. 
 
 The average hight of the tushes when full grown is 
 about three-fourths of an inch. They resemble tri- 
 angles, having broad bases and sharp crowns, the latter 
 being remarkable, says Prof. Owen, "for the folding in 
 of the anterior and posterior margins of enamel, which 
 here includes an extremely thin layer of dentine." 
 They have a slight outward inclination, that of the 
 lower teeth exceeding that of the upper. Their outer 
 surface is oval, the inner (in the young horse) being 
 deeply grooved. As age advances the inner snrfjxce 
 becomes oval also, and the crowns more or less blunt. 
 The root of a tush, which is longer than its body, 
 has a distinct backward curvature, rendering the ex- 
 traction of these teeth almost impossible. The tushes 
 have no "marks" (infundibula), the nerve cavity ex- 
 tending through nearly the entire length of the tooth. 
 
 ^Monsieur Lecoq says : 
 
 "The free portion of the tusk, slightly curved and 
 thrown oiitw^ard, particularly in the lower jaw, presents ^ 
 two faces (internal and external), separated from one 
 another by two sharp borders, which incline to the 
 inner side, and meet in a point at the extremity of the 
 tooth. The external face, slightly rounded, presents a 
 series of fine striae, longitudinal and parallel. The 
 internal has a conical eminence in its middle, whose 
 point is directed toward that of the tooth, and is sep- 
 arated from each border by a deep groove. 
 
SIMPLICITY OF THEIR STRUCTURE. 77 
 
 " The fang of the tusk, more curved than the free 
 j)ortioD, bears internally a cavity analogous to that of 
 the root of the incisors, and, like it, diminishes in size 
 and finally disappears as age advances ; but it is always 
 relatively larger, because of the absence of the infun- 
 dibulum in the canine teeth. 
 
 " The structure of these teeth is much simpler than 
 that of the incisors, consisting, as they do, of a central 
 mass of dentine, hollowed by the pulp cavity, and cov- 
 ered by an external layer of enamel, on which is de- 
 posited a little cement." 
 
 As there is more or less mystery about the tushes, 
 and as they are important factors in the consideration 
 of the problem of the evolution of the horse as well as 
 other animals, a few extracts from the works of well- 
 known scientific men, giving their views on the sub- 
 ject, will i^rove interesting if not instructive. 
 
 Mr. Charles R Darwin gives the following interest- 
 ing account of tushes and their uses in certain animals, 
 among them the horse (" Descent of Man," vol. ii, pp. 
 
 245-6-7) : 
 
 "Male quadrupeds which are furnished with tusks 
 use them in various ways, as in the case of horns. 
 The boar strikes laterally and upward, the musk-deer 
 with serious effect downward. The walrus, though 
 having a short neck and unwieldy body, ^can strike 
 upward, downward, or sideways with equal dexterity.' 
 The Indian elephant fights, as I was informed by the 
 late Dr. Falconer, in a different manner according to 
 the position and curvature of his tusks. When they 
 are directed forward and upward, he is able to' fling a 
 tiger to a great distance — it is said to even thirty feet; 
 
78 THE CANINE TEETH. 
 
 when tliey are short and turned do^Tn^ard, he en- 
 deavors suddenly to pin the tiger to the ground, and 
 in consequence is daugerons to the rider, who is liable 
 to be dismounted. 
 
 '• Very few male quadrupeds possess weapons of two 
 distinct kinds specially adapted for lighting with rival 
 males. The male muntjac-deer {Cervulus), however, 
 offers an exception, as he is provided with horns and 
 exserted canine teeth. But one form of weapon has 
 often been replaced in th.e course of ages by another 
 form, as we may infer from wliat follows. With rumi- 
 nants the development of horns generally stands in an 
 inverse relation with that of even moderately Avell- 
 developed canine teeth. Thus camels, guanacoes, 
 chevrotains, and musk-deer are hornless, and they 
 have efficient canines, these teeth being 'always of 
 smaller size in the females than in the males.' Male 
 deer and antelopes, on the other hand, possess horns, 
 and they rarely have canine teeth, and these when 
 present are always of smaller size, so that it is doubt- 
 ful v/hether they are of anyseiwice in their battles. 
 With Antelope montana they exist only as rudiments 
 in the young male, disappearing as he grows old. 
 Stallions have small canine teeth, but they do not 
 appear to be used in fighting, for stallions bite v/ith 
 their incisors, and do not open their mouths widely 
 like camels and guanacoes. Whenever the adult male 
 possesses canines now in an inefficient state, while the 
 female has either none or mere rudiments, we may 
 conclude that the early male progenitor of the species 
 was provided with efficient canines, which had been 
 partially transferred to the females. . The reduction of 
 these teeth in the males seems to ha,ve followed from 
 some change in their manner of fighting, often caused 
 
TUSHES TEJT FEET LON"G. 79 
 
 (but not ill the case of the horse) by the development 
 of new weapons." 
 
 In the first volume of the "Descent of Man/' page 
 139, Mr. Darwin attributes the reduction in size of the 
 tushes in horses to their " habit of fighting with their 
 incisor teeth and hoofs/' and on page 231, of the sec- 
 ond volume, he continues the discussion of canines in 
 different animals as follows: 
 
 " In the male dugong the upper incisors form offen- 
 sive weapons. In the male narwhal one of the upper 
 teeth is developed into the well-known, spirally-twisted, 
 so-called horn, which is sometimes from nine to ten 
 feet long. It is believed that the males use these horns 
 for fighting together, for ^an unbroken one can hardly 
 be got, and occasionally one may be found with the 
 point of another jammed into the broken place.' The 
 tooth on the opposite side of the head in the male con- 
 sists of a rudiment about ten inches in length, which 
 is imbedded in the jaw. It is not, however, very un- 
 common to find double-horned male narwhals in which 
 both teeth are v/ell developed. In the females both 
 teeth are rudimentary^ The male cach'alot* has a 
 
 * " Spenn-wliale or cachalot {Physeter macrocephalus). My 
 friend Mr. Broderip possesses a tootli of a male Physeter, with 
 the base open and uncontracted, which measures nine inches 
 and a half in length, nine inches in circumference, and weighs 
 three ])Ounds. An ingenious whale-fisher has carved the chief 
 incidents of his exciting and dangerous occupation on one side 
 of this very fine tooth. The other side bears the following in- 
 &cri])tion : ' The tooth of a sperm-whale, that was caught by the. 
 ship Adam's crew, off Albemarle Point, and made 100 bbls. of oil, 
 in the year 1817.' Below tlie inscription are two excellent 
 figures of the cachalot, one spouting, the ot^her dead and marked 
 for flensing."— Ow;e;i'5 "Odontography," Vol. /, pp. 353-4- 
 
80 THE ca:n'I]s-e teeth. 
 
 Lirger head than the female, and it no doubt aids these 
 animals in their aquatic battles. Lastly, the adult 
 male ornithorhyn'chus is provided with a remarkable 
 apparatus, namely, a spur on the foreleg, closely re- 
 sembling the poison fang of a venomous snake. Its 
 use is not known, but we may suspect it serves as a 
 weapon of offense. It is represented by a mere rudi- 
 ment in the female." * 
 
 The foregoing extracts would not be complete with- 
 out giving the viev»^s of this great disciple of evolution 
 concerning the same teeth in man. He says (" Descent 
 of Man," voL i, p. 198) : 
 
 "We have thus far endeavored rudely to trace the 
 genealogy of the vertebrata by the aid of their mutual 
 affinities. We will now look to man as he exists, and 
 we shall, I think, be able partially to restore during 
 successive periods, but not in due order of time, the 
 structure of our early progenitors. This can be effected 
 by means of the rudiments which man still retains, by 
 the characters which occasionally make their appear- 
 ance in him through reversion,! and by tiie aid of the 
 principles of morphology and embryology.| The early 
 
 * For further information concerning this strange animal see 
 tlie " Vocabulary." 
 
 f " The occasional appearance at the present day of canine 
 teeth which project above the others, with traces of a diastema 
 or open space for the reception of the opposite canines, is in all 
 probability a case of reversion to a former state, when the pro- 
 genitors of man were provided with these weapons." — "Descent 
 of Man," Vol. II, p. SOD. 
 
 \ " The human em'bryo re&ombles in various points of struc- 
 ture certain low forms when adult. For instance, the heart at 
 first exists as a simple pulsating* vessel ; the excreta are voided 
 through a cloacal passage, and the os coccyx projects like a true 
 
THE EARLY PROGrXITORS OF MAN". 81 
 
 progenitors of man were no doubt once covered with 
 hair, both sexes having beards. Their ears were 
 pointed and capable of movement, and their bodies 
 were provided with a tail, having tlie proper muscles. 
 Their limbs and bodies were also acted on by muscles 
 which now only occasionally reappear, but are normally 
 present in the quadrumana. ^The great artery and 
 
 tail, 'extending considerably beyond the rudimentary legs.* 
 The great-toe, as Prof. Owen remarks, 'which forms the ful- 
 crum when standing or walking, is perhaps the most character- 
 istic peculiarity in the human structure ;' but in an embryo 
 about an inch in length, Prof. Wyman found that the great-toe 
 was shorter than the others, and instead of being parallel to 
 them, • projected at an angle from the side of the foot, thus cor- 
 responding with the permanent condition of this part in the 
 quadrumana.' * * * When the extremities are developed, 
 * the feet of lizards and mammals, the wings and feet of birds, 
 no less than the hands and feet of man, all arise from the same 
 fundamental form.' (Von Baer)." — "Descent of Man," Vol. I, pp. 
 U-IG. 
 
 "Each human individual is developed from an egg, and this 
 egg is a simple cell, like that of any animal or plant. The em- 
 bryo, in the early stages of development, is not at all different 
 from those of ether animals. At a certain period it has essen- 
 tially the anatomical structure of a lancelet (the lowest verte- 
 brate), later of a fish, and in subsequent stages those of am- 
 phibian and mammal forms. In the further evolution of these 
 mammal forms, those first appear which stand lowest in the 
 series, namely, forms allied to beaked animals (ornithorhyn- 
 chus) ; then those allied to pouched animals (marsupials), which 
 are followed by forms most resembling apes, till at last the 
 peculiar human form is produced as the final result. Every one 
 knows that the butterfly proceeds frpra a pupa, the pupa from a 
 caterpillar, to which it bears no resemblance, and again the cat- 
 erpillar from the e^g of the butterfly. But few, except those of 
 the medical profession, are aware that man, in the course of his 
 individual evolutiou, passes through a series of transformations 
 
82 THE CAKIKE TEETH. 
 
 nerve of the humerus ran through a supra-condyloid 
 fora'men. At this or some earlier period the intestine 
 gave forth a much larger diverticulum or csecum than 
 that now existing. The foot, judging from the con- 
 dition of the great-toe in the fetus, was then prehen- 
 sile, and our early progenitors were no douht arboreal 
 in their habits, frequenting some warm, forest-clad 
 land. The males were*" provided with great canine 
 teeth, which served them as formidable weapons."* 
 
 no less astonishing and remarkable than the xvell known meta- 
 morphoses of the butterfly. * * * An examination of the 
 human embryo in the third or fourth week of its evolution 
 shows it to be ahogether different from the fally developed 
 man, and that it exactly corresponds to the undeveloped em- 
 bryo-form presented by the ape, the dog, the rabbit, the horse, 
 and other mammals, at the same stage of their ontog'eny (germ 
 history), which may be demonstrated by placing the respective 
 embryos side by side. At this stage it is a bean-shaped body of 
 very simple structure, with a tail behind, and two pairs of pad- 
 dles, resembling the fins of fish, and totally dissimilar at the 
 sides to the limbs of man and other mammals. Nearly the 
 whole of the front half of the body consists of a shapeless head, 
 without a face, on the sides of which are seen gilh fissures and 
 gill-arches, as in fishes. •» * * The human embryo j)asses 
 through a stage in which it possesses no head, no brain, no 
 skull ; in which the trunk is still entirely simple and undivided 
 into head, neck, breast, and abdomen, and in which there is no 
 trace of arms or legs," — Ernst Heinrich Haeckel, "The Ewlution 
 of Man,'' Vol. I, pp. 3, IS, 258. 
 
 * Mr. Darwin continues : " At a much earlier time the uterus 
 was double ; the excreta were voided through a cloaca, and the 
 eye was protected by a third eyelid or nictitating membrane. 
 At a still earlier period the progenitors of man must have been 
 aquatic in their habits, for morphology plainly tolls us that our 
 lungs consist of a modified swim-bladder, which once served as 
 a float. The clefts on the neck in the embryo of man show 
 where the branchiae once existed," &c., &c. 
 
DAKWIX OJTLY CORROBORATES HUNTER. 83 
 
 Again, on page 138 of the same volume, Mr. Darwin 
 
 says : 
 
 "The early progenitors of man were, as previously 
 stated, probably furnished with great canine teeth ; but 
 as they gradually acquired the habit of using stones, 
 clubs, or other weapons for fighting with their enemies, 
 they would have used their jaws and teeth less and 
 less. In this case the jaws and the teeth would have 
 become reduced in size, as we may feel sure from nu- 
 merous analogous cases."* 
 
 Dr. John Hunter, writing nearly one hundred years 
 before Mr. Darwin's time, says ('' The Human Teeth," 
 p. 29) : 
 
 " The use of the cuspidati would seem to be to lay 
 hold of substanceSj perhaps even living animals. They 
 are not formed for dividing, as tlie incisors are, nor 
 are they fit for grinding. We may trace in these teeth 
 a similarity in shape, situation, and use, from the most 
 imperfectly carnivorous animal — which we believe to 
 be the human species — to the most perfectly carnivo- 
 rous, namely, the lion." 
 
 The editor of Dr. Hunter's work, Mr. Thomas Bell, 
 F.R.S., comments as follows on the above extract: 
 
 " That our conclusions as to the functions of an 
 organ as it exists in man, when drawn exclusively from 
 analogous structures in the lower animals, will fre- 
 
 * "The jaws, toijether with their muscles, would then have 
 become reduced throiinrh disuse, as would the teeth, throujih the 
 not well understood principles of correlation and the economy of 
 growth ; for we everywhere see that parts which are no longer 
 of service are reduced in size." — "Descent of Man.'" 
 
84 The CANIinE TJEETH. 
 
 quentlyprove erroneous, is strikingly shown in these 
 observations on the use of the cuspidatus. The simple 
 and obvious use of this tooth, in the human species, is 
 to tear such portions of food as are too hard or tough 
 to be divided by tlie incisors ; and we frequently find 
 it far more developed in animals which are known to 
 be exclusively frugivorous. Not only is its structure 
 wholly unadapted for such an object as that assigned 
 to it in the text, but there is no analogous or other 
 ground for supposing that man was originally con- 
 structed for the pursuit and capture of living prey. 
 His naturally erect position and the structure of the 
 mouth would render this impossible by the means in- 
 ferred by Hunter; and the possession of so perfect an 
 instrument as the hand obviates the necessity of his 
 ever employing any other organ for the purpose of 
 seizing or holding food of whatever description." 
 
 Prof. William Youatt says ("The Horse," p. 22G): 
 
 "At the age now under consideration (the fourth 
 year) the tushes are almost peculiar to the horse, and 
 castration does not appear to prevent or retard their 
 development. All mares, however, have the germs of 
 them ill the chambers of the jaws, and they appear 
 externally in the majority of old mares. Their use is 
 not evident. Perhaps in the wild state of the horse 
 they are weapons of offense, and he is enabled by 
 them to more firmly seize and more deeply wound his 
 enemy." * 
 
 " Prof. C. S. Tomes says : " In the domestic races the tiisks of 
 boars are much smaller than in the wild animal, and it is a curi- 
 ous fact that in domestic races which have become wild, the 
 tusks increase in size at the same time that the bristles become 
 more pronounced. Mr. Darwin suggests that the renewed 
 
THEIR PHYSIOLOGICAL RELATIONS. 85 
 
 Surgeon J. H. Winter, the author of a work entitled 
 " On the Horse," says : 
 
 '' It is difficult to assign their use. Their position 
 precludes the possibility of their being used as weapons 
 of offense or defense. They may be viewed as a link 
 of uniformity so commonly traced in the animated 
 world." 
 
 Prof. William Percivall says that the cutting of the 
 tushes causes the constitution more derangement than 
 all the other teeth, and Prof. Youatt and other high 
 authorities entertain similar views. The present chap- 
 ter, therefore, is a proper one in which to discuss " the 
 effects of dentition on the system generally." The 
 discussion of the subject is left to well-known men. 
 Messrs. Youatt and Percivall were many years ago the 
 editors of "The Veterinarian," but their books are 
 probably the best monuments to their memory. Prof. 
 William Williams is the President of the Edinburgh 
 Veterinary College. Prof. Youatt says (" Tiie Horse," 
 p. 230) : 
 
 " This is the proper place to speak of the effect of 
 dentition on the system generally. Horsemen in gen- 
 eral think too lightly of it, and they scarcely dream of 
 the animal suffering to any considerable degree, or 
 
 growth of the teeth may perhaps be accounted for on the prin- 
 ciple of correlation of growth, external agencies acting on the 
 skin, and so indirectly influencing the teeth." 
 
 A strictly analogous result might or might not follow in the 
 case of the horse. If so, the tushes would probably be used as 
 weapons of offonse and defense. It is reasonable to suppose that 
 they were so used by the early progenitors of the horse, whose 
 large tushes are described in the succeeding chapter by Prof. 
 Marsh. 
 
80 THE CAKIN'E TEETH. 
 
 absolute illness being produced. Yet he who has to 
 do with young horses will occasionally discover a con- 
 siderable degree of febrile affection Avhich he can refer 
 to this cause alone. Fever, cough^ catarrhal and cuta- 
 neous affections, diseases of the eyes, diarrhea, dysen- 
 tery, loss of appetite, and general derangement will 
 frequently be traced to irritation from teething. It is 
 a rule scarcely admitting of the slightest deviation, 
 that, when young horses are laboring under febrile 
 affection, the mouth should be examined, and if the 
 tushes are prominent and pushing against the gums, a 
 crucial incision should be made over them."* 
 
 Prof. Percivall says (*• Hippopathology," vol. ii, p. 
 225) : 
 
 "There was a time when I treated the subject of 
 dentition so lightly as to think that horses never suf- 
 fered from such a cause. Experience, however, has 
 altered my opinion. I now frequently discover young 
 horses with disorders or febrile irritations the produc- 
 tion of which I hesitate not to ascribe to teething. 
 Many years ago I was consulted concerning a horse 
 which had fed sparingly for a fortnight and lost rap- 
 idly in condition. His owner, a veterinary surgeon, 
 was apprehensive about his life. Another surgeon was 
 of opinion that the ^cudding' arose from preternatural 
 
 *^ Prof. Youatt's real sentiments are doubtless here expressed, 
 but, unfortunately for bis consistency, on page 227 of tbe same 
 work, in speakina; of tbe deran£:;eraent caused by teetbing in 
 cbildren and dogs, be says : " Tbe borse appears to feel little 
 inconvenience. The gums and palate are occasionally some- 
 wbat bot and swollen, but tbe sli^btost scarification will remove 
 tbis." Perbaps Prof. Youatt, like Prof. Percivall, cbaufred bis 
 opinion late in life, and neglected to remove tbe blemisb from 
 bis book. 
 
WHAT CHAiTaED PROF. PERCIVALL'S MIIiTD. 87 
 
 bluntness of the molar teetli, which were filed. It 
 was after this that I saw the horse, and I must confess 
 I was ut first quite as much at a loss to offer a satisfac- 
 tory interpretation of the case as others had been. 
 While meditating, however, after my inspection of the 
 horse, on the apparently extraordinary nature of the 
 case, it struck me that I had not seen the tushes. I 
 went back into the stable and discovered two little 
 tumors, red and hard, in the situation of the inferior 
 tusks, which, when pressed, gave the animal insuffer- 
 able pain. I instantly took out my pocket-knife and 
 made crucial incisions through them both, from which 
 moment the horse recovered his appetite, and by de- 
 grees his wonted condition. This case was the turn- 
 ing point in my practice, and caused me to look more 
 closely into dentition. 
 
 *^The cutting of the tushes, which may be likened 
 to the eye-teeth of children, costs the constitution 
 more derangement than all the other teeth put to- 
 gether; on which account, no doubt, it is that the 
 period from the fourth to the fifth year proves so crit- 
 ical to the horse. Any disease, pulmonary in particu- 
 lar, setting in at this period, is doubly dangerous. In 
 fact, teething is one cause of the fatality among young 
 horses at this period. 
 
 *^ D'Arboval tells us to observe how the vital energy , 
 becomes augmented about the head, and upon the 
 mucous surfaces in particular. He says: *A local 
 fever originates in the alveolar cavities. The gums 
 become stretched from the pressure of the teeth against 
 them. They dilate, sometimes split, and are red, hot, 
 and painful. The roots compress the dental nerves 
 and irritate the periosteal linings of the alveolar cavi- 
 ties. These causes will enable us to explain many 
 
88 THE CANIKE TEETH. 
 
 morbid phenomena in horses about this, the most crit- 
 ical period of their lives.' 
 
 "When young Jiorses are brought to me now for 
 treatment/' continues Prof. Percivall, "I invariably 
 examine tlie teeth. Should the tiisks be pushing 
 against the gums, I let them through by incisions 
 over their summits, and I extract any of the tempo- 
 rary teeth that appear to be obstructing the growth of 
 the permanent. In this way I feel assured I have seen 
 catarrhal and bronchial inflammations abated, coughs 
 relieved, lymphatic and other glandular tumors about 
 the head reduced, cutaneous eruptions got rid of, de- 
 ranged bowels and urinary organs restored, appetite 
 returned, and lost condition repaired. 
 
 "I am quite sure too little attention has been paid 
 to the teeth in the treatment of young horses, and I 
 would counsel those who have such charges by no 
 means to disregard this remark, trifling as it may 
 appear. The pathognomonic symptoms calling our 
 attention, whether in young or old horses, if not to 
 the teeth themselves, to the mouth in general, are 
 large discharges of saliva from the mouth, with occa- 
 sional slobbering; cudding of the food; difficulty of 
 mastication or deglutition, or both, and stench of buc- 
 cal secretion, perhaps of the breath as well." 
 
 Prof. Percivall continues the discussion of the sub- 
 ject of dentition and its effect on the health of the 
 horse, dwelling more particularly on the disorder 
 known as lampas. He says: 
 
 "There is connected with dentition another pecu- 
 liarity in the horse which we must not allow to pass 
 unnoticed. Although the period of teething, properly 
 
LAMP.iS CAUSED BY TEETHING. 
 
 89 
 
 speaking, may be said to terminate at the fifdi year, 
 yet we must recollect it has been satisfactorily demon- 
 strated that there is a process of growth going on in 
 the teeth throughout the remainder of life ; so that m 
 fact, at no period may the animal be said to be free 
 from the influence of dentition. This accounts for 
 lampas occurring in old as well as young horses, and 
 furnishes mv mind with strong proof that the tumidity 
 of the bars "of the mouth is dependent on operations 
 goino- on in the teeth, and on that cause alone. ^ 
 
 " What we nowadays understand by lampas is an 
 unnatural prominence or tumidity of the cartilaginous 
 bars forming the roof of the mouth, ^^^^^urally, the 
 bars are pale-colored, whereas in a mouth affected with 
 lampas they become red and tumid, losing their cir- 
 cumflecture, and swelling to a level with the crowns of 
 the incisor teeth, and in some cases even beyond them. 
 This apparent augmentation of substance is ascnbable 
 to congestion of blood-vessels, but not to that alone. 
 I believe that in many cases there will be found to be 
 some serous and albuminous infiltration into the cel- 
 lular membrane at! aching the bars to the hard palate, 
 and that this will account for the length of time the 
 swelling sometimes continues, as well as for the httle 
 relief, in regard to their diminution, which in such 
 cases attends lancing of the gums. 
 
 " Although in young horses it is, I believe, admitted 
 that lampas is caused by the cutting of the teeth, yet 
 in old horses there are those who asci;ibe its produc- 
 tion to other causes, and imagine it has a great deal to 
 do with a horse's health, or rather with his fceduig. 
 That lamnas may in some cases be the cause of tender- 
 ness in mastication, 1 do not deny; but, at the same 
 time, I think I may safely ullirm that in nine cases out 
 
 ^ 
 
90 THE CANII^E TEETH. 
 
 of ten the cause of loss of appetite will be found else- 
 where. The reason why lampas appears in aged horses 
 is, in my opinion, as before stated, on account of the 
 continuance of the process of growth in the teeth 
 throughout life, with the nature and law^s of which we 
 are, in our present state oi knowledge, too little ac- 
 quainted to pretend to say why it should exist in one 
 horse and not in another, or why it should only at 
 times appear in the same horse. 
 
 *''ls lampas a disease? Tlie complaints which daily 
 reach our ears persuade us it is. Every groom having 
 an unthriving horse, or one that docs not feed, is sure 
 to search for lampas. If he finds it, in his mind the 
 cause of lack of thrift is detected, and the remedy 
 obvious — burning- Many a horse has been subjected 
 to this torturing operation, and has thereby got added 
 to his other ailment-s a foul, sloughy, carious sore on 
 the roof of his mouth. 
 
 " Supposing that lampas be owing to the teeth, do 
 not the teeth require removal, and not the bars of the 
 mouth? In cutting or burning away lampas we mis- 
 take the effect for the cause. If lampas is not produced 
 by the irritation of teething, then I would like to be 
 informed what does cause it." 
 
 Prof. Youatt says of lampas (" The Horse," p. 219) : 
 
 ^' It may arise from inflammation of the gums, 
 propagated to the bars when the colt is shedding his 
 teeth — young horses being more subject to it than 
 others — or from some febrile tendency in the consti- 
 tution generally, as when a J^oung horse has lately 
 been taken from grass, and has been over-fed or insuf- 
 ficiently exercised. It is well to examine the grinders, 
 
MASHES xVND LANCIKG RECOMMENDED. 91 
 
 and more particularly the tuslies, in order to ascertain 
 whether they are making their way through the gums. 
 If so, incisions should be made across the swollen 
 gums, and immediate relief will follow. At times it 
 appears in aged horses, the process of growth in the 
 teeth of the horse continuing during life. 
 
 ^•The brutal custom of farriers, who sear and burn 
 the bars with a red hot iron, is most objectionable. It 
 is torturing the horse to no purpose, and may do seri- 
 ous injury. In a majority of cases the swelling will 
 subside without medical treatment. A few mashes 
 and gentle alteratives will give relief, but sometimes 
 slight incisions across the bars with a lancet or pen- 
 knife may be necessary. Indeed, scarification of the 
 bars in lampas will seldom do harm, though it is not 
 as necessary as is generally supposed." 
 
 Concerning "Diseases occurring during Dentition" 
 Prof. William Williams says (" Principles and Practice 
 of Veterinary Surgery," p. 476) : 
 
 "In the horse the temporary grinders are replaced 
 by permanent ones when he is from three to four years 
 old, and in the ox at from two years and six months 
 to two years and nine months. In cattle the cutting 
 of the permanent molars is occasionally a matter of 
 some difficulty owing to the unshed crowns of the 
 temporary teeth becoming entangled with the new 
 teeth, and thus proving a source of irritation and pre- 
 venting the animal from feeding. In some parts of 
 the country such animals are called 'rotten,' from their 
 emaciated condition, and perhaps from the fetor ema- 
 nating from the mouth. When cattle of this age stop 
 feeding, lose condition, or drivel from the mouth, the 
 
92 THE CAXIKE TEETH. 
 
 teeth should be examined, and if the unshed molars 
 are causing irritation, they should be removed with 
 the forceps. Hundreds of young cattle have been sac- 
 rificed from this cause — actually dying of starvation. 
 In the horse tlie same condition of the grinders may 
 exist, but it is very unusual. The corner incisors, 
 however, may present the same anomalous condition. 
 Horses from four years to four years and six months 
 old should have their teeth examined occasionally to 
 see if all is going on well. 
 
 '• Horses at four years old are subject to a distressing 
 cough. At this age the third temporary grinder is 
 replaced by its permanent successor, and at the same 
 time the sixth grinder is being cut. Some irritation 
 exists in the gums during the eruption of all the teeth, 
 and in some instances it is excessive, extending from 
 the gums to the fauces and larynx. This is particu- 
 larly the case with the sixth grinder, and as a result of 
 the extension of the irritation, cough is excited, usually 
 in the morning, when the animal begins to feed. It 
 is loud, sonorous, and prolonged, the horse frequently 
 coughing twenty, thirty, or even forty times without 
 ceasing. It is a throat cough, originating in laryngeal 
 irritation. 
 
 " The treatment for this, which may be truly said to 
 be a tootli-cough, is careful dieting on crushed food; 
 hay, not much bran ; grass, if in season, or roots if 
 grass is not obtainable ; alkaline medicines, more par- 
 ticularly the bicarbonate of soda; gentle aperients 
 occasionally, if the bowels be irregular. If the faeces 
 are fetid the fetor will be much diminished by a few 
 doses of the hyposulj^hite of soda, the mouth to be gar- 
 gled with some cooling mixture, such as the borate of 
 soda or alum." 
 
DEisTITION FEYEE. 93 
 
 Of "Dentition Fever" Prof. Williams says ("Prin- 
 ciples and Practice of Veterinary Surgery," p. 479) : 
 
 " Horses from three to four years old are more sub- 
 ject to this species of dental irritation than those of a 
 more tender age, and it is well known among horsemen 
 that they will stand more fatigue at a more tender age 
 than they will at this. The reason is because teething 
 is now at the hight of its activity. When the animal 
 is three years old, eight permanent grinders are being 
 cut, and four permanent incisors are in active growth 
 within the jaws. At four years of age the same num- 
 ber of grinders are out, and the same number of inci- 
 sors are at a more advanced stage of growth within the 
 jaws, in addition to the canme teeth, which make 
 their appearance about this time. 
 
 " No wonder then that the eruption of so many teeth 
 is a source of irritation and fever. The best treatment 
 is to throw the animal off woi'k, turn him to grass if 
 the weather permits, or into a loose box in a well ven- 
 tilated spot, and give him rest until the process of den- 
 tition is completed. If the gums are red and swollen, 
 lancing them will prove a source of great relief." 
 
 On page 503 Prof. Williams, in speaking of crib- 
 biting and wind-sucking, says: "Want of work and 
 the irritation of teething are generally the causes of 
 these vices." 
 
CHAPTEE V. 
 
 THE EEMiS'AIs'T TEETH. 
 
 Usually regarded as Plienomenons. — The Name. — Traced to 
 tlie Fossil Horses, in wliicli (in tlie Pliocene Period) they 
 "Ceased to be Functionally Developed." — Nature's Meta- 
 morphoses. — " The Agencies which are at work in Modeling 
 Animal and Vegetable Forms." — Why Remnant Teeth are 
 often, as it were, Prematurely Lost, — Fossil Horses and a 
 so-called Fossil Man. 
 
 The Eemnant or "so-called wolf-teeth" are one of 
 the most interesting features of the horse's dental sys- 
 tem. They are generally regarded as phenomenons, 
 . hut their line of descent is as direct as that of the first 
 premolars (grinders), which have, as it were, almost 
 absorbed them, and have increased in bulk nearly in 
 proportion to the decrease in bulk of the Eemnant 
 teeth. 
 
 As the word "wolf" is another name for that which 
 is hurtful or destructive, and as these teeth as well as 
 supernumerary teeth, with which, however, they should 
 never be confounded, sometmies do injury, the generic 
 name, " wolf- teeth," is not a bad one. But, since these 
 piirticular teeth are hereditary, being beyond doubt the 
 remains of teeth that were once functionally developed, 
 they require a specific name ; I have therefore adopted 
 the name EsMifAisT Teeth. 
 
PROF, marsh's researches. 95 
 
 In the evolution of the horse from an animal of 
 about the size of a fox to his present proportions, it is 
 not strange that radical physical changes, of the teeth 
 as well as other organs, should have occurred, or that 
 they are in harmony with Ins bodily requirements as 
 well as his usefulness to man. Small, four-toed limbs 
 would support the body of an animal no larger than a 
 fox or a sheep, but they would require additional size 
 and strength to support the small horse (Hipparion) 
 of the Pliocene period, or the large horse of the present 
 period (Equus). This additional strength was gradu- 
 ally acquired by the enlargement of the limbs and the 
 solidification, as it were, of four toes into one, it being 
 as natural, in conformity to the law of adaptation, for 
 a line of succeeding animal forms to undergo bodily 
 changes as for an individual form to do so. 
 
 During these metamorphoses equally A-aried and 
 interesting changes occurred in the horse's dental sys- 
 tem, which are described by Prof. 0. C. Marsh, of Yale 
 College, in the article "Horse, Fossil," in "Johnson's 
 Xew Universal Cyclopedia (vol. ii, p. 906). He gives a 
 general description of the changes that have occurred 
 in species of three geological periods, namely, the 
 Phocene, Miocene, and Eocene, those of the two last 
 named having forty-four functionally developed teeth. 
 The part of the article which refers to the teeth is as 
 follows : 
 
 "In the Pliocene tertiary period the horse was rep- 
 resented by several extinct genera, the best known be- t 
 ing Hipparion (or Hippotherium). The species are 
 small, as the n:ime im])lies, Hipparion being a dimin- 
 utive from the Greek hippos, a ^ horse.' In tlie ui)per 
 molar teeth there is in Hipparion, on the anterior por- 
 
96 THE REMI^AKT TEETH. 
 
 tion of the inner side, an isolated ellipse of enamel 
 inclosing dentine, and not joined with the main body 
 of the tootii by an istlimus of dentine, as in Equus, at 
 least until the teeth are nearly worn out. Anchippns, 
 also from tlie Pliocene, resembled in its teeth Anchi- 
 therium of the Miocene, a genus now considered as 
 typical of a family distinct from that of the horse. In 
 Anchitherium the molars have short crowns, devoid of 
 cement, and are inscribed by distinct fangs. The Mio- 
 cene species were not larger than a sheep. The Eocene 
 representatives of the group were still smaller, the 
 largest hardly exceeding a fox in size. They belong 
 to the genus Orohippus. The dentition is very simi- 
 lar to that of Anchitherium, but the first upper pre- 
 molar is larger and tlie succeeding ones smaller than 
 in that genus. The diastema, or 'place for the bit,' is 
 distinct. The canines are large, and near the incisors. 
 The crowns of the molars are short and jdestitute of 
 cement, and the skeleton is decidedly equina in its 
 general features. 
 
 "The gradual elongation of the head and neck may 
 be said to have already begun in Orohippus, if we 
 compare that form with other most nearly allied mam- 
 mals. The diastema was well developed even then, but 
 increased materially in succeeding genera. The num- 
 ber of teeth remained the same until the Pliocene, 
 when the front lower prenwiar was lost, and suljse- 
 quently the corresponding upper tooth ceased to he func- 
 tionally developed.'-' The next upper premolar, which 
 in Orohippus was the smallest of the six posterior 
 
 * The italics are mine. This " corresponding npper tooth 
 that ceased to be functionally developed," is the identical tootli 
 that now appears as a mere remnant. 
 
THE LARGE TUSHES OF OROHIPPUS. 97 
 
 teeth, rapidly increased in size, and finally became the 
 largest of the series. The grinding teeth had at first 
 very siiort crowns, without cement, and were inserted 
 by distinct roots. In Pliocene species the molars be- 
 came longer, and were more or less coated with cement. 
 The modern horse has very long grinders, without 
 true roots, which are covered witi* a thick external 
 layer of cement Tl»e large canines of Orohippus be- 
 came gradually reduced in the later genera, and the 
 characteristic 'mark' upon the incisors is found only 
 in tlie later forms. It is an interesting fact that the 
 peculiarly equine features acquired by Orohippus are 
 retained persistently throughout the entire series of 
 succeeding forms." * 
 
 * " The raicient Orohippus had all four digits of the fore-feet 
 well developed. In Mesohippus, of the nest period, the fifth 
 toe is only represented by a rudiment, and the limb is supported 
 by the second, third, and fourth, the middle one being the 
 largest. Hipparion of the Later Tertiary still has three digits, 
 but the third is much stouter, and the outer toes have ceased to 
 be of use, as they do not touch the ground. In Equus the lat- 
 eral hoofs are gone, and the digits themselves are represented 
 only by the rudimentary splint-bones. The middle or third 
 digit supports the limb, and its size has increased accordingly. 
 The corresponding changes in the posterior limb of these genera 
 are very similar but not so striking, as the oldest type (Orohip- 
 pus) had but three toes behind. The earlier ancestor of the 
 ^roup, perhaps in the lowest Eocene, probably had four on this 
 foot and five in front. Such a predecessor is as clearly indicated 
 by the feet of Orohippus as the latter is by its Miocene relative. 
 A still older ancestor, possibly in the Cretaceous, doubtless had 
 five toes on each foot, the typical number in mammals. This 
 reduction in the number of toes may perhaps have been due to 
 elevation of the region inhabited, which gradually led the ani- 
 mals to live on higher ground, instead of the soft lowlands, 
 Avhero a many-toed foot would bo most "useful." — Frof. 0. C. 
 Marsh. 
 
 5 
 
98 THE rem:n'A]s^t teeth. 
 
 The article closes as follows: 
 
 "Such is, in brief, a general outline of the more 
 marked changes that appear to have produced in 
 America the highly specialized modern Equus from 
 its diminutive, four-toed predecessor^ the Eocene Oro- 
 hippus. The line of descent appears to have been 
 direct, and the remains now known supply every im- 
 portant intermediate form. Considering the remark- 
 able development of the group throughout the entire 
 tertiary period, and its existence even later, it seems 
 very strange that none of the species should have sur- 
 vived, and that we are indebted for our present horse 
 to the Old World."* 
 
 * The following extracts from Prof. C. S. Tomes's " Dental 
 Anatomy, Human and Comparative" (pp. 247-8, 2'54-5), explain 
 some of the causes of the metamorphoses described by Prof. 
 Marsh : " He would indeed be a rash man who ventured to as- 
 sert that we had recognized all the agencies wjiich are at work 
 in the modeling of animal and vegetable forms ; but it is safe to 
 say that, at the present time, we are acquainted with several 
 agencies which are in constant operation, and which are com- 
 petent to profoundly modify animals in successive generations. 
 We know of 'natural selection,' or 'survival of the fittest,' an 
 agency by which variations beneficial to their possessors will be 
 preserved and intensified in successive generations; of 'sexual 
 selection,' which operates principally by enabling those pos- 
 sessed of certain characters to propagate their race, while others 
 less favored do not get the opportunity of so doing; of 'con- 
 comitant variation' between different parts of the body, an 
 agency much more recondite in its operations, but by which 
 agencies affecting one part may secondarily bring about altera- 
 tions in some other part. 
 
 " The doctrine of natural selection, or survival of the fittest, 
 is as applicable to the teeth of an animal as to any part of its 
 organization, and the operation of this natural law will be con- 
 stantly tending to produce advantages or 'adaptive' differences. 
 On the other hand, the strong power of inheritance is tending to 
 
NOT TtARE, BUT EASILY LOST. 99 
 
 Remnant teeth are not rare, but it is rare for them 
 to persist in the jaws till even middle age. However, 
 
 preserve even that which, in the altering conditions of life, has 
 become of very li ule us \ Tiius we may understand rudimentary 
 teeth to be teeth which are in process of disappearance, having 
 ceased to be useful to their possessors, hut still for a time, 
 through the influence of inheritance, lingering upon the scene. 
 Some teeth have disappeared utterly. Thus the upper incisors 
 of ruminants are gone, and no rudiments exist at any stage ; 
 others still remain in a stunted form, and do not persist through- 
 out the lifetime of the animal, as, for instance, the first premo- 
 lars of the horse, or two out of the four premolars of most bears. 
 
 " Teeth are profoundly susceptible of modification, but amid 
 all their varied forms, the evidences of descent from ancestors 
 whose teeth departed less from the typical mammalian dentition 
 are clearly traceable by the existence of rudimentary teeth and 
 other such characters. * * * The power of inheritance is 
 constantly asserting itself by the retention, for a time at least, 
 of parts which have become useless, and by the occasional reap- 
 pearance of characters which have been lost. •- * * Things 
 that are rudimentary ofren teach us most ; for being of no pres- 
 ent use, they are not undergoing that rapid change in adaptation 
 to the animal's habits which may be going on in organs that 
 are actively employed." 
 
 Horses are not the only animals that have had or are having 
 changes in their dentition. Mr. C. R. Darwin says ("Descent of 
 Man," vol. i, p. 25): "It appears as if the posterior molar or 
 vv'isdom-teeth were tending to become rudimentary in the more 
 civilized races of men. They are rather smaller than the other 
 teeth. In the Melanian races, on the other hand, the wisdom- 
 teeth are usually furnished with three separate fangs, are gen- 
 erally sound, and differ in size from the other molars less than 
 in the Caucasian races. Prof. SchaafFhausen accounts for this 
 difference between the races by 'the posterior dental portion of 
 the jaw being always shortened ' in those that are civilized, and 
 this sliortening may, I presume, be safelv attributed to civilized 
 men habitually feeding on soft, cooked food, and thus using 
 their jaws less. I am informed by Mr. Brnce that it is becoming 
 quite a common practice in the United States to remove some 
 
100 THE KEMNAKT TEETH. 
 
 there may be cases where they never appear; but it 
 by no means follows that because a horse is not in pos- 
 session of them that he never had any. There are 
 various causes for their frequent absence, but the chief 
 cause is their small size. Remnant 
 teeth of the lower jaw, wliich are 
 very rare, are probably cases of ^' re- 
 version to a former state." * If these 
 latter teeth were not expelled in the j.^^,,^,, ,^^,^ . ^^^.^^^ 
 manner explained below by Mons. si^.e.-oric,inai. 
 
 Lecoq, the probability is that they would not long- 
 withstand the friction of the bit. The upper teeth, 
 liowever, while they may sometimes be expelled by the 
 bit, are comparatively little disturbed by i^, which 
 probably accounts for their now and then remaining 
 in the jaws for years. Another reason for their per- 
 sistence is that their roots are long in proportion to 
 their bodies. The reason why these teeth should not 
 be confounded with supernumerary or abnormal teeth 
 will appear in the succeeding chapter, which is devoted 
 to the consideration of the latter. 
 
 Monsieur Lecoq gives cogent reasons for the fre- 
 quent absence of Remnant teeth. He says: 
 
 " Supplementary molars are sometimes met with in 
 front of the true ones, and there may be four of them, 
 two in either jaw, above and below. They are small 
 teeth, having but little recemblance to the others, are 
 frequently shed with the first deciduous molar, and 
 are not replaced. The first rephicing (permanent) 
 molar is always a little more elongated than that 
 
 of the molar teetli of cliildren, as tlie jaw does not grow large 
 eDough for tlie perfect development of the normal number." 
 ♦ See the second reference note, page 80. 
 
HOW THEY MAY BE LOST. 101 
 
 Vv'hich it succeeds, and it frequently expels at the same 
 time tlie supplementary molar; so that if forty-four 
 teeth be developed in the male horse, it is very rare 
 that they are all present at the same time." 
 
 That Eemnant teeth are usually regarded as phe- 
 nomenons is abundantly proved by some of the ex- 
 tracts that follow. In ''Johnson's New Universal 
 Cyclopedia" (p. 995), article "Horse," it is said: 
 
 "An additional small tooth is occasionally found in 
 advance of the upper molar series. This tooth, when 
 present, is the smallest of all the teeth, and, as it has 
 neither predecessor nor successor, its nature is in 
 doubt." 
 
 As the nature of these teeth appeared to be clearly 
 explained in the article "Horse, Fossil," which imme- 
 diately follows that on the " Horse," I wrote to Prof. 
 Joseph Lejdy, telling him I believed the "wolf-teeth" 
 were the remnants of the teeth that "ceased to be 
 functionally developed," and asked his opinion about 
 the matter. Writing under date of "Philadelphia, 
 Nov. 26, 1878," he said: 
 
 * -- * "I think you are right in supposing that 
 the little premolars referred to by Prof. Marsh as the 
 * corresponding upper teeth,' which * ceased to be func- 
 tionally developed,' are the so-called 'w^olf-teeth.'" 
 
 Another letter, addressed to Prof. Theodore Gill, 
 elicited the following reply, which was dated "Smith- 
 sonian Institution, Washington, D. C, Nov. 25, 18T8:" 
 
 * * '•'' "The complete dentition of the adult 
 horse is represented by the formula: I., f ; C, i; 
 D., -}-; P. M., I; M., |x2 = 12. The ^ small wolf or 
 
102 THE REMNAKT TEETH. 
 
 supernumerary tooth that appears in front of the first 
 upper premolar/ is the more or less persistent first 
 deciduous molar (d 1) of the first series, which is not 
 succeeded by a first premolar. The premolars are con- 
 sequently P. M., 2, 3, and 4 of the typical educabilian 
 dentition.^' 
 
 Prof. Richard Owen, who, like Drs. Gill and Leidy, 
 has a clear conception of the subject, says : 
 
 " The second incisor appears between the twentieth 
 and fortieth days, and about this time the first small, 
 deciduous premolar takes its place. ^ * " The 
 representative of the first premolar is a very small and 
 simple rudiment, and is soon shed." 
 
 Surgeon Charles Parnell, in a letter to the editor of 
 "The Veterinarian" (1867, p. 287), says: 
 
 ' " In reading Prof. George Varnell's articles on some 
 of the diseases affecting the facial region of the horse's 
 head, 1 notice a description of wolf-teeth. He says: 
 *They have been supposed to be the cause of disease in 
 the eyes of horses. This idea, however, is quite erro- 
 neous; therefore I shall not occupy any space in dis- 
 cussing this traditional error.' Well, I can safely say 
 that I have in my time extracted a great many of these 
 teeth, and not merely because they existed, but because 
 there was a weeping from both eyes, the cause of which 
 was attributed to wolf-teeth, and generally in the 
 course of a few weeks the weeping has ceased. But 
 what convinces me that they do affect the eye is that 
 in several cases where there were weeping and Aveak- 
 ness of one eye only, I have found a wolf-tooth on the 
 affected side only, and the recovery of the eye has in- 
 variably followed the extraction of the tooth. The 
 
HORSES WITHOUT EARS. 103 
 
 mucous membranes and lachrymal glands appear to 
 be the parts affected, undoubtedly from some connec- 
 tion through the nerves. If these teeth are allowed to 
 remain in the horse's mouth, the sight will become 
 more or less impaired." 
 
 Might not this plan (extracting the teeth), if adopted 
 by all surgeons, eventually rid horses of the so-called 
 wolf-teeth? Nature may be aided or injured. The 
 effect of interfering with nature is illustrated by the 
 following extract from Prof. W. Youatt's work, " The 
 Horse" (p. 154): 
 
 " The custom of cropping the ears of the horse orig- 
 inated, to its shame, in Great Britain, and for many 
 years was a practice not only cruel to the animal, but 
 deprived it of much of its beauty. It was so obsti- 
 nately persisted in that at length the deformity be- 
 came in some hereditary, and a breed of horses born 
 without ears was produced." 
 
 Extracting the Eemnant teeth appears to aid rather 
 than injure nature. The practice is therefore as com- 
 mendable as the cropping of the ears is reprehensible, 
 and if the same result should follow that Prof. Youatt 
 says followed the cropping of the ears, it ought to be 
 adopted. 
 
 C. D. House, an American veterinary dentist, like 
 Surgeon Parnell, invariably extracts the Remnant 
 teeth. He not only claims that they sometimes injure 
 the eyes, but that in some cases, when they encroach 
 on the maxillary branch of the fifth pair of nerves, 
 they cause the horso to act as if insaiie. He saj-s he 
 has more than once extracted these teeth when the 
 " insane " horse was in an onen fiidd. When the tooth 
 
104 THE KEMN'Aiq'T TEETH. 
 
 is drawn and tlie animal is relieyedy it looks aronnd 
 and stares and acts as if wondering where it is and how 
 it got there. Not more than one horse in twenty pos- 
 sessing these teeth, he says, ever suffers injury to its 
 eyes. 
 
 It is notewortliy that Mr. House, who is not a regu- 
 lar surgeon, has a clearer conception of the Remnant 
 teeth than many who hold diplomas. However, he 
 makes no distinction between supernumerary teeth 
 and Remnant teeth, all being designated ^^ wolf- teeth ;" 
 yet he believes the Remnant teeth to be natural teeth, 
 and sa3'S he finds their germs in the cells of the jaws 
 at birth. 
 
 AVhile Mr. House was operating in Worcester, Mass., 
 The Spy (newspaper) says that "in one mouth the 
 wolf-teeth were found to be entirely covered by the 
 gum, and detached from the jaw, so that every time 
 the bit was moved they were turned, crowded, and 
 jammed into the gum.'' 
 
 Prof Williams says of Remnant teeth ("Principles 
 and Practice of Veterinary Surgery," p. 479): 
 
 '^ Small supernumerary teeth are often met with in 
 front of the grinders, called Mvolf-teeth.' They have 
 been supposed to be a cause of ophthalmia, but this is 
 doubtful. They can produce no inconvenience ; but 
 if requested to extract them a practitioner can hardly 
 refuse. The best method is to remove them with the 
 tooth-forceps, 
 
 " The question as to the influence of the teeth on 
 the eyes might perhaps be deemed worthy of discus- 
 sion, inasmuch as the dental nerve is a branch of that 
 which supplies the eyes with common sensibilit}^, 
 namely, the fifth. The older writers maintained that 
 
MOO:!T-BLIiirD>TESS. 105 
 
 'moon-blindness' was due to wolf-teeth, and the first 
 procedure in the treatment was their removal. Now- 
 adays, however, the supposition is not carried quite so 
 far, and the utmost that can be said is that the irrita- 
 tion of teething may be an exciting cause of ophthal- 
 mia in animals whose constitutions are hereditarily or 
 otherwise predisposed to the disease, and the removal 
 of supernumerary teeth, or lancing the gums, may pos- 
 sibly be followed by some remission of the ophthalmic 
 symptoms." 
 
 Prof. Youatt thus accounts for Eemnant teeth : 
 
 ' *'In a fev/ instances the permanent teeth do not rise 
 immediately under the temporary, but somewhat by 
 their side. Then, instead of the gradual process of ab- 
 sorption, the root, being compressed sideways, dimin- 
 ishes throughout its whole bulk. The crown dimin- 
 ishes also, and the tooth is pushed out of its place to 
 the forepart of tlie first grinder, and remains for a con- 
 siderable time under the name o^ 2i zvolf -tooth, causing 
 swelling and soreness of the gums, and frequently 
 wounding the cheeks. They would be gradually quite 
 absorbed, but the process might be slow and the an- 
 noyance great; therefore they are extracted." 
 
 Prof. Youatt's theory is unique, but it fails to give 
 a satisfactory explanation of the "so-called wolf-teeth." 
 Tliat a tooth should be pushed out of its place is sim- 
 ple enough ; but why would the first upper temporary 
 grinder remain in the gum and take root and the first 
 lower not? That "they would be gradually quite ab- 
 sorbed," is disproved by the fact that they sometimes 
 persist till old age; and this fact also disproves the 
 assertion that "they are extracted." Some surgeons 
 
106 FOSSIL HORSES' TEETH. 
 
 do not extract them. Prof. Youatt doubtless meant 
 to say tiiey should be extracted. 
 
 As Remnant teeth are found functionally devel- 
 oped in the jaws of fossil horses— in which they were 
 the largest of all the teeth— a few extracts from the 
 works of well-known men concerning fossil horses and 
 their teeth will be appropriate as a conclusion to this 
 chapter. Prof. Richard Owen says (" Odontography," 
 vol. i, p. 575): 
 
 " Cuvier was unable, from the materials at his com- 
 mand, to detect any characters in the bones or teeth 
 of the different existing species of Eqiius, or in the 
 fossil remains of the same genus, by which he could 
 distinguish them, save by their difference of size. 
 Among the numerous teeth of a species of Equus as 
 large as a horse fourteen and a half hands high, col- 
 lected from the Oreston cavernous fissures, 1 have 
 found specimens clearly indicating two distinct spe- 
 cies, so far as specific differences may be founded on 
 well-marked modifications of the teeth. 
 
 " One of these, like the ordinary Equus fossilis of 
 the drift and pliestocene formations, differs from the 
 existing Equus caballus by the minor transverse diam- 
 eter of the molar teeth ; the other, in the more com- 
 plex and elegant plication of the enamel,* and in the 
 
 * In Prof. Owen's " History of British Fossil Mammals and 
 Birds" (pp. 393-4), the "elegant plication of the enamel" on 
 the crown of this tooth is illustrated. Prof. Owen says : " Fig. 
 153 illustrates the character, above adverted to, of the complex 
 plication of the enamel, as it appears on the grinding" surface of 
 a partially worn upper molar tooth, the second of the right side. 
 The length of this tooth is three inches four lines, and the fangs 
 had not begun to be formed. One cannot view the elegant fold- 
 ings of the enamel in the present fossil teeth, and in those of 
 
TEETH U:N^EAETHED AT ORESTOX, EKG. 107 
 
 bilobed iDosterior termination of the grinding surface 
 of the last upper molar, more closely approximates to 
 the extinct horse of the Miocene period, which Herr 
 von Meyer has characterized under the name of Equus 
 caballus 2irimigenius. The Oreston fossil teeth differ, 
 however, from this in the form of the fifth or internal 
 prism of dentine in the upper molars, and in its con- 
 tinuation with the anterior lobe of the teeth, the fifth 
 prism being oval and insulated in the Equus jirimi- 
 geniiis of Von Meyer. 
 
 " The Oreston fossil teeth, which in their principal 
 characters manifest so close a relationship with the 
 Miocene Equus primigcniiiSf differ, like the later drift 
 species {Eq. fossilis), from the recent horse in a greater 
 proportional antero-posterior diameter of the crown, 
 and also in a less produced anterior angle of the first 
 premolar. I have named this British fossil horse 
 Equus 2JliGide)is. The fossil horse {Eq. curvidens) of 
 South America, which coexisted with the megathe- 
 rium,! and, like it, became extinct apparently before 
 
 the more ancient primigenial species (Hippotlieria) of the conti- 
 nental Miocene deposits, without being reminded of the peculiar 
 character of the enamel of the molars of the Elasmotherium, in 
 which it is folded in elegant festoons. This extinct pachyderm, 
 which surpassed the rhinoceros in size, resembled that genus 
 very closely in the general disposition of the folds of enamel in 
 the grindinjT teeth, but agreed with the modern horse in the 
 deep implantation of those teeth by an undivided base. The 
 Elasmothere appears, therefore, to have formed one of the links, 
 now lost, which connected the horse with the rhinoceros ; and 
 it is interesting to observe that some of the extinct species of 
 horse, in the analogous complexity of the enamel folds, more 
 closely resembled the Elasmothere than do the present species." 
 
 f " The teeth of this most g-igantic of the extinct quadrupeds 
 of the sloth tribe are small in proportion to the size of the ani- 
 
108 FOSSIL HOES_ES' TEETH. 
 
 the introduction of tlie human race, diff3rs from the 
 exiGting horse by the greater degree of curvature of 
 the upper molars." 
 
 The following account of two fossil molar teeth of an 
 extinct species of horse, discovered in South America, 
 may be found in Prof. Owen's "Fossil Mammalia and 
 Mammaha," (pp. 108-9) :• 
 
 ^'■Notice of the remains of a species of Eqmts, found 
 associated witli tlie extinct Edentals and Toxodon at 
 Punta Alta, in Bahia Blanca. and loith the Ifastodon 
 and Toxodon at Santa Fe, in Entre Bios. — The first of 
 these remains is a superior molar tooth of the right 
 side. It was imbedded in the quartz shingle, formed 
 of pebbles strongly cemented together with calcareous 
 matter, which adhered as closely to it as the corre- 
 sponding matrix, did to the associated fossil remains. 
 The tooth was as completely fossilized as the remains 
 of the mjdodon, megatherium, and scelidothere, and 
 was so far decomposed that in the attempt to detach 
 the adherent matrix it became partially resolved into 
 its component curved lamella?. Every point of com- 
 parison that could be established proved it to differ 
 from the tooth of the common Equus cahallus only in 
 a slight inferiority of size. 
 
 "The second evidence of the coexistence of the 
 horse with the extinct mammals of the tertiary epoch 
 of South America reposes on a more perfect tooth, 
 likewise of the upper jaw, from the red argillaceous 
 
 mal. They are five in number on eacli side of the upper jaw, 
 and, probably, four on each side of the lower. They present a 
 more or loss tetragonal figure, and have the grinding surface 
 traversed by two transverse angular ridges." — Owen. 
 
1^ SOUTH AMERICA. 109 
 
 earth of the Pampas at Bojada de Santa Fe, in tlie 
 Province of Entre Rios. This tooth agreed so closeiy 
 in color and condition with the remauis of the masto- 
 don and toxodon, from the same locality, that I have 
 no doubt respecting the contemporaneous existence of 
 the individual horse of which it once formed part. 
 This tooth is figured at Plate xxxii, Figs. 13 and 14, 
 from wliich the anatomist can judge of its close corre- 
 spondence v/ith a middle molar of the left side of tlie 
 upper jaw. 
 
 "' This evidence of the former existence of a genus 
 which, as regards South America, had hecome extinct, 
 and has a second time been introduced into that conti. 
 nent, is not one of the least interesting points of Mr. 
 Darwin's paleontological discoveries.'' * 
 
 * Mr. Darwin, in liis work on " The Descent of Man" (vol. i, 
 pp. 2G0-1), says : " Although the gradual decrease and final ex- 
 tinction of the races of inan is an obscure problem, we can see 
 that it depends on many causes, differing in different places and 
 at different times. It is the same difficult problem as that pre- 
 sented by the extinction of one of the higher animals — of the 
 fossil horse, for instance — which disappeared from South Amer- 
 ica, soon to be replaced, within the same districts, by countless 
 herds of the Spanish horse." 
 
 In his "Journal of Researches" (pp. 130-1-2), Mr. Darwin 
 gives further information concerning the fossil teeth described 
 by Prof Owen, and advances a theory of the introduction of the 
 horse into the " so-cilled New World." He says : " In the Pam- 
 paean deposit of the Bojada I found the osseous armor of a gigan- 
 tic, armadillo-like animal, tlie inside of which, when tlie earth 
 was removed, was like a ^reat cauldron. I also found teeth of 
 the toxodon and mastodon, and one of a horse, in the same 
 stained and decayed state. The latter greatly interested me, and 
 I took scrupulous care in ascertaining that it had been im- 
 bedded contemporaneously with the other remains ; for I was 
 not then aware that among the fossils from Bahia Blanca there 
 
110 FOSSIL HORSES' TEETH. 
 
 Prof. Thomas H. Huxley says (" Critiques and Ad- 
 dresses," pp. 191-5) : 
 
 '^ Let us endeavor to find some cases of true linear 
 types, or forms which are intermediate between others, 
 because they stand in a direct genetic relation to them. 
 It is no easy matter to find clear and unmistakable 
 evidence of filiation among fossil animals. After much 
 
 was a horse's tooth hidden in the matrix ; nor was it then known 
 with certainty that the remains of horses were common in North 
 America. Mr. Lyell has Litely brought from the United States 
 a tooth of a horse ; and it is an interesting fact that Prof. Owen 
 could find in no species, either fossil or recent, a slight but pecu- 
 liar curvature characterizhig it, until he thought of comparing 
 it with my specimen found here. Certainly it is a marvelous 
 fact in the history of the Mammalia, that in South America a 
 native horse should have lived and disappeared, to be succeeded 
 in after ages by the countless herds descended from the few in- 
 troduced by the Spanish colonists ! (1 need hardly state here 
 that there is good evidence against any horse living in America 
 at the time of Columbus). 
 
 " When America, and especially North America, possessed its 
 elephants, mastodons, horse, and hollow-horned ruminants, it 
 was much more closely related in its zoological characters to the 
 temperate parts of Europe and Asia than it now is. As the 
 remains of these genera are found on both sides of Behring's 
 Straits and on the plains of Siberia, we are led to .look to the 
 northwestern side of North America as the former point of com- 
 munication between the Old and the so called New World. And 
 as so many species, both living and extinct, of tliese same genera 
 inhabit and have inhabited the Old World, it seems most prob- 
 able that the North American elephants, mastodons, horse, and 
 hollow-horned ruminants migrated — on land since submerged 
 near Behring's Straits — from Siberia into North America, and 
 thence — on land since submerged in the West Indies — into 
 South America, where for a time they mingled with the forms 
 characteristic of that southern continent, and have since become 
 extinct." 
 
HIPPARIOK AND AKCHITHERIUM. Ill 
 
 Bearch, however, I think that such a case is to be made 
 out in favor of the liorses. The modern horse is rep- 
 resented as far back as the latter part of the Miocene 
 epoch; but iu deposits belonging to the middle of that 
 epoch its place is taken by two other genera, Hipparion 
 aud Anchitherium. A species of Anchitherium was ^ 
 referred by Cuvier to the Paleotheria. The grinding 
 teeth are in fact very similar in shape and in pattern, 
 and iu the absence of any thick layer of cement, to 
 those of some species of Paleotherium. But in the 
 fact that there are only six full-sized grinders in the 
 lower jaw, the first prem.olar being very small; that the 
 anterior grinders are as large as or rather larger than 
 the posterior ones; that the second premolar has an 
 anterior jDrolongation, and the posterior lower jaw has, 
 as Cuvier pointed out, a posterior lobe of much smaller 
 size and different form, the dentition of Anchitherium 
 departs from the type of the Paleotherium and ap- 
 proaches that of the horse. The skeleton of Anchi- 
 therium is extremely equine. 
 
 *'In the Hipparion the teeth nearly resemble those 
 of the horse, though the crowns of the grinders are not 
 so long. Like those of the hcrse, they are abundantly 
 coated with cement. In the modern horse, finally, the 
 crowns of the grinding teeth become longer, and their 
 patterns are slightly modified." t 
 
 Alfred Russel Wallace, F.R.aS., &c., says (^^The 
 Geographical Distribution of Animals," New York 
 edition, vol, i, p. 135): 
 
 ^' Ting uJata.— The animals belonging to this order 
 being usually of large size and accustomed to feed and 
 travel in herds, are liable to wholesale destruction by 
 floods, bogs, precipices, drought, or hunger. It is for 
 
113 FOSSIL HORSES. 
 
 theso reasons, probably, that tlieir remains are almost 
 always more numerous than those of other orders of 
 mammalia. In America they are especially abundant. 
 " Tlie true horses are represented in the PUocene by 
 several ancestral forms. Tlie most nearly allied to the 
 modern horse is Piiohippus, consisting of animals 
 about the size of an ass, with lateral toes not exter- 
 nally developed, but with soma differences of dentition. 
 IMext come Protohippus and Hipparion, in wdiich the 
 lateral toes are developed, but are small and function- 
 less, Protohippus being only two feet and a half high. 
 Then we have the allied genera, Anchippus, Merychip- 
 pus, and Hyohippus, which were still smaller animals. 
 In the older deposits v*^ come to a series of forms, still 
 unmistakably equine, but w^ith three or more toes used 
 for locomotion, and v/ith numerous differentiations in 
 form, proportions, and dentition. In the Miocene we 
 have the genera Anchitherium, Miohippus, and Meso- 
 hippns, v\^ith three toes on each foot, and about the 
 size of a sheep or large goat. In the Eocene of Utah 
 and Wyoming we get a step luither biick, several spe- 
 cies having been discovered abjut the size of a fox, 
 with four toes in front and three behind. These form 
 the genus Orohippus, and are the oldest ancestral 
 horse known." 
 
 The following account of a horse's tooth that was 
 found while digging a well is from The Popular Science 
 Revieiu : 
 
 "In a paper read before the St. Louis Academy of 
 Science, and reported in The American NaturaUst for 
 March, 1871, Mr. G. 0. Broadhead records some in- 
 teresting facts about fossil horses. Alluding to the 
 fact that horse remains have been found in the altered 
 
A TOOTH FOUND IN DIGGING A WELL. 113 
 
 drift of Kansas, he says he is now able to announce 
 that similar remains have been discoveredm a well at 
 Papinville, Bates County, Mo. Mr. 0. P. Ohhngei^ 
 while dioging a well, unearthed a tooth at a depJi ot 
 thirty-one feet from the surface ; it was restmg m a 
 bed of sand beneath a 4-iDch stratum of bluish clay 
 and 2'ravel. Beneath the sand containmg the tooth 
 was a gravel-bed five feet in thickness. He sent the 
 tooth to Prof. Joseph Leidy, of Philadelphia, who pro- 
 nounced it to be the last upper molar of a horse, prob- 
 ably an extinct species." 
 
 In various volumes of the " Proceedings of the Acad- 
 emv of ^^atural Sciences of Philadelphia," accounts oi 
 many other fossil horses' teeth may be found, ot which 
 the following is a specimen (" Proceedings," &c., 1871, 
 p. 113): 
 
 '^Prof. Joseph Leidy exhibited a specimen of an 
 upper molar tooth, which Mr. Timothy Conrad had 
 picked up from a pile of Miocene marl at Greenville, 
 Pitt County, K C. He believed, from its size and the 
 intricacy in the folding of the enamel of the islets at 
 the middle of the triturating surface, that the tooth 
 belon-ed to the Post-Pliocene Equus complicatus, and 
 was an accidental occupant of the Miocene marl. It 
 mioht, however, belong to a Hipparion of the Miocene 
 period, but the imperfection of the specimen at its in- 
 ner part prevented its positive generic determination/' 
 
 In the Proceedings of the same Society for 1854-5 
 (p. 340) is an account of the fossil remains of an am- 
 mal as unlike the genus man as man is unlike the 
 ornithorhynchus. Its exhumation and subsequent 
 exhibition in New Orleans created botii interest and 
 
114 TEETH WEIGHING TWO POUNDS. 
 
 merriment at the time, for it was not then known that 
 the Americas are not only the richest in fossil animal 
 remains of all the continents, but are probably the 
 first that were inhabited by man. The record is as 
 follows : 
 
 " Dr. Joseph Leidy stated that he had received from 
 Dr. 'Nott the bones of the so-called fossil man, exhib- 
 ited in New Orleans several years since. The skeleton 
 was eighteen feet in length. There were two molar 
 teeth, each weighing two pounds, and the fragment of 
 a canine. The bones are those of the mastodon." 
 
CHAPTER VI. 
 
 DENTAL CYSTS AND SUPERNUMERARY TEETH. 
 
 Teeth growing in various parts of the Body. — Some Cysts more 
 Prolific than others, Producing a Second, if not a Third, 
 "Dentition." — Reports and Theories of Scientific Men. — 
 Cases of Third Dentition in Human Beings. 
 
 The developmerit of abnormal teeth in different 
 parts of the body (the human body as well as those of 
 the lower animals, particularly the horse), is not the 
 least interesting feature in the study of dental science. 
 To judge from the reports that follow, one would think 
 the tooth-substance in some horses w^as an unknown 
 quantity. It would be interesting and useful to know 
 whether in such cases the natural teeth are in a per- 
 fectly healthy state, and whether the temperature is 
 natural, instead of being increased, as during certain 
 periods of teething. While the study of these teeth 
 may not be of paramount importance, it serves to 
 further illustrate the physiological relations of the den- 
 tal system, and ought to assist the surgeon in more 
 correctly diagnosing diseases. 
 
 Surgeon George Fleming, of the Ro3'al Engineers, 
 contributed a valuable paper entitled '• Dental Cysts, 
 or Tooth-Bearing Tumors,*' to *'The Veterinarian" for 
 1874 (p. 692), the substance of which is as follows: 
 
 *^ In The Gazetta Medico- Veterinaria of Milan for 
 1873 (p. 274), Profs. Limzillotti-Buonsanti and Gui- 
 
116 DEXTAL CYSTS. 
 
 seppe General!, of the Veterinary School of that city, 
 published a most complete and interesting contribu- 
 tion to our knowledge of the pathology of dental cysts 
 in the horse, well illustrated with wood-cuts, and in- 
 cluding a full bibliographical record and synoptical 
 table of these morbid productions. From their re- 
 searches it would appear tliat dental cysts were first 
 described by Mage Grouille, in 1811.* 
 
 " These teeth-bearing tumors have received different 
 names. Thus they have been designated 'erratic' or 
 'misplaced teeth,' 'dental neoplasies,' 'odontocysts,' 
 'dental degeneration of tlie temporal bone,' 'temporal 
 fistula,' 'abnormal development of teeth in unusual 
 places,' 'auricular teeth,' 'odontocele,' and 'dentiger- 
 ous cysts' or 'teetli tumors.' They may be developed 
 in unusual places, such as the temporal region, the 
 frontal bones, the hase of the ear, the space between 
 the branches of the lower jaw, the lumbar region, the 
 testicles, and the ovaries. Coleman stands alone in his 
 case of a cyst found beneath the right kidney, in which 
 were two small molars and an incisor, attached to a 
 bone that resembled a jaw, though the Milan profes- 
 sors believe the teeth in this instance may have been 
 developed in a testicle retained in the abdominal cav- 
 ity. The most common situation is undoubtedly in 
 the temporal region, as in seventy-nve recorded cases 
 sixty-eight Avere observed there. These cases all refer 
 to the horse. Berger-Perriere, however, found a tem- 
 porary incisor in a fistulous vfound near the right ear 
 
 * "No mention is made of the Ahhr/evo/iefol iv role yrudoic, or 
 niaxillaiy exostoses of Apsyrtus (' Hipp. Gr.' p. G4\ wlio recom- 
 mends tliat these tumors sliould be carefully and completely 
 removed, or thoy will return -of a larger size." 
 
 Th3 reference note is a -so Suro-eon Flemin<r's. 
 
A CYST 3IISTAKEIS" FOR GLAXDEBS. 117 
 
 of a lamb two months and a half old ('Recueil de 
 Mod. Veterinaire,' 1835, p. 586). 
 
 '•'In most instances only one tooth is found. Gurlt 
 was the first to find, on the mastoid process of the 
 temporal bone, a mass of molar teeth fused, as it were, 
 together. Tlie tumor was three inches and a half 
 hio'li, and about two in its lar<2:est diameter. The horse 
 had been destroyed for glanders. Goubaux found two 
 at the posterior portion of the sphenoid bone, and Bay 
 four. In a cyst of the testicle Gurlt discovered six 
 teeth, three separate and three in a mass. Bay at- 
 tended a horse in 1800 that appeared to be suffering 
 with encephalitis. It died twenty-four hours after his 
 visit. It had always shown, on the right temporal re- 
 gion, a tumor without a fistula, but it did not attract 
 notice, as it apparently caused no inconvenience. Nine 
 years afterward, when Bay was preparing tlie head as 
 a pathological specimen, he discovered this supposed 
 exostosis to be constituted by the union of four molar 
 teeth. The two superior teeth projected from the 
 temporal articulation, and the inferior tvvo w^ere situ- 
 ated in the petrous portion of the temporal bone, in- 
 clining obliquely from within outward. The posterior 
 portion of the latter projected in a very salient manner 
 at the seUa furcica, and must have produced much 
 pressure on important parts of the brain. 
 
 "Age does not appear to have any iufluence on the 
 development of these cysts, the animals in which they 
 have been observed ranging in age from eight or nine 
 months to fifteen years. The period of formation also 
 varied greatly. lu regard to the side of the body in 
 "which they Avere developed, in seventeen cases they 
 were on the left, and in tlvirteen on the right. In 
 fourteen cases oboCrved by Macrops, they were indifier- 
 
118 DENTAL CYSTS. 
 
 ently on both sides. In this respect clinical observa- 
 tion has not yielded any fact of practical importance. 
 
 "Sometimes, after the extraction of a tooth, it hap- 
 pens that the cavity of the cyst or the bottom of the 
 fistula does not cicatrize. This is a sure indication 
 that a new tooth is formins:. Rodet noted this fact as 
 long ago as 1827. Macrops has observed a case of this 
 kind. He was compelled to operate twice within three 
 months, each time removing a molar tooth; and when 
 he made his report, in 1860, it was probable that a 
 third tooth was being developed, as the fistula had not 
 closed." 
 
 Surgeon Fleming also mentions cases that were ob- 
 served by Surg"eons Perosino, Martin, Harold, Gamgee, 
 Coclet, Lafosse, and others. He continues: 
 
 "Profs. Lanzillotti-Buonsanti and General! made 
 minute inspection of a specimen of tooth taken from 
 the base of the ear of a foal twenty months old, and 
 they report that microscopically the structure of such 
 teeth does not differ much from natural teeth. The 
 same constituents — dentine, enamel, and cement — 
 were found, the only difference being that they were 
 arranged in an unusual manner. In the tooth they 
 examined, for instance, the cement v^^as abundant in 
 the central part, while in that studied by Oreste and 
 Falconio, the dentine was most abundant and the 
 cement least in quantity." 
 
 Surgeon Fleming next refers to and gives a sum- 
 mary of the views of scientific men, who say that "A 
 certain number of teeth may sometimes be developed 
 as parasitic productions in a cavity similar to and situ- 
 ated near the mouth (in which category is included 
 
A FETUS WITHIJ^ A FETUS. 119 
 
 the excellent case occurring in a woman, and de- 
 scribed, in 1862, by Prof. Generali — an observation 
 unique in the teratology of mankind — namely, a 
 case of parasitic monstrosity, in which, however, the 
 designation 'dental cyst,' so inexact in itself, is in- 
 appropriate a;id false);" that "the ovarian cysts in 
 women, in whicli have ])een found pieces of bone and 
 cartilage, teeth, and a lower jaw, more or less de- 
 formed, ought to be considered as probable cases of 
 ovarian impregnation with an incompletely developed 
 fetus, and in young girls as examples of the intra- 
 uterine formation of a fetus within a fetus;" that 
 "only in this way can be explained the lipomatous 
 and sarcomatous congenital masses contained in cysts, 
 with the teeth and fragments of bone simulating an 
 incomplete jaw, which have been observed on the 
 human orbit (Lobstein and Travers), on the palate 
 (Otto), on the tongue (Stansky), on the side of the 
 jaw, in the cheek, and on the neck, but which Schultze 
 and Panum consider as the simple proliferation of em- 
 bryonic plasmatic cells;" that "some dental cysts are 
 true dermoid cysts, containing hair and teetli," &c., 
 and closes his paper with the following common-sense 
 suggestion : 
 
 " Perhaps direct researches, which have not yet been 
 made, carried out in favorable circumstances, will bet- 
 ter serve in deciding their real nature than all the 
 more or less brilliant academical reasoning." 
 
 John Gamgee, Professor of Anatomy and Physiology 
 in the Edinburgh Veterinary College, in the course of 
 a series of articles on various subjects in " The Veter- 
 inarian " for 185G, tlnis comments on a case of dentig- 
 erous cyst, the history of which was originally written 
 
120 DENTAL CYSTS. 
 
 by Monsieur Lafosse and published in tlie "Journal 
 des Veterin-iire da Midi:" 
 
 *'3I. LafossG, Professor of Clinical Medicine in the 
 Veterinary School of Toulouse, had under his treat- 
 ment a four-year-old rnaro that for two months before 
 admission into the infirmary was affected with a phleg- 
 monous tumor in the re.f^'ion of the left ear. This was 
 opened. The wound that resulted rapidly contracted, 
 but a fistula remained. When Lafosse first saw the 
 case, he found a painful tumor, vv'ith a granulating 
 wound just behind the scutiform cartilage, and near 
 the upper part of the parotid gland. By probing he 
 ascertained that at the bottom of the fistulous tract 
 was some hard substance, Avhich he supposed to be the 
 Bcutiform cartilage in an ossified state, or a portion of 
 the temporal bone exfoliating. A severe operation 
 was performed, and the solid substance extracted. It 
 w\as double, deeply seated, and firmly adherent to sur- 
 rounding textures. Slight hemorrhage ensued from 
 the division of the anterior auricular, but w^as casilv 
 stopped. Tiie wound was dressed, and the animal 
 soon recovered, having shown only a few symptoms of 
 sore throat after the operation, 
 
 '- 1 shall not translate M. Lafosse's description of 
 the products he extracted. They were composed of 
 tooth-substance, and althougii it has been questioned 
 Y/hether it is real tooth that is developed in the shape 
 of accidental growths in the region of the ear, still the 
 fact is now well established, however puzzling to the 
 minds of some it may be to comprehend their origin. 
 
 " Lafosse attempts a teratological explanation, but 
 asks : ^ If teeth are looked on as arising from the tegu- 
 mentary system, considering them in mo&l: animals as 
 
TEETH EMAJn'ATIIfG FRO:.I OSSEOUS SYSTEM. 121 
 
 emanating from papillae and mucous membrtine, where 
 was the dormoid papilla that constituted the basis of 
 development of this tooth, deeply seated and close to 
 the ear, especially as what might be taken as the 
 crown looked toward the inner surface of the skin?^ 
 
 *' Further on Lafosso show^s that iu certain animals 
 teeth absolutely emanate from the osseous system, as 
 in the eolith:}' scaicr and other serpents, in which true 
 osseous eminences, coated by enamel, pierce the esoph- 
 agean tunics, and project into the tube; they are at- 
 tached to about thirty vertebra3, of which they form 
 the inferior spinous process. These are intended to 
 crush the eggs that the serpents feed upo». 
 
 ^' Having established the fact that teeth may spring 
 from bone as well as mucous membrane, Lafosse leads 
 us, where we never suspected, to consider the dental 
 tumors above spoken of as congenital, and he looks 
 on them as having sprung from some rudiment of a 
 maxillary bone. In a word, he looks on the abnormal 
 tooth in question — without offering any plausible ex- 
 planation — as an aberration in development. He does 
 not class such teeth with the teeth formed iu the 
 ovary, &c., but rather with those instances where an 
 extra limb or portion of an extremity is to be met with. 
 It is an accidental excess of parts in an otherwise well- 
 formed bod}^ ^It cannot,' sn^js Lafosse, ^be looked on 
 as an osseous transformation of certain tissues.' 
 
 "I have spoken of the case at bngth, for surgically 
 it is of the very greatest interest. As pathological 
 anatomists, it is our duty to study the laws of disease 
 as v;eil as health. It is praisew^orthy to dive into the 
 mvsterios of the ori^-in of monsters, but it is essential 
 to adhere to facta and not sacriiioe them to theoretical 
 explanations, 
 6 
 
122 DEKTAL CYSTS. 
 
 " In common with others, I have studied several of 
 these dental tumors. They may spring from several 
 of the bones of the head, but especially from the region 
 of the petrous temporal bone. They may project to- 
 ward the interior of the cranium, but tliey more fre- 
 quently project outwardly. They may be strongly 
 implanted in the bone, or get separated; then they 
 are maintained in their situation by the soft textures 
 around. Their development is not more extraordinary 
 than that of other osseous growths that spring from 
 the cranial or maxillary bones ; and their tooth-formed 
 structure (teeth in the region of teeth), is not more 
 wonderful than hony tumors in other parts of the sys- 
 tem, whether connected or not with the skeleton." 
 
 Prof. William Sewell, President of the British Vet- 
 erinary Medical Association, at the meeting of that 
 body on May 15, 1838, advanced an interesting theory 
 of the growth of abnormal teeth. It may be true, for 
 after the teeth have attained their full grow^th, it is 
 reasonable that the dental arteries are less active. But 
 as the teeth continue to grow throughout life, a fact 
 Prof. Sewell does not mention, it is not so reasonable 
 that they even "in a manner cease" to act. The pro- 
 fessor's remarks are thus reported ("Veterinarian," 
 1838, "Proceedings Vet. Med. Ass.," p. 199): 
 
 " The President begged leave to direct the attention 
 of the meeting to a horse's tooth that had been pre- 
 sented to him. It was a fine specimen of the anomaly 
 occasionally observed in the dental system of the liorse 
 — the production of teeth in other places than the 
 alveolar cavities, after the natural teeth had been per- 
 fected. The situations which I^ature in her wander- 
 ings selected were occasionally very singular. He had 
 
TEETH LIKE A CALF'S TOUNG HORN. 123 
 
 seen a tooth wliicli grew from tbc petrous portion of 
 the temporal bone, like a young liorn from the fore- 
 head of a calf. It formed a hard and seemingly very 
 painful tumor, which was ultimately opened, and the 
 bony substance, which proved to be an almost perfect 
 tooth, extracted. He had seen three or four similar 
 cases in which teeth had been thus produced. When 
 the dental arteries in a manner cease to act— the teeth 
 bavin o- attained their full growth— there was a singu- 
 lar predisposition in the neighboring arteries to take 
 on the same action, and teeth, more or less perfect, 
 were formed in parts altogether unconnected with den- 
 tition. In this case there were two, one on either side 
 of the forehead." 
 
 Suro-eon F. Denenbourg makes a detailed report in 
 « The Veterinarian" for 1869 (p. 533) of six cases of 
 dental cyst, five of which he operated on successfully. 
 The first case he treated was in 1837. He confesses 
 that he believed them to be mucous tumors till 18ol, 
 when he found a molar tooth perfectly formed. This 
 tooth which was deposited in an anatomical museum, 
 was a^ large as a pigeon's egg, and had three roots. 
 
 Surgeon C. C. Grice, of New York, makes the fol- 
 lowing report ("Veterinarian," 1867, p. 392) : 
 
 "Whether the case the facts of which I am about to 
 communicate will prove of sufficient interest to be pre- 
 sented to the notice of the veterinary profession, or 
 will add anything to the advancement of veterinaiy 
 pathologv, I know not; yet I would be glac to see it 
 inserted 'in our respectable old journal, ' The Veteri- 
 narian,' for I hold it to be the duty of every member 
 of the profession to advance its interests to the bestot 
 
124 DEKTAL CYSTS. 
 
 his Libility. I send it because to me it is a yery rare 
 case. I have now been in practice more than forty 
 years, and I have not met with anything of the kind 
 before. 
 
 " At the request of Mr. Barnum, a merchant of our 
 city and the owner of a breeding-farm in Westchester 
 County, I attended a two-year-old colt, considered to 
 be very valuable, as he comes from trotting stock. Mr. 
 Barnum merely said the colt had a discharge from the 
 base of the near ear, and that it had existed for ten 
 months. 
 
 '' I found the animal so very shy on account of the 
 previous torturing of his attendants, that I could not 
 approach him ; therefore I had to cast him. The in- 
 troduction of the probe failed to satisfy me that any 
 foreign body existed there; but on dilating the orifice 
 and introducing the most reliable of all probes, my 
 forefinger, I discovered a hard substance, v/hich was 
 firmly attached to the temporal bone and surrounding 
 parts. I could not grasp the substance with the for- 
 ceps, therefore I used the handle of the instrument as 
 a lever, and after using great force dislodged it. Mr. 
 Barnum picked up something in the grass four or five 
 yards from me, and it proved to be a molar tooth. On 
 examining the wound afterward I found some loose 
 fragments of bone, and on removing them they ap- 
 peared to be the socket of the tooth. 
 
 '' I would have sent you a report of this case earlier, 
 but I was desirous of seeing its termination. Mr. Bar- 
 num says the parts have entirely healed and left no 
 blemish." 
 
 Prof William Williams advances an interesting the- 
 ory regarding the cause of dental cysts and also the 
 
AMAUROSIS AND ATROPHY OF THE EYES. 125 
 
 manner of their formation. He saj^s (" Principles and 
 Practice of Veterinary Surgery," p. 412) : 
 
 " Cysts containing teetli have been found in the tes- 
 ticles and other parts of the body, but those which are 
 of importance to practical men are found within the 
 antrum. I hav^e seen several cases of this kind, and 
 have extracted teetli from cysts even so high as the 
 base of the ear. 
 
 "During life these tumors are distinguishable by 
 more or less disfigurement of the face, by a bulging out 
 of the superior maxillary bone, accompanied in some 
 cases by amaurosis of one eye, succeeded by atrophy 
 of the eye from the pressure of the growing tumor. 
 In other cases these complications are not present, but 
 now and then an abscess forms in the post-orbital re- 
 gion, which will be found on examination to contain a 
 hard body — an imperfect tooth. 
 
 " To understand the process by which these tumors 
 are formed, it is necessary to remember that the teeth 
 of all animals belong to and arise from the membran- 
 ous portion of the digestive canal, and that at a very 
 early period of fetal life a provision is made for the 
 development of the permanent teeth as well as the 
 temporary. This provision, according to Goodsir, is 
 as follows : * As early as the sixth week of intra-uteral 
 life (human), a groove appears along the border of the 
 future jaws, called the primitive dental groove, which 
 is lined by the membrane of the mouth. At the bot- 
 tom of this groove projections — papillae — spring up, 
 corresponding in number with the temporary teeth. 
 AYhile the growth of the papilla) is going on, partitions 
 are formed across the grooves, by which they become 
 separated from each other. These partitions subse- 
 
126 DENTAL CYSTS. 
 
 quently form the bony sockets, thus placing each 
 papilla in a separate cavity. Concurrent with this 
 process, small growths take place upon the membrane 
 of the mouth, just as they dip into the papillary cavity 
 or follicle, which finally, by union with other growths, 
 form a lid which covers the papillse in a closed sac or 
 bag. Before the final closing of the follicle, a slight 
 folding inward of its lining membrane takes place. 
 This inward folding of the membrane of the primitive 
 groove is for the purpose of forming a new cavity — the 
 cavity of reserve — which furnishes a delicate mucous 
 membrane for the future formation of the permanent 
 teeth. The cavity in which the permanent tooth is 
 developed is a mere detachment from the lining of the 
 primitive groove, and in it a papilla is formed in the 
 same way as that of a temporary tooth/ * 
 
 " ]^ow, I look on the formation of these tumors as 
 being due to some irregularity in this folding of the 
 lining membrane, by wiiich the * cavity of reserve' is 
 made up of several folds ; that these folds eventually 
 become separated, forming separate cavities of reseiTe, 
 and that a papilla similar to those of the natural teeth 
 is developed in each cavity. These irregular papillae 
 are converted into irregular teeth, whicli, for want of 
 space in the mouth, are forced into the antrum, and 
 may completely block it up, as well as the posterior 
 nasal opening. 
 
 " I have classified them as cystic tumors, as at first 
 they are inclosed in sacs or cysts. They soon burst 
 through their investing membrane, however, and form 
 a large tumor, composed entirely of teeth, having a 
 
 * Compare Professor Goodsir's theory with those advanced 
 by Messrs. Oweu, Tomes, Chauveau, and others in the first 
 chapter. 
 
A BULL WITH AI<r UPPER IJfCISOR. 127 
 
 great variety of shapes, and ranniiig in different direc- 
 tions. The teeth vary in size, some being very small, 
 while others are nearly as large as a permanent grinder. 
 Each tooth has a pnlp cavity, and is composed of the 
 same substances as the natural teeth. Should their 
 removal be desirable, it will be necessary to trephine 
 the superior maxillary sinus and detach them with the 
 forceps.'' 
 
 In the chapter entitled "The Pathology of the 
 Teeth" (the VIII.), Surgeons Bouley and Ferguson, 
 in the course of their memoir on horses' teeth, record 
 some important facts about supernumerary teeth. In 
 one animal the rows of grinders are said to appear 
 double. The facts are given in that particular chap- 
 ter in preference to the present one in order that the 
 memoir may have a connected reading. 
 
 M. Roche Lubin gives the following account of a 
 tooth that he extracted from the upper jaw of a young 
 bull ("Le Zooiatre du Midi," February, 1838): 
 
 " On the 14th of April, 1837, I was requested by M. 
 Bonhome, wiio lives near Rhodez, to extract a tooth 
 which was growing in the middle of the palate of his 
 young bull. The novelty of the thing made me hasten 
 to comply with his request. The animal being secured, 
 I removed the tooth in the usual way. A very consid- 
 erable hemorrhage followed its extraction, which was 
 performed with some difficulty on account of the tooth 
 being firmly implanted in the palatine arch. It was 
 situated at the middle of the median line, and was of 
 precisely the same character as tluat of the usual incisor 
 tooth of the ox. This is, I believe, the only case on 
 record, the incisor teeth being wanting in the upper 
 jaw of cattle." 
 
128 SUPERNUMERARY TEETH. 
 
 Human beings, like the lower animals, are now and 
 then afflicted with a superfluity of tooth-substance, or 
 at least they have supernumerary teeth. John Hunter 
 says (" The Human Teeth," p. 53) : 
 
 '^ We often meet with supeninmerary teeth, and this, 
 as well as some other variations, happens oftener in 
 the upper than in the lower jaw, and, I believe, always 
 in the incisors and cuspidati. 1 have only met with 
 one case of this kind, and it was in the upper jaw of a 
 child about nine months old. The bodies of two 
 teeth, in sliape like the cuspidati, v^'ere placed directly 
 behind the bodies of the two first permanent incisors; 
 so tiiat there werc three teeth in a row, placed behind 
 one another, namely, the temporary incisor, the body 
 of the i^ermanent incisor, and that supernumerary 
 tooth. The most remarkable circumstance was that 
 these teeth v.'ere inverted, their points being turned 
 upward and bent, caused by the bone which was above 
 them not giving way to their growth, as the alveolar 
 process does." 
 
 The following account of cases of third dentition in 
 liuman beings is from "Bond's Dental Medicine" 
 (p. 21G): 
 
 "Third Dentition. — A number of well authenticated 
 cases of partial and even complete dentition, occurring 
 in very old persons, are recorded in the books. In one 
 instance, given in the 'Edinburgh Medical Com.' (vol. 
 iii.), the patient, who was sixty years old and entirely 
 toothless, suflTerecl very severely. At the end of twenty- 
 one days from the beginning of his sufferings, however, 
 he was compensated by the appeojcance of a complete 
 set of new teeth. 
 
THIKD DEXTITIOIsTS FATAL. 129 
 
 " With regard to tlie constitutional effects of this 
 abnormal dentition, Prof. Harris, who relates two 
 cases as having occurred under his own observation, 
 says : 'It seems that the efforts made by nature for the 
 production of a third complete set of teeth are usually 
 so great that they exhaust the remaining energies of 
 tlie system, for occurrences of this kind are generally 
 soon followed by death.' " 
 
CHAPTER YII. 
 
 HORSES' TEETH UKDER THE MICROSCOPE. 
 
 The Dentinal Tubes, Enamel Fibers, and Cemental Canals De- 
 scribed and Contrasted. 
 
 Prof. Richard Owen's description of the micro- 
 scopical appearance of horses' teeth, like the extracts 
 already made from his works, is both interesting and 
 profound. The teeth described are illustrated in the 
 second volume of the " Odontography," the section of 
 the molar being magnified three hundred linear diam- 
 eters; that of the incisor, however, is not magnified. 
 In the first volume (pp. 576-7-8) Prof. Owen says: 
 
 "The body of the long molar teeth of the horse 
 consists of columns of fine-tiibed, unvascular dentine, 
 coated by enamel, which descends in deep folds into 
 the substance of the teeth. The enamel is covered 
 by cement, thickest in the interspaces of the inflected 
 enamel-folds and upon the crowns of the molars, where 
 it is permeated by vascular canals, thinnest on the 
 crowns of the canines and incisors. At the roots of 
 these teeth, aiid on those developed from the w^orn- 
 down molars, the dentine is immediately invested by 
 cement. 
 
 *^ In a vertical section of the incisor, as in Plate 136, 
 Fig. 11, the pulp-cavity, contracting as it approaches 
 
TUBES DICHOTOMOUSLY BRAi^CHED. 131 
 
 the vertical enamel-fold, divides near the end of that 
 fold, and extends a little way between it and the 
 periphery of the incisor, or leaves a few medullary 
 canals and a modified thin tract of irregularly formed 
 dentine between the reflected and the outer coat of 
 enamel, but rather nearer the former. Above this 
 tract, near the summit of the crown, the dentinal tubes 
 proceed in a nearly vertical direction, with a gentle 
 sigmoid primary flexure, where they diverge from the 
 perpendicular. Lower dow^n they diverge in opposite 
 directions, curving from the remains of the pulp- 
 fissure toward the outer and the inner enamel, and are 
 described by Eetzius as being in the form of the Greek 
 e; but the course of two distinct series of dentinal 
 tubes, and not of a single tube, is illustrated by this 
 comparison. AVhen the pulp-cavity couies single and 
 central, as at the lower half of the tooth, the tubes 
 diverge to the periphery, with one principal primary 
 curve, convex toward the crown. Each tube is bent 
 in minute secondary gyrations to within a short dis- 
 tance of its peripheral termination, where it is much 
 diminished in size, and is dichotomously branched. 
 The tubes at their beginning form the upper calcified 
 tracts of the pulp-cavity, which usually retain some 
 remnants of that vascular receptacle in the form of 
 medullary canals, and are strongly and irregularly 
 flexuous before they fall into the ordinary primary 
 curves. These tubes, proceeding toward the inner 
 reflected folds of enamel, are more vertical than the 
 tubes going to the periphery. 
 
 ''A transverse section of the incisor of a young horse 
 or ass, taken across the part marked a in Fig. 11, shows 
 a long oval island of vascular cement in the center, 
 bounded by a border of enamel, with an irregular ere- 
 
132 HORSES' TEETH UNDER THE MICROSCOPE. 
 
 nate edge next the cement, and an eyen edge next the 
 dentine, which is here clearly seen to be divided into 
 an inner and an outer tract by an irregalar series of 
 the vascular canals continued from the summit of the 
 pu]p-eavity, and by the irregularly tortuous dentinal 
 tubeSj which, with the canals, indicate the last con- 
 verted remnant of the pulp in this part of the crown. 
 The inner tract of dentine next the island of enamel 
 is well defined, and a little broader than the secretion 
 of the enamel itself, and shows the extremities of the 
 tubes cut transversely, which, as before observed, were 
 at this point directed chieHy in the axis of the incisor 
 toward the v/orking surface of the crown. The tubes 
 in the outer tract of dentine, inclining more toward 
 the sides of the toothy are more obliquely divided, and 
 at the ends of the section they are seen lengthwise, ele- 
 gantly diverging toward the sides of the section. This 
 tract of dentine is bounded externally by a layer of 
 enamel, one-sixth part thicker than that forming the 
 central island; and the enamel is coated by an outer 
 layer of cement, of its own thickness at the sides, but 
 thinning off at the two ends of the section. Tlie den- 
 tinal tubes proceeding from the residuary pulp-tract 
 make strong and irregular curvatures, diverging to 
 include the divided areas of the vascular canals, and 
 in the outer layer, at one side of the section, they de- 
 sctibe strong zigzag curves at the middle of the outer 
 division of the dentine. 
 
 ''The diameter of the dentinal tubes at their central 
 and largel' ends is pretty regular, about go^op th of an 
 inch ; at the middle of their course, -gVo "o^^^^ ^^ ^^ inch, 
 thence decreasing, and very rapidly, after the terminal 
 bifurcations begin. The tubes are separated from one 
 another by intervals varying between once and twice 
 
THE CURVES OF THE DENTINAL TUBES. 133 
 
 their tliickness. In some parts of the dentine of the 
 incisor they are more closely crowded together, espe- 
 cially near their origin from the pulp-cavity. Their 
 secondary gyrations describe a cnrve of about yy^-oth 
 . of an inch in length. These subside in the slender 
 terminations of the tubes, which bifurcate dichoto- 
 mously once or twice, and send off small lateral 
 branches near the enamel. The small lateral branches 
 are chiefly visible in the peripheral third part of the 
 tubes, and are sent off at very acute angles, except in 
 the strongly and irregularly bent origins from the 
 j)ulp-tract. I have never seen these small branches of 
 the dentinal tubes terminating in radiated cells, like 
 those of cement and bone, as Retzius describes; but 
 the peripheral smallest branches near the enamel occa- 
 sionally dilate into corpuscles much more minute 
 than the radiated cells, as they do in the teeth of most 
 quadrupeds. 
 
 "The dentine, as seen in a longitudinal section of 
 the crown of a molar, by a magnifying power of three 
 hundred linear dimensions, is figured at a, Plate 137. 
 The tubes are hero separated by rather wider inter- 
 spaces than those of the incisor, and do not decrease 
 in size so rapidly. The convexity of the terminal bend 
 of the tubes is turned toward the summit of the crown. 
 In the incisor, the clear dentinal cells are very small 
 near the peripheral part of tlie dentine, but increase in 
 size as they approach the pulp-cavity. They are of a 
 sub-circular figure, with bright, transparent lines. 
 
 "The central cement in the crown of the incisor is 
 permeated by vascular canals, separated by intervals of 
 from two to three times their own diameter, directed 
 in the middle of the substance in the axis of the tooth, 
 but diverging like rays obliquely toward its periphery. 
 
134 horses' teeth under the microscope. 
 
 The clear substance forming the walls of the canals is 
 arranged in concentric layers, the thickness of the 
 walls being about equal or rather less than the area of 
 the canal. The radiated cells, generally of a full oval, 
 sometimes of an angular form, are chiefly dispersed in 
 the interspaces of the vascular canals, and with their 
 long axis parallel with the j^lane of the layers of the 
 coats. The finer system of tubes radiating from the 
 cells, and corresponding by minute branches from the 
 vascular canals, freely intercommunicate. In the 
 peripheral cement of the incisors examined by me, I 
 found no vascular canals, but only the radiated cells, 
 and the fine tubuli which I have called 'cemental,' 
 and which traverse the cement at right angles to its 
 plane, and communicate with the tubes radiating from 
 the cells. These are more usually elliptical than in 
 the thicker central cement, their long axis being par- 
 allel with the borders of the cement. They are most 
 abundant next the enamel, and rarely encroach upon 
 the clear peripheral border of the cement. The exte- 
 rior coronal cement of the molars (Plate 137, c), is as 
 richly permeated by vascular canals (v v), as is the 
 central cement of the incisor. 
 
 *'The enamel-fibers of the horse's incisor are very 
 slender, not exceeding twice the diameter of the denti- 
 nal tubes. They extend, with a single sigmoid curve, 
 through the entire thickness of the layer, contiguous 
 fibers curving in opposite directions. The peripheral 
 border, or that next the cement, is everywhere indented 
 with hemispherical pits from -g-Jir^'^^ ^^ iroVo^^^ ^^ ^^ 
 inch in diameter, from four to six of the radiated cells 
 of the cement being often clustered together in the 
 larger depressions. The inner or dentinal border is 
 nearly even and straight; here are seen the short 
 
CLEARNESS Oi* THE EKAMEL- FIBERS. 135 
 
 cracks or fissures extending into the enamel. The 
 fibers are rather more wavy in the thicker enamel of 
 the molar teeth (Plate 137, §). 
 
 *^If the enamel is viewed in sufficiently thin sec- 
 tions it is free from those wavy, dusky markings which 
 are produced by the more tortuous fibers of the human , 
 enamel; and I have been unable to distinguish any 
 transverse striae in the fine fibers of that tissue in the 
 horse. The appearance of such is given by thicker 
 sections of the enamel-fibers taken obliquely across 
 them, and is produced by the cut ends of the fibers." 
 
CHAPTER VIII. 
 
 THE PATHOLOGY OF THE TEETH. 
 
 Importance of the Subject. — Caries caused by Inflamed Pulps, 
 Blows, Virus, and Morbid Diathesis — Supernumerary Teeth 
 and other Derangements. — Trephining the Sinuses. — Gutta 
 Percha as a Filling. — Cleaning the Teeth. — A Diseased Fos- 
 sil Tooth. 
 
 The importance of the study of the pathology of 
 the teeth is self-evident, for they not only bear iinpor- 
 tant relations to the general system, but, like all other 
 parts of it, are subject to disease and derangement. 
 The fact that disease of tlie teeth is involved in more 
 or less mystery, is an argument in favor of the study 
 of the subject, for, to use Surgeon Gamgee's words, 
 it is a "duty to study the laws of disease as well as 
 health," and "it is praiseworthy to dive into the mys- 
 teries of the origin of" diseases as well as monsters. It 
 is probably not too niuch to say that, to the successful 
 surgeon, knowledge of the diseases and derangements 
 of the teeth is indispensable. 
 
 In order to facilitate the study of and cast light on 
 the subject, I have brought into juxtaposition, as it 
 were, a summary of the views of a few able men in 
 regard to the cause of caries, &c., which, better still, is 
 followed by the reports of well-known surgeons, who 
 give the results of their experiences in detail. 
 
DECAY, EXOSTOSIS, AND ABSCESS. 137 
 
 Prof. Richard Owen says: 
 
 "A tooth, when fully formed, is subject fco decay, but 
 has no inherent power of reparation. '•' ''' '^ ^In 
 growing teeth, with fangs not fully formed, the cement 
 is so thin that the Purkinjean cells are not visible. It 
 looks like a fine membrane, and has been described as 
 the periosteum * of the fangs ; but it increases in thick- 
 ness with the age of the tooth, and is the seat and ori- 
 gin of what are called exostoses of the fangs, which are 
 wholly composed of it.' These growths are subject to 
 the formation of abscess, and all the morbid actions of 
 true bone.'' 
 
 Speaking of a diseased fossil (horse's) tooth, Prof. 
 Owen says: 
 
 "But the cavity had evidently been the result of 
 some inflammatory and ulcerative process in the origi- 
 nal formative pulp." 
 
 Dr. Boon Hayes says : 
 
 "I think it would not be difficult to prove that 
 caries of the teeth more frequently proceeds from in- 
 flammation beginning in the pulpal cavity than from 
 any other cause." 
 
 Dr. Robley Dunglison says: 
 
 "The most common causes of caries are blows, the 
 action of some virus, and morlnd diathesis." 
 
 * Surpreon John Hughes say? : " The iieriosteum of the teeth 
 is not supplied with blood in the way the same membrane in 
 other parts of the body usually is. It is sup])lied by means of 
 vessels coming from the pulp of tlie tooth." If this is true, then 
 it would be easy for inflammation to be conveyed from one to 
 the other. 
 
138 THE PATHOLOGY OF THE TEETH. 
 
 " Odontonecrosis " is defined by him as " dental gan- 
 grene/*' and ''Odontrjpy" as "the operation of perfo- 
 rating a tootli to evacuate the purulent matter con- 
 fined in the cavity of the pulp" (pulpal cavity). 
 
 Prof. William Percivall, referring to two diseased 
 grinder teeth (horses'), says: 
 
 " They seemed to have been cases which had origi- 
 nated in internal injury." 
 
 Surgeons Bouley and Ferguson say: 
 
 "In explaining caries of the teeth, we cannot invoke 
 the aid of inflammation and the modifications wdiich 
 it induces in the tissues it attacks; nor can we say- 
 that inflammation implies an active circulatory move- 
 ment, an afflux of liquid, an alteration, nervous de- 
 rangement, &c." 
 
 Possibly the gentlemen were not aware of the in- 
 flammation that Prof. Owen says may exist "in the 
 original formative pulp," and of that of "the pulpal 
 cavity" — the pulp in the cavity of a full-grown tooth — 
 mentioned by Drs. Hayes and Dunglison. Are not 
 such inflammations liable to be produced by colds or 
 violent shocks? 
 
 Prof. George Varnell, who believes caries of the roots 
 of horses' teeth is usually caused by external violence, 
 says: 
 
 "Inflammation of the alveolo-dental periosteum 
 would tend to this result (caries of the roots). AVhen 
 the nutrition of any part of a tooth becomes arrested, 
 decay is likely to follow. When caries begins from 
 within, it is due to arrestation of nutrition, arising 
 perhaps from disease of only a part of the central pulp 
 
NATURE BARRICADING DISEASE. 139 
 
 of the tooth ; if from without, it will arise from the 
 periodontal membrane where it meets the gum." 
 
 Dr. John Tomes thus describes the conservative ac- 
 tion of nature (barricading disease, as it were) when a 
 tooth is affected with caries (-'Dental Physiology and 
 Surgery"): 
 
 "When a portion of dentine has become dead, it is 
 circumscribed by the consolidation of the adjacent liv- 
 ing tissue. The tubes, becoming filled up, are ren- 
 dered solid, and the circulation is cut off from the dead 
 mass. This consolidation does not go on gradually 
 from without inward, keeping in advance of the decay, 
 but occurs at intervals. It seems that successive por- 
 tions of dentine lose their vitaUty, and that the contig- 
 uous living portions become consolidated." 
 
 Prof M. H. Bouley and Surgeon P. B. Ferguson are 
 the joint authors of a memoir on horses' teeth, which 
 fills thirty or more pages of " The Veterinarian " for 
 1844. The substance of the part which relates to the 
 pathology and dentistry of the teeth is as follows : * 
 
 "'i. Anomalies in the Number of the Teetli. — Some- 
 times, but very rarely, we meet with supernumerary 
 grinders in the horse. The anomaly may be caused 
 by the persistence of the temporary teeth, the develop- 
 ment of abnormal teeth on one or both sides of the 
 arcades (rows of teeth), and the cutting of a greater 
 
 -■• The phraseology of Messrs. Bouley and Ferguson's memoir 
 has been more or less changed and the niatter somewhat con- 
 densed and rearranged. The surgeons' golden ideas deserve to 
 be set forth in clearer and more forcible language than they re- 
 ceive at their own hands, and i^. is believed that some improve- 
 ment has been made. 
 
140 THE PATHOLOGY OF THE TEETH. 
 
 number of permanent teeth than should naturally 
 exist. In the latter case it is necessary to admit the 
 existence of a greater number of dental bulbs than is 
 normal. AYe saw some time ago, at the consultation 
 of the Veterinary €ollege in Alfort/-' a horse which, to 
 use the words of its owner, ' had a double row of teeth 
 in the upper jaw.' 
 
 '^Sometimes the supernumerary tooth is situated in 
 one or the other jaw, in front of the normal range of 
 grinders, without having a corresponding tooth in the 
 opposite jaw ; at other times it is situated either within 
 or without the arcade. The latter anomaly is caused 
 more frequently by the deviation of a normal than by 
 the addition of a supernumerary tooth. In the first 
 instance it is not long before mastication is interfered 
 with. The tooth, by its growth, which is not counter- 
 acted by wear, finally reaches the opposite jaw, lacera- 
 ting the mucous membrane and contusing and some- 
 times fracturing the bone itself. In the second in- 
 stance, the tooth, if within the arcade, is an obstacle 
 to the tongue; if without, to the cheek. Besides these 
 evil effects, supernumerary teeth cause irregularity in 
 the arcades, and consequently prevent the exact appo- 
 sition of the normal teeth. They interfere also with 
 the action of the lower jaw. Hence irregularity in the 
 friction and wear of the teeth follows, the result being 
 that the performance of the all-important function of 
 mastication is almost stopped. 
 
 "^. Anomalies i)i the Form of the Arcades. — Th.e 
 upper rows of grinder teeth form two curves, opposed 
 by their concavities, while the lower rows form two 
 
 * A city of France — Prof. Bouley's home. Surgeon Ferguson, 
 an Englisliman, was attached to the Paris British Legation. 
 
DERANGEMEI!?'TS OF THE GRINDERS. 141 
 
 nearly straight lines, which converge as they descend 
 toward the symphysis of the clun. These (the curves 
 and 'lines) may be, owing, in some cases, to congenital 
 conformation, very irregular. Sometimes, in fact, the 
 curves of the upper jaw are eSaced ; at other times, 
 and most frequently, the lines of the lower jaw are 
 incurvated within the upper arcades. The deformities 
 may exist singly or together. The result is that, in 
 the approach of the jaws, the relation is not identically 
 established betvvTen the surfaces of friction, and the 
 result of this, in turn, is an irregularity of wear and an 
 abnormal development of the borders of the tables (the 
 crowns of the teeth), within in the lower Jaw, without 
 in the upper. 
 
 ".?. Exuberance of particular ^mrfs of the Dental 
 Apparatus.— (A..) The upper grinders are wider than 
 the lower, so that in order to cause friction in their 
 entire thickness, a lateral movement of the lower jaw 
 is required. Sometimes, perhaps because the move- 
 ment is not effected throughout the entire limits of 
 the segment of the circle, the outer borders of the 
 upper teeth do not wear sufliciently, and therefore 
 become elevated and sharp. At other times it is the 
 inner borders of the lower teeth that project. In 
 the former case the cheeks suffer; in the latter, the 
 tongue. 
 
 " In rare cases the tables, which present a normal 
 inclination inverse in the two jaws, at length form 
 planes very oblique. The obliquity is sometimes so 
 great tliat the internal borders of the lower teeth arc 
 very elevated, whVe the external is almost level with 
 the gums. The inverse effect manifests itself at the 
 upper jaw. The consequence is that the half-masti- 
 cated food slips into the pouch of the cheek. 
 
142 THE PATHOLOGY OF THE TEETH. 
 
 " There is in the museum of the College at Alfort a 
 horse's head in which this deformity may be seen in 
 its greatest degree. The tables of the teeth at the right 
 side form ])lancs so much inclined that they close 
 together like the blades of shears. As there was no 
 friction to wear the teeth down, they grew to the hight 
 of three inches. The fourth and fifth teeth of the 
 right side of this rare anatomical specimen are absent. 
 Perhaps they were carious. The rarefied and spongy 
 tissue of the socket-bones indicate the seat of an alter- 
 ation — probably caries — which was the point of depar- 
 ture of the general tumefaction. The last toothy by 
 its oblique direction toward the empty sockets, indi- 
 cates that the loss of the teeth occurred during the life 
 of the animal, some time perhaps prior to its death. 
 The defect of the right side doubtless forced the ani- 
 mal to use the left for the purposes of mastication. In 
 such cases the teeth that do not wear grow till they 
 reach their respective opposite jaws, even when those 
 at the opposite side of the mouth are in exact con- 
 tact, an anomaly never produced in the normal state. 
 The function of mastication operates according to the 
 obliquity of contact, and a parallelism is established 
 by friction between the tables which normally would 
 be superposed. 
 
 " This appears to us to be the only interpretation of 
 the facts, and we have observed two analogous exam- 
 ples in living horses, but we did not think to ascertain 
 whether the deformity of an entire arcade was owing 
 to defect of a binder or to disease of the bone. The 
 solution of the question would be an important acqui- 
 sition to the science of dental pathology. 
 
 " (B.) There is another kind of deformity of the 
 arcades not very uncommon. The lower teeth wear 
 
"GUMMIITG IT." 143 
 
 out more rapidly than the upper, the cause of which 
 is perhaps owing to (he superiority of the latter in size 
 and strength. The crown surface of the lower rows 
 is slightly concave, the upper rows slightly convex. 
 The result is that the lower center teeth are sometimes 
 worn to their sockets, which renders the mastication 
 of hard food impossible. At first, however, there is 
 no interference with mastication, and it is usually only 
 in old age that the defoi'mity reaches its worst stage. 
 There is no remedy for the defect, hut its ^^rogress 
 may he retarded hy the 2ise of soft food. * 
 
 '*• (C.) Lack of regularity in the length of the rows 
 becomes the cause, in horses a little advanced in age, 
 of a peculiar deformity in the first upper and the last 
 lower grinders. Generally the upper range passes that 
 of the lower by some lines, the first upper grinder lap- 
 ping over; but sometimes the case is the reverse, the 
 last lower grinder projecting beyond the last upper. 
 The projecting part of the tooth grows till it reaches 
 the opposite jaw, when, unless it is filed or chiseled off, 
 the most serious consequences will follow. 
 
 " (D.) When a tooth is entirely deficient, the oppo- 
 site tooth grows till it fills the void ; then, no remedy 
 being applied, the work of destruction begins. If a 
 tooth is only partly -deficient, no matter whether it be 
 from fracture, caries, or arrestation of growth, it is 
 gradually destroyed by the opposite tooth. AVhen it 
 is the first upper grinder that is deficient, the first 
 lower acts on the palatine vault like a battering-ram. 
 *I have seen,' says Solle3^sel (1669), 'a mule that had a 
 lower grinder of extreme length, the upper tooth being 
 absent. The palate was pierced to the thickness of a 
 
 * The italicized words are mine. — C. 
 
144 THE PATHOLOGY OF THE TEETH. 
 
 finger, which caused the animal great difficulty when 
 he drank/ 
 
 •^^. Caries of the Teeth. — The grinder teeth of horses 
 are more frequently afiected with a profound alter- 
 ation of their substance than is generally believed. 
 The disease is called Caries ; it may not, however, be 
 strictly analogous to caries of tlie bones, for the bones 
 are vascular, while the teeth have neither vessels nor 
 nerves. Caries of tlie bones implies an active labor, in 
 which the vascular apparatus plays an important jDart. 
 It is a phenomenon of interstitial sup]3uration, under 
 the influence of the inflammation which has set the 
 capillary system of the organ in play. In explaining 
 caries of the teeth, however, we cannot invoke the 
 aid of inflammation and the modifications it induces 
 in the tissues it attacks; nor can we say that inflam- 
 mation implies an active circulatory movement, an 
 afflux of liquid, an alteration, nervous deraugeraent, 
 &c. If the teeth are living, the laws which govern 
 their vitality are entirely unknown to us.* How, then, 
 penetrate into the secrets of the alterations which they 
 undergo, when the conditions of their normal existence 
 are enveloped in obscurity? Neither is it possible to 
 resolve the question as to the essence of the affection 
 designated by the name of caries. Therefore we design 
 to make known only the different modes of expression 
 relative to it. 
 
 "Caries usually attacks the dentine of the crown of 
 the teeth, between two folds of enamel. The dentine 
 becomes of a brownish or blackish color, and dissemi- 
 
 '^' It sliould be borne in mind tbat the above views were enun- 
 clnted more than a third of a contury ago. The gentlemen 
 probably say too much. Compare with Dr. Hayes's views as 
 recorded on page xxii. 
 
DEXTIIs'E DECAYED, EKAMEL SOFTENED. 145 
 
 nates au ofFensive odor sui generis^ which perhaps is 
 as much ovviug to the putrefactiou of the saliva iu the 
 cavity as to the decomposition of the dentine. The 
 decay progresses between tlie folds of enamel, and the 
 latter substance, notwithstanding its great density, 
 takes on the blackish tint of the dentine and becomes 
 sufficiently softened to allow of its being cut by a sharp 
 instrument. Sometimes even the planes of the enamel 
 dissolve, and then the cubic mass of the tooth becomes 
 so much decayed that it resembles a deep cavity, the 
 parietes of which are formed by the planes of enamel 
 laid bare by the caries. Sometimes caries attacks the 
 tooth on one of its four side surfaces; at other times 
 the root is attacked; but wherever its primitive seat 
 may be, the blackish veins always extend into the den- 
 tine, and thus isolate the plies of enamel. 
 
 " Carious teeth rarely preserve either their form or 
 volume. They become hypertrophied at their roots, 
 but the effect does not manifest itself until the disease 
 — having undermined all the layers of dentine in its 
 course — has penetrated the root. "When the caries has 
 penetrated to the socket, the alveolo-dental membrane 
 becomes irritated by the contact of decayed matter, 
 increases its secretion, and deposits a thick layer of 
 osseous matter in the circumference of the root of the 
 tooth, which concretes irregularly upon the normal 
 layers. The deposition does not, however, always take 
 place iu tlie circumference of the root, for in some 
 cases it is only at isolated places that the secretion of 
 the alveolo-dental membrane occurs. Then the root 
 presents a succession of large osseous tubercles, which 
 bar the tooth in, rendering its extraction very difficult. 
 When the irritation has been from the first sufficiently 
 active to cause suppurative inflammation, the normal 
 
 r 
 
146 THE PATHOLOGY OF THE TEETH. 
 
 S9cretion is suspended, and pus collects in the alveolar 
 cavity, around the root, which then ceases to augment 
 in volume. lo the former case, however, the root, 
 augmented in volume, can no longer be contained in 
 the cavity, the walls of which are expanded by its 
 wedge-like action, which accounts for the extreme 
 pain in the adjacent parts, and the particular altera- 
 tions in the osseous tissues. The osseous tissue tume- 
 fies, and suppuration is established in the interior of 
 the socket; the membrane is partly destroyed, which 
 leaves the bone bare and exposed to the maceration 
 of pus and the irritating contact of the morbid matter 
 that continually penetrates into the socket by the 
 dental fistula; the bony tissue sphacelates upon the 
 borders, where its substance is the most compact, and 
 its spongy tissue, which forms the bottom of the cavity, 
 soon becomes the seat of an interstitial suppuration — 
 that is to say, in fact, of veritable caries. The swell- 
 ing may now extend throughout the entire extent of 
 the maxillary bone, and thus render mastication im- 
 possible. 
 
 " It may now be seen, an alteration of this nature 
 being set in action, how the phenomena of the nutri- 
 tion of bone may be modified in their direction to the 
 point of producing osteosarcoma. 
 
 '- Caries of the roots of any of the lower grinders may 
 be complicated with lesions of the jaw, for the lower 
 jaw is continuous in its entire extent. In the upper 
 jaw the phenomena are in principle the same, but the 
 contiguons nasal cavities and sinuses induce complica- 
 tions the study of which is important. It is also im- 
 portant to take into consideration the position of the 
 diseased tooth, in order to appreciate the extent of the 
 . lesions which a simple caries may produce. 
 
COMPLICATIOXS WITH iq-ERYES, SINUSES, ETC. 147 
 
 ''The two first upper grinder teeth are separated 
 from the nasal cavities by a thin bone, wb.ich is easily 
 eatcu througli. When caries attacks their roots, the 
 inflammation extends itself to the membrane lining 
 these cavities, aiid a perforation of the osseous partition 
 may establish communication between tlie mouth and 
 the nose. Under the influence of interstitial suppu- 
 ration, the osseous membrane is destroyed to an enor- 
 mous extent. The aliments pass through the dental 
 fistula into the nose and are expelled by it along with 
 the product of the morbid secretion of the pituitary 
 membrane. 
 
 "The third grinder is situated near the maxillary 
 sinuses, from which the root is separated by a thin dia- 
 phragm. It deserves to be specially noticed on account 
 of an anatomical peculiarity, which renders caries of 
 this tooth very much to he dreaded. We refer to the 
 position of large fascias (bundles) of the superior maxil- 
 lary brancli of the fifth ])air of nerves, which make 
 their exit upon the face by the submaxillary foramen, 
 and which are placed immediately over the root of this 
 tooth. It is easy to imagine the pain that may follow 
 nervous complications in caries of the roots of the 
 third grinder. 
 
 "The position of the fourth, fifth, and sixth grinder 
 teeth, immediately holow the vast maxillary sinuses, 
 from which their roots are separated by thin osseous 
 partitions, gives to caries of these teeth, and to the 
 complications which it induces, a special character, 
 whicli demands that we should speak of it somowliat 
 in detail. These teeth communicate with the sinuses 
 as easily as the first and second do with the nose; but 
 tlie case is far worse for the horse, there being so little 
 outlet for the pus. 
 
148 THE PATHOLOGY OF THE TEETH. 
 
 "When the disease has penetrated the roots, and 
 has induced the usual inflammation, the thin parti- 
 tions that separate them from the sinuses do not resist 
 very long. Destroyed by the dilatory effort of the 
 hypertrophied root and the influence of the caries, the 
 altered matters of the mouth have free access into the 
 sinuses. Under the influence of their contact, the 
 membrane of the sinuses irritates, vascularizes, and 
 thickens by a serous infiltration in the early stage. 
 Then, the primitive cause of this modification contin- 
 uing, the membrane hypertrophies somewhat, and in 
 a short time, owing to its vascular system being richly 
 developed by inflammation, large vegetations of the 
 nature of polypi are elevated upon it. These, on ac- 
 count of the incessant augmentation of their volume, 
 fill the sinuses and cause a swelling of their walls. 
 
 "When the membrane of the sinuses has become 
 the seat of an abnormal vegetation, an abundant quan- 
 tity of purulent matter is secreted, the more liquid 
 l^art of which drains out through the conduits leading 
 to the nasal cavities, while the more concrete part 
 remains in the sinuses. It then, according as it loses 
 its serosity, undergoes a transformation, and finally 
 displays the aspect of cadaveric grease, which it also 
 resembles in its repugnant odor. There is a great 
 analogy between the disease that causes this particular 
 lesion and that of glanders. 
 
 ^'Symptomatology. — The first symptom that indi- 
 cates a derangement of the dental apparatus is a diffi- 
 culty in mastication. The animal, excited by hunger, 
 seizes the food with avidity. The motions of the lower 
 jaw, however, are made with a sort of hesitation, and 
 often only at one side. The imperfectly masticated 
 hay, which on that account will not pass through the 
 
HUXGRY, BUT UXABLE TO EAT. 149 
 
 narrow pharynx, is dropped into the manger in the 
 form of cuds or flattened pellets. The nose is jolanged 
 into the feed, over which the animal fumbles and nib- 
 bles, but of which it eats little. 
 
 "The insufficiency of nutrition soon produces a 
 baneful effect on the whole economy. The coat tar- 
 nishes, becoming dry and staring; the least exertion 
 makes the animal sweat; it is heedless of the whip; 
 the mucous membranes become discolored ; the pulse 
 weakens, and cold infiltrations sometimes appear in 
 the extremities. To see an animal thus suddenly 
 transformed, one is apt to mistake the true cause and 
 attribute it to the influence of some grave organic dis- 
 turbance. 
 
 " These symptoms are common to the different dis- 
 eases and derangements of the dental ajDparatus, and 
 are sufficient to lead to a positive diagnosis. The 
 diagnosis, however, can only be precisely determined 
 when the mouth shall have been examined, for by this 
 means we perceive the particular signs of each of the 
 alterations that opposes the function of mastication. 
 The mouth may be kept open by a sjjeculum oris, or 
 even by drawing out the free portion of the tongue, 
 which should be held by the thumb and the third and 
 fourth fingers, the index being placed between the 
 inner side of the upper lip and the gum, at the space 
 between the grinders and the tushes, while the other 
 hand is left free to aid the inspection by taxis. 
 
 ''If the derangement be tlie result of an exuberance 
 of a tooth, vicious inclination or projections of i\\Q 
 tables, fractured teeth, swollen sockets, &c., the siglit 
 is ordinarily sufficient to detect it, for the teeth are, 
 besides, frequently soiled by the gro?nish remains of 
 food at the affected part, and often even the cheek is 
 
150 THE PATHOLOGY OF THE TEETH. 
 
 filled with an accumulation of malground food. The 
 month should be cleaned with water, in order that the 
 defect may bo more plainly seen ; if, however, on ac- 
 count of its being situated far back in the mouth and 
 the motions of the base of the tongue from side to side 
 intercepting the view, its nature cannot be discov- 
 ered with the eye, it will be necessary to resort to the 
 sense of touch. The mouth being held open by the 
 speculum oris, or some other firmly-fixed apparatus, 
 the fingers should be passed rapidly within and without 
 the arcades, but never on them, because of the danger 
 of having them crushed : whatever may be the degree 
 of forced dilatation of tlie mouth, there can never be 
 much separation of the jaws in the region of the last 
 grinders; besides the animal can lessen it by pressure. 
 
 "When the buccal membrane has been excoriated 
 by the contact of irregularly-worn teeth, the gums in- 
 flamed, the jawbones contused, and the latter sphace- 
 late or suppurate, there are some modifications of the 
 general symptoms. The animal loses its appetite, 
 becomes dull, ^ crest-fiillen,' and agitated with febrile 
 disturbance, however little the heart of the inflamma- 
 tion may be extended. The saliva, which dribbles 
 from the mouth, is stringy, and, when mixed with 
 pus, fetid; the mouth is hot and its membrane in- 
 , jected ; there is a turgescence of the gum at the point 
 of inflammation; a tumefaction of the bone, with a 
 grayish tint at the point where it is denuded and about 
 to exfoliate, or else fistulse abut into the heart of the 
 suppuration in the spongy tissue of the jav/. 
 
 ''Particular Syriiptoms of Carles. — Caries of the 
 grinder teeth is characterized by peculiar symptoms, 
 some of which are common to the teeth in general, 
 while others belong to some grinders in particular. 
 
CARIES DIFFERENT IX DIFFERENT TEETH. 151 
 
 To give precision to the diagnosis, the position of the 
 teeth should be taken into consideration. Besides the 
 symptoms common to all disorders of the teeth, caries 
 in general presents as diagnostic signs — 
 
 *• 1, A fetor very remarkable and sin generis of the 
 mouth, and of the saliva which humefies it. 
 
 '''2. Dribbling of an abundant and stringy saliva 
 froi^i the mouth. 
 
 '' 3. Existence on one of the faces of the tooth, and 
 principally upon its crown, either of a blackish spot or 
 a large cavity of the same color, according to the ex- 
 tent of the disease. 
 
 '' 4. The extreme pain that the animal evinces when 
 the tooth is struck. 
 
 *^ If the disease is of long standing, and especially if 
 it has arisen fi'om the side of the root, in addition to 
 the foregoing modifications and complications, other 
 and more special symptoms manifest themselves. The 
 bone tumefies and the animal evinces pain when it is 
 pressed by the fingers ; the gums are affected with tur- 
 gescence, and bleed from the least contact; all the 
 buccal mucous membrane reflects a red tint, and in 
 the meantime fever sets in, manifesting itself by all 
 its ordinary and general symptoms. 
 
 ^- Caries of the first and second upper grinders may, 
 as already explained, be complicated with lesions of the 
 nasal cavities. Then the pituitary membrane irritates 
 and secretes abundant mucosities, but at one side only, 
 v;ith which the fv)od l;ec;)m.'s mixed, giving it a green 
 tint, but very diff^Tant from the secretions of glanders. 
 The case is diifjrcnt, liuwever, in the complications 
 induced by caries of the last grinders. In fact there 
 
152 THE PATHOLOGY OF THE TEETH. 
 
 is such a close resemblance between the symptomatic 
 expressions of the nose following caiies of these teeth 
 and chronic glanders, that en-or and eoufnsion are 
 common. It is therefore highly important to distin- 
 guish these diseases, so essentially different in their 
 causes and effects. 
 
 " When the membrane lining the sinuses has become 
 diseased, followed by the secretion of pus and polypus 
 growths, a jettage is established at one side of the nose. 
 It is white, lumpy, and abundant, and is augmented 
 in quantity by exercise. The lymphatic ganglions be- 
 come engorged and hard, but remain indolent, and 
 generally roll under the finger. The zygomatic tables 
 of the upper part of the superior maxillary and nasal 
 bones swell at the region of the affected sinuses, and 
 give a dull sound to percussion.* 
 
 * Prof. Varnell says : "I am not aware that any animal suffers 
 from diseases of tlie sinuses of the head to the same extent as 
 the horse. The sinuses differ in size in different breeds, and in 
 individual horses of the same breed. I need scarcely point out 
 the necessity of bearing this fact in mind in forming diagnoses 
 of obscure diseases in this region of the head. In certain cases 
 it is not only important to ascertain whether the sinuses contain 
 anything abnormal, but also the nature and extent of the mor- 
 bific matter. Percu^Bion with the ends of the fingers is one 
 mode of obtaining this information. Both sides of the head 
 should be struck, and the sound produced in one part compared 
 with that in another, and with what it is in health. I would 
 recommend students to become familiar with these various 
 sounds. They will be found to differ, according' to the magni- 
 tude of the sinuses, in the same way that a large empty cask, 
 when struck, will differ in sound from a small one. It will also 
 be well to educate the ea.r to the character of the sounds pro- 
 duced by iJKsrcussing the sinuses in differently formed heads. 
 * * ^^' The sinuses, strictly speakinf>-, are air cavities, 
 which communicate freely with each other, an:l by means of a 
 
DELICATE DIAGXOSTIC SIGNS. 153 
 
 "At the first appearance of this group of symptoms 
 one is apt to suspicion the existence of glanders, but a 
 careful examination will prove it to be unfounded. On 
 examining the nasi: cavity, the lining membrane will 
 be seen to be smocth, polished, and uniformly rosy, 
 with its normal fol icular openings, and on unfolding 
 the superior wing of the nostril, the salient border of 
 the cartilage presents a neat and polished surface, ivitli- 
 out any little pimples or morbid tint. Xow, we know 
 that in glanders, even of the sinuses, which is often 
 unaccompanied by cankers or other ulcerations, it is 
 in those places certain specific morbid signs may be 
 recognized, which, although very superficial and with 
 difficulty seen by the eye, are nevertheless of great 
 value in the diagnosis. Such, for instance, are the 
 peculiar aspect of the sahent border of the wing of the 
 nostril, with its vivid red tint, the small superficial 
 erosions of the fining membrane, entirely hidden under 
 the fold of the cartilage, and those small granular pro- 
 jections called tubercles. In the jettage from caries 
 nothing of this kind exists. There is a marked diifer- 
 ence in the odor too ; in caries the odor is exceedingly 
 fetid, while in glanders it is almost null. 
 
 " If, after this attentive examination, the surgeon is 
 still in doubt as to the specific nature of the nasal dis- 
 
 emall oponing, with the nasal passage also. This opening is 
 situated at the supero-posterior part of the middle meatus, and 
 is guarded by an imperfect valve, which, when pressed upon 
 from within, either partially or wholly closes it. It may also 
 be closed by the mucous membrane beinsr thickened by disease. 
 Internally the sinusas are partially divided into compartments 
 by thin osseous plates, and are lined by a slightly vascular mem- 
 brane, which is continuous with that of the nasal passage, but 
 is not so thick nor so vascular." 
 
154 THE PATHOLOGY OF THE TEETH. 
 
 charge, it will disappear and give place to a -true diag- 
 nosis when he has examined the month and has had 
 time to weigh and compare all the facts in connection 
 with the case. 
 
 '•It is more especially relative to diseases of the teeth 
 that u recognized the truth of the old maxim in sur- 
 gery, SiiUatd causd^ tcdlitur cffectusr (The cause be- 
 ing removedj the effect ceases.) 
 
 For putting irregular teeth in order, the surgeons 
 recommend the use of a coarse, six-inch file, with a 
 handle from twenty to tv/enty-four inches long. How- 
 ever, they say that in their day it was customary among 
 the '"vulgar" to make the liorse clieio a rasp! The 
 process, vvhich they describe, referring among other 
 things to the difficulty of getting the rasp precisely 
 opposite the projections, is too slow, as they admit, to 
 be practicable ; besides it is about as difficult to com- 
 pel a horso to chew as to compel him to drink. 
 
 For the removal of siipernaraerary grinder teeth or 
 the shortening of natural ones that have grown beyond 
 the level of the other teeth, they recommend the use 
 of a chisel and a hammer; two or three well-directed 
 blows with the latter are usually ^sufficient to cut the 
 largest tooth in two. The surgeon requires an assist- 
 ant or " striker." In the case of the first grinder, the 
 blow^s should be light, otherwise the tooth would be 
 loosened in its socket. In tlie case of the last grinder, 
 *'it is necessary for the operator to be perfectly master 
 of the chisel at the moment of its being struck, for, in 
 escaping, it might strike against the velum palati (soft 
 palate) and cut it through." 
 
 In performing these operations they prefer that the 
 horse should be in a standing position, as when in a 
 
DEE]S;CHED WITH TOOTH-FKAGMEXTS. 155 
 
 lying position there is danger of liis swallowing the 
 migments of the teeth. If it is necessary, however, to 
 cast the horse, they recommend that the head rest on 
 the occiput, the operators being as expeditious as pos- 
 sible, to prevent the" animal from swallowing the frag- 
 ments. As the nose points up, the surgeon would 
 have to be expeditious indeed in order to prevent the 
 horse from being drenched, as it w^ere, with tooth- 
 fragments. 
 
 The surgeons next describe an interesting case of 
 dental surgery, in the performance of which the bone- 
 forceps were used to remove the tushes. They say: 
 
 "It sometimes happens that the fleshy and bony 
 structures of the mouth are not well proportioned, and 
 when the anima,! is put to work evil consequences re- 
 sult, especially if the tongue is too large for the space 
 between the branches of the jaws. A remarkable case 
 of this kind lately came under our observation in a 
 horse owned by the Earl of Clonmel. The animal, a 
 remarkably fine oi>e, was a very hard ^puller,' in conse- 
 quence of the bit not coming in sufficient contact with 
 the sensitive bars. The space between the tushes was 
 too narrow for the tongue, which, after the animal had 
 been ridden with restraint by a horse-breaker, was cut 
 nearly through at each side. The consequence was the 
 tongue became swollen to an enormous extent, and 
 as the tushes increased the irritation, their removal 
 became necessary. They were cut off to a level with 
 the gums with the bone-forceps, the tongue was scari- 
 fied and bathed v/ith a cold lotion, and the animal was 
 fit for work at the end of a week. 
 
 " Perhaps at first it may seem better practice in such 
 cases to extract the tushes entirely. But when the 
 
156 THE PATHOLOGY OF THE TEETH, 
 
 length and obliquity of their roots and the fact of their 
 being situated in the weakest part of the jaw are con- 
 sidered, it is plain that snch a procedure would in all 
 probability be followed by the most serious results, 
 SQch as fracture of the jaw, osteo-sarcoma, &c., the 
 former having happened under our own observation.'' 
 
 The surgeons recommend (as any intelligeut jiersou 
 would) the removal of supernumerary or abnormal in- 
 cisor teeth. When the tooth is without the normal 
 range it interferes with the prehensile functiou of the 
 lips; when within, it interferes with the tongue. The 
 former, they say, may either be cut off with the bone- 
 forceps or extracted. In the latter case, however, they 
 prefer to cut them off, but admit that some teeth re- 
 quire extraction, for which the use of the crank-forceps 
 is recommended. 
 
 The Treatment of Caries is the next subject consid- 
 ered. " The only remedy for caries," the surgeons say, 
 "in the great majonty of cases, is the extraction of the 
 tooth. If we were called on to treat the disease at its 
 beginning, cauterizing the black spot would check its 
 progress ; but when the dental bulb has been attacked, 
 the extraction of the tooth is the only remedy." 
 
 The instrument recommended for extracting teeth 
 is the forceps, and under ordinary circumstances, ihe, 
 surgeons say, fracture of the jaws ought not to occur. 
 They mention as useful instruments the key invented 
 by M. Garengeot, the mouth-screw by M. Plasse, and 
 the lever-forceps by Prof. Simonds, but say ; 
 
 "Instances occur in which the carious tooth cannot 
 be seized by any of these instruments. For example, 
 when the last upper grinder is diseased, it is sometimes 
 
THE POWER OF THE TOKGtJE. 157 
 
 impossible to dilate the mouth sufficiently to slide the 
 instrument between it and the corresponding lower 
 tooth. Besides, tlie tongue, however firmly it may be 
 held outside the mouth, has still the power to displace 
 the instrument by the energy of the undulatory move- 
 ments at its base. Again, the back grinders, having 
 ordinarily shorter bodies than the others, afford less 
 hold for the instrument. In some cases they afford no 
 hold at all, as their bodies are worn almost to a level 
 with the gums. 
 
 '^Lastly, in some cases the exostosis of the root of 
 the tooth is so great that it is, as it were, wedged in 
 the socket, and resists all efforts to extract it. What 
 is to be done ? The disease may lead to grave local 
 complications and dangerous general disorders. In 
 such a case we would recommend trephining the dis- 
 eased sinus and punching the tooth mto the mouth. 
 This operation being very unusual, and the observance 
 of some rules requisite for practicing it, we will con- 
 sider it somewhat in detail. 
 
 "If, as sometimes happens, the swelling over the 
 sinus is indistinct, it would be wtII to be guided by a 
 prepared head, in order to apply the trephine in the 
 exact place, wdiich is above the diseased root. A large 
 V or crucial incision should be mad-e, and the trephine 
 manipulated till the sinus is laid open. The opening 
 should be extensive rather than confined; it is more 
 convenient to apply upon the parietes of the sinuses 
 three crowns of the trephine, tangent reciprocally at 
 their circumferences; then, by the aid of a sharp in- 
 strument and a small hammer, the angles may be re- 
 moved. 
 
 "As soon as the mucous membrane of the cavity has 
 been laid bare, the change it has undergone may be 
 
158 THE PATHOLOGY OF THE TEETH. 
 
 seen, and also the vegetations springing from it. At 
 the bottom of tlie sinus, toward the alveolar border of 
 the jaw, among the vegetations, is a hard, granulated, 
 dry surface, resistant to the touch, of a grayish tint, 
 and analogous to sphacelated bone. This is the sum- 
 mit of the root of the tooth. 
 
 " The surgeon then arms himself with an iron punch, 
 rounded at the point, which he applies to the root in 
 the sinus, and having further separated the jaws by a 
 few turns of the speculum oris, commands an assistant 
 to strike sJiort, hard blows, tlie surgeon looking at the 
 tooth to see the effect of each blow. Usually the tooth 
 soon gives way, and falls into the mouth generally in 
 two fragments, according to the direction of the caries. 
 Sometimes, however, from the length of the tooth, it 
 cannot be punched entirely into the mouth, being 
 stopped by the opposite' lov/er tooth ; but it may be 
 wrenched out with a pair of long pincers, the handles 
 of which should be separated to increase the power of 
 the operator. When the operation is terminated, the 
 vegetations of tiie mucous membrane, as far as they 
 can be ]*eached, must be excised. To stop the hem- 
 orrhage, and to modify the state of the mem^brane, 
 pledgets of tow, moistened with a diluted solution of 
 nitric acid, or some other caustic, should be applied. 
 
 *'It is really extraordinary with what rapidity the 
 structural breaches resulting from this operation are 
 restored by the reparatory efforts of the organic econ- 
 omy. The first time we performed the operation we 
 doubted the animal's recovery. The sinuses, laid open 
 by a breach nearly two inches and a half in diameter, 
 communicated with the mouth by an enormous open- 
 ing, the root of the tooth having acquired nearly three 
 times its normal volume. The lining membrane of 
 
' TREATMENT AFTER TIIEPHIKING. 159 
 
 the maxillary sinuses, and the frontal also, had suffered 
 the transformation already described to its greatest 
 degree. And, linally, it required efforts almost beyond 
 belief to loosen the tooth and force it from its socket. 
 Still the animal made a good recovery. 
 
 *' The treatment following the operation should he ^ 
 a? follows: Assiduous attention to cleanliness is nec- 
 essary from the first. On the first day the animal 
 should be deprived of all solid or fibrous food; in fact, 
 a little thin gruel is all it requires, and the mouth 
 should be gargled with an acidulated fluid even after 
 its use. The fluid may be applied with an ordinary 
 syringe. Bleeding is often required, the quantity of 
 blood to be abstracted depending on the energy of the 
 reaction following the operation. 
 
 " On the day after the operation the dressing should 
 be raised. The interior of the sinus, cauterized with 
 nitric acid, reflects a blackish tint. The odor is repug- 
 nant, and there are generally some remains of putrid 
 alimentary matters, mixed with clots of blood, in the 
 sinus. Detergents, such as Lebarraque's -chlorinated 
 solution of soda, mixed with a gentian wine, should be 
 injected into tlie sinus and the mouth cleaned with 
 acid gargles ; a firm pledget of chlorinated tow should 
 be introduced into the socket, to prevent anything 
 passing from the mouth to the sinus. The regimen 
 should consist of gruel only, the gargles to be used 
 often during the day. 
 
 " On the second day the borders of the sinus will be 
 a little swollen. Eeparatory work has begun in the 
 cauterized membrane; the eschars detach themselves, 
 exposing a rosy surface of fiivorable aspect to the view. 
 The odor is less repugnant. Continue the aromatic 
 detergent injections, the same food, with the addition 
 
160 THE PATHOLOGY OF THE TEETH. 
 
 of a little bran, and gargle often. As suppuration be- 
 gins to establish itself, the dressings should be renewed 
 two or three times during the twenty-four hours. 
 
 " It is not our intention to indicate the progress of 
 the wound and the attention it demands from day to 
 day. The tumefied bones and other structures in the 
 region of the wound 2:)roportionally lessen, and the 
 membrane of the sinus takes on a uniformly rosy tint 
 and the glistening, humid aspect proper to a mucous 
 membrane. The nasal flux finally ceases, the matter 
 that may be secreted finding an outlet through the 
 alveolus into the mouth. The opening made by the 
 trephine contracts itself by degrees, but in extreme 
 cases, like the one we have described, it is never suffi- 
 cient to entirely repair the structures cut away. It 
 may be hidden, however, by a leather or metallic j)late, 
 attached to the check of the bridle." 
 
 The surgeons claim that the resort to this severe 
 mode of extracting teeth is justified by the success of 
 the operation and its concomitant results, namely, the 
 advantage of injecting the sinuses and preventing un- 
 healthy secretions by them, and the stopping of the 
 discharge from the nose, which had aroused suspicion 
 of glanders. They further sa}" — and a better argument 
 in favor of veterinary dentistry could not well be ad- 
 vanced — that they believe glanders is often caused by 
 the neglect of diseased teeth, and "that the modus 
 operandi of its production in such cases may be ex- 
 plained on the ground of the absorption of pus by the 
 constitution." 
 
 Of trephining the sinuses they further say; 
 
 "We have treated many cases of caries successfully 
 by simply trephining the frontal and maxillary sinuses 
 
CARIES OF THE SOCKET BONES. 161 
 
 and injecting detergents; but in a far greater number 
 the treatment has been unsuccessful.* Yet we believe 
 that if, in addition to trephining, the teeth had been 
 extracted, and a communication established between 
 the sinus and the mouth, the results would have been 
 more favorable. 
 
 "Monsieur Delafond, in his memoir on the evulsion 
 of the teeth, publislied in 1831, says the operation of 
 trephining is only practicable in the case ot the three 
 first grinders, it being necessary in the case of the three 
 last to make an incision through the zygomatico-maxil- 
 laris muscle and the nervous plexus which is formed 
 on it. We, on the contrary, claim that the fifth pair 
 of nerves will be injured in operating on the three first 
 teeth, but that there will be little injury to the muscle 
 in the case of the three last." 
 
 The memoir concludes as follows: 
 
 ^'Caries Attaclcing the Maxillary Bone after the Ex- 
 traction of the Teeth. — When caries of a tooth has in- 
 duced consecutively interstitial suppuration of the 
 spongy tissue of the socket, it is possible that, even 
 after the extraction of the tooth, the disease may at- 
 tack the bone. Then, more than ever, may we dread 
 the tumefaction of the tissues and sarcomatous altera- 
 tions, which are ordinarily the result of persistent sup- 
 puration in the areolge of the spongy substance of the 
 bones. To prevent these dangerous consequences, the 
 socket should be cauterized with the actual cautery, 
 
 * " Sinuses that may have formed by the matter from ab- 
 scesses in the alveohir processes eatin<i; its way through the wall 
 of the alveolus, and wliieli may open either on some part of the 
 face or within the mouth, are seldom treated with the success 
 one could desire." — Prof. George Varncll. 
 
162 THE PATHOLOGY OF THE TEETH. 
 
 and, if it is practicable, a counter opening by trephin- 
 ing should be made. In some cases in our practice 
 this mode of treatment produced the most satisfactory 
 results. If, however, on account of the circumstances 
 of the case, the actual cautery cannot be used, a strong 
 solution of argenti nitras, applied with pledgets of tow 
 or lint, may be substituted. 
 
 " Complications of Operations on tlic Mouth. — One of 
 the most ordinary and serious complications of opera- 
 tions on the mouth is the excoriation of the ^bars^ by 
 the friction of the speculum oris. The denuded bone 
 often exfoliates, rendering the horse unfit for work for 
 a month or more. The evil may be avoided by envel- 
 oping the transverse bars of the speculum with tow or 
 some other elastic material, and by being expeditious 
 in operating. The hemorrhage, which is never abun- 
 dant enough to be serious, may be checked by pledgets 
 of tow, wet with a solution of either nitric or sulphuric 
 acid. 
 
 ''^Regimen. — The regimen in extreme cases of caries 
 has already been indicated in the account of the case 
 of trephining for caries and exostosis of the root of a 
 grinder. In addition to well-boiled gruel, mixed or 
 unmixed with bran, carrots and similar food will be 
 found beneficial."* 
 
 ^' As horses with defective, diseased, or worn-out teeth require 
 soft or ground food, a few extracts from tlie article on " Food " 
 in Prof. Youatt's work entitled " Tlie Horse " (p. 132) and otlier 
 sources will not be out of place here : " Oatmeal gruel consti- 
 tutes one of the most important articles of diet for the sick 
 horse. Few grooms make good p:ruel. It is either not boiled 
 long enough, or a sufficient quantity is not usxl. The propor- 
 tions should be a pound of meal to a ,ffallon of v/ater. It should 
 be constantly stirred till it boils, and for five minutes afterward. 
 Carrots, according to Stewart's ' Stable Economy,' are a good 
 
PROF. VAR NELL'S VIEWS. 1G3 
 
 Prof. George Varnell, of the Royal Veterinary Col- 
 lege of Loudon, the aathor of a series- of articles "On 
 
 substitute for grass, and in sick or idle horses render corn un- 
 uecossary. They improv^e the state of the skin. At first they 
 are slightly diuretic and laxative, but the effect lessens with use. 
 Half a bushel is a large daily allowance. Swedish turnips and 
 raw potatoes are useful foods. Raw potatoes, sliced and mixed 
 with chaff, may be given t j advantage, but it is better to boil or 
 steam them, as purging rarely ensues. For horses recovering 
 from sickness, barley in the form of malt is serviceable as tempt- 
 ing the appetite and recruiting the strength. It is best given 
 in mashes, water somewhat below the boiling heat being poured 
 upon it, and the vessel kept covere:! for half an hour. Rye is 
 used in Germany, but generally cooked as bread, which is made 
 from the whole flour and bran. It is not unusual in traveling 
 through some parts of Germany and Holland to see the postil- 
 ions help themselves and their horses from the same loaf. In 
 some northern countries peameal is frequently used, not only as 
 food, but as a remedy for diabetes. Linseed, raw, ground, or 
 boiled, is sometimes given to sick horses. Half a y>int may be 
 mixed with the feed every niglit. It is supposed to be useful in 
 cases of catarrh. It is very useful for a cough, but it is too 
 nutritious for a fever. For a cough it should be boiled and 
 given in a bran mash, to which two or three ounces of coarse 
 sugar may be added. Tares, cut after the pods are formed, but 
 some time before the seeds are ripe, lucern, and sainfoin are 
 useful foods. Of the former the variety known as vicia sativa 
 is th.e best." 
 
 On page 511 Prof. Youatt says '' some greedy horses habitu- 
 ally sv/allow their food without properly grinding it." As a 
 remedy he recommends that chaff be mixed with the corn, cats, 
 or beans, which, being too hard and sliarp to be swallowed with- 
 out chewing, compels the horse to mnsticate his food. He says : 
 " Chaff may bo composed of equal quantities of clover or meadow 
 hay and wheaten, oaten, or barley s'raw, cut in pieces of a quar- 
 ter or a half an inch in length, and mixed well together. The 
 allowance of corn, oats, or beans is added afterward, and mixed 
 with the chaff. Many farmers very properly bruise the oats and 
 beans. The whole oat is apt to slip out of the chaff and be lest. 
 
164 THE PATHOLOGY OF THE TEETH. 
 
 Some of the Diseases Affecting the Facial Region of 
 the Horse's Head" ("Veterinarian," 1866-67), and 
 other productions, has made the disorders of horses' 
 teeth a study, and has aided somewhat in clearing the 
 "mystery" that Surgeon Gowing believes will "to a 
 certain extent always remain," for he has succeeded in 
 casting some light on the aetiology of a tooth's greatest 
 enemy — caries. His suggestion as to plugging teeth 
 with gutta-percha is novel, and in some cases might 
 be practicable. However, would not cement, which 
 gives such perfect satisfaction in human dentistry, be 
 preferable ? It is not expensive, and can be as readily 
 introduced into a cavity as gutta-percha; besides, as 
 the cavity must first be thoroughly cleaned (no matter 
 which is used), its use in the end might save time and 
 the tooth be much longer preserved. A horse's tooth 
 that can be got at conveniently, ought to be filled as 
 easily and, in decay of its neck, perhaps a 5 successfully 
 as a human tooth. Prof. Varnell's views are in sub- 
 stance as follows ("Veterinarian," 1867): 
 
 " Caries of the -fangs of the grinder teeth is rare and 
 generally very difficult to account for. I think that, 
 in the majority of cases, it depends upon external vio- 
 
 For old horses, and for those with defective teeth, chaff is pecu- 
 liarly useful, and for both classes the i^rain should be broken as 
 well as the fodder. The proportions are eight pounds of oats 
 and two of beans to twenty of chaff." 
 
 ConcerninfT swallowing without grinding Prof. Youatt further 
 says : " In cases of this kind the teeth should be examined. 
 Some of them may be unduly lengthened, particularly the first 
 of the grinders, or their ragged edges may wound the cheek. In 
 the former case the hors;=^ cannot properly m^.sticate his food ; 
 in the latter he will not, for horses, as too often occurs in sore 
 throat, would rather starve than put themselves to much pain." 
 
THE ALYEOLO-DEXTAL PERIOSTEUM. 165 
 
 lence, although we are not always able to trace it to 
 such a cause. Inflammation of the alveolo-dental peri- 
 osteum, especially where it surrounds the fang or fangs 
 of a tooth, would tend to this result. Other causes 
 may produce the same effect. Indeed, Avhenever or 
 however effected, wiien the nutrition of any part of a 
 tooth ceases, decay is Ukely to foll*Ow. V\^hen caries 
 beirins from within, it is due to cessation of nutrition, 
 arising perhaps from disease of only a part of the cen- 
 tral pulp of the tooth. If from without, it arises from 
 the periodontal membrane where it meets the gum. 
 
 " Caries of the cervix (neck) of the tooth is much 
 more common than it is in the fang ; still it does not 
 occur in more than one horse in five hundred. The 
 question will naturally be asked, To what does this 
 tendency to decay belong ? Under such circumstances 
 are we not forced to the conclusion that it must de- 
 pend either upon a defective structure of the tooth, or 
 that the dentine, enamel, and cement are dispropor- 
 tionately developed, or that one of them is defective in 
 its parts ? Another and perhaps the most frequent 
 predisposing cause of caries of the neck of the grinder 
 teeth is that food becomes impacted betw^een them. 
 Its decomposition may not only affect the teeth, but 
 the alveolar processes also." 
 
 The professor believes that caries of the crown of a 
 tooth is generally caused by the horse biting on a stone 
 or piece of metal during mastication. If the stone is 
 lodged in the cavity of the infundibulum, the pulp of 
 the°tooth may be injured, for, to use the professor's 
 words, '' the thickness of the tooth between the upper 
 part of the pulp-cavity and the bottom of the deepest 
 infundibula is not very great." 
 
166 THE PATHOLOGY OF THE TEETH. 
 
 Of the treatment of caries of the necks and crowns 
 of grmder teeth, the professor says: 
 
 '^ As I am riot avfaro of any treatment by which the 
 decaying' process can be stopped, I would as an experi- 
 ment in suitable cases — that is, in those in which the 
 diseased part may 'be got at — phig tlie tooth with gutta- 
 percha, having first thoroughly cleaned the cavity. If 
 ?ae plug can be retained in its place, some benefit may 
 be derived from its use. Believing, however, that the 
 decomposition of food impacted between the grinder 
 teeth is one of the exciting causes of their decay, I 
 would advise that it be now and then removed. It 
 would not only prevent decay, but in cases where decay 
 had already begun, would to some extent check its pro- 
 gress. Indeed, I think the health of the horse would 
 in many cases be improved by the adoption of such a 
 plan." 
 
 Yfliile the professor recommends gutta-percha plugs 
 for the crowns of slightly decayed grinders, he says 
 that, compared v/ith those of the necks, they are "less 
 likely to be of even a slight benefit, inasmuch as the 
 plug would be removed by attrition." Where the in- 
 terior of the grinder is destroyed by disease, and the 
 usual longitudinal fracture has occurred, he extracts 
 the tooth with the forceps. While, as a rule, the tooth 
 fractures longitudinally, the corners, he says, are some- 
 times broken off. * 
 
 In commenting on the diseases of the alveolar pro- 
 cesses. Prof. Varnell says: 
 
 "The causes which give rise to this condition of the 
 maxillary bones are not easy to define. That a horse 
 so affected is from certain peculiarities predisposed to 
 
DISEASE OF ALVEOLAR PROCESSES. 167 
 
 it, there can be no donbt. For example, tlie teeth be- 
 ing placed at a distance from eacli other, thereby allow- 
 ing the food to lodge between them, mnst be looked 
 npon as a predisposing cause. A strumous diathesis, 
 which I believe to be more common in the horse than 
 is usually supposed, must also be regarded as a predis- 
 joosing cause. The particles of food which become 
 impacted in these unusually wide interdental spaces, 
 after a time decompose and give rise to fetid com- 
 pounds, which act prejudicially on the parts they are in 
 contact with. The membrane which covers the gums, 
 and also that which lines the alveoli and is reflected 
 on the fangs of the teeth, becomes inflamed. The 
 inflammation will extend to the bone, the blood-vessels 
 of which will become enlarged, as will also the Haver- 
 sian canals in which they ramify. The osseous larainaB 
 surrounding these canals v/ill be partially absorbed, 
 and to some extent separated from each other, and the 
 enlarged spaces thus produced will be filled with in- 
 flammatory exudation. Hence the soft, spongy state 
 of the gums and their tendency to bleed from slight 
 causes ; hence also the looseness of the teeth in the 
 alveoli." 
 
 Of the deformity called Parrot- 3Io2{tJi, and irregular- 
 ities of the incisor teeth, Prof. Varnell says: 
 
 " This deformity consists in the upper incisor teeth 
 projecting in front of and overhanging the lower ones 
 to the extent in some instances of an inch and a half. 
 The deformity resembles the upper bill of the parrot, 
 which projects over the lower ; hence the name. The 
 lower incisors, from not being worn off by attrition, 
 may become so long that the roof of the mouth is seri- 
 ously injured. The deformity is generally associated 
 
168 tHE PATHOLOGY OF THE TEETH. 
 
 with an irregular position of the upper grinders rela- 
 tively with the lower. 
 
 '' Sometimes the horse, when at pasture, is unahle to 
 take a sufficient quantity of food to keep himself in 
 condition, and consequently he is considered legally 
 unsound. But if fed from the manger he experiences 
 little trouble in collecting his food; nor will his ability 
 to masticate it be interfered with, except perhaps in 
 old age. 
 
 " Treatment. — The treatment can only be palliative. 
 If the roof of the mouth should become diseased and 
 mastication impaired, the only remedy is to reduce the 
 length of the lower incisors. The instrument generally 
 used is a file or a rasp, but the process is so tedious and 
 slow that it is seldom that much good is done. If the 
 sliding-chisel could be brought to bear on them, their 
 length could be readily reduced. Talking on the sub- 
 ject with my friend, Surgeon Gowing, he suggested a 
 modification of this instrument which, I think, would 
 answer very well. 
 
 "Irregularities of the incisor teeth, both with refer- 
 ence to their position and number, are even.more com- 
 mon than in the grinders, but they seldom cause actual 
 disease." 
 
 Prof. William Williams, like Prof. Yarn ell, has per- 
 formed his part in elucidating the subject of caries of 
 the teeth, and he has also illustrated the transmission 
 of vitality to them from the outside — through the me- 
 dium of the cement— after it has ceased to flow through 
 the pulp on the inside, the pulp having become con- 
 verted into dentine. It appears that anything that 
 disturbs the equilibrium of this flow of vitality, which 
 is the secret of the growth of the teeth throughout 
 
CEMEXT FILLING THE PULP'S OFFICE. 169 
 
 life, may cause caries. Prof. Williams says (" Princi- 
 ples and Practice of Veterinary Surgery," p. 470) : 
 
 *' Caries, dental gangi-ene, or decay, is almost exclu- 
 sively confined to the grinder teeth— although I have 
 seen the incisors in that condition— and may begin 
 primarily in the fang, neck, or crown of the tooth. 
 
 "' Caries of the fang arises from inflammation of the 
 pulp, and may be caused by a constitutional predispo- 
 sition or external injury. Inflammation of the pulp, 
 however, does not always cause caries. I have several 
 cases on record where the fangs were enlarged from 
 periodontal deposit, with abscesses surrounding the 
 fangs, without caries. Caries beginning at the fangs 
 may be due to the obliteration of the pulp-cavity at 
 an age when the vitality of the tooth depends upon 
 the integrity of the pulp. I need scarcely remind the 
 professional reader that the integrity of the teeth de- 
 pends upon a due supply, hoth as to quantity and 
 quality, of nutritive materials. 
 
 *'Ori the fangs of a recently cut tooth but little 
 cement is met with compared with that which exists 
 in old teeth. As age advances the cement increases, 
 and the tooth grows from the outside. In man it is 
 generally agreed that after a given time the dentine 
 ceases to be produced, and that the pulp is converted 
 into osteodentine. In the horse the pulp-cavity be- 
 comes obliterated gradually by the pulp continuing to 
 form dentine, the pulp simply giving way to its own 
 product, which ultimately occupies its place and fills 
 its cavity. In proportion as the pulp diminishes the 
 supply of nutriment is lessened, .until at length it is 
 entirely cut off from the interior; to provide for the 
 vitality of the tooth the cement increases in quantity 
 8 
 
170 THE PATHOLOGY OF THE TEETH. 
 
 on the fang, and at the expense of the perfectly formed 
 dentine lying in immediate contact with its inner sur- 
 face. That is to say, this layer of dentine is converted 
 into cement by the dentinal laconge nndergoing dila- 
 tation and becoming identical with the hollow spaces 
 or cells of the cement. The tooth now draws its nour- 
 ishment from the blood-vessels of the socket, and thus 
 continues, long after the obliteration of its pul]3-cavity, 
 to perform its part in the living organism. 
 
 '•This is the natural condition of old teeth. But 
 when the pulp-cavity is obliterated at an early age, by 
 a too rapid formation of dentine, and consequent ob- 
 literation of the pulp when the cement is not yet suffi- 
 ciently developed to supply nourishment to the whole 
 tooth, caries must be the result. Many cases of caries 
 that have come nnder my observation have resulted 
 from this cause, and very often the disease is confined 
 to that part of the cement that dips with the enamel 
 into the interior of the tooth, splitting it into several 
 longitudinal fragments. 
 
 "Caries of the neck of the tooth is seen in those 
 iiorses whose teeth are wide apart, and is caused by 
 the food remaining in the interspaces, and by decora- 
 position exciting inflammation in the periodontal 
 membrane. Caries of the neck is very commonly met 
 with in the teeth of dogs, sometimes causing abscesses 
 in the cheek. 
 
 ^'Caries beginning at the crown is due to a portion 
 of the dentine losing vitality and the power of resist- 
 ing the chemical action of the fluids of the mouth. A 
 portion of the enamel of the crown may be fractured 
 by biting a stone or piece of metal contained in the 
 food. Mere fracture of the enamel, however, is insuffi- 
 cient of itself to lead to caries of the teeth in the lower 
 
SIFTING THE FEED. 171 
 
 animals, for it is a substance that is gradually worn 
 off by mastication ; but the violence which has caused 
 fracture of the enamel, may at the same time have 
 caused such an amount of injury to the dentine that 
 it dies, and progressively becomes decomposed. In 
 man it seems there should be death of the dentine and 
 acidity of the oral fluids before caries can take place, 
 test-paper applied to a carious tooth invariably show- 
 ing the j^resence of free acid, and a very small perfora- 
 tion in the enamel may coexist with a considerable 
 amount of disease in the dentine." 
 
 Surgeon T. W. G owing, of London, a well-known 
 inventor of dental instruments (veterinary), in an 
 '' Essay on the Diseases of the Teeth of the Horse," 
 which was printed in "The Veterinarian" for 1851 
 (p. G32), in substance says: 
 
 "I am aware that the cause of disease of the teeth 
 must to a certain extent always remain a mystery; yet 
 from observation and reflection we may be able to de- 
 duce conclusions which practice will confirm. 
 
 "Let us consider the two classes of horses that we 
 are principally called upon to attend, namely, the cart 
 or draft-horse, and the hack or carriage-horse. So far 
 as my observations have led me, the latter class are 
 less liable to diseases of the teeth than those of a 
 coarser breed. Now, may not this be caused by the 
 better care they receive in the stable? The good and 
 efficient groom regularly sifts the provender previous 
 to feeding his horses, and thus rids it of stones, glass, 
 &c. Tlie cart-horse and the machine-horse of our 
 London omnibus proprietors, not receiving this atten- 
 tion, are more subject to diseases of the teeth. Be- 
 sides, it is a common practice with carters to sprinkle 
 
172 THE PATHOLOGY OF THE TEETH. 
 
 the provender with sulphuric acid, and we well know 
 how acids affect the teeth. If such practices be al- 
 lowed, diseases of the teeth may be readily accounted 
 for. 
 
 " The teeth being lowly organized, soon lose their 
 power of self-preservation. Tney are affected by the 
 general health of the animal. Should the function of 
 the stomach or alimentary track be deranged, the teeth 
 — from the general health of the animal being inter- 
 fered with, and from the local functional derangement 
 — of all parts of the body, are the first to suffer or de- 
 cay. Absorption of the gums, which may be caused 
 by the decayed food that lodges between the grinders, 
 is often followed by decay of the cement, which, being 
 the most exterior as well as the most highly organized 
 of the three substances composing the teeth, is the 
 first to yield." 
 
 After describing the usual symptoms of diseased 
 teeth. Surgeon Gowing asks : 
 
 " Who that has observed these symptoms, can hesi- 
 tate for a moment to acknowledge that the animal is 
 suffering pain, which, if we were to say arose from 
 toothache, would not be beheved by our employers?" 
 
 Prof. W. Youatt says in substance ("The Horse," 
 p. 230) : 
 
 " Of the diseases of the teeth we know little. Cari- 
 ous teeth are occasionally seen. They not only render 
 mastication difficult, but they sometimes impart a fetid 
 odor to the food, and the horse acquires a distaste for 
 aliment altogether. Carious teeth should be extracted 
 as soon as their real state is known, for the disease is 
 often communicated to the contiguous teeth and to 
 
FUXGUS H^MATODES. 173 
 
 the jaw also. Dreadful cases of 'fungus hsematodes' 
 have arisen from the irritation of caries. 
 
 " Every horse that gets thin or out of condition, 
 without fever or other apparent cause, should have his 
 teeth and mouth examined, especially if, without any 
 indication of sore throat, he * quids' his food; or if he 
 liolds his head to one side while he eats, in order to 
 get the food between the outer edges of his teeth. The 
 cause is irregular teeth. Such a horse is materially 
 lessened in value and is to all intents and purposes 
 unsound, for although the teeth may be carefully sawn 
 down, they will project again at no great length of 
 time. Ahorse cannot be in full possession of his nat- 
 ural powers without perfect nutrition, and nutrition 
 is rendered imperfect by any defect in mastication." 
 
 Prof. R. Owen, in his work entitled "A History of 
 British Fossil Mammals and Birds " (pp. 388-0), gives 
 an account of a diseased fossil horse's tooth which he 
 found at Cromer. He says he is " induced to cite one 
 of the curious examples of disease in an extinct animal 
 from the rarity of its occurrence in the tissue which is 
 the subject of it." The facts of this rare case are as 
 follows: 
 
 " One of the Cromer fossil teeth, from the lower jaw, 
 with a grinding surface measuring one inch five lines 
 in long (antero-posterior) diameter, and eight lines in 
 short (transverse) diameter, presented a swelling of 
 one lobe, near the base of the implanted part of tlie 
 tooth. To ascertain the nature and cause of this en- 
 largement, I divided it transversely, and exposed a 
 nearly spherical cavity, large enough to contain a 
 pistol-ball, with a smooth inner surface. The parietes 
 of this cavity, composed of dentine and enamel of the 
 
174 THE PATHOLOGY OF THE TEETH. 
 
 natural structure, were from one to two lines and a 
 half thick, and were entire and imperforate. The 
 water percolating the stratum in which this tooth 
 had lain, had found access to the cavity through the 
 porous texture of its walls, and had deposited on its 
 interior a thin ferruginous crust; but the cavity had 
 evidently been the result of some inflammatory and 
 ulcerative process in the original formative pulp of 
 the tooth, very analogous to the disease called 'spina 
 ventosa' in bone." 
 
CHAPTER IX. 
 
 THE DENTISTRY OF THE TEETH. 
 
 Reports of Cases Treated by Various Surgeons. — Gutta-Percha 
 as a Filling for Trephined Sinuses. — Teetli Pressing against 
 the Palate. — Passing a Probe through a Decayed Tooth. — 
 Death of a Horse from Swallowing a Diseased Tooth. 
 
 Horsemen, farmers, and otlier practical men will 
 find much useful information in the present chapter, 
 for it is based on the experiences of Veterinary Sur- 
 geons, whose reports appear in the various volumes of 
 *'The Veterinarian" (printed monthly in London), 
 and to which I am so much indebted for other useful 
 information. It is probably not too much to say that 
 the more generally the chapter is read the fewer horses 
 will be killed in the future for ha\ang decayed teeth, 
 accompanied with a discharge from the nostril. 
 
 In ^'The Veterinarian" for 1856 (p. 437) Surgeon J. 
 Horsburgh reports the following interesting case, en- 
 titled "Chronic IS'asal Gleet produced by a Diseased 
 Tooth:" 
 
 '^ About twelve months a^o I was consulted about 
 the case of a mare with a discharge from the near nos- 
 tril. " She had been under treatment for eighteen 
 months, and the superior maxillary sinus had been 
 opened with the trephine. The discharge, however, 
 continued to flow^ both from the nostril and the 
 
176 THE DEIS'TISTRY OF THE TEETH. 
 
 wound, notwithstanding the trephining had been per- 
 formed a year before I saw the animal. 
 
 " The defluction had an offensive smell, and the sub- 
 maxillary gland was enlarged, causing sus])icion of 
 glanders. The opening had been made a little too 
 high, so that the central instead of the superior part 
 of the sinus was perforated. I found that the whole 
 mischief was caused by a dise^ised tooth. With the 
 assistance of a smith I removed the tooth, which was 
 split up its middle and considerably decayed- It was 
 more than two inches long, and was bent forward to- 
 ward the cheek. The odor was most offensive. I then 
 opened the frontal and maxillary sinuses, both of 
 which were filled with fetid pus. The wounds were 
 first treated with a weak solution of chloride of lime, 
 and subsequently with an ordinary astringent lotion. 
 In addition to the local treatment, I administered the 
 diniodide of copper. 
 
 "After a considerable time the wounds were allowed 
 to heal, and the mare appeared much better. But very 
 shortly the discharge began to flow again worse than 
 ever, and the smell was almost intolerable. Deter- 
 mined, if possible, to make a cure of the case, I cut 
 into the sinus again with the skull-saw, taking out a 
 triangular piece of bone about two inches long by one 
 inch and a half broad. At the upper part of the 
 cavity I found some masticated food in a state of de- 
 composition. It had passed through the alveolus into 
 the sinus. Fractured bones were removed, and the 
 opening being extended through into the nostril, a 
 small instrument could be passed dov/n it into the 
 mouth. A weak nitric acid lotion was used to induce 
 fresh inflammatory action, and, if possible, to fill up, 
 by an effusion of lymph, the passage through which 
 
CURED INSTEAD OF KILLED. 177 
 
 the food was pressed upward from the mouth into the 
 cavity. The external wound was dressed with an 
 ordinary heahng lotion, and tow Avas put into it daily, 
 and pressed downward to the mouth. A little Ulster 
 liniment was also occasionally applied. 
 
 ^'Before operating, the frontal sinus on the affected 
 side was considerably more bnlging than the other. It 
 is now reduced, and the wound has healed. The dis- 
 charge from the nose has stopped, and there is no 
 smell. Thus, after about two years and a half of 
 treatment, this mare, now only five years old, is able 
 to resume her work, and has every appearance of being 
 likely to remain well. 
 
 " Had I not been able to effect a cure by the closing 
 of the passage into tlie mouth, I would have tried 
 filling it with gutta-percha. If a discharge w^re to 
 take place again in this case, it would no doubt depend 
 on the existence of a small aperture, and, under such 
 circumstances, I should not hesitate to again cut into 
 the sinus and endeavor to close the opening in the 
 bone with gutta-percha, or some similar substance.'^ 
 
 Surgeon H. Surmon, in an article ^^ On the Extrac- 
 tion of Projecting Teeth," tells how he saved a horse 
 that had been ordered killed by its owner ("Veterina- 
 rian," vol. ii, p. 2b): 
 
 " Last year a neighbor of mine had a horse which 
 had been losing flesh for some time, and his appetite 
 Avas gradually diminishing. When I first examined 
 the horse I saw no appearance of disease that could 
 affect his appetite, and looking at his mouth I per- 
 ceived no laceration of the cheeks or other injury. 
 The horse grew worse, became almost a skeleton, and 
 its owner ordered that it be killed. Beinir informed 
 
178 THE DEITTISTRY OF THE TEETH. 
 
 of the fact, I expressed a wish to examine his mouth 
 once more. I accordingly put a balling-iron into his 
 mouth and introduced my hand, and at the extremity 
 of the grinders I found two teeth, one on each side of 
 the lower jaw, which had grown long enough to press 
 into the roof of the mouth, and thus prevented the 
 animal from eating. I endeavored to extract these 
 teeth with an instrument similar to that used for the 
 human teeth, but without effect, as it could not be 
 got on them. I then contrived an instrument v/hich 
 v.as very simple. When it was passed up the mouth, 
 the tooth became fixed between the divided end of the 
 iron ; the handle being then turned, the tooth was 
 extracted with the greatest ease. From that moment 
 the horse began to feed, and rapidly improved in con- 
 dition. In a short time he v/ent to work, and has done 
 well." 
 
 Surgeon 0. May, of Maiden, Eng., thus tells how he 
 cured "A Case of Disease of the Jaw" (" Veterinarian," 
 1834, p. 93): 
 
 " I was requested by Mr. Earn, of Purleigh, to look 
 at a horse which he told me had a ^cancer' in his jaw. 
 I found my patient, a fine young chaise-horse, looking 
 very poor, and having a constant discharge from the 
 region of the root of the second low^er grinder. There 
 v/as considerable enlargement of the bone, which led 
 me to suspect disease of the tooth, and which, on ex- 
 amination, proved to be true. On introducing a probe 
 into the orifice, I found that it went through the tooth 
 into the mouth. I was inform^ed that this supposed 
 cancer had been under the treatment of a farrier, and 
 that the poor beast bad been subjected to many pain- 
 ful caustic applications. As I was satisfied that no 
 
THREE UPPER GRINDERS EXTRACTED. 179 
 
 good could be done to tlie jaw as long as the tooth re- 
 mained in it, I decided to extract it. I had an instru- 
 ment made similar to the key used in human dentistry, 
 with a handle like that of an auger. Having cast my 
 })atient and lanced the gum, I fixed the instrument on 
 the tooth and succeeded in extracting it, although it 
 required nearly all my strength. Tliere was but 
 trilling hemorrhage, and the 'cancer' soon got well. 
 I think our patients are more frequently the subjects 
 of toothache tlian we suppose. • Perhaps 'quidding' in 
 many of them might be traced to a carious tooth." 
 
 In a report of ten cases of diseased t^eth that were 
 treated at the Edinburgh Veterinary College during 
 tlie year 1845, the details of one is thus given in "The 
 Veterinarian" (1845, p. 626): 
 
 "A cart-horse was brought here with a profuse flow 
 of white, clotty, and offensively smelling matter from 
 the off nostril. The external plate of the superior 
 maxillary bone on the same side was considerably 
 elevated, and pain was evinced on pressing the part. 
 There was no ulceration visible of the Schneiderian 
 membrane, but the submaxillary lymphatic glands 
 were somewhat enlarged. On examination there ap- 
 peared to be disease of the superior maxilla, in which 
 the grinder teeth were involved. Considering the 
 extent to which the facial bones were affected, it was 
 decided, as the only way of effecting a permanent cure, 
 to extract the diseased teeth. The horse was cast, and 
 by means of the ordinary tooth-key three of the upper 
 back teeth were extracted. In a few days after the 
 operation the discharge diminished in quantitv, and 
 under the continued application of proper remedies it 
 entirely subsided, and the horse is now well. 
 
180 TITE DEis"TISTRY OF THE TEETH. 
 
 "There are in this, as in former reports, cases where 
 the superior maxillary bone and its sinuses have been 
 injured from the elongation of the grinders of the in- 
 ferior maxilla, causing a nasal discharge iu many cases 
 mistalien for that of glanders. They are easily reme- 
 died by shortening the teeth with the cntting-forceps." 
 
 Surgeon A. H. Santy says (" Veterinarian," 1875, 
 p. 835): 
 
 "On the 26th of June I bought a six-year-old mare. 
 She continued to work till July 17th, when she was 
 suddenly taken with a slight running from the near 
 nostril, which greatly increased in twenty-four hours. 
 The submaxillary gland on that side -swelled. There 
 was slight tenderness of the throat and loss of appe- 
 tite, which soon passed away. I showed the animal to 
 a brother surgeon, and told him I thought of trephin- 
 ing. He said: * Don't be in a hurry.' It struck me 
 there might be something wrong with the grinders. I 
 examined them, and found the fourth superior near 
 side tooth with a depression on the outside and slightly 
 raised from the surface of the other teeth. There was 
 slight fetor from the food lodging there. I at once 
 cast the mare, and with some difficulty extracted the 
 tooth. I then dressed the wound and nursed the mare 
 for a few days. The discharge from the nostril ceased 
 in ten days. I have the mare now in constant work." 
 
 The above case deserves consideration for several 
 reasons. Thousands of horses with precisely the same 
 symptoms have been killed because the surgeon could 
 not discriminate between diseased teeth and glanders. 
 The "slight tenderness of the throat and loss of appe- 
 tite, which soon passed away," was the result of the pus 
 
*' DON'T BE IN A HURRY.'* 181 
 
 finding an outlet, which gave partial relief. Surgeon 
 Saoty acted on tlie advice, "Don't be in a hurry," and 
 consequently had time to think. The depression on 
 the outside of the tooth and its slight projection above 
 • the common level, were signs that the trained eye only 
 will detect. However, had the operation been delayed 
 for a short time, in addition to the depression on the 
 outside of the tooth, the gum would have been more 
 or less shrunken, and the tooth, as a natural conse- 
 quence, would have appeared longer.* Further, in- 
 stead of the tooth being "slightly raised from the sur- 
 face," it might have been beloAV it; for, the inflamma- 
 tion having subsided, and the roots being shortened 
 by the caries, it is liable to be forced deeper into the 
 socket. Its next natural movement, the caries havin^- 
 destroyed its periosteum, is to drop out altogether. 
 
 As an offset to the foregoing cures, a few cases that 
 terminated in death will be given. Surgeon Samuel 
 Baker, in a letter to the editor of " The Veterinarian " 
 (1845, p. 21G), says: 
 
 "I was called in by a neighboring farmer to examine 
 a two-year-old colt, which had to all apj^earance a polj'- 
 pus as large as a cricket-ball growing out of the right 
 nostril. Respiration through that nostril was stopped. 
 In order to ascertain its nature, I had the colt cast, 
 and found that the nostril was filled with a hard fleshy 
 tumor, which distended the other nostril also. After 
 making an incision through the ala and side of the 
 nostril, I removed a portion of the tumor, over a pound 
 in weight. But, as still no air passed through, and 
 
 * Slirinkaf^e of tlie gum, accordinf^ to C. D. House, invariably 
 follows caries of the roots of the teeth. 
 
182 THE DEHTISTRY OF THE TEETH. 
 
 there seemed not the slightest chance of gaining a 
 passage, I ordered the colt to be killed. 
 
 " In dissecting the head I found that the cause pro- 
 ceeded from a decayed tooth, at the root of which was 
 a bag of matter about the size of a walnut, which by 
 no possible means could relieve itself." 
 
 Surgeon Baker does not say v/hich of the six teeth 
 (of course it was an upper grinder of the right side) 
 was diseased. The complications of the case appear to 
 have been unusual, otherwise the bag of matter would 
 have sooner or later found an outlet through the nos- 
 tril. The extraction of the tooth would have probably 
 afforded an outlet through the alveolus ; this failing, 
 the effect of trephining the sinuses should have been 
 tried. 
 
 Surgeon William Smith, of JSTorwich, Eng., reports 
 a case of caries of the roots of several grinder teeth, 
 accompanied by a discharge from the nostril, which 
 he admits he mistook for ozena. He says ("Veterina- 
 rian," 1850, pp. 381-2): 
 
 ^^I was requested a few days ago to visit a horse 
 which was supposed to be 'glandered.' I found the 
 animal in a most emaciated and pitiable condition, 
 with a copious greenish and very offensive discharge 
 from the left nostril, with slight tumefaction of the 
 gland on the same side. There Avas no appearance of 
 ulceration, but the Schneiderian membrane had a 
 leaden, dirty hue. Taking all the circumstances into 
 consideration, I ordered the animal's destruction, but 
 had its head sent to my infirmary. 
 
 " Meeting Surgeon Gloag, of the Eleventh Hussars, 
 I told him I thought I had a case of ozena. He ex- 
 
OifE TOOTH LOST AXD POUR DISEASED. 183 
 
 pressed a wish to be present at the examination of the' 
 head, and I was glad to avail myself of his assistance. 
 
 "A longitudinal cut was made on each side of the 
 septum nasi, and a transverse one at a line between 
 the center of the orbits. Anotlier longitudinal cut, 
 dividing the maxillary sinuses, was made just above 
 the fangs of the grinder teeth on each side. By this 
 means we had an opportunity of examining tlie sep- 
 tum nasi on each side ; also tlie turbinated bones, and 
 the frontal and maxillary sinuses. 
 
 " On the left side we found an accumulation of pul- 
 taceous food, covered v/ith thick pus, completely filling 
 the maxillary sinus, and extending to the turbinated 
 bones. The frontal sinus contained an accumulation 
 of inspissated (thickened) pus, the septum nasi was of 
 a leaden hue, as also the membrane covering the tur- 
 binated bones, which was much inflamed and thick- 
 ened, but there v/as no appearance of ulceration. 
 
 *•' The difiieulty was to ascertain how the food got 
 there. After careful search, it Vv'as very evident that 
 it could not have passed through the nostril. We 
 therefore gradually dislodged the Ibod and matter, 
 searching for the former's entrance, and at last found 
 a hole in the alveolar space belonging to the last 
 grinder, the fang of which was completely gone, only 
 a small portion of the crown itself remaining. The 
 hole was sufficiently large to admit the little finger. 
 The mystery was solved — the process of mastication 
 had deposited the food in the sinus. The fourth 
 grinder was absent, having been lost evidently from 
 previous disease. 
 
 " On examining the right side of the head we found 
 the turbinated bones and membranes covering the 
 septum nasi comparatively healthy, but we discovered 
 
184 THE DENTISTRY OF THE TEETH. 
 
 a cyst, about the size of a walnut^ in the maxillary 
 sinus. It contained limpid fluid, and occupied the 
 space immediately over the fang of the fourth grinder 
 tooth, which was decayed and quite loose, and beloiu"^ 
 the level of the other teeth. The teeth of the lower 
 jaw appeared healthy." 
 
 Without further examination, Surgeon Smith sent 
 the head to the editor of "The Veterinarian," who 
 
 says : 
 
 "The mare (that being the sex according to the 
 teeth) we should take to have been about twenty years 
 old. Her incisors are sound, and so are the grinders 
 of the lower jaw. But in the near (left) upper jaw, 
 the second, fourth, and sixth teeth are in a state of 
 progressive decay, and the same is true of the fourth 
 tooth of the off side. The vacuity caused by the de- 
 fective last grinder has opened a passage to the an- 
 trum, through which the food has passed, and thence 
 into the near chamber of the nose, between the tur- 
 binated bones, where it was discharged through the 
 nostril. This accounts for the irritation on this side 
 of the head, for the suppurated and even ulcerated 
 condition of the Schneiderian membrane, and for the 
 suspicious discharges. It was evident enough that 
 there was no glanders. The very circumstance of ali- 
 mentary matter being discharged through the nostril 
 was enough to prove the contrary." 
 
 Still another case of destroying a horse for what 
 merely appeared to be glanders is recorded by Prof. 
 
 * The italics are mine. Compare with comments on Surgeon 
 Santy's cape, page 181. 
 
A GOVEENMENT HORSE'S HARD LOT. 185 
 
 William Percivall iu his work entitled "Hippopath- 
 ology" (vol. ii, p. 237). He says: 
 
 "There are instances on record of carious teeth be- 
 ing productive of such evil consequences as to lead, 
 through error, to a fatal termination. The following 
 relation ought to operate on our minds as a warning 
 in pronouncing judgment in cases of glanders, or at 
 least in sucli as assume the semblance of glanders : 
 
 "A horse, the property of government, became a 
 patient of Surgeon Cherry on account of a copious 
 defluction of discolored and purulent matter from the 
 near nostril, unaccompanied by submaxillary tumefac- 
 tion, or by ulceration of the Schneiderian membrane. 
 For two or three months the case was treated for 
 glanders; but no improvement following, a consulta- 
 tion was deemed necessary, the result of which was 
 the horse was shot. 
 
 " On examination of the head, the third upper left 
 grinder proved to be carious, one-third of its fang be- 
 ing already consumed and the remainder rotten. The 
 formation of an abscess within its socket had loosened 
 the tooth, and the matter flowing therefrom had estab- 
 lished a passage into tlie contiguous cluimber of the 
 nose. The antrum was also in part obstructed by the 
 deposition of osseous matter. 
 
 "This is a case which, but for the inquisitiveness of 
 Surgeon Cherry, would have merged into that hetero- 
 geneous class of diseases passing under the appellation 
 of clironic glanders. 
 
 "My father's museum contained several specimens 
 of carious teeth. One was that of a grinder, the inte- 
 rior of which was black and rugged, from being eroded 
 by ulceration, and the fangs had from (he same cause 
 
186 THE DEI^TISTRY OF THE TEETH. 
 
 mouldered away. Two others presented brittle exos- 
 toses upon their sides, forming spacious cavities within 
 and communicating with the contiguous teeth. One 
 of them exhibited a perforation through which pus 
 aj^peared to have issued. Both seemed to have been 
 cases which had originated in internal injury." 
 
 Prof. George Yarn ell closes his series of papers " On 
 Some of the Diseases Affecting the Facial Eegion of 
 the Horse's Head" ("Veterinarian," 18G7), by giving 
 an account of a case of *osteo-sarcoma,' the disease, in 
 his opinion, being caused by carious teeth. The case 
 illustrates the importance of veterinary dentistry ad- 
 mirably. He says : 
 
 "Further to illustrate varieties of the diseases of 
 the sinuses, I will relate a case of osteo-sarcoma which 
 came under my care in July, 1862. I foand tlie horse 
 had an offensive discharge from the left nostril. The 
 face below the orbit was enlarged, and the eye slightly 
 displaced in its cavity. I also found that the three 
 last grinder teeth in the upper jaw of the affected side 
 were quite loose in their sockets, from which a dis- 
 charge of a highly fetid character issued. Percussion 
 on the side of the face indicated extensive disease, and 
 the enlargement readily yielded to pressure. As there 
 was not the slightest prospect of a cure, I suggested 
 that the animal be killed. 
 
 '^Post-mortem Examination. — The outer walls of the 
 sinuses, which were very thin, were first removed, dis- 
 closing a mass of disease the seat of v/hich was oppo- 
 site the fangs of the fourth grinder tooth, which was 
 carious. This abnormal growth occupied the maxil- 
 liiry, malar, lachrymal, and a portion of the frontal 
 sinuses, and had also encroached upon the orbit to 
 
SWALLOWING A DISEASED TOOTH. 187 
 
 such an extent as to displace the e3Tl)all. The outer 
 surface' of the diseased mass was soft' in texture. It 
 had a gelatinous appearance, and when pressed with 
 the blade of the scalpel, a thin, watery fluid oozed from 
 its surface. A section of it presented a grayish-red 
 appearance, with lightish streaks of fibro-osseous mat- 
 ter diverging from its roots and extending irregularly 
 through its entire substance. The facial bones them- 
 selves, in the region of the disease, had in some parts 
 disappeared altogether, wiiile in others the cancelli 
 were much enlarged, their osseous partitions pai-tially 
 absorbed, and their interstices filled with a deposition 
 of a fibro-cellular structure. 
 
 " Such is a brief outline of this malignant and in- 
 curable disease, wliich I have no doubt primarily arose 
 from caries of the fangs of the grinder teeth." 
 
 Prof. Renault, of Alfort, France, is the author of an 
 interesting account of a very unusual case, namely, 
 the swallowing of a diseased tooth by a horse, which 
 appeared originally in the '' Recueil de Medicine Vete- 
 rinaire'' for 183G. It is an argument against casting 
 horses for the purpose of extracting their teeth, for 
 had the horse been in a standing position the accident 
 would not have occurred. When a horse's head rests 
 upon the occiput, the muzzle pointing upward, it is as 
 natural — the tooth being free of the forceps as well as 
 the socket — for it to drop into the throat as it is for 
 water to run down hill. The full history of the case 
 is as follows : 
 
 *' A post-horse, seven years old, had not fed well, and 
 had been losinc: flesh durinof about three weeks. On 
 the 2Gth of November, 1835, I suav him for the first 
 time. The postilion told me that within the last two 
 
188 THE DEIS'TISTRY OF THE TEETH. 
 
 days he had eaten with more difficulty and pain than 
 before, and dropped ahnost the whole of the hay and 
 corn from his mouth before it was perfectly masticated. 
 He had also observed that during the mastication of 
 his food tlie horse always inclined his head to the left 
 side. 
 
 "On examining the mouth, I easily recognized the 
 cause of this difficulty of mastication. The gum, at 
 the second grinder of the right lower jaw, was swollen 
 and ulcerated, both within and without. The least 
 pressure on the gum at this spot inflicted great pain, 
 and the animal also suffered when the crown of the 
 tooth was touched. On that portion of the jawbone 
 contiguous to the diseased tooth, was a considerable 
 swelling, hot and painful, which the postilion told me 
 had existed for about twelve days. It was increasing in 
 size every day. The breath w\as only slightly fetid, 
 and there was nothing to indicate caries of the tooth. 
 I expressed the opinion that the caries, if it existed, was 
 confined chiefly to the root of the tooth, and that the 
 ulceration of the alveolar septa beneath, of which there 
 was no doubt, rendered its extraction necessary. 
 
 " On the following day the horse was cast, and his 
 mouth being kept open by the proper instrument, the 
 key was applied to the tooth. It resisted my first 
 effort to draw it, but, on the second trial, gave way 
 with a peculiar sound, which made me suspect that it 
 was broken. The instrument (gag) was then taken 
 out of the mouth, in order that the tooth might 
 escape, but, to my great surprise, no tooth could be 
 seen, notwithstanding I carefully searched for it. It 
 w^as now plain that the tooth had been swallowed. I 
 then assured myself that the tooth had been entirely 
 extracted, and as, during the operation, the frenulum 
 
OPENIN"G THE JUGULAK. 189 
 
 of the tongue had been wounded, I deferred the cau- 
 terization of the alveolus till the following day. 
 
 *• As to the swallowing of the tooth, I gave mj^self 
 very little concern. I did not think that so small a 
 body was likely to form any serious obstruction in the 
 intestinal canal, or that its temporary sojourn in the 
 large intestine could become at all dangerous; so I 
 merely directed tliat the mouth be frequently washed 
 with warm water, and forbade the use of hard food. 
 
 "29th. I again saw the horse, and no serious con- 
 sequence had yet followed the operation. He ate bar- 
 leymeal mash with appetite, and a small quantity of 
 hay. Two hours afterward he was brought to the 
 School. He was very uneasy, and his belly was enor- 
 mously distended, the sweUing being principally on 
 the right side, where the resonance was considerable 
 on percussion. The horse was continually endeavor- 
 ing to expel something from the anus, and the strain- 
 ing w^as so great that I feared the rectum would pro- 
 trude. The efforts were followed by small mucous 
 dejections, mixed with portions of food. The mucous 
 membrane was of a subdued red color. These symp- 
 toms had been preceded by swelling at the flanks; 
 colicky pains had followed, but they had ceased, 
 and nothing now remained except the enlargement of 
 the belly and the incessant effort to expel the faeces. 
 The artery was full, but the pulse was almost imper- 
 ceptible; the extremities were cold and the mucous 
 membranes of a red violet color. The nostrils were 
 convulsively dilated, respiration difficult and acceler- 
 ated, and the walk staggering; the skin was covered 
 with sweat, and, in a word, the animal presented every 
 symptom of immediate suffocation. On this account I 
 immediately opened the jugular and abstracted about 
 
190 THE DENTISTRY OF THE TEETH. 
 
 twelve pounds of blood. The patient was very con- 
 siderably relieved. I then ordered all four legs to be 
 w^ell rubbed with essential oil of turpentine. 
 
 ''There now appeared to me a conuection between 
 these symptoms and the swallowing of the tooth. But 
 where was this tooth ? Entangled in the pyloric ori- 
 fice of the stomach ? I could not perceive any symp- 
 tom of gastric disease. Was it in the convolutions or 
 the caical portions of the small intestines? How then 
 could I explain the distention of the large intestines 
 and the expulsive efforts, so violent and continued? 
 It was more likely that the tooth was lodged either in 
 the colon or the ca}cum, or in the irregularities of the 
 floating colon, and partially or entirely prevented the 
 passage of the faeces. It was hard to believe that in 
 the lapse of two days the tooth could have reached the 
 further part of the intestines. 
 
 " Having determined on the nature of the disease, I 
 was somewhat embarrassed to ascertain its precise seat. 
 I attempted to introduce my hand into the rectum, 
 but the circumvolutions of the bowels were so much 
 distended with gas, and so completely filled the pelvis, 
 and the mere introduction of my finger caused such 
 violent efforts to expel the contents of the rectum, that 
 I was forced to desist. 
 
 '' In the meantime the swelling rapidly increased, 
 and again threatened suffocation. I then determined 
 to use the only means in my power to prevent this, 
 namely, to puncture the caecum. This was effected 
 with the trocar used for hoove in sheep, and in an in- 
 stant the swelling subsided, and the symptoms of suf- 
 focation disa])peared. I was then enabled to introduce 
 my hand into the rectum, but I could not discover the 
 situation of the tooth. While exploring the rectum, 
 
THE TOOTH IN" THE CmCJJ'il, 191 
 
 liowever, the 'caniila' escaped from the csecum. The 
 swelling now began again, and increased with extraor- 
 dinary rapidity. I was about to plunge the trocar into 
 the intestines once more, when I perceived that all 
 treatment was useless. The animal was in the agonies 
 of death, and in a few moments it expired. 
 
 "The post-mortem examination took place immedi- 
 ately after death. I found in the heart and lun^'s all 
 the lesions which usually accompany death by suffoca- 
 tion. The digestive canal was distended by gas. The 
 stomach was half filled with barleymeal, but not a par- 
 ticle of it was found througliout the whole extent of 
 the small intestines, nor was there the slightest trace 
 of inflammation of the mucous coat. The caecum con- 
 tained a great quantity of blood-tinted fluid, but there 
 was no lesion or redness on any part of its internal 
 face to indicate the source of the blood. Probably it 
 came from the wound made by the trocar. 
 
 "In the cavity of the cJBCum, toward its point, we 
 found the tooth ; but, I repeat it, there was no inflam- 
 mation of its mucous membrane. There w^as, how- 
 ever, a slight discoloration of the membrane toward 
 the end of the colon ; it was of a slate color, and was 
 probably caused by the sulphuretted hydrogen gas. 
 
 "Are we to conclude that tlie death of the horse 
 was caused by the tooth? However extraordinary 
 such a conclusion may at first a])pear, I am very much 
 inclined to believe that it affords the best explanation 
 of the mystery. The horse had scarcely eaten for 
 fifteen days. This long fast had produced a compara- 
 tively empty condition of the digestive canal and an 
 augmentation of its irritability up to the moment of 
 the operation. The quietness of the hofse and his 
 appetite and apparent health during the tv/o days pre- 
 
192 THE DEI^TISTRY OF THE TEETH. 
 
 ceding his death, proved that the tooth passed without 
 obstacle through the first part of the intestinal canal. 
 Having arrived at the caecum, however, which was 
 almost empty, and lying for a greater or less time at 
 the inferior part of its mucous coat, its hard and irreg- 
 ular surface produced irritation ; and as the contrac- 
 tions of this intestine were not efiectual to seize the 
 tootji and return it to the beginning of the colon, the 
 prolongation of the irritation might suspend the diges- 
 tive function of this viscus, augment its secretions, 
 and cause the continual effort to expel the faeces. 
 Hence also arose the gaseous distention of the abdo- 
 men. As to the death of the horse, the tooth was only 
 the indirect cause. The direct cause was suffocation, 
 which was produced by the distention of the bowels." 
 
 Prof. Bouley and Surgeon Ferguson report two 
 fatal cases of swallowing teeth that came under their 
 own observation. " In the first," they say, '^ the horse 
 succumbed in a tympanitic affection, accompanied by 
 extreme pain, and death was produced by asphyxia." 
 The second case, judging by the short description of 
 it in "The Veterinarian" for 1844, is the identical 
 case just described by Prof. Bouley's fellow-townsman, 
 Prof. Eenault. Messrs. Bouley and Ferguson further 
 say: 
 
 "Such, however, is happily not always the result of 
 swallowing a tooth or the fragment of a tooth; but 
 even the possibility of such a result ought to make 
 the surgeon cautious. Moreover, the swallowing of a 
 tooth may cause serious consequences at some future 
 time. We refer to the formation of those productions 
 called ^intestinal calculi.' The tooth, on account of 
 its being indigestible, acts as the nucleus for the future 
 
SWALLOWIN"G A SOUi>rD TOOTH. 193 
 
 calculus, as indeed may any similar body, which fact 
 has been demonstrated by Prof. Morton, of the London 
 Veterinary College, in an excellent paper on 'The For- 
 mation of Calculus Concretions in the Horse.' ''* 
 
 Surgeon W. A. Cartwright reports that he extracted 
 three grinders from a 'quidding' mare, one of which 
 she swallowed ("Veterinarian," vol. iii, second series, 
 p. 277). The tooth was sound, which may account for 
 the favorable result of the case. 
 
 * Tlie Enterprise, publislied in Virginia, Nevada, in its issue 
 for December 13, 1878, contains an article entitled " A Stone 
 found in a Horse's Jaw," which is in substance as follows : " For 
 a long time a lump has been noticed in the side of the jaw of a 
 horse belonging to Superintendent Osbiston, of the Gould and 
 Curry and Best and Belcher mines. It was near the jawbone, 
 and no liniment had power to soften or drive it away. Yester- 
 day a veterinary surgeon made an incision, and to his astonish- 
 ment removed a stone about two inches long and one inch in 
 diameter. It is yellowish-white in color, and apparently as hard 
 as marble. Mr. M. M. Frederick, the jeweler, divided it longi- 
 tudinally, and in its center was what appeared to be a petrified 
 grain of barley, whicli was also divided longitudinally. Around 
 this nucleus the stone had formed in regular layers, the rings of 
 which could be distinctly traced. The material of which the 
 stone was composed appeared to be the same as that of the in- 
 crustations on the tubes of boilers. It is conjectured that*the 
 grain of barley pierced the gum and imbedded itself in the flesh, 
 and that the saliva, flowing in, deposited limy matter similar to 
 that which is sometimes found on the teeth of horses as well as 
 men. A small concretion having thus been formed, it gradually 
 grew, the channel by which the grain of barley entered no doubt 
 remaining open and allowing an inflow of saliva." 
 
 The above case is another proof that Dr. Dunglison was right 
 when he said that calculi "may form in every part of the animal 
 body." 
 
 9 
 
CHAPTER X. 
 
 FKACTURED JAWS. 
 
 How Caused, and how to Distinguish an Abrasion of the Gums 
 from a Fracture of the Bone. — Replacing an Eye, Amputa- 
 ting part of a Lower Jaw, taking a Fractured Tooth and 
 Bones out through the Nostril, &c. 
 
 Fractures of the jaws of the horse are of common 
 occurrence. They may exist independently, but they 
 are often complicated with and the cause of diseases of 
 the teeth. Caries of the jawbone proper, and even 
 some of the facial bones, is often communicated to the 
 alveoli, and when necrosis ensues the destruction of 
 the teeth is inevitable. This is as true in the case of 
 the horse as in that of man. 
 
 The rami (branches) of the lower jaw are common 
 seats of fracture, a frequent cause of which is the use 
 of sharp curved bits ; but rou^h usage by the rider or 
 driver will now and then cause fractures even with a 
 smooth bit. As a rule, at first, the gums only are 
 affected; but in a short time the periosteum and bone 
 are reached. Prof Varnell says : " If the matter that 
 escapes be of a grayish-brown color and fetid, it wdll 
 indicate disease of the bone ; but if it is from a sub- 
 cutaneous abscess, the discharge will be simply of a 
 puiTilent nature, and a speedy cure may be effected by 
 the application of very simple remedies." 
 
SUEGEOX FLEMING'S DISCOVERY. 195 
 
 When a fracture has been produced, inflammation 
 and fetor will follow, and the horse loses his appetite. 
 If the bone is removed and the horse is allowed to rest 
 for a few daj^s, the wound will heal; otherwise the 
 most serious consequences may follow- The removal 
 of the bone may be effected sometimes soon after the 
 fracture; but if, after cutting into the gum, it be found 
 too firmly attached to the surrounding parts, it is bet- 
 ter to wait a week or two that nature may loosen it. 
 Bones an inch or more in length are often removed. 
 Thus that which at first appears to be "only a sore 
 mouth," may, if neglected, prove the ruin of a valuable 
 horse. 
 
 Fractures are often caused by external violence. A 
 severe blow, accidental or otherwise, in the region of 
 the roots of the teeth may cause a fracture that will 
 necessitate the removal of both the bone and the teeth. 
 
 "The lower jaw," says Prof. Youatt, "is more sub- 
 ject to fracture than the upper, particularly at the 
 point between the tushes and the incisor teeth, and at 
 the symphysis (of the chin) between the two branches 
 of the jaw. Its position, length, and the small quan- 
 tity of muscle covering it, especially anteriorly, render 
 it liable to fracture. The same circumstances, how- 
 ever, combine to^render a reunion of the parts easy." 
 
 The following extraordinary case of accidental frac- 
 ture is reported by Surgeon George Fleming ("Veteri- 
 narian," 1874, p. 694) : 
 
 "' In 18G5, while stationed near Aldershot, I was 
 driving one day in the neighborhood of Farnborough, 
 when, in a narrow lane, our progress was somewhat 
 checked by a farmer's wagon in front, which compelled 
 us to travel at a walking pac2 for some distance. Dur- 
 
196 FKACTURED JAWS. 
 
 ing this delay my attention was attracted to the sbaft 
 horse, which had an enormous tumor on the I'ight side 
 of its face. It had such a singular appearance that I 
 dismounted from the carriage and induced the driver 
 of the wagon to halt, when I inquired into the history 
 of the case, and made an inspection of the tumor. It 
 was as large as half a good-sized cocoanut, occupied 
 nearly the whole side of the face^ and was literally 
 a mass of what at first appeared to be fragments of 
 bone, but which, on a closer examination, proved to 
 be imperfectly developed gi-inder teeth. The tumor 
 looked as if it were composed entirely of them. I was 
 informed that, when two years old, the foal had taken 
 fright and ran away, and in trying to get through a 
 gate, a wooden stump ran into its face, making a large 
 hole. The hole filled up, the tumor gradually formed 
 on it, and since that time these 'bits of bone/ as the 
 wagoner called them, were constantly shed from its 
 surface. The growth was so large that the collar was 
 passed over the head with great difficulty. I was so 
 much interested in the case that I offered to keep the 
 animal wdiile the removal of the tumor was attempted; 
 but the farmer could not spare it from work at the 
 time, and I did not have another opportunity.-' 
 
 * 
 
 The following accounts of cases of fractured jaws 
 
 treated by various surgeons are from Prof. Youatt's 
 work, " The Horse" (p. 44:5) : 
 
 "^ Surgeon Cartwright had a mare in which the up- 
 per jawbone was fractured by a kick at the point 
 where it unites with the lachrymal and malar bones. 
 He applied the trephine, and removed many small 
 bones. The wound was then covered by adhesive 
 plaster, and in a month the parts w^ere healed. 
 
MM. REVEL AND BOULEY'S SKILL. 197 
 
 " Surgeon Claywortli reports the case of a mare that 
 fell while being ridden almost at full speed, and frac- 
 tured the upper jaw three inches above the corner in- 
 cisors. The teeth and jaw were turned, like a hook, 
 completely within the lower teeth. The mare was cast, 
 a balling-iron put into her month, and the teeth and 
 jaw pnlled back to their natural position; she was then 
 tied so that she c.ould not rub her muzzle against any- 
 thing, and was fed with bean-meal and linseed tea. 
 Much inflammation ensued, but it gradually subsided, 
 and at tlie expiration of the sixth week the mouth was 
 healed, scarcely a vestige of the fracture remaining. 
 
 " An account of a very extraordinary fracture of the 
 superior maxillary bone is given in the records of the 
 Royal and Central Society of Agriculture in France. 
 A horse was kicked by another horse, fracturing the 
 upper part of the superior maxillary and zygomatic 
 bones, and almost forcing the eye out of its socket. 
 Few men would have dared to undertake a case like 
 this, but Monsieur Eevel shrank not from his duty. 
 He removed several small bones, replaced the larger 
 ones, returned the eye to its socket, confined the parts 
 with sutures, slung the horse, and in six weeks he was 
 well. 
 
 " Surgeon Blaine relates that in treating a fracture 
 of the lower jaw he succeeded by incasing the entire 
 jaw in a strong leather frame. I have myself effected 
 the same object by similar means. 
 
 ^' Prof. Bouley says (" Recueil de Medicine Yeteri- 
 naire," 1*838) that he treated a horse whose lower jaw 
 had been completely broken off at the neck — that is, 
 at the point between the tushes and the corner incisor 
 teeth, the detached bone being held by the membrane 
 of the mouth. 
 
198 rilACTUKED JAWS. 
 
 '•The liorse was cast, the corner tooth on the left 
 side extracted, the wound thoroughly cleansed, and 
 the fractured bones brought in contact. Holes were 
 drilled between the tushes and the second incisors of 
 both jaws, through which brass Avireswere passed. A 
 compress of tow and a ligature, the bearing-place of 
 the latter being over the tushes, surrounded the whole. 
 Thus the jaws were a})parently fixed immovably to- 
 gether. The wires yielded somewhat to the struggles 
 of the horse, but the bandage of tow was tightened so 
 as to retain the fractured edges in apposition. 
 
 "Th.e wound now began to exhale an infectious odor, 
 and gangrene was evidently approaching. M. Bouley 
 determined to amputate the fractured portion of the 
 jaw, its union to the main bone being apparently im- 
 possible. The sphacelated portion of the jaw was en- 
 tirely removed ; every fragment of bone that had an 
 oblique direction was sawn away, and the rough por- 
 tions which the saw could not reach wT,re rasped off. 
 
 "Before night the horse had recovered his natural 
 spirits, and was reaching for something to eat. On the 
 following day he ate oats, and no one looking at him 
 would have suspected that he had been deprived of his 
 lower incisor teeth. The next day he ate hay. In a 
 fortnight the wound was nearly healed." 
 
 0. D. House, veterinary dentist, performed an unu- 
 sual operation on a seven-year-old horse, the property 
 of Mr. J. T. Allen, of Hartford, Conn. In 1876 a 
 surgeon (?) made an incision in the right cheek and 
 Icnoched out a large part of the fifth upper grinder. 
 The violence of the operation fractured both the tooth 
 and the jaw, imbedding a large fragment of the former 
 in the bone above the socket. A year afterward, the 
 
SKILL VERSUS BRUTALITY. 
 
 199 
 
 horse still suffering and discharging matter from the 
 nostril,, Mr. House was requested by Mr. Allen to ex- 
 amine and if possible cure him. He failed, however, 
 to discover the cause of the discharge, and it was not 
 till the expiration of another year that he determined 
 to probe the case to the bottom, the horse in the mean- 
 time having suffered as usual. Making an instrument 
 of the proper size and shape, he introduced it into the 
 nostril, seized the tooth fragment and drew it forth, 
 the horse at that instant making a deep expiration, 
 which blew out several fragments of bone and a part 
 of the root of the tooth. The animal made a good 
 recovery.* 
 
 * The Worcester, Mass., Spy for July 13, 1877, says : "C D. 
 House, veterinary dentist, was in the city yesterday, operating 
 on the horses of the Hambletonian Breeding Stud. A case was 
 found where the grinders had been worn rough, and were be- 
 sides slightly displaced, so that the horse in eating lacerated the 
 lining of the cheek. Another case was where a colt's temporary 
 tooth, after being partially forced from its place by the perma- 
 nent, had remained fastened by one fang, and in such a position 
 as to injure the gum while the animal was feeding ; and yet so 
 nicely had the decaying tooth been lodged, that its presence was 
 only detected by the oflfunsive odor. Several cases of inflamma- 
 tion of the gums were found, which were accounted for by tlio 
 presence of tartar. The tartar was removed. 
 
 " Mr. House says that in all his experience he has not seen but 
 two cases of glanders ; but he has known of hundreds of horses 
 being killed for what was supposed to be glanders. The cause 
 of the discharges from the nostrils in most of these cases arose 
 from disease of the roots of the grinders. Horses are more sub- 
 ject to dis -ases of the teeth, he says, than is generally supposed. 
 The famous sire, Rysdyk's Hambletonian, died of the toothache, 
 as have also many other blooded horses. 
 
 " Mr. House's mode of operating is unique. He uses no gag, 
 and the animal stands free. He passes his hands over the teeth 
 of the most vicious horses, and was never yet bitten. He has 
 
200 FRACTURED JAWS. 
 
 Surgeon J. P. Heatli thus describes a case of frac- 
 tured jaw (" Veterinarian," 1878, p. 288) : 
 
 " In May last I was called to see a horse that had 
 been kicked by another horse. I found a transverse 
 fracture of the left side of the lower jaw, between the 
 first and second grinders, with lesion of the buccal 
 membrane. The bone protruded inward, the tongue 
 hung out of the mouth, and a constant flow of saliva 
 existed. The animal's appetite was good, but there 
 was of course a total inability to masticate. The horse 
 was seventeen years old, but as the farmer (Mr. Gale, 
 of Exniinster, Devon,) could ill afford his loss, I agreed 
 to try to cure him. 
 
 "I procured a wedge-shaped piece of wood, six or 
 seven inches long by half an inch thick, which, after 
 fitting it between the branches of the jaw^ I well be- 
 smeared with warm pitch and pressed it tightly be- 
 tween the fractured end of the bone. I then fixed 
 another piece of wood of the same length, but two 
 inches thick, which was also besmeared with pitch, 
 outside the fracture, placing a bandage six inches wide 
 over the whole, and tying it over the face below the 
 eyes. 
 
 operated on Edward Everett, Jud^e Fullerton, Emperor (owned 
 by S. D. Houghton, of this city), and other notoriously vicious 
 horses." 
 
 The statement about Mr. House's mode of operating is strictly 
 true. His control of a horse appears to be a gift. He never 
 confines a horse, not even in performing the operation of castra- 
 tion. In an " interview" with a reporter of The New York 8mi, 
 printed in 1877, in reply to the question, " How do you know 
 when a horse has tlie toothache ? " he said : " He telh me that he 
 has it." So Mr. House must understand " horse-talk " as well as 
 horse-dentistry. 
 
SURGEOJ^ HEATH'S SKILL. 201 
 
 "For the first fortnight I do not tliink the animal 
 took more than a gallon of the thin mashes and gruel 
 with which he was supplied; but after that time the 
 use of the muscles of the tongue began to return, and 
 he was able to swallow a little. In about three weeks 
 he could lick up oatmeal and oilcake gruel made thick, 
 and in less than a month I removed the bandage (al- 
 though the sphnts remained for six weeks), as by tliis 
 time he could swallow a little pulped mangold grass, 
 cut into chaff. For nine weeks he could only feed on 
 cut fodder, when he was turned out to grass. At the 
 present time he is in perfect health, feeding on ordi- 
 nary diet and working constantly. The first and sec- 
 ond grinders, which were loosened, appear now to be 
 as firmly fixed as the others." 
 
 The editor of "The Veterinarian" reports the case 
 of a pony that came near starving from having a stick 
 fastened in its mouth. No fracture of the bone was 
 produced, but the account of the case is worthy of in- 
 sertion here notwithstanding that fact, for it illustrates 
 a class of mishaps to which the horse is subject. He 
 says ("Veterinarian," 1855, p. 330): 
 
 "A pony was turned into a pasture, and was not 
 seen for several days. The owner found it standing in 
 a corner of the field, looking dejected and thin, Avith a 
 small quantity of viscid saliva escaping from its mouth. 
 He took care of tlie pony for a few days, during w^hich 
 time it took nothing but a little water, which it drank 
 with great difficulty. Our attendance was now re- 
 quested. Examination disclosed a stick about the size 
 of one's finger, firmly wedged across the palate, be- 
 tween the corner incisors. Its pressure had produced 
 
202 TREATMENT FOR ABRASED GUMS. 
 
 extensive sloughing, so thafc the bone was completely 
 exposed. The pain was so great that the poor animal 
 stoutly resisted our efforts to remove the cause of its 
 suffering. This, however, was soon done, and the parts 
 being cleaned with tepid water, were afterward dressed 
 with Tinct. Myrrhae. Little after treatment was nec- 
 essary beyond the daily application of the tincture, a 
 mash diet, and the substitution of oatmeal gruel for 
 plain water." 
 
CHAPTER XI. 
 
 THE TEETH AS IIs"DICATORS OF AGE. 
 
 Their various ways of Indicating Age.— The "Mark's" Twofold 
 Use. — The Dentinal Star. — Marks with too much Cement. — 
 Tricks of the Trade. — Crib-biting. — Signs of Age Independ- 
 ent of the Teeth. 
 
 The incisor teeth of the horse, which, as before said, 
 differ "from those of all other animals by the fold of 
 enamel which penetrates the body of the crown, from 
 its broad, flat summit, like the inverted finger of a 
 glove," indicate age (1) by their cutting; (2) by their 
 growth; (3) by their shedding; (4) by their marks;* 
 (5) by their change of shape ; (6) by their change of 
 color; (7) by their length, and (8) by the degree of 
 their outward inclination. The cutting, growth, and 
 shedding (of the tushes and grinders as well as the in- 
 cisors — the cutting and shedding occurring at com- 
 paratively regular periods, and the growth being grad- 
 ual), indicate age from birth till about the sixth year; 
 tlie marks of the lower incisors from the sixth month 
 till the eighth year; those of the upper incisors, though 
 
 * Prof C. S. Tomes says "the mark exists in Hipparion, but 
 not in the earlier progenitors of the horse." Prof. O. C. Marsh 
 says : " The largo canines of Orohipous became gradually re- 
 duced in the later genera, and the characteristic mark of the 
 incisors is found only in the later forms." 
 
204 TSE TEETH AS i:srDICAT0K3 OF AGE. 
 
 perhaps less reliable, during the same period, and for 
 about four or five years longer (say the twelfth or thir- 
 teenth), and the change in shape,* color, and position 
 from about the seventh year till old age. The change 
 in the shape of the teeth is caused by their wear and 
 growth, the wear counteracting the growth and the 
 growth the wear. 
 
 hi foals and young horses the marks are prol^ably 
 the surest guides by which to judge of the age. One 
 peculiarity of them is that, as the teeth wear down, 
 they approach the jjosterior edge. Besides their utility 
 in indicating age — being composed of enamel (the ad- 
 amantine substance) — they greatly enhance the dura- 
 bility of the teeth — that is, during the first third of 
 the horse's life. As a rule the variations in the size 
 and appearance of the marks will be as follows: f 
 
 At six months of age they are oblong and distinct 
 in the central incisors, and if not already visible in the 
 dividers, will become so before the seventh month. 
 
 At one year they are shorter and less distinct in the 
 centrals, and are becoming so in the dividers, but are 
 large and plain in the corner teeth. 
 
 At one year and a half they are small and round in 
 the centrals, are diminished in size in the dividers, but 
 are still large and distinct in the corners. 
 
 At two years they are no longer visible in the cen- 
 trals (in some cases these teeth are even shed at this 
 period) ; they are smaller and rounder in the dividers 
 and still plain in the corners. 
 
 * Surgeon W. A. Cherry, of England, says the shape and gen- 
 eral character of the teeth are much better criterions of age at 
 all periods of life than the marks/ 
 
 f For the dimensions of the marks (Surgeon Hughes's mea- 
 surements), S3e page 58. 
 
WHAT MAY PUZZLE A KOVICE. 205 
 
 At two years and a half the centrals are shed; the 
 marks are faint in the dividers, but are distinct in the 
 corners. 
 
 At three years the permanent centrals are nearly 
 grown ; the marks in the dividers are just visible, and 
 have become smaller in the corners. 
 
 At three years and a half the marks in the centrals 
 are long and very distinct; the dividers are shed, and 
 the marks in the corners are foint. 
 
 At four years the marks in the centrals show the 
 effects of wear, but are still long and distinct ; the per- 
 manent dividers are growing, and the marks in the 
 corner teeth have almost disappeared. 
 
 At four years and a half the marks in the centrals 
 are still large and distinct, and the dividers are about 
 grown. The contrast between the large permanent 
 incisors and the small temporary corner teeth, which 
 have lost their marks, is striking at this age. 
 
 At five years the marks in the centrals are getting 
 smaller and rounder, but are large and distinct in the 
 dividers ; the corners are usually shed at this age. 
 
 "At six years," says Prof. Youatt, "the marks of 
 the central nippers are worn out. There will, however, 
 still be a difference of color in the center of the tooth. 
 The cement filling the hole made by the dipping of 
 the enamel will present a brow^ner hue than the other 
 part of the tooth. It vn]\ be distinctly surrounded by 
 an edge of enamel, and there will remain even a little 
 depression in the center, and also around the case of 
 enamel ; but the deep holes in the center of the teeth, 
 with the blackened surface wdiich they present, and 
 also the elevated edge of enamel, will have disappeared. 
 Persons little accustomed to horses are often puzzled 
 here. They expect to find a plain surface of uniform 
 
206 
 
 THE TEETH AS INDICATORS OF AGE. 
 
 color, and know not what conclusion to draw when 
 they see both discoloration and irregularit^y." The 
 marks in the dividers are much reduced in size, but 
 those of the corner teeth are large and distinct. 
 
 At seven years the marks disappear from the divider 
 incisors, and at eight from the corner teeth. 
 
 Monsieur Girard thus describes the changes in shape 
 of the incisors, referring also to the disappearance of 
 the marks in the upper teeth: 
 
 ^* At nine the central incisors become rounded, the 
 dividers oval, and the corner teeth narrower. The cen- 
 tral enamel (mark) diminishes and 
 approaches the posterior edge. 
 
 "At ten the dividers are rounder, 
 and the central enamel is very near 
 the posterior edge and rounded; at 
 eleven they have become rounded, and 
 the enamel has disappeared. 
 
 "At twelve the corner teeth are 
 rounded. The yellow band is larger, 
 and occupies the center of the wear- 
 ing surface. 
 
 "At thirteen all the lower incisors 
 are rounder; the sides of the centrals 
 are becoming longer. The central 
 enamel remains in the upper corner 
 teeth, but is round and approaching 
 the posterior edge. 
 
 "At fourteen the lower central in- 
 cisors have a triangular appearance; 
 the dividers are becoming long at their sides. 
 
 "At fifteen the central incisors are triangular, and* 
 the dividers are becomino- so. 
 
 The forms successive- 
 ly assumed by the dental 
 table of an incisor in con- 
 sequence of fiiction.— 4. 
 Chauceau. 
 
CAUSE OP THE YELLOW COLOR. 207 
 
 *'At sixteen the dividers are triangular, and the cor- 
 ner teeth are becoming so. 
 
 *' At seventeen the corner teeth, like the dividers and 
 centrals, have become triangular, the sides of the tri- 
 angles being equal. 
 
 "At eighteen the lateral portions of the triangles 
 lengthen in succession— first in the centrals, next in 
 the dividers, and then in the corners; so that at nine- 
 teen the lower centrals are flattened from one side to 
 the other; at twenty the dividers are flattened, and at 
 twenty-one the corners also are." 
 
 The three following extracts give some idea of the 
 difficulties to be encountered in judging the age by 
 the teeth. Prof. Youatt says : 
 
 "Stabled horses have the marks sooner worn out 
 than those at grass, and a 'crib-biter' may deceive the 
 best judge by one or two years. At eleven or twelve 
 the lower nippers change their original upright posi- 
 tion and project forward. They become of a yellow 
 color, the cause of which is that the teeth grow to 
 offset their wear ; but the enamel which covered their 
 surface when they were j^oung cannot be repaired, and 
 that which wears this yellow color in old age is the 
 part which was formerly in the sockets. The gums 
 recede and waste away, and the tushes wear to stumps 
 and project outward." 
 
 Surgeon Ewd. Mayhew says ("The Horse's Mouth: 
 Showing the Age by the Teeth") : 
 
 " That the teeth of the horse denote age appears to 
 have been a very ancient belief, which the experience 
 of centuries has not changed. Within certain limits 
 
208 THE TEETH AS INDICATORS OF AGE. 
 
 the belief is well founded, for perhaps no development 
 is more regular than the teeth of the horse, and no 
 natural process so little exposed to the distortions of 
 artifice. We are, nevertheless, not to expect that the 
 animal carries in its mouth a certificate of birth, writ- 
 ten in characters so deep that they cannot be obliter- 
 ated or misinterpreted. He who would judge of the 
 age by the teeth must study them, and be prepared to 
 eucounter difficulties. In proportion as he has done 
 the one, and is enabled thereby to overcome the other, 
 will be his success. The qualified judge alone will 
 read the teeth correctly. He will make allowance 
 where certain marks are indistinct or absent, and he 
 will be cautious in pronouncing an opinion. The vet- 
 erinary practitioner knows that the teeth are worthy 
 of attention, and he feels that their indications, scien- 
 tifically interpreted, will seldom mislead." 
 
 Surgeon J. H. Walsh, in his excellent work, "The 
 Horse; in the Stable and in the Field," says: 
 
 "In order to be able to estimate the age of the horse 
 by his teeth, it is necessary to ascertain, as nearly as 
 may be, the exact time at which he puts up his milk 
 teeth, and also the periods at which they were replaced 
 by the permanent. Finally it becomes the province 
 of the veterinarian to lay down rules for ascertaining 
 the age from the degree of attrition which the perma- 
 nent teeth have undergone. For these several purposes 
 the horse's mouth must be studied from the earliest 
 period of his life up to old age." 
 
 Judging the age by the teeth is even more comj)li- 
 cated and difficult than is shown by the foregoing ex- 
 tracts. Among other complications worthy of consid- 
 eration are the following: 
 
LIKE CREEDMOOR MARKS, HARD TO HIT. 209 
 
 About the ninth year a mark, which is sometimes 
 mistaken for the infundibnlum, or mark proper, ap- 
 pears on the central incisors. M. Girard named it the 
 dentinal'^ stctr^ but it is also called the fang-hole and 
 secondary mark. Dentinal star is perhaps the most 
 proper name, for the mark is "due to the presence of 
 secondary dentine, into which the remains of the pulp 
 has been converted." It may be distinguished from 
 the first formation of dentine by its yellow tint. The 
 dentinal star may not afford, as some authors claim it 
 does, reliable data by which to judge of the age, but 
 its presence is 'prima facie, evidence that the tooth has 
 been worn to the original pulpal cavity. f The more 
 the teeth wear, it is said, the plainer the star becomes. 
 
 The marks of some teeth arc disproportionately 
 composed of cement, a fact Prof A. Chauveau says he 
 is not aware has ever been taken into account in "cal- 
 
 * The reason for using the word dentinal in preference to den- 
 tal, in the above as well as in many other cases throughout this 
 work, is very clearly and forcibly given in a reference note (by 
 Prof. Owen) on page viii, 
 
 f Dr. John Hunter says (" The Human Teeth," pp. 50-1) : " A 
 tooth very often wears down so low that its cavity would be ex- 
 posed if no counteracting alteration were produced in it. To 
 prevent this Nature has taken care that the bottom of the cavity 
 shall be filled by new matter in proportion as the crown of the 
 tooth is worn. This new matter is easily distinguished from the 
 old, for when a tooth has been worn almost to the neck, a spot 
 may be seen in the center, which is more transparent and at the 
 same time of a darker color (occasioned in some measure by the 
 dark cavity under it), and generally softer than the surrounding 
 parts. Any one may be convinced of the truth of the matter by 
 taking two teeth of the same kind, one just full-grown, the other 
 worn almost to its neck. In the latter the dark spot is visible, 
 and if as much material is cut from the former as has been worn 
 from the latter, its cavity will be cut through." 
 
210 THE TEETH AS Il^DICATORS OP AGE. 
 
 culating the progress of wear." Such teeth would soon 
 wear out, for there is as much difference in the density 
 of cement and enamel as between cartilage and bone. 
 
 The obliteration of the mark may be hastened in a 
 small or medium-sized tooth by the friction of one that 
 is abnormally large, while a stunted or dead tooth n^ay 
 never lose its mark. 
 
 The more upright the teeth the faster they wear. It 
 is said that the crowns will be worn to the extent of a 
 quarter of an inch between the fifth and sixth years 
 (when they are most upright), while only about that 
 quantity of material will wear away between the twen-, 
 tieth and twenty-fifth years. 
 
 A horse's food is a matter also to be taken into ac- 
 count. The mastication of grass, carrots, turnips, 
 potatoes, bread, &c., does not cause much wear to the 
 teeth. However, when grass is procured by grazing, 
 the incisors suffer much friction — caused, not by the 
 grass, but by the teeth grinding one another, for they 
 meet edge to edge, and are employed in this occupa- 
 tion for hours, whereas a ''feed" of com is shelled in 
 a few minutes. In the former case the incisors suffer 
 great friction ; in the latter, the grinders. Again, it is 
 said that "horses fed on salt marshes, where the sea- 
 sand is washed among the grass, or on sandy plains or 
 meadows, are affected by the increased friction of their 
 teeth." But no matter how soft a horse's food may 
 be, if he is addicted to the vice called "crib-biting," 
 his teeth may be ruined before those of the corn-fed 
 horse have even lost their marks. 
 
 Several trade tricks are also to be noted. Of "bish- 
 oping," Prof Youatt says : 
 
 " Dishonest dealers resort to a method of imitatins: 
 
youatt's compliments to bishop. 211 
 
 the mark in the lower nippers. It is called Bisliopingy 
 from the name of the scoundrel who invented it. The 
 horse of eight or nine years is thrown, and with an 
 engTcivc/s tool a hole is dug in the now almost plain 
 surface of the corner teeth, its shape resembling the 
 mark in those of a seven-year-old horse. The hole is 
 then burned with a heated iron, and a j)ermanent 
 black stain is left. The next pair of nippers are some- 
 times lightly touciied also. 
 
 ''An unprofessional man would be easily deceived by 
 this fraud, but it cannot deceive the trained eye of the 
 horseman. The irregular appearance of the cavity, 
 the diffusion of the black stain around the tushes — 
 the sharp points and concave inner surface of which 
 can never be given again — the marks on the upper nip- 
 pers, together with the general conformation of the 
 horse, will prevent deception. Moreover, in compar- 
 ing the lower with the upper nippers, unless the oper- 
 ator has performed on the latter also, they will be 
 found to be considerably more worn than the lower, 
 the reverse of which ought to be the case. Occasion- 
 ally a clever operator will burn all the teeth to a prop- 
 erly regulated depth, and then a practiced eye alone 
 will detect the imposition." * 
 
 * Rough oisr the Russians. — Surgeon John C. Knowlson 
 makes the following open confession (" The Complete Farrier, 
 or Horse Doctor," p. 150): "I was hired by Anthony Johnson, 
 of Wincolmlee, Hull, as farrier to a number of horses that were 
 goinj^ to ^loscow, Russia. We had a little gTay, seventeen-year- 
 old liorse, named Peatum, whose mouth I bishoped. He passed 
 for six years old, was the first horse sold, and brought £oOO, 
 Enp^lish money ! I only mention this as a caution to horsemen."' 
 
 Surgeon Knowlson could liave evidently beaten the late Pres- 
 ident Lincoln in a (wooden) horse trade. 
 
212 THE TEETH AS IITDICATORS OF AGE. 
 
 Of a deception practiced by sellers of two-year-old 
 foals, namely, passing off an early two-year-old for a 
 late three-year-old, Prof. Youatt says: 
 
 " The age of all horses used to be reckoned from 
 May, but some are foaled as early as January. A two- 
 year-old foal of the latter date may, if it has been well 
 nursed and fed and has had its central nippers drawn 
 (that three or four months' time may be gained in the 
 appearance of the permanent), be sold at the former 
 date for a three-year-old. To horsemen, howev^er, the 
 general form of the animal, the little development of 
 the forehand, the continuance of the mark in the divi- 
 der nippers, its more evident existence in the corner 
 ones, and some enlargement or irregularity about the 
 gums, from the violence used in forcing out the teeth, 
 are a sufficient security against deception." 
 
 And again of four-year-old foals: 
 
 "Now, more than at any other time, will the dealer 
 be anxious to put an additional year npon the animal, 
 for the difference in strength, utility, and value be- 
 tween a four-year-old colt and a five-year-old horse is 
 very great. But the lack of wear in the central and 
 divider nippers, the small size of the corner ones, the 
 little growth of the tushes, the low forehand, the leg- 
 giness of the colt, and the thickness and little depth of 
 the mouth, will at once detect the cheat." 
 
 The following is Prof. Youatt's description of crib- 
 biting and its effect on the teeth ("The Horse/' pp. 
 511,519): 
 
 ^^ The horse lays hold of the manger with his teeth, 
 violently extends his neck, and then, after some con- 
 
COLICKY ClUB-BITERS. 213 
 
 vulsive action of the throat, a slight grunting is heard, 
 accompanied b}^ a sucking in of air. It is not an effort 
 at simple eructation, arising from indigestion, but is 
 merely the inhalation of air. It takes j^lace with all 
 kiuds of diet, and when the stomach is empty as well 
 as when it is full. 
 
 " The effects of crib-biting are plain enough. The 
 teeth are worn away and occasionally broken, and in 
 old horses to a very serious degree. Sometimes graz- 
 ing is rendered difficult or almost impossible. Coru is 
 often wasted, for the horse will frequently 'crib' with 
 his mouth full of it, and the gi-eater part of it will fall 
 over the edge of the manger. Much saliva escapes also, 
 wdiich impairs digestion. Crib-biting horses are more 
 suliject to colic than others, and to a species difficult 
 of treatment and frequently dangerous. 
 
 ''The only remedy is a muzzle, with bars across the 
 bottom sufficiently wide to allow the horse to pick np 
 his corn and pull his hay, but not to grasp the edge of 
 the manger. Some recommend turning out for five or 
 six months; but this will never succeed except with 
 young horses, and rarely with them. Tlie old crib- 
 biter will substitute the gate for the manger. We have 
 often seen him galloping across the field for the mere 
 object of having a gripe at a rail." 
 
 Prof. Youatt further says that the vice is a species 
 of unsoundness, having been so decided in the courts. 
 It is often the result, he says, of imitation, but oftener 
 the consequence of indigestion. Mischief, he says, is 
 another cause of it. 
 
 The mouth, it is said, is broader at seven years of 
 age than at any other time; but, so far as judging the 
 age is concerned, this fact (assertion) is of little prac- 
 
214 THE TEETH AS INDICATORS OF AGE. 
 
 tical use. The facts that follow, however, are of more 
 or less use, and are worthy of perusal. Prof. Youatt 
 
 says : 
 
 '^ The indications of age, independent of the teeth, 
 are deepening of the hollows over the eyes ; wrinkles 
 over the eyes and about the mouth ; gray hairs, par- 
 ticularly over the eyes and about the muzzle; the 
 countenance and general appearance; thinness and 
 hanging down of the lips; sharpness of the withers; 
 sinking of the back; lengthening of the quarters, and 
 the disappearance of windgalls, spavins, and tumors of 
 every kind. * ^ * ^1^ mne or ten the 'bars' of 
 the mouth become less prominent, and their regular 
 diminution will designate increasing age." 
 
 Of another deception Prof Youatt says: 
 
 " We form some idea of the age of the horse by the 
 depth of the pits above the eyes. There is at the back 
 of the eye a quantity of fatty substance, on which it 
 may revolve without friction. In aged horses, and in 
 diseases attended with general loss of condition, much 
 of this disappears. The eye becomes sunken, and the 
 pit above it deepens. Dishonest dealers puncture the 
 skin, and, with a tobacco-pipe or tube, blow into the 
 orifice till the depression is almost filled. This, with 
 the aid of 'bishoped' teeth, may deceive the unwary. 
 The fraud may be easily detected, however, by press- 
 ing on the part.'' 
 
 "Frank Forester" (William Henry Herbert), says 
 (" The Horse of America," vol. i, p. 72) : 
 
 " Much stress is laid by many persons on the depth 
 of the supra-orbital cavities, and more yet on the length 
 and extreme protrusion of the nippers beyond the 
 
SUNKEN PITS AI!TD HOLLOW BACKS. 215 
 
 gums, as also, in a less degree, on the hollowuess of the 
 back. All these are doubtless indications of age; but 
 I have many times seen colts — got by stallions in ex- 
 treme oge — having all these indications of advanced life 
 in a degree scarcely inferior to those of their sires, be- 
 fore they had yet acquired a full m-outh, much less lost 
 the mark. And more than once I have seen foals, 
 newly dropped, with the deep supra-orbital cavities 
 and hollow backs bequeathed to them by their aged 
 sires before they had got their colt's teeth.'' 
 
CHAPTER XII. 
 
 THE TRIGEMIKUS OE FIFTH PAIR OF KERVES. 
 
 Its Nature and tlie Relation it bears to the Teeth. — Its Course in 
 tlie Horse and in Man. 
 
 The thread-like nerves of the teeth are derived from 
 the superior and inferior maxillary branches of the 
 trigeminus or fifth jiair of nerves. In the horse these 
 branches are four or five times as thick as a ribbon 
 and about five-eighths of an inch wide. The ophthal- 
 mic branch is smaller and shorter, its course extend- 
 ing only from the brain to the eye, while that of the 
 two former extends to the lips, running parallel to and 
 about an inch from the roots of the grinder teeth.* 
 
 The description of the trigeminus and its course is 
 from a lecture by Prof. Youatt to veterinary students, 
 and may be found in "The Veterinarian" for 1834 
 (p. 121). In the first part of the lecture the nature of 
 the trigeminus— its double origin and function — is 
 expatiated upon, a summary of which is that the sensi- 
 tive and motor roots, are contained Vv^ithin the same 
 sheath; that the sensitive root is so much larger and 
 its fibrils so much more numerous than the motor that 
 
 * For the preparation of an anatomical specimen showinir the 
 g-eneral course of the trie^eminns, I am indebted to Prof. J. M. 
 Heard, of the New York College of Veterinary Surgeons. 
 
THE Two ROOTS. 217 
 
 it may still be called the sensitive nerve of the face; 
 that the trigeminus is the only nerve of the brain that 
 bestows sensibility to the face, except a few branches 
 from the cervicals, w^hich may be traced to the lower 
 part of it ; that there arc some anatomical facts which 
 incontestably prove that the motor nerve exists : that 
 Sir Charles Bell laid the root of the trigeminus bare in 
 an ass immediately after the animal's death, and that 
 on irritating the nerve the muscles of the jaw acted 
 and the jaw closed; that he divided the root of the [ 
 nerve in a living animal, and the jaw fell;* that he 
 
 * " Re-establish:\ient of Sensibility after Resection 
 OF Nerves. — A memoir by MM. Arloing and Tripier was read 
 before the French Academy, November 28tb, on the efiFect of re- 
 section of certain nervous trunks. Clinical facts have several 
 times shown tbat after wounds which have altered or destroyed 
 a portion of a nerve, sensibility returns in the integuments to 
 which the nerve is distributed. MM, Arloing and Tripier made 
 nervous resections in dogs, and saw sensibility reappear after a 
 certain time in the integuments to which the branches of the 
 nerve were distributed, and in the peripheral end of the nerve 
 itself." — Popular Scisnce Eevieio, 1867. 
 
 "How Motor-Nerves End in NoN-STrviATED Muscitlar 
 Tissue. — A very valuable communication stating the results of 
 M. Henocque's researches has been published in "I'Archives de 
 Physiologie," and may be thus abstracted : 1. The distribution 
 of the nerves in smooth muscle is not only identical in man and 
 other vertebrate animals in which it has been observed, but is 
 essentially similar to all the organs containing smooth muscle. 
 
 2. B^^foro terminating in the smooth muscle, the nerves form 
 three distinct plexuses or networks — (a) a chief or fundamental 
 plexus, containing numerous ganglia, and situated outside the 
 smooth muscle ; (b) an intermediate plexus ; and (c) an intra- 
 muscular plexus, situated mtliin the fasciculi of smooth fibers. 
 
 3. The terminal fibrils are everywhere identical. They divide 
 and subdivide dichotomously, or anastomose, and terminate by 
 a sliglit swelling or knob, or in a punctiform manner. The ter- 
 
 10 
 
218 THE FI]?TH PAIR OF KERYES. 
 
 divided the superior maxillary branch on both sides, 
 the animal losing the power of using the lips; that 
 Mr. Mayo divided the root of both the superior and 
 inferior maxillary, the result being that the lips no 
 longer remained in perfect apposition, and the animal 
 ceased to use them in taking up his food; that the 
 sensitive root, or a portion of it, after entering the cav- 
 ernous sinus, swells out into or passes through a gan- 
 glion, and that the motor root can be traced beyond 
 the ganglion, uniting afterward with its fellow and 
 forming the perfect nerve; that the ganglion, being 
 composed of sensitive fibrils only, resembles a brain. 
 
 minal swellinof appears to occupy different parts of the smootTi 
 muscular fiber, but most frequently to be in the neighborhood 
 of the nucleus, or at the surface of the fibers, or, lastly, between 
 them." — The Monthly Microscopical Journal, 1870. 
 
 " Structure op Nerves. — M. Roudanoosky says that the 
 primitive elements of nerves are tubes having- a pentagonal or 
 hexagonal configuration. As to their' constitution, he says that 
 every nerve has a substratum of brain-matter, and also of the 
 spinal marrow, and probably of the ganglionic matter also. The 
 gray matter, he says, is the fundamental nervous substance, and 
 plays the principal part in the functions." — " Veterinarian^' 
 1S65, p. 313. 
 
 In a letter to his brother, G. J. Bell, written in 1807, Sir 
 Charles says : " I consider the organs of the outward senses as 
 forming a distinct class of nerves. I trace them to corres]X)nd- 
 ing parts of the brain, totally distinct from the origin of the 
 others. I take five tubercles within the brain as the internal 
 senses. I trace the nerves of the nose, eye, ear, and tongue 
 j to these. Here I see established connection ; there, the great 
 mass of the brain receives processes from the central tubercles. 
 Again, the great masses of the cerebrum send down processes 
 or crura, which give off all the common nerves of voluntary mo- 
 tion. I establish thus a kind of circulation, as it were." — Medi- 
 cal Gazette. 
 
THE COURSE OF THE NERVE. 219 
 
 Prof. Youatt's description of the course of the tri- 
 geminus is as follows : 
 
 "The trigeminus has been described as springiug 
 by a multitude of fllaments from the crura cerebelli, 
 and forthwith running for safety into the cavernous 
 sinuses, and there suddenly enlarging into or passing 
 through a ganglion. The nerve, as its name implies, 
 divides into three parts, the division taking place in 
 the cavernous sinus, after the superior or sensitive 
 root has been joined by the inferior or motor root. 
 Each part, before it leaves the cranium, assumes a dis- 
 tinct investment of dura mater. The branches are 
 named, from the parts to which they are destined, the 
 Ophthalmic, the Superior Maxillary, and the Inferior 
 Maxillary. 
 
 "The opMhalmic is the smallest of the three. It is 
 formed within the sinus, where it is in conjunction 
 wdth the superior maxillary, v/hich it soon leaves, and, 
 passing through the foramen lacerum into the orbit, 
 subdivides and forms three distinct branches — the 
 Supra-orbital (the frontal), the Lachrymal, and the 
 Lateral Nasal (the nasal). The supra-orbital climbs 
 behind the muscles of the eye, giving filaments to the 
 rectus superior and the superior oblique, and some 
 also to the fatty matter of the eye. The main branch, 
 escaping through the superciliary foramen, is soon lost 
 in ramifications on the elevator of the superior eyelid, 
 the integument of the forehead, and the periosteum. 
 The lachrymal, as its name implies, is chiefly concerned 
 with the lachrymal gland; a few ramifications, how- 
 ever, are sent to the conjunctiva and also to the ciliary 
 glands of the upper eyelid, while a distinct twig of it 
 passes out at the angle between the zygoma and the 
 
220 THE FIFTH PAIR OF KERVES. 
 
 frontal orbital process, where it anastomoses with the 
 sapra-orbital and with ramifications from the superior 
 maxillary. It is also lost on the integument and 
 muscles of the forehead. The lateral nasal is the 
 largest of the three. Almost at its beginning we ob- 
 serve the filaments that help to form the Ophthalmic 
 Ganglion. They are more numerous and more easily 
 traced in some of our domesticated animals than in 
 others, and the ganglion itself is differently developed, 
 but for what physiological purpose I know not. It is 
 comparatively larger in the ox than in the horse, and 
 sends more filaments to the iris. Four distinct fila- 
 ments may be traced in the ox, but seldom more 
 than two in the horse or the dog. To these fila- 
 ments others of the ophthalmic, that have not passed 
 through the ganglion, afterward join themselves; so 
 that the ciliary are also minute compound nerves of 
 motion and sensation.* 
 
 * " The best account, however, of this is <?iven by Dr. Jonas 
 Quain (' Qaain's Anatomy,' p. 7fi8). He considers the ganglion 
 as a center of nervous influence — a little brain, as it were — and 
 the filaments which some anatomists describe as composing, he 
 speaks of as branches given out from it. ' It lies,' says he, 
 ' within the orbit, about midway between the optic foramen and 
 the globe of the eye, and is inclosed between the external rectus 
 muscle and the optic nerve. It is exceedingly small and, owing 
 to its being imbedded in the soft adipose tissue which fills tlie 
 interstices of the different parts within the orbit, difficult to find. 
 Its branches are the following: From its anterior border from 
 sixteen to twenty filaments issue, which proceed forward to the 
 surface of the sclerotic, and pierce it through minute foramina. 
 These are the ciliary nerves. In their course to the globe of the 
 eye they are joined by one or two filaments derived from the 
 nasal nerve, but they do not form a plexus (an interlacement). 
 They become, however, dispersed or divided into two fasciculi, 
 one above and the other below the optic nerve, the latter being 
 
THE OPHTHALMIC NERVE. 221 
 
 "The ophthalmic nerve, after running between the 
 rectus superior and the retractor muscles, gives a 
 
 the more numerous. They pass between the choroid membrane 
 and the contiguous sui'face of the sclerotic — lodged in grooves in 
 the latter — and on reaching the ciliary li^^ament, pierce it, a few 
 appearing to be lost in its substance, while all the rest pass in- 
 ward and ramify in the iris. From the posterior border of the 
 ganglion, which seems as if terminated by two angles, two 
 branches issue, one of which passes backward and upward to 
 the nasal branch of the ophthahnic nerve, appearing to be the 
 medium of communication between the ganglion and the rest of 
 the ganglial system, by being prolonged to the carotid plexus. 
 The other, the shorter branch, passes downward and backward 
 to the inferior oblique branch of the motor nerve of the eye.' 
 
 "For my own part," says Prof. Youatt, "I am now disposed 
 to be very much of Dr. Quain's opinion. It was not fitting that 
 the motions of the iris should be under the control of the will — 
 they should respond to the varying intensity of the light." — W. 
 Youatt in " Veterinarian" for 1S36, p. Jfi. 
 
 Mou3. Cuvier says : " It divides into two ramifications, one of 
 which proceeds toward the optic, unites with the small branch 
 of the third pair, and by this union produces a nervous enlarge- 
 ment called the lenticular or ophthalmic ganglion. Tiiis gan- 
 glion usually sends off the ciliary nerves, disposed in two bun- 
 dles. They are each composed of several filaments, which enter 
 the globe of the eye obliquely. The iris receives a great num- 
 ber of small ramifications from the ciliary nerves, which, after 
 having perforated the sclerotic and passed around the choroides 
 longitudinally, like ribbons, but without penetrating it, are lost." 
 — " Comparative Anatomy" Vol. II, j)- '^06. 
 
 Prof. W. Percivall says: " Upon the outer side of the optic 
 nerve, between i t and that part of the motor oculi from which 
 the branch nerves spring, is situated the ophthalmic ganglion. 
 This little body is principally constituted of branches from the 
 third pair, but it receives a filament or two from the sixth. The 
 nervous threads transmitted by the ganglion surround the sheath 
 of the optic nerve, and pursuing their course over it, penetrate 
 the globe of the eye, and run to be dispersed upon the iris."— 
 "Anatomy of the Horse " p. 336. 
 
222 THE FIFTH PAIR OF KERVES. 
 
 branch to the 'membrana nictitans/ and then takes a 
 singular course. Some ramifications go to4he frontal 
 sinuses and the foramina, and, piercing the orbit of 
 the eye for this purpose, present a beautiful view in 
 young animals, particularly the sheep. The main 
 branch .then enters the cranium again through the 
 internal orbital foramen, passes under the dura mater, 
 returns through the cribriform plate, and ramifies on 
 the membrane of the nose, sending some branches as 
 low as the false nostril and alae. 
 
 '' The superior maxillary nerve, or second branch of 
 the trigeminus, contains little that is peculiar to or 
 has a practical tendency in quadrupeds. The different 
 situation and conformation of the bones of the face 
 cause the principal or only variation in the distribu- 
 tion of this branch in the biped and the quadruped. 
 It leaves the cranium through the foramen rotundum, 
 and at the base of the skull gives off small ramifica- 
 tions to the inner canthus of the eye, the antrum, and 
 the two posterior grinder teeth. It also supplies the 
 lateral portion of the nasal cavity through the spheno- 
 palatine foramen, while filaments are given off from 
 the origin of the trunk to the temporal muscle. A 
 branch also runs along the upper border of the septum 
 nasi to the palate, and a larger branch, which trav- 
 erses the palate in company with its blood-vessels, 
 passes through the foramen incisivum to the upper 
 lip. The main trunk of the nerve now enters into the 
 superior and exterior foramen, in the hiatus between 
 the palatine bone and the tuberosity of the superior 
 maxillary bone, leading into a bony canal (easily traced 
 in the horse) between the maxillary sinus and the an- 
 trum, and appearing as a great pillar passing tlirough 
 the palatine sinuses in the ox. It traverses this canal, 
 
THE GOOSE'S FOOT. 223 
 
 and at length emerges on the face through the fora- 
 men infra-orbitariiim, and under the levator labii supe- 
 rioris muscle. It no sooner escapes from this canal 
 than it forms the ^pes anserinus' (the goose's foot, for 
 it divides something like the foot of this bird). It 
 anastomoses with or receives numerous branches from 
 the seventh pair, and forms an intricate plexus abt)ut 
 the lower part of the face and muzzle. The nerves, 
 however, are wisely and beautifully interwoven, for the 
 lips, being the seat of touch, require all the flexibility 
 and more than the sensibility of the human hand. 
 
 "The inferior maxillary nerve, or third branch of 
 the trigeminus, emerges from tlie cranium through 
 the foramen lacerum basis crauii, and very soon gives 
 o^ four important branches. The first branch, reck- 
 oning posteriorly, proceeds backward below the con- 
 dyle of the jaw, whore it divides into two portions. 
 The first runs up to the parotid gland, ramifies into 
 many filaments, and unites with the seventh pair. It 
 dips deep into and principally supplies the temporal 
 muscle, and penetrates and is distributed through the 
 masseter muscle. In this division there seems to be 
 concentrated the greater part of the motor fibrils of 
 the trigeminus, for these are muscles of extensive and 
 powerful action. There are few muscles of the frame 
 that are oftener or more powerfully employed than 
 those concerned in mastication ; but with the motor 
 fibrils those of sensation are doubtless conjoined. 
 
 ''The second branch is a long and slender one. It 
 first dips into the pterygoideus muscle, which is sup- 
 plied by it; consequently it is here also a motor as well 
 as a sensitive nerve. It then passes around or behind 
 the tuberosity of the upper jaw, supplying the bucci- 
 nator muscle — possibly witli sensitive fibrils alone, for 
 
224 THE FIFTH PAIR OF KERVES. 
 
 others go to this muscle from the seventh pair. In 
 the buccinator these fibrils are usually lost; but some- 
 times a few of them may be traced to the lower lip. 
 
 '' The third branch, in the order of its being given 
 off, is the dental nerve. This is generally considered 
 the continuation of the trunk of the inferior maxillary 
 nerve. It passes across the pterygoideus and enters a 
 canal (the dental canal), on the inner face of the lower 
 jawbone, near the upper edge, and at the bending or 
 angle of the jaw. It takes its course along the interior 
 of the bone (the canal), close to the roots of the teeth, 
 and sends out filaments to each of them. Emerging 
 through the lower maxillary foramen, it divides into 
 two branches, one of which is distributed in numerous 
 ramifications on the outside of the lower lip, and the 
 other in fewer ramifications on the inside. These are 
 evidently sensitive fibrils, the power of motion being 
 derived from the seventh pair of nerves. 
 
 " The fourth branch in point of order, but which 
 does not enter the 'dental canal,' is the gustatory or 
 lingual 7ierve, the largest of the four. It is singularly 
 flat, like a little ribbon. It runs along the inside of 
 the lower jaw, and a branch of it enters a foramen in 
 the jaw to supply the roots of the incisor teeth ; but 
 the main nerve, proceeding obliquely downward, gives 
 fibrils to the submaxillary glands, and to i\\Q glands 
 and muscles at the base of the mouth generally. These 
 fibrils form true plexuses about the salivary glands and 
 the mnscles of the tongue. They anastomose freely 
 with the twelfth pair (the lingnales or motor nerve of 
 the tongue), as the twelfth had already done with the 
 seventh (the 'portio dura'). The gustatory branch 
 penetrates the substance of the tongue between the 
 stylo and genio-glossal muscles, passing obliquely to 
 
RICH PLEXUSES AND LOOPED FILAMENTS. 225 
 
 the surface of the tongue, and terminating in the pa- 
 pillag. The papillae, thus endowed with nervous influ- 
 ence, are the seat of the sense of taste." 
 
 Of the fifth nerve (in man and in the horse) Prof. 
 Owen (quoting partly from Dr. Swan), says (" Odon- 
 tography," vol. i, pp. Ixv-vi) : ' 
 
 "The nerves of the teeth are derived from the tri- 
 geminal, or fifth pair, of which the second division sup- 
 plies those of the upper Jaw, the third division those 
 of the lower. In the human subject, the three dental 
 branches of the infra-orbital nerve intercommunicate 
 by their primary branches, from which, and from a 
 rich plexus formed by secondary branches upon the 
 membrane lining the antrum, two sets of nerves are 
 sent off to the alveolar processes of the upper jaw; one 
 set {rami dentales) supplies the teeth, the other {rami 
 gingivales) the osseous tissue of the gums. The latter 
 agree in number with the intervals of the teeth, as the 
 proper dental nerves do with the teeth themselves. 
 These two sets are not, however, so distinct but that 
 some intercommunications are established between the 
 fine branches sent off in their progress to the parts 
 they are specially destined to supply. The rami den- 
 tales take the more direct course (through the middle 
 part of the osseous tissue to the teeth) penetrate the 
 orifices of the fangs, and form a rich plexus with 
 rhomboidal meshes upon the coronal surface of the 
 pulp, the peripheral elementary filaments returning 
 into the plexus by loops. In the lower jaw the dental 
 nerve, besides supplying the proper nerves to the teeth, 
 also forms a rich plexus, in which it is joined by some 
 branches from the division of the nerve that afterward 
 escapes by the foramen mentale, and from this plexus 
 
226 THE FIFTH PAIE OF ITERVES. 
 
 the cancellous tissue of the bone and the vascular 
 gums are supplied. * * * * 
 
 " In the horse the maxillary plexus is most devel- 
 oped above and between the alveoli of the three pre- 
 molar teeth. It is less complex where it supplies the 
 molar teeth, their alveoli, and the gums. In the 
 lower jaw of the horse a very rich plexus begins to be 
 formed in the cancellous substance of the bone by 
 branches of the dental nerve, soon after its entry into 
 the canal." 
 
VOCABULARY. 
 
 Note, — The definitions, wliere not otherwise credited, are 
 from " Dunglison's Medical Dictionary." 
 
 A. 
 
 Ala (plural, alae). A term often used by anatomists for parts 
 which project like a wing from the median line; as the alae 
 nasi, alsB of the uterus, &c. 
 
 Albu^men (wliite). An immediate principle of animals and veg- 
 etables, which constitutes the chief part of the white of egg. 
 It is found in the serum, chyle, synovia, serous fluids, &c. 
 There is not much difference in chemical composition be- 
 tween animal and vep:etable albumen, fibrin, and casein. 
 Fibrin alona appears, however, to be possessed of plastic 
 properties. Also the white (sclerotic) of the eye. 
 
 Alve'olar Arches are formed by the margins or borders of 
 tlie two jaws, which are hollowed by the rJveoli. 
 
 Alveolar Artery, arises from the internal maxillary, de- 
 scends beliind the tuberosity of the upper jaw, and gives 
 branches to the up]x;r molar teeth, gums, periosteum, mem- 
 brane of the maxillary sinus, and buccinator muscle. 
 
 Alveolar BORDEPt. The part of the jaws that is hollowed by 
 the alveoli. 
 
 Alveolar Membranes are very fine membranes, situated be- 
 tween the teeth and alveoli, and formed by a portion of the 
 sac wliich incloses the tooth before it pierces the gum. By 
 some this membrane has been called the ' alveolo-dental 
 periosteum.' 
 
 Alveolar Vein. This has a distribution similar to the artery. 
 
228 TOCABULARY, 
 
 ALVE'oiiTTS (pi. alveoli). The alveoli are the sockets of tlie 
 teeth, into which they are, as it were, driven. Their size 
 and shape are determined by the teeth which they receive, 
 and they are pierced at the apex by small holes wliich give 
 passage to the dental vessels and nerves. 
 
 Anastomo'sis (* a mouth '). Communication between two ves- 
 sels. By considering the nerves to be channels, in which a 
 nervous fluid circulates, their communication likewise has 
 been called anastomosis. By means of anastomoses, if the 
 course of a fluid be arrested in one vessel, it can proceed 
 along others, 
 
 Anisodac'tyle. Hoofed quadrupeds with toes (on the hind- 
 feet at least) in uneven numbers, as one, three, or five, the 
 latter being manifested by the Proboscidians. All these have 
 a simple stomach and an enormous coecum. Examples : 
 Horse, ^apir, rhinoceros, elephant. R. Owen. 
 
 Ante'bioh (from ante, ' before '). Situate before. Great con- 
 fusion has prevailed with anatomists in the use of the terms 
 before, behind, &c. Generally, the word anterior is applied 
 to parts situate before the median line, the body being in the 
 erect posture, with the face and palms of the hands turned 
 forward, and the feet applied longitudinally together. 
 
 Antrum. A cavern. A name given to certain cavities in 
 bones, the entrance to v/hich is smaller than the bottom. 
 
 Antrum op Highmore. A deep cavity in the substance of the 
 superior maxillary bone, communicating with the middle 
 meatus of the nose. It is lined by a prolongation of the 
 Schneiderian membrane. 
 
 Arach'noid Membrane. A name given to several mem- 
 branes, v/hicli, by their extreme thinness, resemble spider- 
 webs. The moderns use it for one of the membranes of the 
 brain, situate between the dura mater and pia mater. It is a 
 serous membrane, composed of two layers, the external being 
 confounded, in the greater part of its extent, witli the dura 
 mater, and, like it, lining the interior of the cranium and spi- 
 nal canal ; the other is extended over the brain, from which 
 it is separated by the pia mater, without passing into the 
 sinuosities between the convolutions, and penetrating into 
 the interior of the brain by an opening at its posterior part, 
 under the ' corpus callosum.' It forms a part of the investing 
 
VOCABULARY. 229 
 
 sheath of nerves, as they pass from the encephalic cavities. 
 Its chief uses seem to be to envelop and, in some measure, 
 protect the brain, and to secrete a fluid for the purpose of 
 keeping- it in a state best adapted for the performance of its 
 functions. 
 • AitE'OLA. A diminutive of 'area.' Anatomists understand by 
 areola? the interstices between the fibers composing organs, 
 or those existing between laminae, or between vessels which 
 interlace with each other. 
 Aegen'ti Nitras. Nitrate of silver ; lunar caustic. The vir- 
 tues of nitrate of silver are tonic and escharotic. It is given 
 in chorea, epilepsy, &c.; locally, it is used in various cases as 
 an escharotic. Dose, gr. 1-8 to gr. 1-4, in pill, three times 
 a day. 
 Armadil'lo. (So called from being protected or armed by a 
 scaly covering like the plate armor of the middle ages.) A 
 genus of South American quadrupeds, belonging to the order 
 of edentata, and characterized by a defensive armor of small 
 bony plates, covering the head and trunk, and sometimes the 
 tail. Br ancle. 
 
 AnTicuL ACTION. The union of bones with each other, as well 
 as the kind of union. Articulations are generally divided 
 into two kinds — movable and immovable. The articulations 
 , are subject to a number of diseases, which are generally some- 
 what severe; they may be physical, as wounds, sprains, lux- 
 ations, &c., or they may be organic, as ankylosis, extraneous 
 bodies, caries, rheumatism, gout, &c. 
 At'rophy. Progressive and morbid diminution in the bulk of 
 the whole body or of a part. Atrophy is generally sym|> 
 tomatic. Any tissue or organ thus affected is said to be 
 ' atrophied.' 
 AuRic'uLAR. (The ear.) That which belongs to the ear, espe- 
 cially the external car. 
 
 B. 
 
 Batra'chia. An order of reptiles including toads, frogs, and 
 
 salamanders. Brande. 
 
 One of the five classes into which the vertebrate animals 
 
 are usually divided, though some writers have reduced the 
 
 class to the rank of an order of reptiles, a class with which 
 
230 VOCABULARY. 
 
 they are popularly confounded. The batrachians are cold- 
 blooded and oviparous, and in most living- species are with- 
 out scales, and the blood is partly aerated through the skin. 
 The young, for the most part, breathe by gills like those of 
 fishes; they assume a fish-like form (as the tadpole), and 
 finally, when adult, with few exceptions, loss their gills and 
 breathe by lungs, like true or scaly reptiles. They generally 
 have limbs, but not always. Johnson's JSF. U. Oyc. 
 
 Bi'furcation. (A fork.) Division of a trunk into two 
 branches, as the bifurcation of the trachea, aorta, &c. 
 
 Buccal. That which concerns the mouth, and especially the 
 cheek. 
 
 C. 
 
 Cjecum. The blind gut ; so called from its being perforated at 
 one end only. That portion of the intestinal canal which is 
 seated between the termination of the ileum and beginning 
 of the colon, and which fills, almost wholly, the right iliac 
 fossa, where the peritoneum retains it immovably. Its length 
 is about three or four fingers' breadth. The ileo-ccecal valve, 
 or valve of Bauhin, shuts oflT all communication between it 
 and the ileum, and the 'Appendix vermiformis cseci' is at- 
 tached to it. 
 
 In the horse the csecum (water stomach) will hold four gal- 
 lons. A horse will drink at one time a great deal more than 
 his stomach will contain ; but even if he drinks a less quan- 
 tity, it remains, not in the stomach or small intestines, but 
 passes to the csecum, and is there retained, as in a reservoir, 
 to supply the wants of the system. Youatt. 
 
 Cal'culus. a diminutive of ' calx,' a iime-stone. Calculi are 
 concretions, which may form in every part of the animal 
 body, but are most frequently found in the organs that act 
 as reservoirs, and in the excretory canals. They are met 
 with in the tonsils, joints, biliary ducts, digestive passages, 
 lachrymal ducts, mamma?, pancreas, pineal gland, prostate, 
 lungs, salivary, spermatic, and urinary passages, and in the 
 uterus. The causes which give rise to them are obscure. 
 Those that occur in reservoirs or ducts are supposed to be 
 owing to the deposition of the substances, which compose 
 them, from the fluid as it passes along the duct ; those which 
 occur in the substance of an organ are regarded as the pro- 
 
VOCABULARY* 231 
 
 duct of some clironic irritation. Their general effect is to 
 irritate, as extraneous bodies, the parts with wliich they are 
 iu contact, and to produce retention of the fluid wlience they 
 have been formed. The symptoms differ, according to the 
 ■ Sensibility of tlio organ and the importance of the particular 
 I secretion whose discharge they impede. Their 'solution' is 
 i generally impracticable. Spontaneous expulsion or extrac- 
 tion is the only way of getting rid of them. 
 Cancel'li. ' Lattice- work,* The cellular or spongy texture of 
 bone, consisting of numerous cells, communicating with each 
 other.' They contain a fatty matter, analogous to marrow. 
 This texture is met with principally at the extremities of 
 long bones, and some of the short bones consist almost wholly 
 of it. It allows of the expansion of the extremities of bones, 
 without adding to their weight, and deadens concussions. 
 Can'dla. Diminutive of canna, ' a reed.' A small tube of gold, 
 silver, platinum, iron, lead, wood, elastic gum, or gutta- 
 percha, used for various purposes in surgery. 
 Cap'illahy (from cajnllus, ' a hair ')• Hair-like ; small. 
 Capillary Vessels are the extreme radicles of tlie arteries 
 and veins, which together constitute the capillary, interme- 
 diate, or peripheral vascular system— the methce'mata blood 
 channels of Dr. Marshall Hall (that is, the system of vessels 
 in which the blood undergoes the change from venous to 
 arterial, and conversely). They possess an action distinct 
 from that of the heart. 
 Carries. An ulceration of bone—' necrosis' being the death of 
 a bone. It resembles the gangrene of soft parts. It is recog- 
 nized by the swelling of the bone which precedes and accora- 
 ! panics it ; by the abscesses it occasions ; the fistulre which 
 ; form ; the sanious character, peculiar odor, and quantity of 
 the suppuration, and by the evidence afforded by probing. 
 The most common causes of caries are blows, the action of 
 some virus, and morbid diathesis. When dependent on any 
 virus in the system, this must be combated by appropriate 
 remedies. When entirely local, it must be converted, where 
 practicable, into a state of necrosis, or death of the affected 
 part. To this end apply stimulants, tlif^ actual cautery, &c. 
 Cahot'ids. The great arteries of the neck, vv'hich carry blood 
 to the head. 
 
232 VOCABULARY. 
 
 Car'tilage. a solid part of the animal body, of a consistence 
 between bone and ligament, wliicli in the fetus is a substi- 
 tute for bone, but in the adult exists only in the joints, at 
 the extremities of the ribs, «&c. 
 
 Cer'vical. Everything which concerns the neck, especially 
 the back part. 
 
 Ciievrotain'. a species of the geuus Moschus, related to the 
 deer, but having no horns, and otherwise peculiar. It is 
 small, light, and graceful, and lives in the mountains of Asia, 
 from the Altai to Java. Dana. 
 
 Choroid Membrane. A thin membrane, of a very dark color, 
 which lines the sclerotic internally. It is situate between the 
 sclerotic and retina, has an opening posteriorly for the pas- 
 sage of the optic nerve, and terminates anteriorly at the great 
 circumference of the iris, where it is continuous with the cili- 
 ary processes. The internal surface is covered with a dark 
 pigment, consisting of several layers of pigment cells. Its 
 use seems to be to absorb the rays of light after they have 
 traversed the retina. 
 
 Cil'iary. Relating to the eyelashes, or to cilia. This epithet 
 has also been applied to different parts, which enter into the 
 structure of the eye, from the resemblance between some of 
 them (the ciliary processes) and the eyelashes. 
 
 Colon. That portion of the large intestines which, extends 
 from the caecum to the rectum. The colon is usually divided 
 into four portions. 1. The right lumbar or ascending colon, 
 situate in the right lumbar region, and beginning at the 
 C33cum. 2. The transverse colon — transverse arch of the 
 colon — the portion which crosses from the right to the left 
 side, at the upper part of the abdomen. 3. The left lumbar 
 or descending colon, extending from the left part of the trans- 
 verse arch, opposite the outer portion of the left kidney, to 
 the corresponding iliac fossa. . 4. The iliac colon, or sigmoid 
 flexure of the colon ; the portion which makes a double cur- 
 vature in the left iliac fossa, and ends in the rectum. 
 
 In the horse the colon is exceedingly large, and is capable 
 of containing no less than twelve gallons of liquid or pulpy 
 food. It is of considerable length ; completely traversing the 
 diameter of the abdominal cavity, it is then reflected upon 
 itself, and retraverses the same space. Touatt. 
 
VOCABULARY. 233 
 
 Com'missures, The point of union between two parts ; thus 
 
 the commissures of the eyelids, lips, &c., are the angles which 
 
 they form at the place of union. 
 
 Comparative Anat'omy. The science which treats of the 
 
 structure and relation of organs in the various branches of 
 
 . the animal kingdom, without a knowledge of which it is im- 
 
 ) possible to understand the beautifully progressive develop- 
 ment of organization, necessary even for the full comprehen- 
 sion of the uses of many parts of the human body, which, 
 apparently rudimentary and useless in man, are highly de- 
 veloped in other animals. This science is also the basis of 
 physiology and the natural classification of animals. 
 
 American Cyclopedia. 
 
 Con'dyle. An articular eminence, round in one direction, flat 
 in the other. A kind of process, met with more particularly 
 in the ginglymoid joints, such as the condyles of the occipi- 
 tal, inferior maxillary bone, &c. 
 
 Congen'ital (from con and genitus, 'begotten'). Diseases 
 which infants have at birth; hence, congenital allectionsare 
 those that depend on faulty conformation, as congenital her- 
 nia, congenital cataract, &c. 
 
 CoNJUNCTi'vA Membra' xa. A mucous membrane, so called 
 because it unites the globe of the eye Avith the eyelids. It 
 covers the anterior surface of the eye, the inner surface of the 
 eyelids, and the 'caruncula lachry malis. ' It possesses great 
 general sensibility, communicated to it by the fifth pair of 
 nerves. 
 
 Copyba'ra is the largest known quadruped of the order Ro- 
 dentia, and belongs to the family Cavidss. It is an aquatic 
 animal, a native of South America, and feeds on vegetable 
 food exclusively. Its dentition resembles that ofthecavy, 
 except that the grinding teeth are formed of many trans- 
 verse plates, the number of plates increasing as the animal 
 advances in age. It is inoffensive and easily tamed. The 
 flesh is esteemed good food. It is somewhat smaller than 
 the common hog. Johnson's New Unicersal Cyclopedia. 
 
 Cokpus'cle A minute particle or physical atom; one of the 
 very small bodies which compose large bodies, not the ele- 
 mentary principles of matter, but such small particles, simple 
 or compound, as arc not dissolved or dissipated by ordinary 
 
234 VOCABULARY. 
 
 heat. An animal cell, or cellular anatomical element, as a 
 blood corpuscle ; a lymph corpuscle. Webster. 
 
 Coreela'tion (mutual relation) OF Fokces (otherwise called 
 'Transmutation of Force or Energy'). A phrase of recent 
 origin, employed to express the theory' that any one of the 
 various forms of physical force may bo converted into one or 
 more of the other forms. The cardinal point in this theory 
 is the doctrine of heat and its relation to other agents, espe- 
 cially to mechanical motion. For example, the heat mani- 
 fesred when we rub two fiat surfaces briskly against each 
 other, is only our own muscular motion checked by the fric- 
 tion, and changed thereby into the heat which the surfaces 
 reveal. On the other hand, this muscular motion is only the 
 heat of our bodily frame expending itself in this way. In 
 either case the energy has hot been annihilated, but only 
 transferred, and appears in a nevv^ form. 
 
 Johnson's N. IT. Cyc, article revised by J. H. Seelye. 
 
 Crura. The plural of cms, ' a leg.' Applied to some parts of 
 the body, from their resemblance to legs or roots, as the 
 ' crura cerebri,' ' crura cerebelli,' &c. 
 
 Cul-de-sac. Any bag-shaped cavity, tubular vessel, or organ, 
 open only at one end. Dana. 
 
 I>. 
 
 Dental Canal. The bony canals through which the vessels 
 
 and nerves pass to the interior of the teeth. 
 Dental Cavity. A cavity in the interior of the teeth, in which 
 
 is situate the dental pulp. (More properly the pulpal cavity.) 
 Dental Pulp. The pultaceous substance, of a reddish-gray 
 
 color, very soft and sensible, which fills the cavity of the 
 
 teeth. It is well supplied w^ith capillary vessels. 
 Dentig'erous. Tooth-carrying, as dentigerous cysts ; one 
 
 containing teeth. 
 Dermal. Relating or belonging to the skin. 
 Dermatoid or Dermoid. That which is similar to the skin. 
 
 This name is given to different tissues which resemble the 
 
 skin. The dura mater has been so called by some. 
 Deter'gents. Medicines which possess the power to deterge 
 
 or cleanse parts, as wounds, ulcers, &c. They belong to the 
 
 class of stimulants, or to that of emollients. 
 
VOCABULARY. 235 
 
 Diabe'tes. a disease cbaracterized by great augmentation and 
 often manifest alteration in the secretion of urine, with ex- 
 cessive thirst and progressive emaciation. The quantity of 
 urine discharged in 24 hours is sometimes 30 pints and up- 
 ward, each pint containing 3| ounces saccharine matter. 
 
 Dl'APiinAGM. 1. A dividing membrane or thin partition, com- 
 monly with an opening through it. 2. The muscle separa- 
 ting the chest or thorax from the abdomen or lower bellv ; 
 the midriff. Webntei: 
 
 Diath'esis. Disposition, constitution, affection of the body ; 
 predisposition to certain diseases rather than to others. The 
 principal diatheses mentioned by authors are the cancerous, 
 scrofulous, scorbutic (pertaining to scurvy), rheumatic, gouty, 
 and calculous. 
 
 DicnOT'oiious. Regularly divided by pairs, from top to bot- 
 tom ; as, a dicliotomous stem. Martyn. 
 
 DiVERTic'uLTJ^r. A blind tube branching out Crom the course 
 of a larger one. An organ which is capable of receiving an 
 imusual quantity of blood, when the circulation is obstructed 
 or modified elsewhere, is said to act as a diverticulum. Also 
 a malformation or diseased appearance of a part, in which it 
 passes out of its regular course. It is sometimes applied to 
 such a condition of the alimentary canal. Also a hole to get 
 out at. A by- passage. 
 
 Dugong'. a herbivorous, cetaceous animal of the Indian Ocean, 
 with a tapering body ending in a crescent-shaped fin. The 
 fabled mermaid seems to have been founded on the dugong. 
 
 Gilbert. Brande, 
 It is generally from eight to twelve feet long, though it is 
 said to sometimes attain the length of twenty-five feet. The 
 upper lip is thick and fleshy, and forms a kind of snout ; the 
 upper jav/ bonds downward almost to a right angle ; the 
 eyes are very small, with a nictitating membrane ; the skin 
 is thick and smooth. Its flesh is said to resemble beef, and 
 
 . is prized as food. The oil is recommended as a substitute for 
 cod -liver oil. Johnson' .s JV. U. Cyc. 
 
 DuKA Matek, a fibrous, semi-transparent membrane, of a 
 pearly-white color, thick and very resisting ; lines the cavity 
 of the cranium, and contains the spinal marrow ; protects the 
 brain and marrow, and by its various expansions — the falx 
 
236 VOCABULARY. 
 
 cerebri, tentorium, &c. — supplies tlie different parts of tlie 
 cerebral mass. 
 
 E. 
 
 Econ'omy. By the term 'animal economy' is understood the 
 aggregate of the laws wliicli govern the organism. The word 
 economy is also used for the aggregate of parts which con- 
 stitute man or animals. 
 
 Edenta'ta. In natural history, an order of animals that are 
 destitute of front teeth, as the armadillo and ant-eater. Bell. 
 
 Eden'tulus. One without teeth. 
 
 Em'bryo. The fecundated germ, in the early stages of its de- 
 velopment in utero. At a certain i)eriod of its increase, the 
 name 'fetus' is given to it, but at what period is not deter- 
 mined. Generally, the embryo state is considered to extend 
 to the perio.l of quickening. 
 
 Encephali'tis. This term has been used by some nosologists 
 (classifiers of diseases) synonymously with ' cephalitis ' and 
 'phrenitis.' By others it has been appropriated to inflam- 
 mation of the brain, in contradistinction to that of the mem- 
 branes. 
 
 E'OCENE. In geology, a term applied to the earlier tertiary de- 
 posits, in which are a few organic remains of existing species 
 of animals. Hence the term eocene (recent), which denotes 
 the dawn of the existing state of things. 
 
 Dana. Lyell. Mantell. 
 In America the eocene strata contain numerous fossils, 
 mostly marine moUusks, but also include some gigantic ver- 
 tebrates, a carnivorous cetacean seventy foet in length, and a 
 shark of which the teeth are sometimes six inches in length. 
 The Wyoming beds have furnished the remains of a remark- 
 able group of mammals, which are thought by. Prof. Marsh 
 to form a new order, and which he has named ' Dinocerata.' 
 The largest of these (Dinoceras mirabilis) had the bulk of an 
 elephant, and was provided with three pairs of horns and a 
 pair of great saber-like canine teeth. JoJin son's K U. Cyc. 
 
 Epider'mis. a transparent, dry, thin membrane, devoid of 
 nerves and vessels, which covers all the surface of the body, 
 except the parts that correspond to the nails. It appears to 
 consist of minute scales placed one above the other. The 
 epidermic system, in general anatomy, comprises three parts. 
 
VOCABULARY. 237 
 
 1, External epidermis. 2. Epidermis spread over the mu- 
 cous membranes. 3. The nails and liair. 
 Epithe'lium. Tiie thin layer of ei)idermis wliich covers parts 
 deprived of derma, properly so called, as the nipple, mucous 
 membranes, Jips, &c. 
 Eschar. A slougli, crust, or scab. 
 
 Escharot'ic. Any substance whicli, when applied upon a liv- 
 incT part, gives vise to an eschar, such as caustic potassa, con- 
 centrated mineral acids, «Sic. 
 Esoph'agus, The gullet. A musculo-membranous canal, 
 extending from the inferior extremity of the pharynx to the 
 upper oritice of the stomach. 
 Ethmoid. Shaped like a sieve. 
 
 Ethmoid Bo.ne. One of the eight bones which compose the 
 cranium, so called because its upper plate is pierced by a con- 
 siderable number of holes. It is situate at the anterior, in- 
 ferior, and middle part of the cranium. 
 Evolu'tion. According to the hypothesis of evolution, in its 
 simplest form, the universe as it now exists is the result of 
 " an immense series of changes," related to and dependent 
 upon each other, as successive steps, or rather growths, con- 
 stituting a progress ; analoorous to the unfolding or evolving 
 of the parts of a living organism. Evolution is defined by 
 Herbert Spencer as consisting in a progress from the homo- 
 geneous to the heterogeneous, from general to special, from 
 the simple to the complex ; and this process is considered to 
 be traceable in the formation of the worlds in space, in the 
 multiplication of the types and species of plants and animals 
 on the globe, in the origination and diversity of languages, 
 literature, arts, and sciences, and in all the changes of human 
 institutions and society. Hrnry Ilartsliorne. 
 
 The animal kingdom displays a unity of plan or a correla- 
 tion of parts by which common principles are traced through 
 the most disguising diversities of form, so that in aspect, struc- 
 ture, and functions the various tribes of anim:ils pass into 
 each other hy sliffht and gradual transitions. The arm of a 
 man, the fore limb of a qnndruncd, the wing of a bird, and 
 the fin of a fish are homologous, that is. they rontnin the 
 same essential parts, modified in correspondence with the dif- 
 ferent circumstances of the animal ; and so with the other 
 
238 VOCABULARY. 
 
 organs. Prof. Cope says : " Every individual of every species 
 of a given branch of the animal king-dom is composed of ele- 
 ments common to all, and the differtsuces whicli are so radi- 
 cal in the higher grades are but the modifications of the same 
 elemental parts." E. L. Youmans. 
 
 Exfolia'tion (from ex s^ndi folium, ' a leaf). By this is meant 
 the separatio2i of the dead portions of a bone, tendon, apon- 
 eurosis (a white shining membrane), or cartilage, under the 
 form of himellee (small scales). Exfoliation is accomplished 
 by the instinctive action of the parts, and its object is to de- 
 tach the dead portions from those subjacent, which are still 
 ^ alive. For this purpose the latter throw out fleshy granula- 
 tions, and a more or less abundant suppuration occurs, which 
 tends to separate the exfoliated part — now become an extra- 
 neous body. 
 
 ExosTo'sis. An osseous tumor, which forms at the surface of 
 bones, or in their cavities. 
 
 Exostosis Dentium. Exostosis of the teeth. 
 
 F. 
 
 Ferhu'ginous (chalyb'eate). Of or belonging to iron ; contain- 
 ing iron. Any medicine into which iron enters, as chalyb- 
 eate mixture, pills, waters, &c. 
 
 Fe'tus. See ' embryo.' 
 
 Fiber. An organic filament, of a solid consistence, and more or 
 less extensible, wliich enters into the composition of every 
 animal and vegetable texture. 
 
 Fil'ament. a thread. This word is used synonymously with 
 fibril ; thus we say a nervous or cellular filament or fibril. 
 
 Fis'tula. ' A pipe or reed.' A solution of continuity (a division 
 of parts previously continuous) of greater or less depth and 
 sinuosity, the opening of which is narrow, and the disease 
 kept up by an altered texture of parts, so that it is not dis- 
 posed to heal. A fistula is ' incomplete ' or ' blind' when it 
 has but one opening, and ' complete ' when there are two, the 
 one communicating with an internal cavity, the other exter- 
 nally. It, is "lined in its whole course by a membrane which 
 seems analogous to mucous membranes. 
 
 Fol'licle. a follicle or crypt is a small, roundish, hollow 
 body, situate in the substance of the skin or mucous mem- 
 branes, and constantly pouring the fluid which it secretes on 
 
VOCABULARY. 239 
 
 their surfaces. Tlie use of the secretion is to keep the parts 
 on which it is poured supple and moist, and to preserve them 
 from the action of irritating bodies with which they have to 
 come in contact. 
 
 Foka'men. Any cavity pierced through and through. Also 
 the orifice to a canal. 
 
 Fossa. A cavity of greater or less depth, the entrance to which 
 is always larger than the base. 
 
 FRiENUM. A small bridle. A name given to several membran- 
 ous folds, which bridle and retain certain organs. 
 
 Frontal Bone. A double bone in the fetus, single m the adult, 
 i situate at the base of the cranium, and at the superior part 
 of the face. 
 
 Function. The action of an organ or system of organs. Any 
 act necessary for accomplishing a vital phenomenon. A 
 function is a special oflace in the animal economy, which has 
 as its instrument an organ or apparatus of organs. 
 
 Fungus. The mushroom order of plants. In pathology the 
 word is commonly used synonymoasly with fungosity (my- 
 cosis). 
 
 Fungus H^mato'des (Hacmatodes Fungus). An exceedingly 
 alarming carcinomatous (cancerous) affection, which was fii'st 
 described with accuracy by Mr. Jolui Burns, of Glasgow. It 
 consists in the development of cancerous tumors, in which 
 the inflammation is accompanied with violent heat and pain, 
 and with fungus and bleeding excrescences. 
 
 G. 
 
 Gang'lion. Nervous ganglions are enlargements or knots in 
 the course of a nerve. 
 
 Gastric. Belonging or relating to the stomach. 
 
 Gastric Juice. A fluid secreted from the mucous membrane 
 of the stomach.- It assists digestion. 
 
 Gentian Wine (vinura gentians compositnm, or wine bitters). 
 'Gentiana Lutea' is the systematic name of the officinal 
 gentian. The plant is common in the mountains of Europe. 
 The root is almost inodorous, extremely bitter, and yields 
 its \irtues to ether, alcohol, and water. It is tonic and 
 stomacliic, and, in large doses, aperient. It is most fre- 
 quently, however, used in infusion or tincture. 
 
240 VOCABULAET. 
 
 Geol'ogt is that branch of natural science which treats of the 
 structure of the crust of the earth and the mode of formation 
 of its rocks, together with the history of physical changes 
 and of life on our planet during the successive stages of its 
 history. It has been inferred that its actual crust must be 
 very thick, perhaps not less than 2,500 miles. Geology de- 
 pends upon mineralogy for its knowledge of the constituents 
 of rocks, and upon chemistry and physics for its knowledge 
 of the laws of change ; and in its study of fossil remains it is 
 closely connected with the sciences of zoology and botany. 
 A knowledge of geology lies at the base of physical geogra- 
 phy, and is essential to the skillful prosecution of minini^ 
 and other useful arts. ^ J. W. Dawson. 
 
 The facts proved by geology are that during an immense 
 but unknown period the surface of the earth has undergone 
 successive changes ; land has sunk beneath the ocean, while 
 fresh land has risen up from it ; mountain chains have been 
 elevated ; islands have been formed into continents, and con- 
 tinents submerged till they have become islands ; and these 
 changes have taken place, not once merely, but perhaps 
 hLuulrcds, perhaps thousands of times. A. L. Wallace. 
 
 Prof. Dana says the " earth was first a featureless globe of 
 fire ; then had its oceans and dry land ; in course of time re- 
 ceived mountains and rivers, and finally all those diversities 
 of surface which now characterize it." 
 
 Gland. (An acorn ; a kernel.) Softish, g^ranular, lobated or- 
 gans, composed of vessels and a particular texture, which 
 draw from the blood the molecules necessary for the forma- 
 tion of new fluids, conveying them externally by means of 
 one or more excretory ducts. Each gland has an organiza- 
 tion peculiar to it, but we know not the intimate nature of 
 the glandular texture. 
 
 Guana'co. The ' Auchenia Huanaca,' a species of the genus of 
 ruminant mammals to which the llama belongs. It inhabits 
 the Andes, and is domesticated. It is allied to the camel. 
 
 Webster. 
 
 The guanaco is especially abundant in Patagonia and 
 
 Chili, where it forms large flocks. It is about three feet high 
 
 at the shoulders, and is extremely swift. In domestication it 
 
 is ill-tempered, and has a disagreeable habit of ejecting saliva 
 
VOCABULARY. 241 
 
 upon unwelcome visitors. In its wild state it seldom diiiiks 
 water. Its flesh is edible and its skin valuable. 
 
 Johnson's iV. U. Gyc- 
 H. 
 
 Haversian Canals. (Canals of Havers, nutritive canals, &c.) 
 The canals through which the V(issel3 pass to the bones. 
 They are lined by a very line lamina of compact texture, or 
 are formed in the texture itself. There is generally one large 
 nutritious canal in a long bone, situate toward its middle. 
 
 Hia'tus. xV foramen or aperture. Mouth. The vulva. Also 
 yawning. 
 
 Histol'ogy is the branch of anatomy which treats of the minute 
 structure of the tissues of which living beings are composed. 
 It is divided into ' human histology,' which treats of the tis- 
 sues of man ; ' comparative histology,' which treats of the tis- 
 sues of the lowor animals, and ' vegetable histology,' which 
 treats of the tissues of plants. Each of these divisions may 
 be subdivided into 'normal' and 'pathological' histology, 
 the first referring to the healthy tissues, the second investi- 
 gating the changes they undergo in disease. J. J. Vioodicard. 
 
 Hoove. A disease in cattle, consisting in the excessive inflation 
 of the stomach by gas, ordinarily caused by eating too much 
 green food. Gardner. 
 
 Hyper' TROPnY. The state of a part in which the nutrition is 
 performed with greater activity, and which on that account 
 at length acquires unusual bulk. The part thus aflected is 
 said to be hypertrophied or hypertrophous. 
 
 I. 
 
 Infiltr ACTION. To filter; effusion. The accumulation of a 
 fluid in the areolae of a texture, and particularly in (he areo- 
 lar membrane. The fluid eff'used is ordinarily the 'liquor 
 sanguinis,' sound or altered ; sometimes blood or pus, faeces 
 or urine. When infiltration of a serous fluid is general, it 
 constitutes 'anasarca' (droj)sy) ; when local, ' oedema.' 
 
 Intersti'tial. Applied to that which occurs in the interstices 
 of an organ, as interstitial absorption, interstitial pregnancy, 
 &t;. (See ' Suppuration.') 
 
 Intra-uterine. {lutri, 'within.,' uterus, 'the womb.') That 
 which takes place within the womb, as intra-uterine life. 
 11 
 
24,2 VOCABULARY. 
 
 Iris. So called from its resembling the rainbow in a variety of 
 colors. A membrane, stretclied vertically at the anterior 
 part of the eye, in the midst of the aqueous humor, in which 
 it forms a iiini of circular, flat partition, separating the an- 
 terior from the posterior chamber. It is perforated by a cir- 
 cular opening called the pupil, which is constantly varying 
 its dimensions, ovv^ing to the contractions of the fibers of the 
 iris. 
 
 Isodac'tyle. Hoofed quadrupeds with toes in even number, as 
 two or four, and which have a more or less complicated 
 stomach, with a moderate-sized, simple caecum. Examples: 
 Ox, hog, peccary, hippopotamus. 11. Owen. 
 
 Li. 
 
 Lach'hymal. Belonging to the tears. This epithet is given 
 to various parts. 
 
 Lacuna of Bone. Certain dark, stellate spots, with thread- 
 like lines radiating from them, seen under a high magnifying 
 power. These were first believed to be solid (jEseous cor- 
 puscles or cells (corpuscles of Purkinje), but are now re- 
 garded as excavations in the bone, with minute tubes or 
 canalic'uli proceeding from them and commmiicating with 
 the Haversian canals. The lacunse and canaliculi are fibers 
 concentrated in the transit of nutrient fluid through the osse- 
 ous tissue. 
 
 Lam'iNA. a thin, flat part of a bone ; a plate or table, as the 
 cribriform lamina or plate of the ethmoid bone. Lamina and 
 lamella are generally used synonymously, although the latter 
 is properly a diminutive of the former. 
 
 Lesio T. Derangement, djsorder; any morbid change, either in 
 the exercise of functions or in the texture of organs. ' Or- 
 ganic legion ' is synonymous with organic disease. 
 
 Lipo'ma. a fatty tmnor of an encysted or other character. 
 
 LiPOiNi^ATOUS. Having the nature of lipoma, as a lipomatous 
 ra ass. 
 
 LiQTjOU Sang'uinis. a term given by Dr. B. Babington to one 
 of the constituents of the blood, the other being the red par- 
 ticles. It is the eft\rsed material (called yd^sma, coagulable 
 or plastic lymph, intercellular fluid, &c.), from which the cells 
 obtain the constituents of the different tissues and secretions. 
 
VOCABULARY. 243 
 
 M. 
 
 Malar. Beloncrlng to tlic clisek, as tlie malar bone. 
 
 Malar Process. Z/goniatic process. (Cheek bone process.) 
 
 Masseter, a muscle situate at tlio posterior part of the cheek, 
 and lying upon the ramus ot the lower jawbone. Its office is 
 to raise the lower jaw and to act in mastication. 
 
 Mas'todon. An extinct genus of quadru[>eds. When alive it 
 must have been twelve or thirteen feet high, and, iucluding 
 the tusks, a'oout twenty-five feet long. The tusks measui-e 
 ten feet eleven inches, about two and a Imlf feet being im- 
 planted in the socket. According to Owen, the teeth are 
 seven on each side, above and below. The molars have 
 wedge-shaped, transverse ridges, the summits of which are 
 divided hj a depression lengthwise with the tooth, and sub- 
 divided into cones, more or less resembling the teats of a cow. 
 In some species there are from three to five ridges to each 
 posterior molar; in other species five or more. 0. 0. Marsh. 
 (The mastod )u takes its name from the mastoid or nipple- 
 like processes of its teeth.) 
 
 Mastoid. Having the form of a nipple. 
 
 Max'illary. Relating or belonging to the jaws. 
 
 Mea'tus. A passage or canal. 
 
 Median Line. A vertical line, suppdSed to divide a body lon- 
 gitudinally into two equal j)arts, the one light, the other left. 
 
 Med'ullary. Relating to the marrow, or analogous to marrow. 
 
 MEaATHE'RiU-M. An extinct, genus of Quaternary mammals. 
 'Megatherium Cuvieri,' from South America, exceeded the 
 rhinoceros in size, its skeleton measuring eighteen feet in 
 length. The vertebrae of the tail are very large and |x>wer. 
 fnl, and that organ, with tlie lund-legs, seems to have formed 
 a support for the heavy body, while X\v^ liiige fore-legs were 
 employed in breaking the branches from trees or tearing 
 tliem down for food. There are four toes in front and two 
 behind. The teeth, five above and four below on each side, 
 resemble those of the sloths. They grew from persistent 
 pulp", nnl are deeply implantc 1 in the jaws; they have a 
 grinding sarfacL^ of triangular ridges, and were fitted for mas- 
 ticating coarse vegetable food. 0. C. Marsh. 
 
 Membrank a name given to diffbi-ent thin organs, represent- 
 
244 VOCABULARY. 
 
 ing" a S]3ecies of supple and more or less elastic webs, varying 
 in tlieir structure and vital properties, and intended, in gen- 
 eral, to absorb or secrete certain linids, and to separate, en- 
 velop, and form other organs. Bicliat has divided the mem- 
 branes into siniple and compound. 
 
 Membra'na Nic'titans. The ' haw ' of the horse's eje. It is 
 a triangular-shaped cartilage, concealed within the inner cor- 
 ner of the eye, and is black or pied. It is used by the horse, 
 in lieu of hands, to wipe away dust, insects, &c. The eye 
 of the horse has strong mnscle& attached to it, and one, 
 peculiar to quadrupeds, by the aid of which the eye may be 
 drawn back out of the reach of danger. When this muscle 
 acts, the haw, which is guided by the eyelids, shoots across 
 the eye with the rapidity of lightning, and thus carries off 
 the offending matter. Its return is eqmilly rapid, Youatt. 
 (Prof. Youatt denounces the practice of cutting out tlie 
 haw as barbarous, that is, in ordinary cases of inflammation. 
 Ho says that if farriers and grooms were compelled to walk 
 for miles in the dust without being permitted to wipe or 
 cleanse their eyes, they would feel the torture to which they 
 often subject the horse.) 
 
 Mi'ocEiME. Literally, less recent. In geology, a term applied 
 to the middle division of the tertiary strata, containing fewer 
 shells of recent species than the Pliocene, but more than the 
 Eocene. Lydl. 
 
 The Miocene is apparently the culminating age of the 
 mammalia, so far as physical development is concerned, 
 which accords with its remarkably genial climate and exu- 
 berant vegetation. In Europe the beds of this age present 
 for the first time examples of the monkeys. Among carniv- 
 orous animals, we have cat-like creatures, one of which is dis- 
 tinguished from all modern animals of its group hy the long-, 
 saber-shaped canines of its upper jaw, fitting it to pull down 
 and destroy those large i^achyderms which could have easily 
 shaken off a lion or a tiger. Here also we have the elephants, 
 the mastodon, a great, coarsely -built, hog-like elephant, 
 ^ome species of which had tusks both in the upper and lower 
 jaw ; the rhinoceros, the hippopotamus, and the horse, all of 
 extinct species. J. W. Bairson. 
 
 MORPnOLOG'iCAL.. That which has relation to the anatomical 
 
VOCABULARY. 245 
 
 conformation of parts. Applied at times to tlie alterations 
 in tlie ' for;n ' of the several parts of the embryo, in contra- 
 distiuctioa to ' histological,' which is applied to the transfor- 
 mation by which the tismes are gradually generated. In 
 comparativa anatomy it is applicvl to the history of the modi- 
 fications of forms which the same organ undurofocs in differ- 
 ent animals. 
 
 MoKPnOL'OGiY is that brancli of zoology, in its widest sense, 
 which treats of the general form (not outline) and organiza- 
 tion of animals, and the principles involved, as well as the 
 correspondence in the various forms of tlie several members 
 and parts, so far as tliey are comparable in any structural 
 characters, but entirely independent of the uses of the parts 
 and organs. It tlius contrasts with animal physiology, "which 
 treats of tlie organization in whol;;, so far as respects adapta- 
 tion to surroundings, as ^vell as the various parts and organs, 
 so far as their uses and functions are concerned. To discover 
 the unity of organization in divers3 forms of the animal king- 
 dom, and the essential similarity in their mode of evolution, 
 are the principal problems within the province of morphol- 
 ogy. Theodore Gill. 
 
 Mucous. An epithet for all bodies containing mucilage or mu- 
 cus. It is also sometimes used synonymously with gummy. 
 
 Mucus. A substance analogous to vegetable mucilage, from 
 which, however, it differs by affording subcarbonate of am- 
 monia on distillation. Mucus exudes through the skin, in a 
 state of combination with a peculiar oily matter, and, drying, 
 forms the epidermis. It constitutes, in part, the different 
 epidcrnieous productions, as the hair, nails, wool, and horns 
 of animals, feathers of birds, and scales of fish. It is found 
 at the surface of the mucous membranes, and presents some 
 difference in its composition and properties, according to the 
 peculiar membrane from which it is obtained. Mucus pre- 
 serves the membranes moist, and in a state best fitted for tho 
 performance of their functions. 
 
 Mu?x-DEEii. A small, hornless deer of Central Asia, inhabiting 
 lofty mountain ranges. It is a timid, active creature of 
 nocturnal habits, and is much hunted for its yield of musk, 
 whicii is obtained from a sac beneath the abdomen, on tho 
 male alone. The flesh is estesmed, though that of tho malo 
 
245 VOCABULAEY. 
 
 is very rank and somewhat musky. It ranges from Siberia 
 to Tonquin. Johnson's N. IT. Oyc. 
 
 MCNTJAC, of India, Java, &c. , a small doer, but little over two 
 feet high. The males have small horns ; the females are 
 hornless. Their flesh is excellent. The Chinese muntjac, 
 like the preceding, is often half domesticated, and is some- 
 times bred in European parks. Johnsons N. U. Gyc. 
 
 Myi/odo^si. An extinct edentate animal, allied to the megathe- 
 riam. Lyell. 
 
 Nar'whal, or Sea-Untcorn. It is most nearly related to the 
 Vv'hite whale. Belonging to an order in which many of the 
 members never develop teeth at all, it, of all animals, is sup- 
 plied with a tooth altogether out of proportion to its size, and 
 it is, moreover, developed in utter contravention of the rules 
 of bi lateral symmetry, v/hich in e"^ery known case among 
 vertebrates govern the production of the teeth. In both 
 sexes the lower jaw is edentulous. The male, however, is 
 provided, on the left side of the upper jaw, wiih a tusk from 
 eight to ten feet long. It is straight, spirally gi'ooved ex- 
 ternally, and hollowed within into a persistent pulp-cavity. 
 On the right side the corresponding tooth generally remains 
 hi'Jden, smooth, and solid, within the jaw. In addition to 
 these, there are two small rudimentary molars concealed in 
 the upper jaw. The narwhal, which is considered one of 
 the greatest curiosities of natural history, attains to a length 
 of fifteen feet. Its single spiracle or blow-hole is situated on 
 the top of the liead. E. G. H. Day. 
 
 Necro'sis. or death of a bone, corresponds to mortification of 
 the soft structures, and is as distinct from caries as mortifica- 
 tion is from ulceration. Necrosis is divided into four varie- 
 ties, namely: 1. The scrofulous. 2. The superficial, or that 
 which involves the outer lamellre, and presents itself in the 
 . flat and long bones. 3. That form which destroys the in- 
 i ternal part of a bone, and in which the outer shell is not af- 
 fected. 4. That in wliich the whole thickness of the bono 
 dies. W. Willianis, 
 
 O. 
 
 Odontal'gia. Toothache. 
 
 Obontog'eny. Generation or mode of development of the teeth. 
 
VOCABULAEY. 247 
 
 ODO^s^TOG'riAPHY. A description of tlie teeth. 
 
 Odon'toid. Tooth-shaped. 
 
 Odontot/ithos. a sort of incrustation, of a yellowish color, 
 which forms at the caronse of the teeth, and is called ' tartar.' 
 It consists of 79 parts of phosphate of iime, 12i of mucus, 1 
 of a particular salivary matter, and 7^ of animal substance, 
 soluble in clilorohydric acid. A species of infusoria, * dentlc- 
 ola hominis,' has been found in it. 
 
 Odontol'ogy. Au anatomical treatise of the teeth. 
 
 Oral. Relating to the moutfi or to speech. 
 
 Oral Epitite'liu:*.!. See 'Epithelium.' 
 
 OiixiTiioiaiYN'cnus. An eflfodient (digj^inij), raonotrematoua 
 mammal, with a horny beak resembling that of a duck, aud 
 two merely fibrous cheek teeth on each side of both jaws, not 
 fixed in any bone, hut only in the frwm ; with pentadactylous 
 (iive-nngere:l) paws, webbed like the feet of a bird, and 
 formed for swimmiupf, and with a spur in the hinder feet, 
 emitting a poisonous liquid from a reservoir in the sole of the 
 foot, supplied by a gland situated above the pelvis, and by 
 the side of the spine. The animal is covered with a brown 
 fur. It is found only in Nev»' Holland, and is sometimes 
 called Water Mole. Bell. 
 
 As the name of the order imports, the alimentary, urinary, 
 and reproductive organs open into a common cloaca, as in 
 birds ; mammary glands are present, secreting milk for the 
 young, which are born blind and naked ; there are no prom- 
 inent nipples, and the mammary openings are contained in 
 slits in the integument ; M. Verreaus says the young, when 
 they are able to swim, suck in the milk from the surface of 
 the water, into which it is emitted. American Cyc. 
 
 ' Duck-Bill,' the English name of the Ornithorhynchus par- 
 adoxus, found in Van Diemen's land and Australia. In its 
 bill-like jaws, its spurs, its monotrematous character, its non- 
 placontal deveiojiment, and its anatomy, it appears to be a 
 connecting link between birds and mammals. The Duck-Bill 
 is the only animal of its genus. It is about fifteen inches 
 long; it climbs trees with facility, and dig.s burrows, often 
 thirty feet long, in the river bank, with one opening above 
 and another belovv^ water. It inhabits ponds and quiet 
 streams, swimming about with its head somewhat elevated, 
 
218 VOCABULARY. 
 
 often diving for its food, wliicli consists of insects and other 
 small aquatic animals. JolinsorCs N. U. Gi/c. 
 
 Of all the mammalia yet known, the Ornithorliynchus 
 seems the most extraordinary in its conformation, exhibiting 
 the perfect resemhlauce of the beak of a duck engrafted on 
 the head of a quadruped. Dr. Shaw. 
 
 Accurdini^ to Ernst H. Hae^kel, these animals " are he- 
 coming less numerous year by year, and will soon he classed, 
 with all their blood relations, among the extinct animals of 
 our globe." 
 
 Os. A bone ; also a mouth. 
 
 Osteol'ogy. The part of anatomy which treats of bones. 
 
 Osteo-sarco'ma. Disease of the bony tissue, which consists in 
 softening of its laminae, and their transformation into a flesliy 
 substance, analogous to that of cancer, accompanied with 
 geaeral symptoms of cancerous alfection. The word has also 
 often been used synonymously with 'spina ventosa.' 
 
 O'v ARIES (ovum, egg). The two organs in oviparous animals 
 in which tlie ova, the generative product of the female, are 
 formed. They are termed by Galen ' testes muliebres,' since 
 they are in women the analogues of the testes in men. The 
 ovaries in adult women are situated on either side of the 
 uteras, in the iliac fosste ; they are included in the two pel- 
 vic duplicatures of the peritoneum, which are called the 
 broad ligaments. Each ovary is also attached by a round, 
 fibrous cord — the ovarian ligament — to the side of the uterus, 
 and by a lesser fibrous cord to the fringed edge of the Fallo- 
 pian oviduct. The ovary is an oblong, ovoid, flattened body, 
 of a whitish color and uneven surface. It is {- to |^ an inch 
 thick, I of an inch wide, and 1 inch to 1^- long; it weighs 
 from 1 to 2 drachms. M Darwin Hudson, Jr. 
 
 Oze'na. An affection of the pituitary membrane, which gives 
 occasion to a disagreeable odor similar to a crushed bed-bug. 
 
 P. 
 
 Paleontot/ogy. The study of ancient beings. The science 
 which treats of the evidences of organic life upon the earth 
 during the different past geological periods of its history. 
 These evidences consist in the remains of plants and animals 
 imbedded or otherwise preserved in the rocky srata or upon 
 their surfaces, and in other indications of animal existence, 
 
VOCABULARY. 249 
 
 sucli as trails, footprints, burrows, and coprolitic or otlicr 
 organic material found in the rocks. Pythagoras, Plaio, 
 Aristotle, and othtr ancient,?, allude to the existence of ma- 
 rine shells at a (lis: a'lce from the sea : it was considered con- 
 clusive evidence tliat the rocks containing tliem had formerly 
 been submer^-ed beneath the ocean. Ain. Cyc. 
 
 Papil'la. Tlie end of the nipple, or an eminence similar to a 
 nipple. 
 
 Tlie minute elevations of the surface of the skin, tongue, 
 &c. They serve to increase the extent of surface for vascular 
 distribution, or subserve sensitive or mechanical purposes. 
 Some contain one or more vascular loops ; others, nervous 
 elements. Some are surmounted by dense epithelial fila- 
 ments, as those which give the roughness to the tongue. 
 
 ^^'ebstcv. 
 
 Par'asite. Parasites are plants which attach themselves to 
 other plants, and animals which live in or on the bodies of 
 other anini'ils, so as to subsist at their expense. The mis- 
 tletoe is a parasitic plant, the louse a parasitic animal. 
 
 Pari'etes. a name given to parts which form the inclosure or 
 limits of different cavities of the body, as the parietcs of the 
 cranium, chest, «Src. 
 
 Parot'id. ('About the ear.') The largest of the salivary 
 glands, seated under the ear and near the angle of the lower 
 jaw. It secretes saliva. 
 
 Pathol'ogy. The branch of medicine whose object is the 
 knowledge of disease. It has been defined ' diseased physiol- 
 ogy,' and * physiology of disease.' It is divided into general 
 and special. The first considers diseases in common ; the 
 second the particular history of each. It is subdivided into 
 internal and external, or medical and surgical. 
 
 Pelvis The part of the trunk which bounds the abdomen 
 below. 
 
 Pehiodomti'tis. Inflammation of the membrane that lines the 
 socket of a tooth. 
 
 Per'Os'teum. The periosteum is a fibrous, white, rer^isting 
 medium, which surrounds the bones every where, except the 
 teeth at their coronoe (crowns), and the parts of other bones 
 that are covered with cartilage. The external surface is 
 united, in a more or less intimate manner, to the adjoining 
 
250 TOCABULAllY. 
 
 parts by areolat tissue. Its inner surface covers tlie bones, 
 whose depressions it accurately follows. It is united to tiio 
 bone by sinail fibrous i^rolongations, and especially by a pro- 
 digious quantity of vessels, which penetrate their subslance. 
 It unites the bones to the neighboring parts, and assists in 
 their growth, either bj'' furnishing, at its inner surface, an 
 albuminoas exudation, wiiicli becomes cartilaginous and at 
 length ossifies, or by supporting the vessels which penetrate 
 them to carry tlie materials of their nutrition. 
 
 Petrous. Resembling stone ; having the hardness of stone. 
 
 Phlegmon, Inflammation of the areolar texture, accompanied 
 with redness, circumscribed swelling, increased heat and 
 pain, which, at first, is tensive and lancinating and afterward 
 pulsatory and heavy. It is apt to terminate in suppuration. 
 It requires the antiphlogistic (opposed to inflammation) treat- 
 ment until suppuration seems inevitable, when the suppura- 
 tion must be encouraged as the next favorable termination 
 to 'resolution.' 
 
 PiA Mater, The pia mater is a very delicate membrane which 
 overs the brain immediately, penetrates into its anfractuos- 
 ities (grooves or furrows), and envelops also the cerebellum, 
 the sjnnal prolongation, &c. 
 
 PlTU'iTART. Concerned in the secretion of mucus or phlegm. 
 A name given to several parts. 
 
 Pituitary Membrane. (Schnaiderian membrane,) The mu- 
 cous membrane which lines the nasal fossae, and extends 
 to the different cavities communicating with the nose. It 
 receives the impression of odors by means of the expansion 
 of the olfactory nerves upon it, and is the seat of smell. 
 
 Plas'ma. See 'Liquor Sanguinis.' 
 
 Plastic. That which forms or serves to form. 
 
 Pleistocene. A term used to denote the newest tertiary de- 
 posits. Jolimon's N. XJ. Gyc. 
 
 Pli'ocene. In geology, the tenn applied to the most modern 
 of tertiary deposits, in which most of the fossil shells are of 
 recent species. Lyell. 
 
 With regard to animal life, the Pliocene continues the con- 
 ditions of the Miocene, but with signs of decadence. The 
 Pliocene was terminated by the cold or Glacial period, in 
 which a remarkable lowering of temperature occurred over 
 
VOCABULARY. 251 
 
 all the northern hemisphere, accompanied, at least in a por- 
 tion of the time, by a very general and great subsidence, 
 whic'i laid all the lower part of our continent under water. 
 This terminated much of the life of the Pliocene, and re- 
 plac3d it with boreal and arctic forms, some of them, like the 
 great hairy Sibs.ian mammoth and the wooJly rhinoceros, fit 
 sttcc2ssors of the gigantic Miocene fauna. J. W. Dawsoiu 
 
 Pol'ypus. a name given to tumors which occur in mucous 
 membranes especially, and which have been compared to cer- 
 tain zoo[)hyte3. Polypi may Ibrm on every mucous mem- 
 brane. They vary much in size, number, mode of adhesion, 
 and intimate nature. Fibrous polypi are of a 'dense, compact 
 t3sture and whitish color. They contain few vessels and do 
 not degenerate into cancer. Tlic scirrhous or carcinomatous 
 are true cancerous tumors, painful and bleeding. 
 
 Pons Varolii. An eminence at the upper part of the medulla 
 oblongata, first described by Varolius. It is formed by the 
 union of the crura cerebri and crura cerebelli. 
 
 Poste'iiior. Opposed to ' anterior,' which see. 
 
 Pteii'ygoid. a name j^iven to two processes at the inferior 
 surface of the sphenoid bone, the two laminae which form 
 them having been compared to v/ings. 
 
 Pylor'ig. That which relates to the ' pylorus.' An epithet 
 given to different parts. 
 
 Pylo'rus. a 'gate,' a 'guardian.' The lower or right orifice 
 of the stomach is called 'pylorus' because it closes the en- 
 trance into the intestinal canal, and is furnished with a cir- 
 cular, flattened, fibro-niucous ring, Avliich causes the total 
 closure of the stomach daring digestion in that organ. It is a 
 fold of the inucous and muscular membranes of the stomach, 
 and is the ' pyloric muscle' of soine authors. 
 
 Q. 
 
 Quadruma'na. (Quatuor, ' four,' and manus, ' hand.') A name 
 employed by Blumenbach (in 1791) as an ordinal designation 
 for the monkeys, lemurs, and related types, man ha^'ing 
 been is dated as the representative of a peculiar order named 
 Bimanus. The views thus expressed were for a long time 
 pi-'i ):ninant ; but a closer study of the structure of the forma 
 indicated by those names has convinced almost all livinjf 
 naturalists that they were erroneously separated, and the two 
 
252 VOCABULARY. 
 
 types are now generally combined in one order named Pri- 
 mates, under whicli head man and tlio monkeys ar6 com- 
 bined tog-ether in one sub-order (Anthropoidea), and con- 
 trasted with the lemurs, which constitute another sub-order 
 (Prosimit.e). Theodore Gill. 
 
 \l. 
 
 Rectum. The third and last portion of the great intestine. It 
 forms the continuation of the sigmoid flexure of the colon, 
 occupies the posterior part of the pelvis, and extends from 
 the sacro- vertebral articulation to the coccyx (rump or crup- 
 per bone), before which it opens outward by the orifice called 
 the 'anus.' 
 
 ReGt'ime. Mode of living; government, administration. 
 
 Reg'imen. ~ The rational and methodical use of food and of 
 everything essential to life, both in a state of health and dis- 
 ease. It is often restricted in its meaning to ' diet.' It is 
 sometimes used synonymously with hygiene (health). 
 
 Ru'minant. a division of animals having four stomachs, the 
 first so situated as to receive a large quantity of vegetable 
 matter coarsely bruised by a first mastication, which passes 
 into the second, where it is moistened and formed into little 
 pellets ; these the animal has the power of bringing again to 
 the mouth, to be rechewed, after which it is swallowed into 
 the third stomach, from which it i:)asses into the fourth, 
 where it is finally digested. Websfe): 
 
 (Several v\'ell authenticated cases of human beings who 
 ruminated their food are on record.) 
 
 S, 
 
 Sarco'ma. Any species of excrescence having a fleshy consist- 
 ence^ 
 
 Schneider lAisf Membrane. See ' Pituitary membrane.' 
 
 Sclerot'ic, a heavy, resisting, opaque membrane, of a pearly 
 white color and fibrous nature, which covers nearly the pos- 
 terior four-fiuhs of the globe of the eye, and has the form of 
 a sphere truncated before. 
 
 Sella Tur'cica. (Turkish saddle.) A depression at the upper 
 surface of the sphenoid bone, wliich is bounded, anteriorly 
 and posteriorly, by the clinoid processes, and lodges the pitu- 
 itary gland. It is so called from its resemblance to a Turkish 
 saddle. 
 
VOCABULARY. 253 
 
 Septum. A part intended to separate two cavities from each 
 oriier, or to divide a principal cavity into several secondary 
 cavities. 
 
 Serous. Tiiin, watery. Relating to the most watery portion 
 
 of auiiual liiiicis, or t.) meuibraues tliat secrete them. 
 
 • SoL'iPED. An animal whose liuof is not cloven ; one of a group 
 
 of animals with undivided hoofs; a soiid ungulate. Webster. 
 
 The family ' Solipeda' consists of several species of horse, 
 
 namely, the ass, the mule, and the quagga. Youatt. 
 
 Sphenoid. Wedge-shaped. 
 
 SPiiEXOin Bone. An azygous (single) bone, situate on the me- 
 dian line, at the base of the craniimi. It articulates with all 
 the bones of that cavity, supporting them and strengthening 
 their union. Its form is singular, resembling a bat with its 
 wings extended. 
 
 Spina Vento'sa. See ' Osteo-sarcoma.' 
 
 Styloid. (A style, a peg, a pin.) Shaped like a peg or pin. 
 
 SuBMAx'iLLARY (from siih, 'under,' maxilla, 'the jaw'). That 
 which is seated beneath the jaw. 
 
 Suppuiia'tion. Formation or secretion of pus. It is a frequent 
 termination of inflammation, and may occur in almost any of 
 the tissues. This termination is announced by slight cliills, 
 by remission of the pain, which, from being lancinating, be- 
 comes heavy ; by a sense of weight in the part, and, when 
 the collection of pus can be easily felt, by fluctuation. Wlu:u 
 pus is thus formed in the areolar membrane, and is collected 
 in one or more cavities, it constitutes an 'abscess.' If ii be 
 formed from a surface exposed to tlie air, it is an ' ulcer.' and 
 such ulcers we are in the habit of establishing artificially iu 
 certain cases of disease. 
 
 Supra. A common Latin prefix, signifying 'above.' 
 
 Suture. A kind of immovable articulation, in which the bones 
 unite by means of serrated e;lges, which are, as it were, dove- 
 tailed into each other. The articulations of the greater part 
 of the bones of the skull are of this kind. 
 
 Sym'physis. a union of bones. The bond of such union. The 
 aggregate of means used for retaining bones in .situ (natural 
 situations) in the articulations. The name symphysis has, 
 however, been more particularly appropriated to certain artic- 
 ulations, as the ' symphysis pubis,' ' sacro-illac symphysis,' &c. 
 
254 TOCABULAEY. 
 
 T. 
 
 TeleosTS (or Teleostei). The name of that sub-class of fishes 
 which embraces the great majority of living species, and so 
 desig-nated (by Johannes Miiller) on accomit of the ossified 
 condition of the skeleton in all the representatives of the 
 group. Theodore Gill. 
 
 Teratol'ogt. a treatise on monsters. 
 
 TEa'TiARy. Third; of the third formation. In geology, a 
 series of strata, more recent than the chalk, consisting of 
 sandstones, clay beds, limestones, and frequently containing 
 numerous fossils, a few of which are identical with existing 
 species. It has been divided into Eocene, Miocene, and Pli- 
 ocene, which see. Dana. 
 
 Tinctu'r A Myrrhs. (Tincture of Myrrh.) Tonic, deohstruent 
 (removing obstructions), antiseptic (opposed to putrefaction), 
 and detergent. It is chiefly usad in gargles, and is applied 
 to foul ulcers, spongy gums, &c. 
 
 Tissue. By this term, in anatomy, is meant the various parts 
 which, by their union, form the organs, and are, as it were, 
 their anatomical elements. ' Histological anatomy ' is the 
 anatomy of the tissues, Avhich are the seat of the investiga- 
 tions of the pathological anatomist. The best division, in- 
 deed, of diseases would be according to the tissues mainly 
 implicated. 
 
 Tox'ODON. A gigantic, pachydermatous quadruped, now ex- 
 tinct, having teeth bent like a bow. Brande. 
 
 Transuda'tion. (To sweat.) The passage of a fluid through 
 the tissue of any organ, which may collect in small drops on 
 the opposite surface, or evaporate from it. 
 
 TREPmNE'. The instrument which has replaced the trepan in 
 some countries. It consists of a simple, cylindrical saw, with 
 a handle placed transversely, like that of a gimlet ; from the 
 center of tlie circle described by the saw a sharp little per- 
 forator, called the center-]>in, projects. The center-pin is 
 capable of being removed, at the surgeon's option, by means 
 of a key. It is used to fix the instrument until the teeth of 
 the saw have made a groove sufficiently deep for it to work 
 steadily. The pin must then he removed. Sometimes the 
 pin is made to slide up and down, and to be fixed in any 
 position, by means of a screw. 
 
VOCABULARY. 255 
 
 Tko'car. An instrument used for evacuating fluids from cavi- 
 ties, particularly in ascites (serous fluid in the abdomen, or, 
 more properly, dropsy of tiie peritoneum), hydrocele (watery 
 tumors), &c. A trocar consists of a perforator, or stylet, and 
 a canula. The canala is so adapted to the perforator that, 
 I when the puncture is made, both enter tiie wound with facil- 
 ity ; the perforator, being then withdrawn, the fluid escapes 
 through the canula. 
 
 Tu'beucle. a tumor in the substance of organs, from the pro- 
 duction of new matter ; sensation null, growth sluggish. In 
 pathological anatomy, the term is generally given to a spe- 
 cies of degeneration which consists of an opaque matter, of a 
 pale yellow color. This, in its crude condition, has a con- 
 sistence analogous to that of concrete albumen. It subse- 
 quently becomes soft and friable, and gradually acquires a 
 consistence and appearance analogous to that of bone. Tu- 
 bercles may be developed in diffl-rent parts of the body, but 
 they most frequently occur in the lungs and mesentery. 
 
 Punic. An envelop. A name given to different membranes 
 which envelop organs, as the tunics or coats of the eye, 
 stomach, bladder, &c. 
 
 TuRGBs'CENCE. Superabundance of humors in a part. The 
 term 'turgescenc3 of bile' was formerly used to denote the 
 passage of that fluid into the stomach, and its discharge by 
 vomiting. 
 
 Tympani'tes. a flatulent distention of the belly ; tympany. 
 (Also inflammation of the lining membrane of the middle 
 ear.) 
 
 u. 
 
 Un'gulate. Shai^ed like a hoof. Having hoofs, as ungulate 
 
 quadrupeds. Webster. 
 
 U'VEA (from uvea, a grape). The choroid coat of the eye ; the 
 
 posterior layer of the iris. 
 U'VEOUS. Resembling a grape ; applied to the choroid coat of 
 
 the eye. 
 
 Y. 
 VAs'ctJLAR. That which belongs or relates to vessels — arterial, 
 
 venous, lymphatic — but generally restricted to blood-vessels 
 
 only. Full of vessels. 
 Velu-M Pala'ti. The soft palate. (Uvula.) 
 
256 VOCABULARY. 
 
 Veb'tebr^. The bones wLich form the spinal column. 
 
 Tis'cus (plural, vis'cera). One of the organs contained in the 
 great cavities of the body ; any one of the contents of the 
 cranium, thorax, or abdomen ; in the plural, especially ap- 
 l>lied to the contents of the abdomen, as the stomacli, intes- 
 tines, &c. Webste7\ 
 
 Vit'iieous. Of, pertaining to, or dorived from glass. The vit- 
 reous humor of the oye is so called because it resembles 
 melted glass. 
 
 Z. 
 
 Zool'ogy. That part of biology (science of life) which relates 
 to animal life, and, as generally understood, the science 
 which treats of the structure, classification, distribution, hab- 
 its, and derivation of living animals. In its broadest sense, 
 however, zoology includes the structure, relations, and his- 
 tories of extinct as vv^ell as living forms ; but this branch of 
 the science is generally considered by itself under the title 
 of ' paleontology.' The derivation and life-histories of many 
 groups of aniihals have been found written in the records of 
 the past, and many mysteries, not only of relation but of 
 structure, have been solved by going back to find dwarfed 
 organs in full development and wldely-s .^pirated forms linked 
 together. The zoology of the future will therefore include 
 the animal life of b;3tli the past and the present. 
 
 J. S. Neicberry. 
 
 Zygomat'tc. That which rebates to the zygoma or cheek bone. 
 
INDEX. 
 
 Alfort, Veterinary College of, 
 
 140. 142. 
 AJleu, J. T., 198. 
 Amt'i'icas, the, ricliness of fossil 
 
 remains of, 114. 
 Anchippus, teeth of, 96. 
 Ancliitheriam, teeth of, 96, 111, 
 
 lie. 
 
 Anoplothere, t(;eth of, 65. 
 Antelope moutana, 08. 
 Apparatus, dental, exuberance 
 
 of particular parts of, 141-3. 
 Apsyrtus, advice of, 116. 
 Arcades (of teeth) anomalies in 
 
 form of, 140, 141. 
 Arisi"otle, mistake of, 63. 
 Arloing, M., resection of nerves, 
 
 2i7. 
 Armadillo, the, 229. 
 Astor Library, the, 4. 
 
 Babtrgton, B., 242. 
 
 Bac'jn, Francis, theory of, 15. 
 
 Bdcer, S., report of, 181, 182. 
 
 Birauni, Mr., 124. 
 
 Batrachia, tlie, 229, 230. 
 
 Bav, Sariyeon, discoverv of, 117. 
 
 B.^il, C, disc weries of, 217, 218. 
 
 Bell, a. J , 218. 
 
 Bji!, Thom-is, theories of, 26, 
 
 27, 83. 81. 
 Bcrirer-Perrlere, discoveries of, 
 
 116.117. j 
 
 B.jrzelius, discoveries of, 15. 
 "Bisiio,)iug," modus operandi, 
 
 of, 211. I 
 
 Black, Surgeon, experiment of, 
 29. 
 
 Blaine, Surgeon, fracture lower 
 jaw, 197. 
 
 Blastema, the, nature and color 
 of, 34, 35. 
 
 Boar, the masked, grinders of, 
 10. 
 
 Bojauus, discoveries of, 52. 
 
 Bunliome, M., 127. 
 
 Bond's Dental Medicine, extract 
 from, 128, 129. 
 
 Bouley, M. H., development of 
 teeth, 45 ; grinders, 62 ; for- 
 mation of enamel, 61; growth 
 of teetli during life, 73; dis- 
 eases of teeth, 138; diseases 
 and dentistry of teeth, 139 to 
 162 ; swallowing teeth, 192, 
 193 ; removal of fractured 
 iaw, 197, 198. 
 
 Bourgelat, Prof, 69. 
 
 Brace. Mr., 99. 
 
 Bioadhoad. G. C, account of 
 f-'ssil tooth, 112, 113. 
 
 Broderip, Mr., a whale's tooth, 
 79. 
 
 Burns, John, 239. 
 
 CAcnALOT, the, 79. 
 Calcigerous, origin and use of 
 
 Avord, 18. 
 Cattle, teething period of, 91, 93. 
 Camel, the, toeth of, 66. 
 Camper, Pierre, ou temporary 
 
 cauines, 52. 
 
358 
 
 IKDEX. 
 
 Canines, temporary, 51, 53. 
 Calculus Concretions, 193, 193, 
 
 Caries, cause and symptoms of, 
 114 to 154 ; treatmeat oi", loO 
 to 171 ; definition of, 281. 
 
 Cartwriglit, W. A., report of, 
 193 ; fracture of jawbone, 196. 
 
 Cattauacl), C. C, 4. 
 
 Cattanacn, J. S., 4. 
 
 Caucasian Races, teeth of, 09. 
 
 Cement, the, 9 ; size ot tubes of, 
 1*5 ; use of, 17 ; mistaken for 
 tartar, 17 ; vascularity of, 17 ; 
 thinness of, 17 ; color of, 18 ; 
 resemblance to bone, 23 ; 
 germs of, 43 ; a protecting 
 varnish, 59, 60 ; cells of, 133. 
 
 Chauveau, A., harmony of teeth 
 with general system, 11 ; de- 
 velopment of tooth-germs, 41, 
 42; description of incisors, 58, 
 59, 00 ; growth of teeth dur- 
 ing life, 73. 
 
 Cherry, W. A., shedding teeth, 
 50, 51 ; judging age by shape 
 of teeth, 204. 
 
 Chevrotaln. the, 78 ; description 
 of, 232. 
 
 CLiy w^ovth, Sujg , report of, 197. 
 
 Coleman, Surgeon, cUscoverv of. 
 116. 
 
 Coluber Scaber, the, 121. 
 
 Comparative Amitomy, 233. 
 
 Conrad, T., discovery of, 113. 
 
 Cboper Union, the, 4. 
 
 Cope, Prof, on evolution, 238. 
 
 Copybara, the, grinders of, 10 ; 
 .descrii)tion of, 233. 
 
 Cougliing and Teething', 02. 
 
 Cox, Stephen J., 4. 
 
 Cuvier, M., 16 ; note on, 66 ; 
 bones and teeth of recent and 
 fossil horse?, 106 ; ophthalmic 
 ganglion, 221. 
 
 Dana, Prof., geology and evo- 
 lution, 240. ' 
 Dandini, J. , theory of, 26. 
 D'Arboval, teething, 87. 
 
 Darwin, C. R., tushes of various 
 animals, 77, 78, 79 ; changes 
 in human teeth, 9;.). 
 
 Dawson, J. W. , geology, 240 ; 
 miocene period, 244 ; plio- 
 cene period, 250. 
 
 Day, E. C. 11., uarv/hal, 246. 
 
 Delafond, M., theory of, 161. 
 
 Denenbourg, F., report of, 123. 
 
 Dental Cysts, 115 to 126. 
 
 Dentinal, origin and use of 
 word, 8. 
 
 Dentinal Tubes, oiRce and color 
 of, 22, 23 ; their two curva- 
 tures, 23 ; the puip, 33, 34 ; 
 dichotomously branched, 131, 
 1;J3 ; daameter of, 132 ; length 
 of curves, 133. 
 
 Dentine, the, 8, 14. 
 
 Dentine Germ, 43, 59. 
 
 Dentition Fever, 93. 
 
 Dentition, permanent, 53 to 74. 
 
 Dentition, tem]>orary, 47 to 52. 
 
 Dentition, third, cases of, 128. 
 
 Dinoceras mirabilis, horns and 
 canine teeth of, 236. 
 
 Draper, John.W,, 4. 
 
 Dugong, the, 79 ; description of, 
 
 Duuglison, E., development of 
 
 teeth, 45; diseases of teeth, 
 137 ; vocabulary, 227 to 256. 
 
 Edinbuegh Veterinat^y Col- 
 lege, report of, 170, 180. 
 
 Editor Veterinarian, comments 
 of, 184 ; report of, 201, 202. 
 
 Elasmothere, the, enamel fes- 
 toons of molars of, 107 ; con- 
 necting link between horse 
 and rliinocerds, 107. 
 
 Elephant, grinders of, 10. 
 
 Embryology, 80 to 82. 
 
 Enamel, the, 10; tubes of, 18, 
 1-,) ; color of, 19 ; membranous 
 si 1 cat] IS of, 59 ; plications of, 
 106. 
 
 Enamel- Fibers, direction of, 20 ; 
 curves of, 20 ; form and size 
 of, 20 ; diameter of, 134. 
 
INDEX. 
 
 259 
 
 Enterprise, the, 193. jGrouille, Mage, 116. 
 
 Eocene (period) fossils of, 23f>. jGuanaco, the, 78 ; description 
 
 Evolution, doctrine of, 7'7 to 79 : of, ■340. 
 
 237, 238. Gubernaculum Dcntis, the, 43. 
 
 Exostoses, 17, IIG. Gurlt, Sarg., discovery of, 117. 
 
 Faenkel, discoveries of, 15. j 
 
 Foiraeld, R G., 4. ' 
 
 Falconer, Dr., 77. i 
 
 Fakonio, Sur., discovery of, 118. 
 
 Ferpjuson, P. B., development 
 of teeth, 40 ; pTiuders, G2 ;' 
 the formation of enamel, 64 ; 
 growth of teeth during life, 
 73 ; diseases of teeth, 138 ; dis- 
 eases and dentistry of teeth, 
 139 to 162 ; swallowing teeth, 
 192, 193. 
 
 Fetus within a Fetus, 119. 
 
 Fleming, G., dental cysts, 115 
 to 119 ; fractured jaw, 195, 
 106. 
 
 Foithomme, M., temporary ca- 
 nines, 52. 
 
 Fossil Tooth, a diseased, 173. 
 
 Fracture! Jaws, 194 to 202. 
 
 Frederick, M. M., 193. 
 
 Gamgee, J , report of, 120-3. 
 
 Garengeot, M , 156. 
 
 General!, Prof., 116. 
 
 Geology, definition of, 240. 
 
 Gill, T., nature of "teeth, 12 ; 
 dental formula f u' horse, 101 ; 
 morphology, 245 ; quadruma- 
 na, 251, 252 ; teleosts, 254. 
 
 Girard, M., teeth and age, 206, 
 207. 
 
 Gloag, Surgeon, 182. 
 
 Gom pilosis, 73. 
 
 Goodsir, Prof, 125. 
 
 Goubaux, Sur., discovery of, 117. 
 
 Gowjng, T. W., diseases of 
 teeth, 171, 173. 
 
 Grice, C. C, report of, 123, 124. 
 
 Grinders, the, 54 ; tables of, 61 ; 
 figures formed by, 61 ; con- 
 trasts between, 61. 62; their 
 own whetstones, 63; roots of, 
 68,70; shedding of, 70, 71. 
 
 •Tae'^kel, E. H., embryos, 81-2. 
 
 Harris, Prof., 3d dentition, 129. 
 
 Hartshorne, 11., evoluti<m, 237. 
 
 Haschischat ed dab, efiect of on 
 teeth, 25. 
 
 Hayes, B., theories of, 23 to 24; 
 diseases of teeth, 137. 
 
 Heard, J. M., 4, 216. 
 
 Heath, J. P., report of, 200, 201. 
 
 Eienocque, M., motor nerves, 
 217, 218. 
 
 Herbert, W. H., age, 214, 215. 
 
 Hipparion, the, teeth of, 95, 96, 
 111,112. 
 
 Hippopotamus, the, canine teeth 
 of, 63. 
 
 Histology, definition of, 241. 
 
 Hog, canine teeth of, 63. 
 
 Horsburgh, J,, report of, 175. 
 
 Horse, the, theory of introduc- 
 tion into America, 110. 
 
 Horse, the fossil, 95 to 98 ; 106 
 to 113 ; extinction of in South 
 America, 109. 
 
 Houghton, S. D., 200. 
 
 House, G. D., 4 ; size of tooth- 
 germs, 31 ; theory of teeth- 
 ing, 47, 48 ; grinders, 62 ; 
 remnant teeih, 103, 104; re- 
 moval fractured tooth through 
 nostril, 198, 199; operations 
 in Worcester, Mass., 199. 
 
 Hudson, E. D., Jr., ovaries, 248. 
 
 Hunter. J., ttie :»ries of, 24 to 27 ; 
 enamel of grinders, 63 ; at- 
 tachment of teeth, 72 ; use of 
 canines, 83 ; su[5ernunierary 
 teeth, 128; proving the for- 
 mation of new dentine, 209. 
 
 Hughes, J., dimensions of teeth, 
 49; ])eriosteum of teeth, 137. 
 
 Huxley, T. H., teeth of tapir, 
 rhinoceros, and horse, (iiy, (jd; 
 fossil horses, 110, 111. 
 
260 
 
 liN'DEX. 
 
 Hyoliippus, the, 113. 
 
 Igua'todon, tlie, molars of, 63. 
 Incisors, the permaneut, 5'd ; 
 
 length of, 57 ; curvatures of, 
 
 57; Chauveau's description of, 
 
 5S to 60. 
 Incisors, temporary, 47 to 50. 
 Inferior Maxillary Nerve, the, 
 
 228, 324. 
 
 Knowlson, J. C, bishoping, 
 211. 
 
 Lafosse, Prof., dental cysts, 
 130. 
 
 Lanii>as, cause of, 88 to 91. 
 
 Lanzillotti-Biionsanti, Prof., on 
 dental cysts, 114. 
 
 Lecoq, Prof., canine follicles, 44 ; 
 temporary canines, 53 ; de- 
 scription of grinders, 69 to 
 71 ; do. canines, 77; remnant 
 teeth, 100. 
 
 Leeawenho^k, discoveries of, 13. 
 
 Legros, C, experiments of, 37. 
 
 Leidy, J., letter from, 101 ; fos- 
 sil teeth, 113 ; mastodon, 114. 
 
 Lincoln, A., 211. 
 
 Lion, tiie, canine teeth of, 83. 
 
 Liquor Sanguinis, the, 23, 342. 
 
 Lubln, II., discovery of, 137. 
 
 Lyell, Mr., 110. 
 
 MvcROrs, Surgeon, experiences 
 of, 117-18. 
 
 Madder, effect of on teeth. 24. 
 
 Magitot, E.,27; development of 
 tooth-^erms, human fetus, 46. 
 
 Malpighi, discoveries of, 13. 
 
 Man, canine teeth of, 82, 83. 
 
 Man, early progenitors of, 80-3. 
 
 Marks, dimensions of, 57, 53 ; 
 twofol.l use of, 301. 
 
 Marsh, 0. C, evolution of horse. 
 95 t.) 93 ; no ' mark' in teeth 
 of early forms, 293; descrip- 
 tion of mastodon and mega- 
 therium, 313 
 
 Mastodon, the, 100, 114, 243. 
 
 May, C, report of, 178, 179. 
 
 May hew, E., the cement, 17, 18 ; 
 judging age by teetii, 307-8. 
 
 Mayo, Mr., experiments of, 313. 
 
 Meg-utberium, the, teeth of, 107, 
 lo8 ; description of, 243. 
 
 Melanian Kaces, teeth of, 99. 
 
 Membrana Nictitans, 244. 
 
 Mer > chippiiS, the, 113. 
 
 Mesohippus, the, toes of, 97, 113. 
 
 Miocene (period) fossils of, 344. 
 
 Miohipptts, the, 113. 
 
 Molars, the, 54 ; inclination of, 
 54. 
 
 Moon -Blindness, cause of, 105. 
 
 Moore, T., 35, 26. 
 
 Morphology, definition of, 345. 
 
 Morton, Prof., 193. 
 
 Miiller, Prof., discovery of, 14-5. 
 
 Muntjac-Deer, the, 77, 78 ; de- 
 scription of, 246. 
 
 Musk-Deer, the, 78 ; description 
 of 345 
 
 Mylodon, the, 108, 346. 
 
 Nakwhal, the, tushes of, 79; 
 
 description of, 346, 
 Newberry, J. S., zoology, 256. 
 
 Niebuhr, opinion of, 25. 
 Nippers, the, 47. 
 NoLt, Dr., 113. 
 
 Odontolithos, the, 17, 247. 
 
 Odontonecrosis, 13b. 
 
 Odontrypy, 138. 
 
 Ohlinger, 0. P., discovery of, 
 113. 
 
 Ophthalmic Nerve, the, 219-22. 
 
 Oruithorhynchus, the, 80 ; de- 
 scription of, 347. 
 
 Operating, rules for, 154 to 160. 
 
 Oreste, Surg., discovery of, 118. 
 
 Oroliipyms, the, t 'eth of, 96, 97; 
 to-sof, 97; size of, 97, 112. 
 
 Osbiston, Supt., 193. 
 
 Osteo-sarcoma, case of, 186. 
 
 OvvM3n, R., dental science, 8, 10, 
 12, 28 ; tooth-germs, 32 to 37 
 breadth and thickness, 49 
 temporary canines, 51 ; teeth- 
 
INDEX. 
 
 2G1 
 
 in^, 53 ; description of grind- 1 
 ers, ()4 to GO ; teetli ot aiioplo- 1 
 there, Go ; do. ruminants, G5 ; ; 
 do, tapir, G5 ; do. rhinoceros, j 
 C7; do. megcitherium, 107 ;| 
 reamant leo:ii, 102; fossil' 
 hors.-'s' teeth, lOo to 109 ; 1 
 : microscopical appearance of 
 horses' teeth, l;jO lo 185 ; dis- 
 eases of teeth, 137 ; diseased 
 fossil tooth, 173, 174; the' 
 fifth pair of nerves, 235, 32G. 
 
 Paleontology, 248. 
 
 Paleothere, teeth of, 68, 111. 
 
 Parnell, C, remnant teeth, 102. 
 
 Parrot-Mouth, 167, 168. 
 
 PatholoQiy of the Teeth, 136. 
 
 Percivail, W., teething, SQ to 
 88 ; lampas, 88 to 90 ; dis- 
 eases of teeth, 138, 185, 18G; 
 ophthalmic aanglion, 221. 
 
 Plasse, M., 156. 
 
 Pliocene (period) fossils of, 250. 
 
 Pliohippus, the, 112. 
 
 Pony, o-reat suffering of a, 201. 
 
 Portal, learning of, 14. 
 
 Premolars, the, 53 ; inclination 
 of, 54. 
 
 Processes, alveolar, diseases of, 
 166, 1G7. 
 
 Protolii))pus, the, 112, 
 
 Pulpal Cavity, relation of, 22, 
 
 Purkinje, discoveries of, 14, 16 ; 
 corpuscles of, 9 ; cells of, 16. 
 
 QuADRi MANA, the, 36, 81, 251. 
 
 Quain, Jonas, fifth nerve and 
 
 ophthalmic gan<?lion, 220. 
 
 Renault, P^of . , report of, 187. 
 
 Kegimen, 102 to 164. 
 
 Ketzius, Prof., discoveries and 
 
 conjsctures of, 16, 19, 20, 21, 
 Revel, M,, re])ort of, 197. 
 Reversion, doctrine of, 80. 
 Rhinoceros, the, teeth of, 67. 
 Rhinoceros, the woolly, 251. 
 RitTot, temporary canines, 52, 
 Robin, C, 27. 
 
 Rodet, Surgeon, 118, 
 Roudanoosky, M,, 218. 
 Rousseau, J\l., 48. 
 Ruminants, teeth of, Go; four 
 
 stomachs of, 252. 
 Ruini, discoveries of, 69. 
 
 Santy, a. H., report of. ISO. 
 Scelid there, remains of, 108. 
 Schaaff;:aui-en, Prof., 90. 
 Schwann, Dr., researches of, 20. 
 Seelye, J. H., 234. 
 Sewell, W., dental cysts, 122. 
 Simonds, Prof,, 156. 
 Sinuses, descrii)tion of the. 152; 
 
 gutta-percha recommended as 
 
 a filling for, 177. 
 Smith, W., report of, 182 to 184. 
 Smitli, W, B., 4, 
 Speculum Oris, use of, 149. 
 S[}encer, H. , evolution, 237. 
 Sjw, the Worcester, 199, 
 Star, dentinal. -59, 209. 
 Sun, the New York, 200. 
 Superior Maxillary Nerve, the, 
 
 222, 223, 
 Supernumerary Teeth, 127 to 
 
 129; 139. 
 Surmon, H.. report of, 177. 
 Swallowing a Diseased Tooth, 
 
 deatli of a horse from, 187. 
 Swan, Dr,, 225. 
 
 Tables of Geixders, the, 61. 
 
 Tapir, the, teeth ot, 65, 
 
 Te6tli, variety and use of, 10, 
 11 ; in harmony with general 
 system, 11 ; readily preserved 
 in a fossil state, 12 ; tubes of, 
 12 ; l»ow affected by madder, 
 24 to 26 ; transplanting of, 26. 
 
 Teeth, horses', tem])orary, 47 to 
 52 ; permanent. 53 to 74 ; ca- 
 nines 75 to 93; remnant, 94 
 to 114; abnormal, 115 to 127; 
 supernumerary, 1^9; under 
 the microscope, 130 to 135 ; 
 ]iathology of. 136 to 174 ; den- 
 tistry of, 175 to 193; indica- 
 tors of age, 203 to 215, 
 
262 
 
 INDEX. 
 
 Teeth, remnant, 94; reffai-ded 
 as phenomenons, 94, 101 ; line 
 of descent, 94 ; not to i^e con- 
 founded with siipernnmeraiy 
 teeth, 94 ; why named rem- 
 nant, 94; easily lost, 90, 100. 
 
 Tenon, discovery of, Gc). 
 
 Thurber, (1., 4. 
 
 Tomes, C. S., tooth-g-emis, 37 to 
 41; temporary canines, 52; 
 dentine, enamel, and cement, 
 63 ; attachment of teeth, 72 ; 
 gTowtli of (iiorses') teerh dur- 
 ing life, 74 ; tuslies of boars, 
 84, 85 ; evolution, 98, 99 ; no 
 ' mark ' in teeth of early fossil 
 horses. 203. 
 
 Tomes, J., a tooth barricading 
 disease, 189. 
 
 Tooth, nature of, 7, 8; irides- 
 cence of, 12, 16 ; no inherent 
 power of reparation, 137. 
 
 Tootli and Bone, analogy of. 23. 
 
 Tooth-Germs, development of, 
 31 to 46. 
 
 Tooth-Cough, 92. 
 
 Tooth, a diseased fossil, 173-4. 
 
 Tooth Pulp, description of the, 
 31. 
 
 Toxodon, remains of, 109 ; de- 
 scription of, 254. 
 
 Trephine, the, 254. 
 
 Irephining Sinuses, 157 to 161. 
 
 Tripier, M., resection of nerves, 
 217. 
 
 Trocar, the, 255. 
 
 Tushes, horses', [jractically use- 
 less, 75 ; different from other 
 teeth, 75; distances from in- 
 cisors and grinders, 75, 76 ; 
 shape and dimensions of, 76 ; 
 curvatures of roots, 70. 
 
 Tushes, removal of, 155. 
 
 Varnell, G., opinion of, 102; 
 diseasesof teeth, 1C8, 139; the 
 sinuses, 151, 153, 161 ; Ci^ries, 
 164 to 166 ; diseases of alveo- 
 
 lar processes, 160, 167 ; par- 
 rot-mouth, 107, 168 ; osteo- 
 sarcoma, 186, 187; fractured 
 jaws, 194. 
 
 Vv^'allace, a. R., cause of de- 
 struction of ungulata. 111 ; 
 fossil horses, 112 ; geology, 
 210. 
 
 Walrus, the, mode of fighting 
 of, 77. 
 
 Walsh, J H., judging age by 
 teeth, 208. 
 
 Williams, Prof. W., teething, 
 91; remnant teeth, 104, 105; 
 dental cvsts, 125 to 127 ; ca- 
 ries, 169'to 171. 
 
 Williams, W., necrosis, 246. 
 
 Winter, J. H., use of tushes, 85. 
 
 V/oodward, J. J., histology, 241. 
 
 Works, general, 4. 
 
 Works, special, 4, 
 
 Wyman, Prof., discovery of, 81. 
 
 YouATT, W., sugar ns food, 29 ; 
 tooth-germs, 44, 45; infundi- 
 bula of grinders, 58 ; move- 
 ment of lower jaw, 62 ; use 
 of tushes, 84 ; teething, 85-6 ; 
 lampas, 90; croppinp; iiorses' 
 ears, 103 ; remnant teeth, 105 ; 
 food, 162 to 164 ; diseases of 
 teeth, 172, 173; fractured 
 jaws, 196 to 198; 'mark' of 
 central nippers, 205 ; difficul- 
 ties of judging age, 207 ; bish- 
 oping, 211 ; trade tricks, 212, 
 214 ; crib-biting, 212, 213 ; in- 
 dications of age independent 
 of teeth, 214; fifth i air of 
 nerves, 216 to 225 ; csecum, 
 230: colon, 232; membrana 
 nictitans, 244 ; solipeds. 253. 
 
 Youmans, E. L.. evolution, 237. 
 
 Zebra, temporary canine teeth 
 
 of, 52. 
 Zoology, definition of, 256. 
 
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