ep pyri. ae WETS “ Re m ae io wv ste stags o . Et) SASS i epee) cant) a ab torrets ce STEM Pee ite Baiieoent Did aaa a eee td ey tee tS * Bante ce) ¥2 yz. f er ¢ a Gil aa Nate a emit cs Be ea Bate dy Paty Set ie pease ries Sus Teh ii 2 ¥ ra 53, F7% PoP Bia a Seba Nuke ALS Aided Hass ara ‘ Tarunteree 23 aN 3s vay i . ¥0 ute Prt i Vi Nene 4 : PON Pein: faci 42 ie eyee es hel PUekG fir hug , wee! re ays SMe +e, . idee hot naan tn Abela ei era ee i kale Po x Pa Sh teat ayaa seiitt Sp. Het Baa : sat heag rentate es erannes Bot Ha pigy 3 a Laruskiscseasee ey far pila ieit he err a SSE SESE GE GRE Sess Deets ide tse sarees te ” RED evese rs ra es a2 tees isxuneht i Seep ees Fd eng a cae Pee as 3 A Ree a ere BORSA gee ak pit LARC ER 3 IHR? eu Bt HIRE Wiaerseae SH ea ; teat by eithes i #0 eth ; bs} 19) Sen pynks > ‘ pryarratehd ere rar seg se? 3 ees Sa 2333 ae ey PSUR MES FREES EATEN ASAI, BEARS bs UM StSS sare chet kt Beth d ert HOTT A ier SED TE Ga TS aS PTO GOS SELES PARE FRIAR SAA Hep ieereatees es PKB RBS 5 tia ONION at niwernas Bas ikas pe Ret yee aay i423 Hi bb Be . Leese hegre Pie he? . risssspi vege rar yee Dei PaaS. PORES fe Ps ta $3 feist SESE NSAI CIS ne PPG She aa ieee ADEs sone ; 7 oo PR SA ne Hagen ROM TiRTOH NTRS gsedreers Tegreeu Rate tie OR i ee BAe sibeseees ae Wels oH ets ie vrata +4 Tae wut % Pee eras aired: Sita BSS Pep Preigt at iou a, ea ot ae 4 are ice Son Eaten ae a Loa pig awe Ge LW An . Sev nlp eat atee Se ae ace CMS ~ wy ate EE let th RAPA te 7 Bete EA! ; ess Des DEAT BONA NRE Ts) } St +, stvistay Nitya ine? lea one. Eat) IFNy? ? s TAREE shta's2s * oe Be er yee Ryned SMBS EASA IA DET Oe a PURE et APES ba Soha ge tes 7 fete fit Hae By ye “a, eae ~e rs RA ESP mee) as A —_ a ~ - hake fens es ates is rm 1 Romo Lik hr MODE OF DEVELOPMENT, PHYSIOLOGICAL RELATIONS, ANATOMY, MICROSCOPICAL CHAR- ACTER, PATHOLOGY, AND DENTISTRY ; BASED ON THE WORKS OF WELL-KNOWN Odontologists and Veterinary Surgeons; TO WHICH IS ADDED A VOCABULARY OF THE MEDICAL AND TECHNICAL WORDS USED, a | a NEW YORE: PUBLISHED BY THE AUTHOR. 1880. —, Copyright, 1879, by Wiiit1am H. CLARKE, Smita & McDoveat, ELecTRoTYPERS, 82 Beekman St., N. Y. $4, OD a De ne, Al , *Oh-rs S PREFACH. IKE all Special Works, the present volume will 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. Phe work 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. IV PREFACE. 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 relieye 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. My. 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. 8. 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, who perceived at a glance that the subject is “so suggestive;” Dr. George Thurber, of the Orange Judd Company, and W. B. Smith, Esq., of the Authors’ Publishing Co., Iam under obligation for encourage- ment to persevere in my labors. W..H. C. CONTENTS. INTRODUCTION... 1... cc ceeseccscc csc eccvccessccces CHAPTER I. TOOTH-GERMS (ODONTOGENY). Periods at which 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, the Lower from Four. —Similar de- velopment of the Human Teeth.......++.ssese seers CHAPTER Il. 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. CHAPTER III. THE PERMANENT DENTITION. Distinction between Premolars and_Molars.—The Bow-like Incisors. —Contrasts between Upper and Lower Grind- ers, and Rows formed by them.—The Incisors saved from Friction.—Horses’ Teeth compared with those of other Animals.—Measurements.—Time’s Changes, Xe. CHAPTER IV. THE CANINE TEETH OR TUSHES. Practically Useless.—Different in their Nature from other Teeth.—Were they formerly Weapons of Offense and Defense?—Views of Profs. Darwin, Hunter, Bell, You- att, and Winter.—Time of Cutting a Critical Period. . CHAPTER V. THE REMNANT TEETH. Usually regarded as Phenomenons.—The Name.—Traced to Fossil Horses, in which (in the Pliocene Period) they Ceased to be Functionally Developed.—Nature’s Meta- morphoses.—‘“ The Agencies which are at work in Mod- eling Animal and Vegetable Forms,”—Why they are often, as it were, Prematurely Lost.—Fossil Horses... 31 47 53 75 94 — vi CONTENTS. “ PAGE CHAPTER VI. DENTAL’ CYSTS AND SUPERNUMERARY TEETH. Teeth growing in various parts of the Body.—Some very Prolifie Cysis, Producing a Second, if not a Third, “ Dentition.”—Re; ports and ‘Theories of Scientific Men. 115 _ CHAPTER AVIt HORSES’ TEETH UNDER THE MICROSCOPE. The Dentinal Tubes, Enamel Fibers, and Cemental Canals Described and Contrasted.c.. 0.2035 .j¢.0 ceases sere 180 CHAPTER. .VIII THE PATHOLOGY OF THE TEETH. Importance of the Subject.—Caries caused by Inflamed Pulps, Blows, 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. .......... rey a .. 136 CHAPTER IX. THE DENTISTRY OF THE TEETH. Reports of Cases Treated by Various Surgeons.—Gutta- Percha as a Filling for Trephined Sinuses.—Teeth Pressing against the Palate.—Death of a Horse from eee tee Swallowing a Diseased Tooth. i. 5. 20.4. 5s setenv sree 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 Fractured Tooth and Bones out through the Nostril, &......... 194 COP ALP TR axe 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.............. 203 CHAPTER XII. THE TRIGEMINUS OR FIFTH PAIR OF NERVES. Its Nature and the Relation it bears to the Teeth—TIts Gourse,in. thé Horse-and-in Mane. .3 ok.) oe 216 VOCABULARY... .. PEE ir cihin ap ee Geaisee ky: SRSah Re aile,e\o x to'6r0.0.4 waka ee ace a | INTRODUCTION, Tue following matter, which is designed to give at least a synopsis of the fundamental principles of dental science, is compiled from the works of the best known odontologists. It is 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 vill INTRODUCTION. of acellular 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. ‘« In describing the simplicity of the structure of the horse’s canine teeth (tushes), Prof. Lecoq says: «The disposition of the developing follicle is in har- mony with the simplicity of their structure. At the bottom there is a simple and conical papilla for the internal cavity; on the inner wall, a double longitu- dinal ridge, on which are molded the ridge and grooves on the inner face 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 jelly-like substance, is found in a little cell within the jawbone of the unborn animal. It assumes by degrees the shape of the tooth, and then the jelly begins to change _in the lower. ‘The jelly in them GREAT USE OF THE CEMENT. 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. “Tn the formation of the grinders there are origin- ally five membranous bags in the upper jaw and four gives place to bony matter, which is supplied by little ves- sels, and which is represented by the darker portions of the at 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 theory 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. H. 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 lines 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 mm the 46 TOOTH-GERMS. pulp, is a physiological point of which a satisfactory solution remains to be given.* * Of the development of teeth in the human fetus Monsieur EK. Magitot says (“Comtes Rendus,” 1874): “Seventh Week— The epithelial eminence and epithelial inflection of Kdélliker 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. Minth—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 temporary follicles. Tenth— The wall of the follicle detaches itself from the base of the bulb and rises up its sides. ifteenth—The epithelial band begins its transformation into an enamel-organ. The enamel-germ of the first permanent molar may now be seen springing from the epithelial inflection. Sivteenti—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 the corresponding deciduous teeth, appear. Svventeenth—Appearance of the cap of dentine of the central and lateral incisors; also the bulb of the first permanent molar. HMighteenth—Appearance of the dentine caps of the first and second molars ; also the wall of the follicle of the perma- nent molar. Twentieth—Hight ofthe 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 inclosure of wali and rupture of band of first molar. Twenty- fifth—Dentine caps, .07, .054. The permanent follicle walls, which appeared after the twenty-first week, have acquired a cer- tain distinctness. 7Jwenty-e7ghth—Dentine caps, .098, .078. The epithelial germs of the permanent follicles begin their transfor- mation into enamel-organs; dentine cap first molar, .003 to .007. Thirty-second—Dentine caps, .118, .098. The first permanent molar cusps, which form upon the several apices of the dentine organ, have coalesced. Thirty-sizth—Dentine caps, .118, .109; permanent molar, .004 to .039. Thirty-ninth—Dentine caps, 136, .118 ; permanent molar, .039 to .073. The permanent follicle walls close. The dentine caps appear one month after birth.” CHAPTER II. THE TEMPORARY DENTITION. 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 foal’s temporary teeth (known also as milk or deciduous teeth), are 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: 7 ” ©. . € Ad . * 6 Incisors, 3—%; molars, 3—3—24. According to Veterinary Dentist C. D. House, who says the care and treatment of foals will affect the growth of their*teeth as much as they will their gen- b * 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 nippers,” 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 DENTITION. eral development, 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 cut. The incisors are cut 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 as 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 than 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 being terminated by the appearance of the 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 ‘colt’s mouth’ by veterinary authors. The deciduous incisors have thinner and more trenchant, normally-shaped crowns than those of their permanent successors.” SHED GR ABSORBED. 49 The incisors, which stand in an almost upright position, are smooth and rounded 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, the slant resembling that of a chisel. A little wear, however, dulls the teeth, and brings the edges toa 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 are shed, and the permanent dividers are * « Breadth is antero-posterior diameter; thickness is trans- verse diameter.”—R. Owen 3 a0) THE TEMPORARY DENTITION. ready before the corners are shed. Wowever, during the shedding periods, particularly that of the central teeth, foals experience more or less difficulty in graz- ing; but if they are given a moderate quantity of soft, green food, their health will net be impaired, nor will they lose much flesh. The central incisors are shed when the foal is about two vears and a half old, the dividers at three and a half or four, and the corners at four and a half or five. ‘The ees which Prof. Richard Owen says sooner begin to develop roots than the permanent, are shed with even less inconvenience to the foal than the im- cisors. The fourth grinder, the first permanent tooth cut, is ready for use before the first temporary molar is shed, and the fifth and sixth are ready before the second and third are shed. ‘be time of shedding the twelve teeth varies somewhat, and the falling off of the “caps” of the uppers will precede those of the lower teeth several weeks. The thin shells (caps) that fall off are all that is left of the tempora ry molars, their roots and bodies having been absorbed by the permanent teeth, except of course that part which has been worn from the crown by attrition. Thus, when Nature islet alone, the oe 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 avout 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. There is, he says, a sufficient ae of time between the shedding of the upper and lower molars for the new tecth in the UNFUNCTIONALLY DEVELOPED CANINES. 51 upper jaw to meet the old ones in the lower; sometimes the respective teeth, when the caps fall off, are not more than the sixteenta 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 docs no harm to* remoye locse sheils, the punching out of a pair of incisors, which 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 menticn the interference with grazing. The temporary tecth are often broken of at the neck and the sockets injured; this sometimes causes the permanent to grow irregu- larly, which in the ease of the horse 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, such as abnormal growths, 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. they have been shed, and that the animal is older than it really is. Veterinary authors, as a rule, do not mention the temporary tushes. A few odontologists, however, have described them. Prof. Owen (“ Odontography,” vol. 1, p. 580) says “the small deciduous canine” is cut about the sixth month, at the time the third or corner inci- sors are cut. The lower tush, owing to its diminutive size, and its being so close to hee incisor, “is shed almost as soon as the crown of the contiguous incisor is in full place, being carried out by the same move- Ginn” * -, 52 THE TEMPORARY DENTITION. ment.” Bojanus,* Prof. Owen says, first “drew the attention of veterinary authors to it by his memoir ‘De Dentibus Caninis Caducis, &c. Bojanus never found the lower deciduous canine retained beyond the first year. The deciduous canine of the upper 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 t observations to retain their place longer in the zebra: than in the horse.” Monsieur Leeoq 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 spicula or point, which, in the majority of horses, precedes the eruption of the real tusks.” Prof. C. 8. 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., tom. xii, part ii, p. 697. 1825.” + “ Gauvres de Pierre Camper. Paris, 1805.” OU 7. od ae gee Ie THE PERMANENT DENTITION. Distinction between Premolars and Molars.—The Bow-like In- cisors.—Contrasts between the 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 developed ;* in the females thirty-six, the latter, as a rule, having no canine teeth. However, their rudiments exist in the jaws, 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,t and twelve molars. The dental formula is expressed thus: * The teeth that are not functionally developed are treated of in the chapter entitled ‘‘ Remnant Teeth.” + ‘“Premolars are teeth in front of the molars; they usually differ from them by being 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 DENTITION. The incisors and premolars absorb and replace the entire temporary dentition, except the shells or caps _ described in the preceding chapter, but the canines and molars are cut through the gums. In veterinary 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. C. 8. Tomes says the premolars and molars “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), which replace the temporary molars, are slightly larger than the molars (the three last back teeth). ‘They have besides a backward inclination, while the molars incline forward ; the respective teeth are thus set toward one another. Both kinds are properly called grinders. The permanent teeth are 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 lower teeth precede the upper. About a year’s time elapses between the cut- ting of the respective pairs of teeth; that is, when the central incisors are cut, it will 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 twenty-four of these teeth have to be cut during horse); ner do they always displace deciduous predecessors (e. g., they do not all do so in the marsupials) ; so that this defi- nition is not absolutely precise. Still, asa matter of practice, it is usually easy to distinguish the premolars, and the division into premolars and molars is useful.”—C. 8. Tomes, “Dental Anatomy,” &¢., p. 258. eA eee ee, ee ee rh ae ed st tt? . . ‘oor ee et ale . > : = ew ‘ J 5 ; Stes 4 oes a“ ve “ye r q . > 3 TIME OF CUTTING. ee Tee Se the same period of time that the twelve incisors are eut. A permanent tooth attains its growth in about a year. According to the best authorities, the molar and canine teeth are cut at the 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 them room, notwithstand- 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 ee by the time the foal is two years old. The second molars are cut at about the 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 yvear.* The time of the appearance of the incisors and pre- molars has already been indicated in the preceding chapter. However, the following extract from Prof. Ovwen’s “ Odontography” is appropriate in this place, as it throws further light on the subject, and to some extent agrees with thre. dates already given: “The first true permanent molar appears between the cleventh and thirteenth months. The second fol- * Bor further particulars concerning the tushes the reader is referred to the succeeding chapter, 56 THE PERMANENT DENTITION. lows between the fourteenth and twentieth months. The crowns of the premolars and the last true molar are now advaneing in the closed sockets of reserve. The first premolar displaces the second,* and usually 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 check by the retention of its rudimental predecessor. Its appearance indicates the age of four years; but it sometimes appears earher, 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 pre- 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 foala 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 should be understood that Prof. Owen calls the ‘““very small deciduous molar” here referred te 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 second premolar the third deciduous molar, and the third. the fourth. 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- face, 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, LV ease eine gS eh 2S the age of six years the bodies are. |: hae 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 DENTITION. ccntral enamel, &e., according to Surgeon J. Hughes’s measurements, penetrates the lower centrals to the depth of from three-fifths 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 intundibula, which penetrate to their roots. The following is Prof. A. Chauvean’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 Whose con- euvity is toward the mouth. The base of this pyra- mid, the crown of the tooth, is flattened before and behind. The summit cr extremity of the fang, is, on the contrary, depressed on both sides. The shaft of the pyramid presents at different points of its hight, a series of intermediate conformations, which are utilized as indications of age, the continual growth of the teeth bringing cach of them in succession to the frictional surface of the crown. “Hxamined 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, which 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- . Le ais ¢ to : ~ r. THE TWO RINGS OF ENAMEL. 59 scribing a cavity named the external dental cavity, or, better, infundibulum. 'This cavity terminates by a conical cul-de-sac, which descends more or less deeply into the substance of the tooth. The margins are desiguated the anterior and posterior. ‘The latter, less elevated than the former, is cut by one or more notches, which are always deepest in the corner teeth. It is by the wear of these margins that the surface of friction is formed, and in the center of which the in- fundibulum persists during a certain period of time. “The fang is perforated by a single aperture, through which the pulp of the tooth penetrates into the inter- nal cavity. _ “In the composition of the incisor teeth are found the 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 formation. 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, however, 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 cirele is called the encirciing enamel, the second the central enamel. In the virgin tooth the central enamel is continuous with the external enamel, and passes over the border which circumscribes the entrance to the infundibulum. “The cement is applied over the enamel like a pro- ee Ieee sete ree CO Sy PO vn oe 60 THE PERMANENT DENTITION. 3 tecting varnish, but is not everywhere of the same thickness. On the salient portions it is extremely thin, and the friction caused by the food, the lips, and the tongue soon wears it away altogether. It is more abundant in depressed situations, as in the longitudi- nal groove on the anterior face of the tooth, and par- ticularly at the bottom of the infundibulum. The quantity aceuniulated 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 teeth, 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 erinders atid 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 onter surface, thus affording the tongue fuller and freer play, without the danger of its being lacerated, as would be the case were 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 DINNER TABLES. ER same as that of the 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,’ whereon 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. The crown surfaces 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 figures formed by tne upper and lower rows of erinders, 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 averages 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 jaws, the space between the 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- ecived that it is only alternately that the rows are used in the performance of the masticatory function, and that were 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; otherwige they would be easily broken off. As the * Prof. Youatt says: “The branches of the lower jaw termi- nate in two processes, the coracoid (beak-like), and the condy- loid (rounded). ‘he coracoid passes under the zygomatic arch, the temporal muscle being inserted into it and wrapped round it. The condyloid is received into the glencid (shallow) cavity of the 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 putintoa mill. It¢s put into a mill, and as perfect a one as imagination can conceive. The construction of the glenoid cavity gives the required lateral or grinding motion.” , - y - * ‘ + af ‘a , e - RELATIVE SIZE OF THE GRINDERS. val mediately below the eee teeth, and divide their two fangs into four, the absorbing process continuing until the bodies are reduced to mingle plates and fall off.” In measuring the teeth in a large-sized head the following facts and figures were elicited: Length of srinder 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, 242; first grinders, not including the space of the angles, 234. Lower rows: Between the sixth grinders, 24; center of rows, 14%; first grinders, 14. Upper tush from first grinder, 24; from third incisor, 14. Lower tush from grinder, 34; from incisor, 4. Space between the upper tushes, 2; between the lower, 3,. Space between the upper corner incisors, measur- ing from center of teeth, 2; lower, 143; between the upper dividers, 14; lower, 12. Distance around semi- circle of upper incisors, 44,3 around lower, 31%. As a supplement to the above, the following extract _is made from “ An Essay on ue Teeth” by Surgeon John Hughes~ (“ Veterinarian,” 1841, “ Proceedings Vet. Med. Ass.,” p. 22): “The upper and lower grinders will measure from 24 to 3 inches in length. In transverse diameter the former exceed the latter in the 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 14, the third 14, the fourth 1, the fifth 1, and the sixth 14. The breadth of the corresponding lower teeth is about the same as that of the upper.” AY 27 ithe 5 x ea rs aig ed ea Me Re wr at “Oy Oe ee eh et, eas ie See toe es ty ee 2 THE PERMANENT DENTITION. There is a difference in the structure of all the teeth, and an expert can tell to which socket each belongs. They fit their sockets accurately,* are braced all round by the jawbone processes, and receive besides support aad 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. * . Z Ber). . i. VOCABULARY. 239 DIABE’TES. A disease characterized 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 2! ounces saccharine matter. Dr’arHraGgM. 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 belly ; the midriff. Webster. 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, scrofuious, scorbutic (pertaining to scurvy), rheumatic, gouty, and calculous. Dicuor’omous. Regularly divided by pairs, from top to bot- tom ; as, a dichotomous stem. Martyn. Divertic’uLuM. A blind tube branching out from the course ofa larger one. An organ which is capable of receiving an unusual 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. Ducone’. 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 jaw bends 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 oi] is recommended as a substitute for cod-liver oil. Johnson’s N. U. Cye. Dora Mater. 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 the different parts of the cerebral mass. Ki. Econ’omy. By the term ‘animal economy’ is understood the aggregate of the laws which govern the organism, The word economy is also used for the aggregate of parts which con- stitute man or animals. EpEentTa’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. ou VED Em’sryo. The fecundated germ, in the early stages of its de- velopment in utero, Ata certain period 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 period of quickening. ENCEPHALITIS. 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’ocEeNE. 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. Mantel. In America the eocene strata contain numerous fossils, mostly marine mollusks, but also include some gigantic ver- tebrates, a carnivorous cetacean seventy feet in length, anda shark of which the teeth are sometimes six inches in leneth. 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. Johnson’s N. U. Oye. EpIper’MIs. A transyarent, 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 anpears to consist of minute scales placed one above the other. The epidermic system, in general anatomy, comprises three parts. = 2 r oT VOCABULARY. 237 1. External epidermis. 2. Epidermis spread over the mu- cous membranes. 38. The nails and hair. : EpiTHe’Lium. ‘The thin layer of epidermis which covers parts deprived of derma, properly so called, as the nipple, mucous membranes, lips, Xe. Escuar. A slough, crust, or scab. Escuaror’tc. Any substance which, when applied upon a liv- _ ing part, gives-rise to an eschar, such as caustic potassa, con- centrated mineral acids, Xe. Ksopy’acus. The gullet. A musculo-membranous canal, extending from the inferior extremity of the pharynx to the upper orifice of the stomach. ETHMOoID. Shaped like a sieve. ErumoiD Bonz. 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. Evouvu’t1on. 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 ; analogous 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. Henry Hartshorne. 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 animals pass into each other by slight and gradual transitions. The arm ofa man, the fore limb of a quadruned, the wing of a bird, and the fin of a fish are homologous. that is, they contain the same essential parts, mddified in correspondence with the dif- ferent circumstances of the animal; and so with the other 4 Vv 8 VOCABULARY. organs. Prof. Cope says: “Every individual of every species of a given branch of the animal kingdom is composed of ele- ments common to all, and the differences which are so radi- cal in the higher grades are but the modifications of the same elemental parts,” . L. Youmans. EXFOLIATION (from ew and folium, ‘a leaf’), By this is meant the separation of the dead portions of a bone, tendon, apon- eurosis (a white shining membrane), or cartilage, under the form of lameilce (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. Exostrosis DENTIUM. Exostosis of the teeth. F. FERRU GINOUS (chalyb’eate). Of or belonging to iron ; contain- ing iron. Any medicine into which iron enters, as chalyb- eate mixture, pills, waters, &. Fr’tus. See ‘embryo.’ Fiser. An organic filament, of a solid consistence, and more or less extensible, which enters into the composition of every animal and vegetable texture. Fu/amunt. A thread. This word is used synonymously with fibril ; thus we say a nervous or cellular filament or fibril. Fis’tuna. ‘A pipeorreed.’ 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 mucons membranes. For/ticin. 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 Cee Pn eee re rs er ee ao VOCABULARY. 239 their surfaces. The 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. Fora’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. FRaNUM. A small bridle. A name given to several membran- ous folds, which bridle and retain certain organs. Frontat Bong. A double bone in the fetus, single in the adult, 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 office in the animal economy, which has as its instrument an organ or apparatus of organs. Funeus. The mushroom order of plants. In pathology the word is commonly used synonymously with fungosity (my- cosis). Fungus HaMaro’DEs (Hematodes Fungus). An exceedingly alarming carcinomatous (cancerous) affection, which was first described with accuracy by Mr. John 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 aud bleeding exerescences, G. GANG’LION. Nervous ganglions are enlargements or knots in he 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 (vinum gentiane compositum, or wine bitters), ‘Gentiana Lutea’ is the systematic name of the officinal gentian. The plant is common in the mountains of Kurope. The root is almost inodorous, extremely bitter, and yields its virtues to ether, alcohol, and water. It is tonic and stomachic, and, in large doses, aperient. It is most fre- quently, however, used in infusion or tincture. 240 VOCABULARY. GEOL’oGY 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 zodlogy and botany. A knowledge of geology lies at the base of physical geogra- phy, and is essential to the skillful prosecution of mining 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 bas 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 hundreds, 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.” GuaNnpb. (An acorn; akernel.) Softish, granular, 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. 3 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 drinks water. Its flesh is edible and its skin valuable. : Johnson's NV. U. Cye. H. HAVERSIAN CANALS. (Canals of Havers, nutritive canals, &c.) The canals through which the vessels pass to the bones. They are lined by a very fine lamina of compact texture, or are formed in the texture itself. There is generally one large nutritious canal in a Jong bone, situate toward its middle. H1a’tus. a ee *“v - through the canula, eA TUBERCLE, A tumor in the substance of organs, from the pro- ; duction of new matter; sensation null, growth sluggish. In i; pathological anatomy, the term is generally given to a spe- cies of degeneration which consists of an opaque matter, of a ve pale yellow color. This, in its crude condition, has a con- st 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-

~ 935. Dunglison, R., Coleman, Surgeon, discovery of, Lis. Coluber Scahber, the, 121. Comparative Anatomy, 259. Conrad d, T., discovery of, 113. Cooper Union, the, 4. Cope, Prof., on evolution, 238 Copybara, the, grinders of, 10; description of, 233. Coughing and Teething, 92. Cox, Stephen J., 4. Cuvier, M,, 16; note on, 66; bones and teeth-of recent and, fossil horses, 106 ; ophthalmic, ganglion, 221. DANA, Prof., geology and evo- lution, 240. Dandini, J., theory of, 26. D’Arboval, teething, 87. teeth, 45; diseases of teeth, 137; ‘voeabulary, 227 to 206. EDINBURGH VETERINARY COL- LEGH, report of, 179, 180. Hditor Veterinarian, comments of, 184 ; report of, 204, 202. Elasmothere, the, enamel fes- toons of molars of, 107; con- necting link between horse and rhinoceros, 107. Elephant, grinders of, 10. Embryology, 80 to 92. Enamel, the, 10; tubes of, 18, 19; color of, 19; membranous sheaths of, 59; plications of, 106. Enamel-Fibers, direction of, 20; curves cf, 20; form and size of, 20; diameter of, i34. , 79; deseription of, cevelopment of — Db Ce ENS Cte te am ’ aS oS Ea a ee ee Oe 4 th Fe] ae ; Enterprise, the, 193. Hocene (period) fossils of, 286. Evolution, doctrine of, 77 to 79; 237, 288. ~ Esostoses, 17, 116. FAENKEL, discoveries of, 13. Fairfield, F. G., 4. _ Falconer, Dr., 77. Faleonio, Sur., discovery of, 118. Ferguson, P. B., development ~ of teeth, 46; erinders, 62; 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 INDEX. Grouilié, Mage, 116. Guanaco, the, 78; description of, 240. Gubernaculum Dentis, the, 42. Gurlt, Surg., discovery of, 117. | TAECKEL, E. H., embryos, 81-2. Harris, Prof., 8d dentition, 129. ‘Hartshorne, H., evolution, 237. ,Haschischat ed dab, effect of on | teeth, 25. Hayes, B., theories of, 22 to 24; diseases of teeth, 137. |Heard, J. M., 4, 216. _ ‘Heath, J. P., report of, 200, 201. Hénocque, M., motor nerves, 217, 218. Herbert, W. H., age, 214, 215. Hipparion, the, teeth of, 95, 96, ETL Fi: to 119; fractured jaw, 195,) Hippopotamus, the, canine teeth 196. of, 63. ' Forthomme, M., temporary ca-|Histology, definition of, 241. nines, 52. Fossil Tooth, a diseased, 178. Fractured Jaws, 194 to 202. Frederick, M. M., 193. GAMGEE, J., report of, 120-2. Garengeot, M, 156. Generali, Prof., 116. . Geology, definition of, 240. Gill, I’, nature of teeth, 12; dental formula for horse, 101; morphology, 245; quadruma- na, 251, 292; teleosts, 254. Girard, M., teeth and age, 203, 207. Gloag, Surgeon, 182. Gomphosis, 72. Goodsir, Prof., 125. Goubaux, Sur., discovery of, 117. Gowing, T. W., diseases of teeth, 171, 172. Grice, C. C., report of, 125, 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, 79, 71. Hog, canine teeth of, 65. Horsburgh, J., report of, 175. Horse, the, theory of introduc- tion into America, 110. Horse, the fossil, 95 to $8; 106 to 113; extinction of in South - America, i109. Houghton, 8. D., 200. House, C. D., 4; size of tooth- germs, 31; theory of teethi- ing, 47, 48; grinders, 62; remnant teeth, 103, 104; re- moyal iractured tooth through nostril, 198, 199; operations in Worcester, Mass., 199. Hudson, E. D., Jr., ovaries, 248. Hunter, J., theories of, 24 to 27; enamel of grinders, 63; at- tachment of teeth, 72; use of canines, 83; supernumerary teeth, 128; proving the for- mation of new dentine, 209. Hughes, J., dimensions of teeth, - 49; periosteum of teeth, 137. ‘Huxley, T. H., teeth of tapir, rhinoceros, and horse, 65, 66; | fossil horses, 110, 111. 260 Hyohippus, the, 112. IcuA“ODON, the, molars of, 68. Incisors, the permanent, 958; length of, 57; curvatures of, 57; Chauveau’s description of, 53 t0.60- Incisors, temporary, 47 to 50. Inferior Maxillary Nerve, the, 228, 224. Know.xson, J. C., bishoping, 211. LAFossE, Prof., dental cysts, 120. Lanipas, cause of, 88 to 91. Lanzillotti-Buonsanti, Prof., on dental cysis, 114. Lecoq, Prof., canine follicles, 44; temporary canines, 52; de- scription of grinders, 69 to 71; do. canines, 77; remnant teeth, 100. Leeuwenhoek, discoveries of, 13. Legros, C.,.experiments of, 27. Leidy, J., letter from, 101; fos- sil teeth, 113; mastodon, 114. Lincoln, A., 211. Lion, the, canine teeth of, 83. Liquor Sanguinis, the, 22, 242. Lubin, R., discovery of, 127. Lyell, Mr., 110. MAcRops, Surgeon, experiences of, 117-18. Madder, effect of on teeth, 24. Magitot, E.,27; development of tooth-germs, human fetus, 46. Malpighi, discoveries of, 18. Man, canine teeth of, 82, 83. Man, early progenitors of, 80-3. Marks, dimensions of, 57, 53; twofold use of, 204. Marsh, O. C., evolution of horse. 95 to 93; no ‘mark’ in teeth of early forms, 298; descrip- tion of mastodon and mega- therium, 248 Mastodon, the, 109, 114, 248. INDEX. | May, C., report of, 178, 179. Mayhew, E., the cement, 17, 18; judging age by teeth, 207-8. Mayo, Mr., experiments of, 218. Megathberium, the, teeth of, 107, 108; description of, 243. Melanian Races, teeth of, 99. Membrana Nictitans, 244. Merychipnus, the, 112. Mesohippus, the, toes of, 97, 112. Miocene (period) fossils of, 244. Miohippus, the, 112. Molars, the, 54; inclination of, 54. Moon-Blindness, cause of, 109. Moore, T., 20, 26. Morphology, definition of, 245. Morton, Prof., 198. | Miiller, Prof., discovery of, 14-5. Muntjac-Deer, the, 77, 78; de- scription of, 246. Musk-Deer, the, 783; description of, 245. Mylodon, the, 108, 246. NARWHAL, the, tushes of, 79; description of, 246. Newberry, J. 8., zodlogy, 256. Niebuhr, opinion of, 20. Nippers, the, 47. Nott, Dr., 118. ODONTOLITHOS, the, 17, 247. Odontonecrosis, 135. Odontrypy, 188. Ohlinger, O. P., discovery of, ie Ophthalmic Nerve, the, 219-22. Ornithorhynchus, the, 80; de- scription of, 247. Operating, rules for, 154 to 160. Oreste, Surg., discovery of, 118. Orohippus, the, teeth of, 96, 97; toes of, 97; size of, 97, 112. Osbiston, Supt., 193. Osteo-sarcoma, case of, 186. Owen, B., dental science, 8, 10, 12, 28; tooth-germs, 32 to 37; | breadth and thickness, 49; temporary canines, 51; teeth. ing, 55; description of grind- ers, 64 to 66; teeth of anoplo- | there, 63; do. ruminants, 65; do. tapir, 65; do. rhinoceros, 67; do. megatherium, 107;, ae, remnant teeth, 102; fossil es horses’ teeth, 106 to 109;| _ ~~! microscopical appearance of , horses’ teeth, 130 to 135; dis-. Fs ss eases of teeth, 187; diseased | (ey fossil tooth, 1738, 174; the! ser fiith pair of nerves, 225, 226 oA a PALEONTOLOGY, 248. _. Paleothere, teeth of, 68, 111. Pag Parnell, C., remnant teeth, 102. Bk. 5 Parrot-Mouth, 167, 168. of : Pathology of the Teeth, 136. Se Pereivall, W., teething, 86 to bit 88; lampas, 88 to 99; dis- Bees? eases-of teeth, 188, 185, 186; besa ophthalmic ganglion, 221. ae Plasse, M., 156. ~~ Pliocene (pericd) fossils of, 250. ge Pliohippus, the, 112. Pe Pony, great suffering of a, 201. cE Portal, learning of, 14. 3 Premolars, the, 53; inclination of, 54. Processes, alveolar, diseases of, BS. 166, 167. Protohippus, the, 112. ~Pulpal Cavity, relation of, 22. Purkinjé, discoveries of, 14, 16; corpuscles of, 9; cells of, 16. QUADRUMANA, the, 36, 81, 251. Quain, Jonas, fifth nerve and ophthalmic ganglion, 220. et RENAULT, Prof., report of, 187. | Sah Regimen, 162 to 164. ia Retzius, Prof., discoveries and | conjectures of, 16, 19, 20, 21. | Revel, M., report of, 197. Reversion, doctrine of, 80. Rhinoceros, the, teeth of, 67. INDEX. Rhinoceros, the woolly, 251. _Rigot, temporary canines, 52. Robin, C., 27. Ae es R01 Rodet, Surgeon, 118. Roudanoosky, M., 218. ' Rousséau, M., 48. tuminants, — of, 65; four stomachs of, 252. Ruini, discoveries of, 69. Santy, A. H., report of, 180. Scelidcthere, remains of, 108. Schaaffiausen, Prof., 99. Schwann, Dr., researches of, 20. Seelye, J. H., O34, Sewell, W., dental cysts, 122, Simonds g, Prof, 156. sinuses, description of the, 1 52; gutta-percha recommended as a filling for, 177. Smith, W. , report of, 182 to 184. Smith, W. B., 4, Sp eculum Oris, use of, 149, Spencer, H., evolution, 287, Spy, the Worcester, 199. Star, dentinal, 59, 209. Sun, the New York, 200. Superior Maxillary Nerve, the, 322 223. 127 to SI) hd Fey Supernumerary Teeth, 129; 189. Surmon, H.. report of, 177. Swallowing a Diseased Tooth, death of a horse from, 187. Swan, Dr., 225. TABLES OF GRINDERS, the, 61. Tapir, the, teeth of, 65. Teéth, variety and use of, 10, 11; in harmony with general Sy stem, LL readily preserved ina fossil state, 12; tubes of, 12; how affected by madder, 24 to 26 ; transplanting of, 26. pees horses’ , temporary, 47 to ; permanent, 53 to 74; ea- isa 1D to 93; remnant, 94 to 114; abnormal, 115 to 127; ; supernumerary, i: 9; under the microscope, 130 ’to 159 ; pathology of, 186 to 174; den- tistry of, 175 to 195; indica tors of age, 203 to 215. 262 Teeth, remnant, 94; of descent, 94; teeth, 94; nant, 94; Tenon, discovery Thurber, G., 4. Tomes, C. 5S 41; temporary canines, 52; dentine, enamel, and cement, 63 ; ee iment of teeth, 72; growth of (horses’) teeth dur- ing life, 74; tushes of boars, 84, 85; evolution, 98, 99; no ‘mark’ in teeth of ea ply fossil horses. 203. Tomes, J., a tooth barricading disease, 139. Tooth, nature of, 7, 8; cence of, 12, 16; power of repazation, 157. Tooth and Bone, analogy of, 238. Tooth-Germs, development of, 31 to 46. Tooth-Cough, 92. Tooth, a diseased fossil, 173-4. Tooth Puip, description of the, al. Toxodon, remains of, 109; de- scription of, 254. Trephine, the, 254. Trephining Sinuses, 157 to 161. Pripier, M., re section of nerves, 217. Trocar, the, 255. Tushes, horses’, practically use- less, 78 ; different from other teeth, 75; distances from in- cisors and grinders, 75, 73; shape and dimensions of, 76; curvatures of roots, 76. Tushes, removal! of, 155. why na easily lost, 99, oi, 69. 100. irides- VABNELL, G., opinion of, 102 diseases of teeth. 128, 139; the sinuses, 151, 152, 161; caries, 164 to 166; diseases ane alve regarded as phenomenons, 94, 101; ; line not to be con- founded with supernumerary med rem- S., tooth-germs, 37 to no inherent INDEX. lar processes, 166, 167; par- rot-mouth, 167, 168; osteo- sarcoma, 186, 187; fractured jaws, 194. WALLACH, A. R., cause of de- struction of ungulata, 111; fossil horses, 112; geology, 240. Walrus, the, mode of fighting On 77, Walsh, J. H., judging age by teeth, 208. Williams, Prof. W., teething, 91; remnant teeth, 104, 105; dental cysts, 120 to 197; ; ca- ries, 169 to 171. Williams, W., necrosis, 246. Winter, J. H., use of tushes, 85. Woodward, J. J., histology, 241. W ors, eeneral, ‘4, Works, special, 4. Wyman, Prof., discovery of, 81. YouatTt, W., sugar as food, 29; tooth-germs, 44, 45; infundi- ae of orinders, 58; move- ment of lower jaw, 62 ; use of tushes, 84; teething , 85- 6; lampas, 99; cropping “horses? ears, 103; remnant teeth, 105; food, 162 to 164; diseases of teeth, 172, 173; fractured jaws, 196 to 188; ‘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 pair of. nerves, 216 to 225; cecum, 200: colon, 232; membrana nictitans, O44 - solipeds, 253, Youmans, E. L., evolution, 227. ‘Zebra, temporary canine teeth of, 52 - Zodicgy, definition of, 256. LIBRARY OF CONGRESS