.290 H943ir 1839 < v. , WK: v i S^: %$&& ARMY MEDICAL LIBRARY FOUNDED 1S36 tNftja 4JM(Jtt| WASHINGTON, D.C ^ I i t A , ■x. I ^i0ffl lUff, I ,*-- ^ i y I wU^x. /C ~L ( j o m in: m ir h f i m Drawn for the Americans Journal of ~f)ental Science rd* J- tk. *lf.U«4ji. &. ,4\y. ¥ £ THE NATURAL HISTORY HUMAN TEETH, EXPLAINING THEIR STRUCTURE, USE, FORMATION, GROWTH, AND DISEASES, ILLUSTRATED WITH PLATES. BY JOHN HUNTER, SURGEON EXTRAORDINARY TO THE KING, AND F. R. S. LONDON. WITH NOTES, BY ELEAZAR PARMLY. NEW-YORK : 1839. vVz Hi5l 4 BIOGRAPIIY. by offices of affection, is powerful upon the young mind; and the circumstances of Mr. Hunter's family were calculated to give such feelings their full power over such a character as his. They lived retired, in that state of independence which a small landed property confers on the elder members, while the young men are compelled to seek their fortunes at a distance from home. John Hunter neglec- ted books, but he was not insensible to the pride and gratification ex- pressed by every member of the family on hearing of his elder broth- er William's success, and the pleasure which that brother's letters gave to all around him. These feelings made him ashamed of his idleness, and inclined him to go to London, and become an assistant to Dr. William Hunter in his anatomical inquiries. William consen- ted to this arrangement; and the subject of our memoir quitted his paternal home in 1748 ; certainly without that preparation of mind which should lead us to expect a very quick proficiency in medical pursuits. At an earlier age he bad displayed a turn for mechanics, and a manual dexterity, which led to his being placed with a cabinet- maker in Glasgow to learn the profession : but the failure of his mas- ter had obliged him to return home. Dr. William Hunter had at this time obtained celebrity as a teacher of anatomy. He won his way by very intelligible modes. His upright conduct and high mental cultivation gained him friends ; and his professional merits were established by his lectures, which, in extent and depth, as well as eloquence, surpassed any that had yet been delivered. There was a peculiar ingenuity in his demonstrations, and he had a happy man- ner exactly suited to his subject. The vulgar portion of the public saw no marks of genius in the successful exertions of Dr. Hunter ; his eminence was easily accounted for, and excited no wonder.— They saw John Hunter's success, without fully comprehending the cause ; and it fell in with their notions of great genius that he was somewhat abrupt and uncourtly. Dr. Hunter immediately set his brother to work upon the dissec- tion of the arm. The young man succeeded in producing an admi- rable preparation, in which the mechanism of the limb was finely displayed. This at once showed his capacity, and settled the relation between the two brothers. John Hunter became the best practical anatomist of the age, and proved of the greatest use in forming Dr. Hunter's splendid museum, bequeathed by the owner to the Universi- ty of Glasgow. He continued to attend his brother's lectures; was BIOGRAPHY. 5 a pupil both at St. Bartholomew's and St. George's Hospitals ; and had the farther advantage of attending the celebrated Cheselden, then retired to Chelsea Hospital. And here we must point out the advan- tage which John Hunter possessed in the situation and character of his elder brother, lest his succes shoud encourage a laxity in the stu- dies of those who think they are following his footsteps. It would indeed have been surprising that his efforts for the advancement of physiology commenced at the precise point where Haller's stopped, if he had really been ignorant of the state of science at home and abroad. But he could not have been so, unless he had shut his eyes and stopped his ears. In addition to his anatomical collection, Dr. Hunter had formed an extensive library, and possessed the finest cab- inet of coins in Europe. Students crowded around him from all countries, and every one distinguished in science desired his acquain- tance. John Hunter lived in this society, and at the same time had the advantage of being familiar with the complete and systematic course of lectures delivered by his brother. He was thus furnished with full information as to the actual state of physiology and patho- logy, and knew in what directions to push inquiry, whilst the natural capacity of his fine mind was untramelled. In 1755, John Hunter assisted his brother in delivering a course of lectures ; but through life the task was a painful one to him, and he never attained to fluency and clearness of expression. In 1760, his health seems to have been impaired by his exertions : and in the recollection that one brother had already died under similar circum- stances, his friends procured him a situation in the army, as being less intensely laborious than his mode of life. He served as a staff surgeon in Portugal and at the siege of Bellisle. On returning to London he recommenced the teaching of practical anatomy. In 1767, he was elected a fellow of the Royal Society, having al- ready gained the good opinion of its members, by several papers on most interesting subjects. There is this great advantage in the pur- suit of science in London, that a man remarkable lor success in any branch can usually select associates the best able to assist him by their experience and advice. It was through John Hunter's influence that a select club was formed out of the fellows of the Royal Society. They met in retirement, and read and criticised each other's papers before submitting them to the general body. This club originally consisted of Mr. Hunter, Dr. Fordyce, Sir Joseph Banks, Dr. So- 6 BIOORAPHY. lander, Dr. Maskclyne, Sir George Shuckburgh, Sir Henry Engle- field, Sir Charles Blagden, Mr. Ramsden, and Mr. Watt. To be the associate of such men could not but have a good effect on a mind like Hunter's active and vigorous, but deficient in general ac- quirement, and concentrated upon one pursuit. At this time, and for many years afterwards, he was employed in the most curious physiological inquiries ; and at the same time form- ing that museum, which remains the most surprising proof both of his genius and perseverance. It is strange that Sir Everard Home should have considered this collection as a proof of the patronage Hunter received. He had many admirers, and many persons were grateful for his professional assistance ; but he had no patrons. The extent of his museum is to be attributed solely to his perseverance ; a quality which is generally the companion of genius, and which he displayed in every condition of life. Whethsr under the tui- tion of his brother, or struggling for independence by privately teach- ing anatomy, or admidst the enticements to idleness in a mess-room, or as an army surgeon in active service, he never seems to have forgotten that science was the chief end of his life. Hence the ama- zing collection which he formed of anatomical preparations; hence too the no less extraordinary accumulation of important pathologi- cal facts, on which his principles were raised. It was only towards the close of life that Hunter's character was duly appreciated. His professional emoluments were small, until a very few years before his death, when they amounted to £6000 a year. When this neglect is the portion of a man of distinguished merit, it has sometimes an unhappy influence on his profession. Men look for prosperity and splendour as the accompany ments of such merit ; and, missing it, they turn aside from the worthiest models, to follow those who are gaining riches in the common routine of prac- tice. Dr. Darwin said that he rejoiced in Hunter's late success as the concluding act of a life well spent; as poetical justice. But throughout life he spent all his gains in the pursuit of science, and died poor. His museum was purchased by government for £15.000. It was offered to the keeping of the College of Physicians, which declined the trust. It is now committed to the College of Surgeons, in Lin- coln's Inn Fields; where it is open to the inspection of ihe public during the afternoons of Monday, Wednesday, and Friday. The BIOGRAPHY. 7 corporation has enlarged the museum, instituted professorships for the illustration of it, and is now forming a Library. The most va- luable part of the collection is that in the area of the great room, consisting of upwards of 2000 preparations, which were the results of Mr. Hunter's experiments on the inferior animals, and of his re- searches in morbid human anatomy. All these were originally ar- ranged as illustrative of his lectures. The first division alone in support of his theory of inflammation, contains 602 preparations. Those illustrative of specific diseases amount to 1084. There are besides 652 dried specimens, consisting of diseased bones, joints, and arteries. On the floor, there is a very fine collection of the skele- tons of man and other animals; and if the Council of the College continue to augment this collection with the same liberal spirit which they have hitherto shown, it will be creditable to the nation. The osteologica! specimens amount to 1936. But the most interesting portion ; we might say one of the most interesting exhibitions in Europe to a philosophical and inquiring mind, is that which ex- tends along the whole gallery. Mr. Hunter found it impossible to explain the functions of life by the investigation of human anatomy, unaided by comparison with the simpler organization of brutes ; and therefore he undertook the amazing labour of examining and preparing the simplest animals, gradually advancing from the lower to the higher, until, by this process of synthesis, the structure of the human body was demonstrated and explained. Let us take one small compartment in order to understand the effect of this me- thod. Suppose it is wished to learn the importance of the stomach jn the animal economy. The first object presented to us is a hydatid an animal, as it were, all stomach ; being a simple sac with an exteri- or absorbing surface. Then we have the polypus, with a stomach opening by one orifice, and with no superaded organ. Next in order is the leech, in which we see the beginning of a complexity of struc- ture. It possesses the power of locomotion, and has brain, and nerves, and muscles, but as yet the stomach is simple. Then we advance to creatures in which the stomach is complex: we find the simple mem- braneous digesting stomach ; then the stomach with a crop attached to macerate and prepare the food for digestion ; then a ruminating stomach with a succession of cavities, and with the gizzard in some animals for grinding the food, and performing the office of teeth ; and finally, all the appended organs necessary in the various classes of 8 BIOGRAPHY. animals ; until we find that all the chylopoietic viscera group round this, as performing the primary and essential office of assimilating new matter to the animal body. Mr. Hunter's papers and greater works exhibit an extraordinary mind : he startles the reader by conclusions, the process by which they were reached being scarcely discernible. We attribute this in part to that defective education which made him fail in explaining his own thoughts, and the course of reasoning by which he had arrived at his conclusions. The depth of his reflective powers may be esti- mated by the perusal of his papers on the apparently drowned, and on the stomach digested after death by its own fluids. The impor- tance of discovering the possibility of such an occurence as the last is manifest, when we consider its connexion with medical jurispru- dence, and the probability of its giving rise to unfounded suspicions of poisoning. His most important papers wrere those on the muscu- larity of arteries ; a fine piece of experimental reasoning, the neglect of which by our continental neighbours threw them back an age in the treatment of wounded arteries and aneurisms. But the grand discovery of Mr. Hunter was that of the life of the blood. If this idea surprise our readers, it did no less surprise the whole of the medical profession when it was first promulgated. Yet there is no doubt of the fact. It was demonstrated by the closest inspection of natural phenomena, and a happy suite of experiments that the coagu- lation of the blood is an act of life. From this one fact, the pathologist was enabled to comprehend a great variety of phenomena, which without it, must have ever remained obscure. Mr. Hunter died of that alarming disease, angina pectoi%is: alarming because it comes in paroxysms, accompanied with all the feelings of approaching death. These sensations are brought on by exertion or excitement. In St. George's Hospital the conduct of his col- leagues had provoked him; he made no observations, but, retiring into another room, suddenly expired October 16, 1793. After these details no man will deny that John Hunter possessed hio-h genius, and that he employed his talents nobly. He was in- deed of a family of genius: his younger brother was cut off early, but not until he had given promise of eminence. Dr. Hunter was in our opinion, equal in talents to John, the subject of this memoir, though his mind received early a different bias. And in the next generation the celebrated Dr. Baillie, nephew to these brothers, con- BIOGRAPHY. 9 tributed largely to the improvement of pathology, and afforded an instance of the most active benevolence joined to a plainness of man- ner most becoming in a physician. Joanna Baillie, his sister, still live?, honoured and esteemed, and will survive in her works as one of our most remarkable female writers. A portrait of John Hunter was painted, at the suggestion of the celebrated engraver Sharpe, by Sir Joshua Reynolds, and was a- mong his last works. There could not indeed be a more picturesque head, nor one better suited to the burin. The original picture is in the College of Surgeons. It exhibits more mildnes than we see in the engraving of Sharpe. 2 H THE NATURAL HISTORY OF THE HUMAN TEETH. OF THE UPPER JAW. Before we enter into a description of the Teeth themselves, it will be necessary to give an account of the Upper and Lower Jaw- bones, in which they are inserted; insisting minutely on those parts which are connected wiih the Teeth, or serve for their motion and action, and passing over the others slightly. The Upper Jaw is composed of two bones, which generally re- main distinct through life. They are very irregular at their posterior and upper parts, sending upwards and backwards a great many pro- cesses, that are connected with the bones of the face and skull. The lower and anterior parts of the Upper Jaw are more uniform, making a kind of a circular sweep from side to side, the convexity of which is turned forward; the lower part terminates in a thick edge, full of sockets for the teeth. This edge is called in each bone the Alveolar Process. Behind the Alveolar Processes there are two horizontal lamellae, which uniting tg ether, form part of the roof of the Mouth, which is the partition between the Mouth and the Nose. This plate, or partition, is situated about half an inch higher than the lower edge of the Alveolar Process; and this gives the roof of the Mouth a considerable hollowness. The use of the Upper Jaw is to form part of the Parietes of the Mouth, Nose, and Orbits; to give a basis, or supply the Alveolar Process, for the superior row of Teeth and to counteract the Lower Jaw; but it has no motion itself upon the bones of the Head and Face. 12 JOHN HUNTER. OF THE LOWER JAW. As the Lower Jaw is etremely moveable, and its motion is indispen- sibly necessary in all the various operations of the Teeth, it requires to be more particularly described, it is much more simple in its form than the Upper, having fewer processes, and these not so irregu- lar. Its anterior circular part is placed directly under that of the Upper-Jaw: but its other parts extend father backwards. This Jaw is at first composed of two disiinct bones ; but these, soon after birth, unite into one, at the middle of the chin. This union is called the Symphysis of the Jaw. Upon the upper edge of the body of the bone is placed the Alveolar Process, a good deal sim- ilar t<» that of the upper Jaw. The Alveolar Process extends all round the upper part of the bone, from the Coronoide Process of one side, to that of the other. In both Jaws they are every where rela- tively proportional to the Teeth ; being thicker behind, where the Teeth are larger, and more irregu'ar, upon account of the more nu- merous fangs inserted into them. The Teeth that are situated back- wards, in the Upper-Jaw, have more fangs than those that corres- pond with them in the lower, and the sockets are accordingly more irregular. The Alveolar Process of the upper-Jaw, is a section of a larger circle than that of the lower, especially when the Teeth are in the sockets. This arises chiefly from the anterior teeth in the Up- per-Jaw being broader and flatter than those in the lower. The pos- terior part of the bone on each side rises almost perpendicularly, and terminates above in two processes : the anterior of which is the high- est, is thin and pointed, and is called the Coronoide Pr cess. The an- terior edge of this process forms a ridge, which goes obliquely down- ward and forward on the Jaw, upon the outside of the posterior sockets. To this process the Temporal Muscle is attached ; and as it rises above the centre of motion, that Muscle acts with nearly equal advantage in all the different situations of the Jaw. The t'osterior Process, which is made for a moveable articulation with the head, runs upward, and a little backward ; is narrower, thicker and shorter, than the anterior ; and terminates in an oblon» rounded head, or Condyle, whose longest axis is nearly transverse! The Condyle is bended a little forward; is rounded, or convex, from the fore to the back part; and likewise a little rounded from one end to the other, or from right to left. Its external end is turned a little forward, and its internal a little backward ; so that the axes of the two Condyles are neither in the same straight line, nor parallel to each other ; but the axis of each Condyle, if continued backwards, would, meet, and form an angle of about one hundred and forty-six degrees ; and lines drawn from the Symphysis of the Chin, to the middle of the Condyle, would intersect their longest axis, at nearly right angles. There are, however, some exceptions ; for in a Low*- er jaw, of which I have a drawing, the angle formed by the supposed continuation of the two axes, instead of being an angle of one hun- dred and forty-six degrees, is of one hundred and ten only The JOHN HUNTER. 13 Lower-Jaw serves for a base to support the Teeth in the Alveolar Process, during their action on those of the upper-jaw in mastication; and to give origin to some muscles that belong to other parts. OF THE ALVEOLAR PROCESSES. The Alveolar Processes are composed of two thin bony plates, one external, and the other internal. These two plates are at a greater distance from each other at their posterior ends, than at the anterior or middle part of the Jaw. They are united together by thin bony partitions going across, which divide the processes at the anterior part, intojust as many distinct sockets as there are Teeth ; but at the posterior part, where the teeth have more than one root or fang, there are distinct cells, or sockets, for every root. These transverse partitions are more protuberant than the Alveolar Plates ; and thus add laterally to the depth of the cells, particularly at the anterior part of the Jaw. At each partition, the external plate of the Alveolar Process is depressed, and forming furrows, or a fluting rounds the cells, or cavities, for the roots of the teeth. This is ob- servable in the whole length of the Alveolar Process of the Upper- Jaw ; and in the fore-part particularly of the Lower-Jaw. The Alveolar Processes of each Jaw, form about one half of a circular, or rather of an cllip'ical figure; and at the forepart in the Lower- Jaw they are perpendicular, but project inwards at the posterior part, and describe a smaller circle than the body of the bone upon which they stand ; as we shall observe more particularly hereafter, when we come to treat of the Jaws of old People. The Alveolar Processes of both Jaws should rather be considered as belonging to the Teeth, than as parts of the Jaws ; for they begin to be formed with the teeth, keep pace with them in their growth, and decay, and entirely disapear, when the teeth fall ; so that, if we had no teeth, it is likely we should not only have no sockets, but not even these processes, in which the sockets are formed ; and the Jaws can perform their n otions, and give origin to muscles, without either the teeth, or Alveolar Processes. In short, there is such a mu- tual dependence of the teeth, and Alveolar Processes on each other, that the destruction of the one seems to be always attended with that of the other. In the head of a young subject which I examined, I found that the two first incisor teeth in the upper-jaw had not cut the Gum; nor had they any root or fang, excepting so much as was necessary to fasten them to the Gum, on their upper surface ; and on examining the Jaw, I found there was no Alveolar Process, nor sockets, in that part. What had been the cause of this I will not pretend to say : whether it was owing to the teeth forming not in the Jaw, but in the Gum ; or to the wasting of the fangs. The appearance of the tooth favoured the first supposition ; for it was not like those, whose fangs are decayed in young subjects, in order to the shedding of the teeth ; 14 JOHN HUNTER. and as it did not cut the Gum, it is reasonable to think it never had any fang. That end from which the fang should have grown, was formed into two round and smooth points, having each a small hole leading into the body of the tooth, which was pretty well formed. OF THE ARTICULATION OF THE LOWER JAW. Just under the beginning of the Zygomatic Process of each Tem- poral Bone, before the external Meatus Auditorius, an oblong cav- ity may be observed ; in direction, length, and breadth, in some measure corresponding with the Condyle of the Lower-Jaw. Be- fore, and adjoining to this cavity, there is an oblong eminence, placed in the same direction, convex upon the top, in the direction of its shorter axis, which runs from behind forwards ; and a little concave in the direction of its longer axis, which runs from within outwards. It is a little broader at its outer extremity ; as the outer correspon- ding end of the Condyle describes a larger circle in its motion than the inner. The surface of the cavity, and eminence, is covered with one continued smooth cartilaginous crust, which is somewhat liga- mentous, for by putrefaction it peels off, like a membrane, with the common Periosteum. Both the cavity and eminence serve for the motion of the Condyle of the Lower-Jaw. The surface of the cavi- ty is directed downward; that of the eminence downward and back- ward, in such a manner that a transverse section of both would rep- resent the Italic letter & Though the eminence may, ou a first view of it, appear to project considerably below the cavity, yet a line drawn from the bottom of the cavity, to the most depending part of the eminence, is almost horizontal, and therefore nearly parrellel with the line made by the grinding surfaces of the teeth in the Upper-J aw; and when we consider the Articulation farther, we shall find that these two lines are so nearly parallel, that the Condyle moves almost directly forwards, in passing from the cavity to the eminence ; and the parallelism of the motion is also preserved by the shape of an in- termediate cartilage. In this joint there is a moveable cartilage, which, though common to both Condyle and cavity, ought to be considered rather as an ap- pendage of the former than of the latter, being more closely connec- ted with it; so as to accompany it in its motion along the common surface of both the cavity and eminence. This cartilage is nearly of the same dimensions with the condyle, which it covers ; is hollow- ed on its inferior surface, to receive the Condyle : on its upper sur- face it is more unequal, being moulded to the cavity and eminence of the articulating surface of the Temporal bone, though it is consider- ably less, and is therefore capable of being moved with the Condyle, from one part of that surface to another. Its texture is ligamento- cartilaginous. This moveable cartilage is connected wiih both the Condyle of the Jaw, and the articulat'ng surface of the Temporal Bone, by distinct ligaments, arising from its edges all round. That JOHN HUNTER. 15 by which it is attached to the Temporal Bone, is the most free and loose ; though both ligaments will allow an easy motion, or sliding of the cartilage on the respective surfaces of the Condyle, and Tempo- ral bone. These attachments of the cartilage are strengthened, and the whole articulation secured, by an external ligament, which is common to both, and which is fixed to the Temporal bone, and to the neck of the Condyle. On the inner surface of the ligament, which attaches the cartilage to the Temporal Bone, and backwards, in the cavity, is placed what is commonly called the Gland of the Joint; at least, the ligament is there much more vascular than a$ any other part. OF THE MOTION IN THE JOINT OF THE LOWER JAW. The Lower-Jaw, from the manner of its articulation, is susceptible' of a great many motions. The whole Jaw may be brought horizon- tally forwards, by the Condyles sliding from the cavity towards the eminences on each side. This motion is performed chiefly when the teeth of the Lower-Jaw are brought directly under those of the Up- per, in order to bite, or hold any thing very fast between them. Or, the Condyles only may be brought forwards, while the rest of he Jaw is tilted backwards, as in the case when the mouth is open ; for on that occasion the angle of the Jaw is tilted backwards, and the chin moves downwards, and a little backwards also. In this last motion, the Condyle turns its face a little forwards ; and the centre of motion lies a little below the Condyle, in the line between it and the angle of the Jaw. By such an advancement of the Condyles forwards, together with the rotation mentioned, the aperture of the mouth may be considerably enlarged ; a circumstance necessary on many obvious occasions. The Condyles may also slide alternately backwards and forwards, from the cavity to the eminence, and vice versa ; so that while one Condyle advances, the other moves backwards, turning the body of the Jaw from side to side, and thus grinding, between the teeth, the morsel separated from the larger mass by the motion first described. In this case, the center of motion lies exactly in the middle between the two Condyles. And it is to be observed, that in these slidings of the Condyles forwards and backwards, the moveable cartilages do not accompany the Condyles in the whole extent of their motion ; but only so far as to adapt their surfaces to the different inequalities of the Temporal Bone : for as these cartilages are hollow on their low- er surfaces where they receive the Condyle, and on their opposite upper surfaces are convex where they lie in the cavity ; but forwards at the root of the eminence, that upper surface is a little hollowed ; if they accompanied the Condyles through the whole extent of their motion, the eminences would be applied to the eminences, the cavi- ties would not be filled up, and the whole articulation would be render- ed very insecure. This account of the motion of the Lower-Jaw, and its cartilages, 16 JOHN HUNTER. clearly demonstrates the principle use of these cartilages : namely, the security of the articulation ; the surfaces of the cartilage accom- modating themselves to the different inequalities, in the various and free motions of this joint. This cartilage is also very serviceable for preventing the parts from being hurt by the friction ; a circumstance necessary to be guarded against, where there is so much motion. Accordingly, 1 find this cartilage in the different tribes of Carnivo- rous Animals, where there is no eminence and cavity, nor other ap- paratus for grinding; and where the motion is of the true ginglimus kind only. In the Lower-Jaw, as in all the joints of the body, when the mo- tion is carried to its greatest extent, in any direction, the muscles and ligaments are strained, and the person made uneasy. The state, therefore, into which every joint most naturally falls, especially when we are asleep, is nearly in the middle, between the extremes of mo- tion ; by which means all the muscles and ligaments are equally re- laxed. Thence it is, that commonly, and naturally, the Teeth of the two Jaws are not in contact; nor are the Condyles of the Lower- Jaw so far back in the Temporal Cavities as they can go. OF THE MUSCLES OF THE LOWER JAW. Having described the figure, Articulation, Motion, and use of the Lower-Jaw, it will be necessary, in the next place, to give some ac- count of the Muscles that are the causes of its motion. There are five pairs of Muscles,each of them capable of produ- cing various motions, according to the situation of the Lower-Jaw, whether they act singly, or in conjunction with others ; and two or more of them may be so situated, as to be capable of moving the Jaw in the same direction ; and every motion is produced by the action of more than one Muscle at a time. Thus, if the Jaw is depressed, and brought to one side, either the Masseter, Temporal, or Pterigoidaeus internus of the opposite side will not only raise the Jaw, but bring it to its middle state. It will be neces- sary in the description of each Muscle, to give its use in the dif- ferent situations of the Jaw; by which means, after they are all de- scribed, their compound actions will be better understood. I shall first describe those which raise the Jaw; then those which give it the lateral motion ; and lastly, those which depress it ; proceeding in each class as they rise in dissection. The most superficial is the Masseter: it is situated upon the posterior and lower part of the face, between the cheek-bone, and angle of the Lower-Jaw, directly before the lower part of the Ear. It is a thick, short, complex Muscle, and a little flattened : it appears to have two distinct origins, an anterior outer, and a posterior inner; but that is owing only to its outer edge at its origin being slit, or double ; and the fibres of these two edges having a different course, decussating each other a little. The anterior, and outer portion of the Muscle JOHN HUNTER. 17 begin to rise from a small part of the lower edge of the Malar Pro- cess of the Maxillary Bone, adjoining to the ()s Malse; and con- tinues its origin all along the lower horizontal edge of this last bone to the angle where its Zygomatic Process turns up, to join that of the Temporal Bone. The external layer of fibres in this portion are tendinous at their beginnings, while the internal are fleshy. The posterior and inner portion of this Muscle begins to rise part- ly tendinous, and partly fleshy, from the same lower edge of the Os Malae ; not where the origin of the other portion terminates, but a little farther forwards ; and this origin is continued along the lower edge of the Zygomatic Process of the Temporal Bone, as far back- wards as the eminence belonging to the articulation of the Lower Jaw. From this extent of its origin, the Muscle passes downwards to its insertion into the Lower-Jaw. The anterior external portion is broader at its insertion than at its origin ; for it occupies a triangu- lar space of the Lower-Jaw above the angle, and on the outside, of about an inch in size to about an inch and a half from the angle towards the Chin. In consequence of this extent of insertion, the fibres of this portion divaricate very considerably. They are mostly fleshy at their insertion, a few only being tendinous, particularly those that are in- serted backwards. The posterior and inner portion of the Masseter is narrower at its insertion than at its origin ; its posterior fibres run- ning forwards, as well as downwards, while its anterior run almost directly downwards. It occupies in its insertion the remaining part of the scabrous surface, above the angle of the Lower-Jaw, which lies between the anterior portion and the two upper processes, viz. the Condyle and Coronoid. As the anterior fibres of this portion rise on the inside of the posterior fibres of the 6ther portion ; and as its pos- terior fibres run forwards as well as downwards, and its anterior run almost directly downwards, while the fibres of the oiher portion radi- ate both forwards and backwards ; these two portions in some meas- ure decussate, or cross one another. The anterior fibres, which run farthest and lowest down, are tendinous at their insertion, while the posterior and shortest are fleshy. The use of the whole Muscle is to raise the Lower-Jaw ; and when it is brought forwards, the posterior and inner portion will as- sist in bringing it a little back ; so that this Muscle becomes a rota- tor, if the Jaw happens to be turned to the opposite side. We may observe, that this Muscle is intermixed with a number of tendinous portions, both at its origin and its insertion ; which give rise to a greater number of fleshy fibres, and thereby add to the strength of the Muscle. TEMPORALIS. It is situated on the side of the Head, above, and somewhat before the Ear. It is a pretty broad, flat, and radiated Muscle; broad and thin at its origin ; narrow and thick at its insertion ; and is covered with a pretty strong Fascia, above the Jugum. 3 18 JOHN HUNTER. This Fascia is fixed to the bones round the whole circum- ference of the origin of the Muscle. Above, it is fixed to a smooth white line, that is observable upon the Skull, extending from a little ridge on the lateral part of the Os Frontis, continued across the Parietal Bone, and making a turn towards the Mamillary Process. It is fixed below, to the ridge where the Zygomatic Process begins, just above the Meatus Auditorius; then to the upper edge of the Zygomatic Process itself, and anteriorly to the Os Malse. This ad- hesion, anteriorly, above, and posteriorly, gives, as it were, the cir- cumference of the origin of the Temporal Muscle. This Muscle arises from all the bones of the side of the head, that are within the line, for insertion of the tendinous Fascia, viz. from the lower and lateral part of the Parietal Bone, from all the squam- mous portion of the Temporal Bone, from the lower and lateral part of the Os Frontis, from all the Temporal Process of the Os Sphenoi- des, and often from a process at the lower part of this surface, (which portion however, is often common to this Muscle, and the I'terygoi- daeus externus) and from the posterior surface of the Os Malse. Out- wardly, it rises from the inner surface of the Jugum, and from the whole inner surface of the Fascia above described. At this origin, from the Jugum it is not to be distinguished from the Masseter, being there in fact, one and the same Muscle ; and indeed the Masseter is no more than a continuation of the same origin, under the edge of the Jugum ; and might properly enough be reckoned the same, both as to its origin and insertion, and in some measure in its use also. The origin is principally fleshy ; and the muscle passes from it, in general, downwards, and a little forwards, converging, and forming a thin middle tendon. After which the muscle runs downwards, on the inside of the Jugum, and is inserted into the Coronoid Process of the Lower-Jaw, on both sides tendinous and fleshy, but principally tendinous. It reaches farther down upon the inside of the Coronoid Process, than upon the outer side, where the insertion is continued as low as the body of the bone. The posterior and inferior edge of this Muscle passes over the root of the Zygomatic Process of the Temporal Bone, as over a pulley, which confines the action of the Muscle to that of raising the Lower-Jaw, more than if its fibres had passed in a direct course from their origin to their insertion. The use of the Temporal Muscle, in general, is to raise the Low- er-Jaw ; and as it passes a little forwards to its insertion, it must bring the Condyle at the same time backwards, and so counteract the Pterygoidaeus externus of the opposite side ; and if both Muscles act they counteract both the Pterygoidsei, by bringing back the whole of the Jaw. PTERYGOIDjEUS internus. It is situated upon the inside of the Lower-Jaw, opposite to the Masseter, which is upon the outside. It is a strong short Muscle, a little flattened, especially at its insertion. It arises tendinous and JOHN HUNTER. 19 fleshy from the whole internal surface of the external Ala of the Sphenoid Bone ; from the external surface of the internal Ala, near its bottom; from that process of the Os Palati that makes part of the Fossa Pterygoidaea ; likewise from the anterior rounded surface of that process, where it is connected to the Os Maxillare superius. From thence the Muscle passes downwards, a little outwards and backwards, and is inserted tendinous and fleshy into the inside of the Lower-Jaw, from the angle, up almost to the groove for the admis- sion of the Maxillary Nerve, where the surface of the bone is re- markably scabrous. The use of this muscle is to raise the Lower-Jaw; and from its direction, one would suspect that it would bring the Condyle a little forwards; but this motion is contrary to that of the Lower-Jaw, for it is naturally brought back when raised. PTERYGOIDjEUS externus. Is situated immediately between the external surface of the exter- nal Ala of the Pterygoid Process, and the Condyle of the Lower-Jaw; lying, as it were, horizontally along the basis of the skull. It is somewhat radiated in some bodies; broad at the origin, and small at the insertion; but the greater part of it forms a round, strong, fleshy belly ; so that the part that makes it of the radiated kind is thin. The thick and ordinary portion of it arises tendinous and fleshy, from almost the whole external surface of the external Ala of the Pterygoid Process of the Sphenoid Bone, excepting a little bit of the root at the posterior edge; and towards the lower part, it arises a little from the inner surface of that Ala. The thin portion arises from a ridge of the Sphenoid, that is continued from the process to- wards the temple, just behind the Foramen Lacerum inferius, which terminates in a little protuberance. This origin is sometimes want- ing ; and in that case, the Temporal Muscle arises from that protube- rance ; and very often this origin is common to both. These two origins of this Muscle are sometimes so much separated, as to make it a Biceps. From these origins the Muscle passes outwards, and a little back- wards, converging ; that is, the superior fibres passing outwards and backwards, and a little downwards ; while the inferior, or larger por- tion of it passes a little upward. It is inserted tendinous and fleshy into a depression on the anteri- or part of the Condyle and Neck of the Lower-Jaw, upon the inside of that ridge, which is continued from the Coronoid Process. Like- wise a little portion into the anterior part of the moveable cartilage. A little portion is likewise inserted into the anterior part of the move- able cartilage of the joint. When this Muscle acts singly it is a rotator; for it brings the Con- dyle of the Jaw forwards, and likewise the moveable cartilage, which throws the Chin to the opposite side : but if it acts in conjunc- tion with its fellow of the opposite side, instead of being turned to 20 JOHN HUNTER. one side, the whole Jaw is brought forwards, and thus these counter- act the temporal, &c. These two Muscles generally act alternately ; and when they do so, one acts at the time of depression, the other at the time of eleva- tion ; so that these Muscles act, both when the lower Jaw is raised, and when it is depressed : yet they do not assist either in raising or depressing it. DIGASTRICUS, It is situated immediately under, and a little upon the inside of the Lower Jaw, and outside of the Fauces, extending from the Mastoid Process to the Chin, nearly along the angle made by the Neck and Chin, or Face. The name of this Muscle expresses its general shape, as it has two fleshy bellies, and of course a middle tendon. Yet some of its anterior belly does not arise from the tendon of the posterior, but from the Kascia which binds it to the Os Hyoides. These two fleshy bellies do not run in the same line, but form an angle, just where the tendon runs into the anterior belly ; so that this tendon seems rather to belong to the posterior, which is the thickest and longest. This Muscle arises from the Sulcus made by the inside of the Mastoid Process, and a rMge upon the Temporal Bone, where it is united with the Os Occipitis. The extent of this origin is about an inch; it is fleshy upon its outer part, viz : that from the Mastoid Process, and tendinous on the inside from 'he ridge. From its origin it passes forwards, downwards, and a little inwards, much in the di- rection of the posterior edge of the Mammillary Process ; and forms a round tendon first in its centre and upper surface. This tendon passes on in the same direction ; and when got near the Os Hyoides, it commonly perforates the anterior end of the Stylo Hyoideus Mus- cle ; and from the lower edge of this tendon, some fibres seem to go off, which degenerate into a kind of Facia, that binds it to the Os Hyoides; and some of it goes across the lower part of the Mylo- Hyoidaeus, and joins its fellow on the opposite side ; binding the Os Hyoides by a kind of belt. At this part the tendon becomes a little broader, makes a turn upwards, inwards, and forwards, and gives ori- gin to the anterior belly, which passes on in the same direction, to the lower part of the Chin, where it is inserted tendinous and fleshy, into a slight depression on the under, and a little on the posterior part of the Lower Jaw, almost contiguous to its fellow. Besides the at- tachment of the middle tendon to the Os Hyoides, there is a liga- mentous binding, which serves, in some measure, as a pulley. This is more maiked in some subjects than in others ; and this depends on the strength of the tendinous expansion, which binds the tendon of the Digastricus to the Os Hyoides. When we say that these parts are attached to the Os Hyoides, we do not mean that they can be traced quite into it, like some other tendons in the body ; but the Os Hyoides seems to be the most fixed point of attachment. Very often we find two anterior bellies to each JOHN HUNTER. 21 Muscle ; the uncommon one, which is the smallest, does not pass to the Cnin, but joins with a similiar portion of ttie other side, in a mid- dle tendon, which is often fixed to the Os Hyoides. At other limes, we find such a portion on one side onlv; in which ca^e it is com- monly fixed to the middle tendon of theMylo-Hyoidseus. The use of these Muscles with regard to the Lower-Jaw, is prin- cipally to depress it; but according as one acts a little more forcibly than the other, it thereby gives the Jaw a small rotation ; and be- comes, in that respect, a kind of antagonist to the Pterygoidaeus Ex- ternus. Besides depressing the Lower-Jaw, when we examine the dead body, they would appear to raise the larynx. But although they have this effect, a proper attention to what happens in the living body, will probably shew, that their principal action is to depress the lowerjaw, and that they are the Muscles which are commonly em- ployed for this purpose. Let a finger be placed on the upper part of the Sterno-Mastoidaeus Muscle, just behind the posterior edge of the mastoid process, about its middle, touching that edge a little with the finger; then depress the lower jaw; and the posterior head of the digastric will be felt to swell very considerably, and so as to point out the direction of the Muscle. In this there can be no deception ; for there is no other muscle in this part that has the same direction ; - and those who are of opinion that the digastric does not depress the lowerjaw, will more readily allow this, when they are told, that we find the same head of the Muscle act in deglutition ; but not with a force equal to that which it exerts in depressing the lower jaw.— Further, if the Sterno-Hyoidei, Sterno-Thyroidei, and Costo-Hyoidei, acting at the same time with the Mylo-Hyoidei, and Genio-Hyoidei, assisted in depressing the jaw, the Os Hyoides, and Thyroide Carti- lage, would probably be depressed, as the bellies of the Sterno-Hyo- idei, and of the other lower muscles, are by much the longest ; but on the contrary, we find that the Os Hyoides, with the Theroide Car- tilage, is a little raised in the depression of the jaw, which we may suppose to be done by the anterior belly of the digastric : and sec- ondly, if these muscles were to act to bring about this motion of the jaw, these parts would be brought forwards, nearer to the straight line between the chin and sternum, which is not the case in this ac- tion ; whereas we find it to be the case in deglutition, in which these evidently act. By applying our fingers upon the Genio Hyoideus, and Mylo-Hyoideus, near the Os Hyoides, between the two anterior bellies of the Digastric, (not near the chin where the action of these two bellies may occasion a mistake,) we find these Muscles quite flaccid; which is not the case in deglutition, nor in speaking, in which they certainly do act; nor do we find the Muscles under the Os Hyoides at all affected, as they are in the motion of the Larynx. It has been observed, that when we open the mouth, while we keep the Lower Jaw fixed, the forepart of the Head or Face is ne- cessarily raised. Authors have been at a good deal of pains to ex- plain this. Some of them considered the Condyles of the Jaw, as the centre of motion; but if this were the case, that part of the Head, 22 JOHN HUNTER. where it articulates with the Spine, and of consequence the whole bodv, must be depressed, in proportion as the Upper Jaw is raised ; which is not true in fact. Others have considered the Condyles of the Occiput as the centre of motion; and they have considered the Extensor Muscles of the Head to be the moving powers. The Muscles which move the Head in this case, are pointed out by two circumstances, which attend all muscular motion; in the first place, all actions of our body have Muscles immediately adapted to them ; and secondly, when the mind wills any particular action, its power is applied by instinct to those Muscles only, which are naturally adapted to that motion; and further, the mind being accustomed to see the part move which is naturally the most moveable, attends to its motion in the volition, although it be in that instance fixed, and the other parts of the body move towards it: and although the other parts of the body might be brought towards it by other Muscles, and would be so, if the mind intended that they should come towards it, yet these Muscles are not brought into action. Thus the Flexors of of the Arm commonly move the hand to the body; but if the hand be fixed, the body is moved by the same Muscles to the hand. In this case, however, the mind wills the motion of the hand towards the body, and brings the Flexors into action ; whereas if it wished to bring the body towards the hand, the Muscles of the f»repart of the body would be put into action, and this would produce the same effect. To apply this to the Lower-Jaw ; when we attempt to open the mouth, while the Lower Jaw is immoveable, we fix our attention upon the very same muscles (whatever they are) which we call into action, when we depress the Lower Jaw ; and we find that we act with the very same muscles ; for our mind attends to the depressing of the jaw, and not the raising of the face ; and under such circum- stances the mouth is actually opened. We find then by these means the head is raised ; and the idea that we have of this motion, is the same that we have in the common depression of the jaw; and we should not know, except from circumstances, that the Jaw was not really depressed ; and we find at this time too, that the extensors of the head are not in action. On the contrary, when the jaw is fixed in the same situation, if we have a mind to raise the head, or upper jaw, which of course must open the mouth, we fix our attention to the muscles that move the head backwards, without having the idea of opening our mouth ; and at this time the extensors of the head act. This plainly shows, that the same muscles which depress the jaw, when moveable, must raise the head, when the jaw is kept fixed. This is a proof, too, that there are no other muscles employed in depressing the lowerjaw, than will raise the head under the circum- stances mentioned. This will further appear from the structure of the parts ; wherein four things are to be considered, viz : the articu- lation of the jaw; the articulation of the head with the neck ; the origin, and the insertion of the digastric muscle. jaE6*> i*^"?'**' a8Bt«c*-i JOHN HUNTER. 23 Suppose the upper jaw to be fixed, and the lower jaw to be move- able on the Condyle : if the Digrastic contracts, its origin and inser- tion will approach towards one another; in which case it is evident, that the lower jaw will move downwards and backwards. But if the lower jaw be fixed, as in the case supposed, and the Vertebrae be also fixed, the Condyle will move upwards and forwards upon the emi- nence in the joint, the forepart of the head will be pushed upwards and backwards by the Condyle, and the hind part of the head will be drawn down ; so that the whole shall make a kind of circular mo- tion upon the upper Vertebra ; and the Digastric muscle pulling the hind part of the head towards the lower jaw, and at. the same time pushing up the Condyles against the fore part of the head, acquires, by this mechanism, a very considerable additional power. OF THE STRUCTURE OF A TOOTH, AND FIRST OF THE ENAMEL. A tooth is composed of two substances, viz : enamel and bone.— The enamel, called likewise the vitreous, or cortical part, is found only upon the body of the Tooth, and is there laid all around, on the outside of the bony, or internal substance. It is by far the hardest part of our body ; insomuch that the hardest and sharpest saw will scarce make an impression upon it, and we are obliged to use a file in dividing or cutting it. When it is broken it appears fibrous or stri- ated ; and all the fibres or striae are directed from the circumference to the centre of the tooth. This, in some measure, both prevents it from breaking in mastica- tion, as the fibres are disposed in arches, and keeps the tooth from wearing down, as the ends of the fibres are always acting on the food. The enamel is thickest on the grinding surface, and on the cutting edges, or points of the teeth ; and becomes gradually thinner on the sides, as it approaches the neck, where it terminates insensibly, though not equally low, on all sides of the teeth. On the base or grinding surface it is of a pretty equal thickness, and therefore is of the same form with the bony substance which it covers. It would seem to be an earth united with a portion of animal sub- stance, as it is not reducible to quick lime by fire, till it has first been dissolved in an acid. When a tooth is put into a weak acid, the enamel, to appearance, is not hurt; but on touching it with the fingers, it crumbles down into a white pulp. The enamel of teeth, exposed to any degree of heat, does not turn to lime : it contains animal mu- cilaginous matter ; for when exposed to the fire, it becomes very brittle, cracks, grows black, and separates from the inclosed bony part of the Tooth. It is capable, however, of bearing a greater de- gree of heat than the bony part, without becoming brittle and black. This substance has no marks of being vascular, and of having a circulation of fluids : the most subtile injections we can make never reach it ; it takes no tinge from feeding with madder, even in the 24 JOHN HUNTER. youngest animals ; and, as was observed above, when soaked in a gentle acid, there appears no gristly, or fles/nj part, with which the earthy part had been incorporated. We shall speak of the use and lormalion of the enamel hereafter when they will be better understood. THE BOXY PART OF A TOOTH. The other substance of which a tooth is composed, is bony; but much harder than the most compact part of bones in general. This substance makes the interior part of the body, the neck, and the whole of the root of a tooth. Jt is a mixture of two substances, viz. calcarious earth and an animal substance, which we might suppose to be organized and vascular. The earth is in very considerable quantity ; it remains of the same shape after calcination, so that it is in some measure kept together by cohesion ; and it is capable of being extracted by steeping in the muriatic, and some other acids The animal substance, when deprived of the earthy part, by steeping in an acid, is more compact than the same substance in other bones, but still is soft and flexible. That part of a to»»th which is bony, is nearly of the same form as a complete tooth ; and thence, when the enamel is removed, if. has the same sort of edge, point, or points, as when the enamel remained. We cannot by injection prove that the bony part of a tooth is vascu- lar ; but from some circumstances it would appear that it is so; for the fangs of teeth are liable to swellings, seemingly of the spina ven- tosa kind, like other bones; and they sometimes anchylose with the socket by bony and inflexible continuity, as all other contiguous bones are apt to do. But there may be a deception here, for the swelling may be an original formation, and the anchylosis may be from the pulp that the tooth is formed upon being united with the socket. The following considerations would seem to shew that the teeth are not vascular:" first, I never saw them injected in any preparation nor could 1 ever succeed in anv attempt to inject them, either in' voung or old subjects; and therefore believe that there must have been some fallacy in the cases where they have been said to be in- fected Secondly, we are not able to trace any vessels going from the pulp into the substance of the new-formed tooth: and whatever nart of a tooth is formed, it is always completely formed, which is ^ot the case with other bones. But what is a more convincing proof, is reasoning from the analogy between them and other bones when he annnalLs been fed with madder. Take a young annual viz. a tnc annua, i madfier for three or four weeks ; then kill the JOHN HUNTER. 25 while the animal was taking the madder that are dyed ; for what were already formed will not be found in the least tinged. This 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 the part that is forming; therefore as we know that all other bones when formed are vascular, and are thence suscep- tible of the dye, we may readily suppose that the teeth are not vas- cular, because they are not susceptible of it after being once formed. But we shall carry this still farther; if you feed a pig with madder^ for some time, and then leave it off for a considerable time before you kill the animal, you will find the above appearances still subsist- ing.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 shall have white, then red, and then white again; and so we shall have the red and the white colour alternately through the whole tooth.(a) Note (A.) Many Dentist's, and among them, some of the best educated of the profession, have adopted the opinion of Mr. Hunter, and carried it out in their practice—that the teeth are inorganic bodies :—and perhaps there is no sub- ject connected with the healing art on which many practitioners are more grossly ignorant than of the delicate sensibilities of the human teeth, and of their intimate connexion with other parts. With a subject on which so much depends in relation to individual success in dental practice, and where. such good or evil consequences result to our patrons and friends, one would at once suppose that every dentist would be familiar. But unfortunately, this is not the case ; and for the want of this knowledge, the teeth, so essential to our health and happiness when in a sound condition, and so productive of suffering and inconvenience when diseased or lost, are abused and mal-treated by far the greater number of those who are engaged in the profession, and call themselves dentists. As the organization of the teeth is a subject oh which the profession are not generally agreed, I think there cannot be a better time or place than the pre- sent to adduce a few facts, which 1 hope will lead to a more careful and thorough' investigation of the subject, and thereby correct the evils that have been so long and so severely felt. In consequence of the high repute of that great man, and accurate observer, John Hunter, his work on the teeth has long been, and still is, to a great extent, a kind of textbook and guide to many who are pursuing this branch ofchi- rurgical science ; and although his researches enabled him to' strike out a vast field of usefulness, and in some measure, laid the foundation for a new and use- ful profession ; yet I think, I may safely say, ihat his erroneous views in relation to the organic structure of the teeth, have, in a great degree, retarded the ad- vancement of that profession which his labours did sO much to distinguish. His opinions have produced this effect, by leading to a course of practice entirely mechanical upon the the teeth which he considered as bodies deprived almost entirely of organic life and its dependencies, instead of regarding them as they really are, as highly sensitive, living and perfectly organized structures.requiring the most careful and judicious management, and nicest surgical skill in the pro- motion of their just arrangement, and in the treatment of their diseases. On the 58th page of Mr. Hunter's work.and the 24th of the republication, will be found his reasons for not believing the teeth to be vascular. First, that he never saw them injected in any preparation and could never succeed in injecting them either in young or old subjects ; and therefore he believes there must have' been soma fallacy in those eases where they are said to-have been injected. 4 26 JOHN HUNTER. This experiment shews, that the tooth once tinged, does not lose its colour; now as all other bones that have been once tinged lose their colour in time, when the animal leaves off feeding with madder Dr Kimball * in his very able and perspicuous dissertation on the teeth, when speaking on th'is subject, has the following remarks :--« Admitting however, that they have not been and cannot be injected, yet surely this cannot be sufficient evidence for believing them to be destitute of vascularity, for neither can tendons or cartilages be injected, and yet the organization of them is, I believe, doubted by no one. "It is believed that this fact entirely does away the force of the objection, but even if it does not, it would by no means follow that because vessels have not been injected, therefore there are none to be injected." Another strong proof of their organization is their hereditary character which is as decidedly marked as are Phthisis, Scrofula or Gout ; and children resemble their parents as often in dental peculiarities as in feature or any other attribute. A remarkable instance of this is related by Mr. Brown, in the first number of this Journal. The specimen in the possession of Mr. Baker, an account of which is given in the same number, is more conclusive than all the arguments that Ian- guage could bring together, that the teeth, to a great degree, possess the active and living principle peculiar to organic life. This is probably the most remarka- ble specimen of the kind in the world, and by it. nature herself has proved to complete and perfect demonstration, what the learning and science of both the old and the new world have tailed so decidedly to establish. As it will be in the power of but few to examine this specimen for themselves, I will adduce other testimony which will enable those who are doubting to make similar examinations for the purpose of satisfying themselves. Mr. Thomas Bell in his late, invaluable work, says-—" I have, in many cases, on breaking a tooth immediately after extraction, where the pain and inflamma- tion have been severe, found distinct red patches in the very substance of the bone." In speaking of the difficulty of injecting the teeth, he says ;—"But what art has failed to effect, nature or rather disease has done for us. I have in my possession a set of teeth from the head of a young woman who died of jaun- dice, every one of which is tinged with a bright yellow colour." "I have," continues Mr Bell, " frequently examined the teeth of persons, whose death has been occasioned by hanging or drowning, and have invariably found the osseous parts coloured with a dark, dull red, which could not possibly have been the case if these structures had been devoid of a vascular system. In both instan- ces the enamel remains wholly free from discoloration." Dr. Fitch, of Philadelphia, gives the following testimony :—" I have at this time five teeth, taken from the jaws of a very plethonck woman, aged 27 years, who died of a very violent inflammatory fever, which apppear to be completely and beautifully injected with red blood. Their enamel is perfectly natural, whilst the bony structure is of a deep red." Dr. Kimball speaks of having " examined minutely with Dr Flagg, a tooth that had been filled, when in the bottom of the cavity there was a space left open which had been completely filled with new bone." Numerous instances could be adduced of a similar kind, but as it is earnestly hoped that some of our pro- fessional brethren will in some subsequent number furnish an article where these matters can be discussed at greater length, and wherein the diseases to which the teeth are liable, such as necrosis, exostosis, mollities ossium, and the numerous forms of decay observable in them, may be alleged in proof of their organization. *It is with deep regret that I here take occasion to say that Dr. Kimball, so highly and so well i,ualified for usefulness, has been compelled, on account of ill health to abandon his profession ;—but it gives me pleasure to add, that in retiring from a practice in which he was eminently successful, he has taken with him the grateful remembrances of his friends and patrons, and the respect and esteem of all who were engaged in the same field of labor with him. JOHN HUNTER. 27 (though very slowly,) and as that dye must be taken into the consti- tution by the absorbents, it would seem that the teeth are without ab- sorbents, as well as other vessels (b) This shews that the growth of the teeth is very different from that of other bones. Bones begin at a point, and shoot out at their sur- face ; and the part that seems already formed, is not in reality so, for it is forming every day by having new matter thrown into it, till the whole substance is complete ; and even then it is constantly changing its matter. Another circumstance in which teeth seem different from bone, and a strong circumstance in support of their having no circulation in them, is that they never change by age, and seem never to under- go any alteration, when completely formed, but by abrasion ; they do not grow softer, like the other bones, as we find in some cases, where the whole earthy matter of the bones has been taken into the con- stitution. From these experiments it would appear, that the teeth are to be considered as extraneous bodies, with respect to a circulation through their substance ; but they have most certainly a living principle, by which means they make part of the body, and are capable of uniting with any part of a living body ; as will be explained hereafter : and it is to be observed, that affections of the whole body have less influ- ence upon the teeth than any other part of the body. Thus in chil- dren affected with the rickets, the teeth grow equally well as in health though all the other bones are much affected ; and hence their teeth being of a larger size in proportion to the other parts, their mouths are protuberant. OF THE CAVITY OF THE TEETH. Every tooth has an internal cavity, which extends nearly the whole length of its bony part. It opens, or begins at the point of the fang, where it is small ; but in its passage becomes larger, and ends in the body of the tooth. This ei.d is exactly of the shape of the body of the tooth to which it belongs. In general it may be said, that the whole of the cavity is nearly of the shape of the tooth itself, larger Note (b.) In relation to the teeth beingsupphed with absorbents, we have the fob lowing convincing fact from the work of Mr. Bell before quoted :—He says—"This subject does not rest upon doubtful experiment. A case which occurred to me some years since, the preparation of which is now in my possession, appears to me satisfactorily to prove the presence of absorbents in the teeth ; it was, in fact, an instance of true abscess in the bone of a tooth. Inflammation had existed for a considerable time, and afier extraction, upon sawing the tooth through for the purpose of ascertaining the state of the internal structure, as no diseased appear- ances were found on the external surface, or any other part of the tooth, I found a cavity formed in the very substance of the tooth, communicating with the natural cavity, and filled with pus." Mo one will pretend to argue that this cavity could have been formed without the agency of the absorbents ; and how could pus have been formed without the agency of the secreting vessels ! the existence of both of which is proved by this case. 28 JOHN HUNTER. in the body of the tooth, and thence gradually smaller to the extreme ty of the fang; simple, where the tooth has but one root; and in the same manner compounded, when the tooth has two or more fangs. This cavity is not cellular, but smooth in its surface ; it contains no marrow, but appears to be filled with blood-vessels, and I suppose, nerves, united by a pulpy or cellular substance. The vessels are branches of the superior and inferior maxillaries; and the nerves must come from the second and third branches of the fifth pair. By injections we can trace the blood-vessels distinctly through the whole cavity of the tooth; but I could never trace the nerves dis- tinctly even to the beginning of the cavity.(c) OF THE PERIOSTEUM OF THE TEETH. The teeth as we observed, are covered by an enamel only at their bodies; but at their fangs they have a Periosteum, which, though yery thin, is vascular, and appears to be common to the tooth which it incloses, and the socket which it lines as an investing internal mem- brane. It covers the tooth a little beyond the bony socket, and is there attached to the gum. OF THE SITUATION OF THE TEETH. The general shape and situation of the teeth are obvious. The opposition of those of the two jaws, and the circle which each row describes, need not be particularly explained, as they may be very well seen in the living body, and may be supposed to be already un- derstood, from what was said of the alveolar processes. We may just observe, with regard to the situation of the two rows, that when they are in the most natural state of contact, the teeth of the upper jaw project a little beyond the lower teeth, even at the sides of the jaws; but still more remarkable at the fore part, where in most people the upper teeth lie before those of the lowerjaw; and at the lateral part of each row, the line, or surface of contact, is hollow from behind forwards, in the lower jaw; and in the same proportion it is convex in the upper jaw. The edge of each row is single at the forepart of the jaws ; but as the teeth grow thicker backwards, it there splits into an internal and external edge. The canine tooth, which we shall call Cuspidatus, is the point from which the two edges go off; so that the first grinder, * Note (c.) Although Mr. Hunter was not able to discover the nerves entering the cavity of a'tooth.yet every practical man is certain of their existence, which can be as clearly proved as that there are blood vessels and absorbents. If those gen- tlemen who maintain the opposite theory to that which we advocate, had been practically acquainted with the diseased and healthy condition of the bony structure of tne teeth, it is believed that a theory which so directly tends to substi- tute in the place of surgical treatment founded upon scientific principles, mere mechanical manipulation, would not have had the support of the justly celebra- ted Hunter, nor in more modern times, the countenance of Blainville and Lawrence. JOHN HUNTER. 29 or what we shall call the first Bicuspis, is the first tooth that has a double edge. OF THE NUMBER OF TEETH. Their number in the whole, at full maturity, is from twenty-eight to thirty-two: I once saw twenty-seven only,never more than thirty-two. Fourteen of them are placed in each jaw, when the whole number is no more than twenty eight; and sixteen, when there are thirty-two. If the whole be twenty-nine or thirty-one in number, the upper jaw sometimes, and sometimes the lower has one more than the other; and when the number is thirty, I find them sometimes divided equally between the two jaws; and in other subjects sixteen of them are in one jaw, and fourteen in the other. In speaking of the number of teeth, I am supposing that none of them have been pulled out, or otherwise lost; but that there are from eight to twelve of those large posterior teeth, which I call grinders, and that they are so close plant- ed as to make a continuity in the circle : and in this case, when the number is less than thirty-two, the deficiency is in the last grinder. The teeth differ very much in figure from one another; but those on the right side in each jaw resemble exactly those on the left, so as to be in pairs; and the pairs belonging to the upper jaw nearly re- semble the corresponding teeth of the lower jaw in situation, figure, and use. Each tooth is divided into two parts, viz: first, the body, or that part of it which is the thickest, and stands bare beyond the Alveoli and gums; secondly, the fang, or root which is lodged within the gum and Alveolar Process : and the boundary between these two parts, which is grasped by the edge of the gum, is called the neck of a tooth. The bodies of the different teeth differ very much in shape and size, and so do their roots. The difference must be considered hereafter. The teeth of each jaw are commonly divided into three classes, viz : Incisors, Canine, and Grinders; but from considering some cir- cumstances of their form, growth and use, I choose to divide them into the four following classes, viz: Incisores, commonly called Fore Teeth ; Cuspidati, vulgarly called Canine ; Bicuspides, or the two first Grinders; and Molares. or the three last Teeth. The number of each class, in each jaw, for the most part, is four Incisores, two Cuspidati, four Bicuspides, and four, five, or six Molares. There is a regular gradation, both in growth and form through these classes, from the Incisores to the Molares, in which respect the Cuspidati are of a middle nature, between the Incisores and Bicus- pides, as the last are between the Cuspidati and Molares ; and thence the Incisores and Molares are the most unlike in every circumstance. OF THE INCISORES. The Incisores are situated in the anterior part of the jaw; the oth- ers more backwards on each side, in the order in which we have named them. The bodies of the Incisores are broad, having two flat 30 JOHN HUNTER. surfaces, one anterior, the other posterior. These surfaces meet in a sharp cutting edge. The anterior surface is convex in every di- rection, and placed almost perpendicularly; and the posterior is concave and sloping, so that the cutting edge is almost directly over the anterior surface. These surfaces are broadest and the tooth is thinnest at the cutting edge, or end of the tooth, and thence they become gradually nar- rower and the tooth thicker towards the neck, where thesurfaces are continued to the narrowest side or edge of the fang. The body of an Incisor, in a side-view, grows gradually thicker, or broader from the edge or end of the tooth to its neck ; and these coincide with the flat or broad side of the fang ; so that when we look on the fore part, or on the back part of an Incisor, we observe it grows constantly narrower from its cutting edge to the extremity of its fang. But in a side-view it is thickest or broadest at its neck ; and thence becomes gradually more narrow, both to its cutting edge, and to the point of its fang. The Enamel is continued farther down, and is thicker on the ante- rior and buck part of the Incisores than on their sides, and is even a little thicker on the fore part than upon the back part of the tooth. If we view them latterally, either when entire, or when cut down through the middle, but especially in the latter case, it would seem as if the fang was driven like a wedge into, and had split the body or enamel of the tooth. They stand almost perpendicularly, their bodies being turned a little forwards. Their fangs are much shorter than those of the Cuspidati, but pretty much of the same length with all the other teeth of this jaw. In the upper jaw they are broader and thicker, especially the two first: their length is nearly the same with those of the lower jaw. They stand a little obliquely, with their bodies turned much more forwards (the first especially) and they generally fall over those of the underjaw. The two first Incisores cover the two first, and half of the second of the lower jaw, so that the second Incisor in the upper jaw covers more than half of the second, and more than the half of the Cuspi- datus of the underjaw. The edges of the Incisores by use and friction, in some people, be- come blunt and thicker ; and in others they sharpen one another, and become thinner. OF THE CUSPIDATUS. The Cuspirlatus is the next after the Incisores in each jaw ; so that there are four of them in all. 'I hey are in general thicker'than the lncisoies, and considerably the longest of all the teeth. The shape of the body of the Cuspidatus may be very well con- ceived, by supposing an Incisor, with its corners rubbed off, so as to end in a narrow point, instead of a thin edge; and the fang differs from that of an Incisor, only in being much larger. JOHN HUNTER. 31 The outside of the body of a Cuspidatus projects most at the side next the Incisores, being there more angular than any where else. The enamel covers more of the larteral pacts of these teeth than of the Incisores; they stand perpendicularly, or nearly so, projecting farther out in the circle than the others, so that the two Cuspidati and the four Incisores often stand almost in a straight line, especially in the lower jaw. This takes place only in adults, and in them only when the second teeth are rather too large for the arch of the jaw ; for we nev^r find this when the tee'.h are at any distance from one another, or in young subjects Their points commonly project beyond the horizontal line formed by the row of teeth, and their fangs run deeper into the jaws, and are oftener a little bent. In the upper jaw they are rather longer, and do not project much beyond the circle of the adjacent teeth ; and in this jaw they are not placed vertically, their bodies being turned a little forwards and outwards. When the jaws are closed, the Cuspidatus of the upper jaw falls between, and projects a little over the Cuspidatus and first Bicuspis of the lowerjaw. When they are a little worn down by use, they commonly first take an edge somewhat like a worn Incisor, and after- wards become rounder. The use of the Cuspidati would seem to be, to lay hold of sub- stances, perhaps even living animals ; they are not formed for dividing as the Incisores are ; nor are they fit for grinding. We may trace in these teeth a similarity in shape, situation, and use, from the most im- perfectly carnivorous animal, which we believe to be the human spe- cies, to the most perfectly cornivorous, viz : the lion. OF THE BICUSPIDES. Immediately behind the Cuspidati, in each jaw, stand two teeth, com- monly called the first and second grinders, but which, lor reasons hinted at above, I shall suppose to constitute a particular class, and call them Bicuspides. These (viz: the fourth and fifth tooth from the symphisis of the jaw) resemble each other so nearly, that a description of the first will serve for both. The first indeed is frequently the smallest, and has rather the longest fang, having somewhat more of the shape of the Cuspidatus than the second. The body of this Tooth i^ flattened latterally, answering to the flat side of the fang. It terminates in two points, viz : one external and one internal. The external is the longest and thickest; so that on looking into the mouth from without, this point only can be seen, and the tooth has very much the appearance of a Cuspidatus ; espe- cially the first of these teeth. The internal point is the least, and indeed sometimes so very small, that the tooth has the greatest resem- blance to a Cuspidatus in any view. At the union of the points the tooth is thickest, and thence it loses in thickness, from side to side, to 32 JOHN HUNTER. the extremity of the fang; so that the fang continues pretty broad to the point, and is often forked there. All the teeth hitherto described1 often have their points bent, and more particularly the Cuspidati. The enamel passes somewhat farther down externally and upon the inside, then latterally ; but this difference is not so considerable as in the Incisores, and Cuspidati; in some indeed it terminates equally all round the tooth. They stand almost perpendicularly, but seem to be a little turned inwards, especially the last of them. In the upper jaw they are rather thicker than in the lower, and are turned a very little forwards and outwards. The first in the upper jaw falls between the two in the lower. The second falls between the second and the first grinder; and both project over those of the lower jaw, but less than the Incisores and Cuspidati. The Bicuspides, and especially the second of them, in both jaws, are oftener naturally wanting than any of the teeth, except the Denies Sapientice; thence we might conjecture that they are less.useful; and this conjecture appears less improbable, when we consider, that in their use they are of a middle nature between cutters and grinders ; and that in most animals, so far as I have observed, there is a vacant space between the cutters and grinders. 1 have also seen a jaw in which the first Bicuspis was of the same shape and size as a grinder, and projected, for want of room, between the Cuspidatus and second Bicuspis. These and the grinders alter very little in shape on their grinding surfaces by use; their points only wear down, and become obtuse. OF THE GRINDERS. In describing the grinders we shall first consider the first and second conjunctly, because they are nearly the same in every par- ticular ; and then give an account of the third or last grinder, which differs from them in some circumstances. The twr» first grinders differ from the Bicuspides, principally in being much larger, and in having more points upon their body, and more fangs. The body forms almost a square, with rounded angles. The grinding surface has commonly five points, or protuberances, two of which are on the inner, and three on the outer part of the tooth ; and generally some smaller points at the roots of these larger protube- rances. These protuberances make an irregular cavity in the mid- dle of the tooth. The three outer points do not stand so near the outer edge of the tooth, as the inner do on the inside ; so that' the Jbody of the tooth swells out more from the points, 'or is more convex on the outside. The body towards its neck becomes but very little smaller, and there divides into two flat fangs, one forwards, the other backwards, with their edges turned outwards and in wards, and their sides consequently forwards and backwards; the fangs are but very little narrower at their ends, which are pretty broad, and are often bifurcated. There are two cavities in each fang, one towards JOHN HUNTER. 33 each edge, leading to the general cavity in the body of the tooth. 1 hese two cavities are formed by the meeting of the sides of the fang in the middle, thereby dividing the broad and flat cavity into two; and all along the outside of these (and all the other flat fangs) there is a corresponding longitudinal groove. These fangs at their middle, are generally bent a little backwards. The enamel covers the bodies of these teeth pretty equally all round. The first grinder is somewhat larger and stronger than the second; it is turned a little more inwards than the adjacent Bicuspides, but not so much as the second grinder. Both of them have generally shorter fangs than the Bicuspides. There is greater difference between these grinders in the upper and lower jaw, than any of the other teeth. In the upper jaw they are rather rhomboidal, than square in their body, with one sharp angle turned forwards and outwards, the other backwards and inwards ; besides they have three fangs, which diverge, and terminate each in a point; these are almost round, and have but one cavity. Two of them are placed near each other perpendicularly, over the outside of the tooth ; and the other, which generally is the largest, stands at a greater distance on the inside of the tooth, slanting inwards. In this jaw these two grinders are inclined outwards, and a little forwards ; they project a little over the corresponding teeth of the lower jaw, and they are placed further back in the mouth, so that each is partly opposed to two of the lower jaw. The second in the upper jaw is smaller than the others, and the first and second are placed directly under the maxillary sinus. J once saw the second grinder naturally wanting on one side of the lowerjaw. The third grinder is commonly called Dens Sapientice; it is a little shorter and smaller than the others, and -inclined a little more in- wards and forwards. Its body is nearly of the same figure, but rather rounder, and its fangs are generally not so regular and dis- tinct, for they often appear squeezed together ; and sometimes there is only one fang, which makes the tooth conical ; it is much smaller than the rest of the grinders. In the upper jaw this tooth has more varie- ty than in the lower, and is even smaller than the corresponding tooth of the lower, and thence stands directly opposed to it; but for this circumstance the grinders would reach farther back in the upper jaw than in the lower, which is not commonly the case. In the upper jaw this third grinder is turned but a very little out- wards ; is frequently inclined somewhat backwards; and it projects over that of the under jaw. It oltener becomes loose than any of the other teeth. They are placed under the posterior part of the maxillary sinus, and there the parts which compose the sinus are thicker than in the middle. The variations as to the natural number of the teeth, depend commonly upon these Dentes Sapiential. Thus from the Incisores to the first grinder, the teeth become gradu- ally thicker at the extremity of their bodies, and smaller from tbfc 5 34 JOHN HUNTER. first grinder to the Dt-ns Sapiential From the Cuspidatus to the Dens Sapiential, the fangs become much shorter ; the Incisores are nearly of the same length with the Bicuspides. From the first Incisor to the last grinder, the teeth stand less out from the sockets and gums. The bodies of the teeth in the lowerjaw are turned a little out- wards at the anterior part of the jaw, and thence to the third grinder, they are inclined gradually more inwards. The teeth in the upper jaw project over those of the under, especially at the fore part, which is owing to the greater obliquity of the teeth in the upper jaw; for the circle of the sockets is nearly the same in both jaws. This oblique situation, however, becomes gradually less, from the Incisores backwards to the last grinder, which makes them gradually project less in the same proportion. The teeth in the upper jaw are placed farther back in the circle than the corresponding teeth of the lower; this is owing to the two first Incisores above being broader than the corresponding Incisores below. All the teeth have only one fang, except the grinders, each of which has two in the lowerjaw, and three in the upper. The fangs bear a proportion to the bodies of the teeth ; and the reason is evident, for otherwise they would have been easily broken, or pushed out of their sockets. The force commonly applied to them is oblique, not perpendicular ; and they are not so firmly fixed in the upper jaw, that is, the alveolar process in that is not so strong as in the underjaw : it is. herhaps, on this account, that the grinders in that jaw have three fangs. This particular structure in the alveolar process of the upper jaw, is, perhaps, to give more room for the Antrum Highmorianum ; on this supposition the fangs must be made accordingly, i. e. so that they shall not be pushed into that cavity ; now, by their diverging, they inclose, as it were, the bottom of the Antrum, and do not push against its middle, which is the weakest part; and the points of three diverging fangs will make a gieater resistance (or not be so easily pushed in) than if they were placed parallel. If there had been only two, as in the lowerjaw, they must have been placed opposite to the thinnest part of the Antrum ; and three points placed in any direc- tion but a diverging one, would have had here much the same effect as two; and as the force applied is endeavouring to depress the tooth, and push it inwards, the innermost fang diverges most, and is supported by the inner wall of the Antrum. That all this weakness in the upper jaw is for the increase of the Antrum is probable, be- cause all the teeth in the upper jaw are a good deal similar to those in the lower, excepting those that are opposite to the maxillary sinus ; and here they differ principally in the famjs, without any other ap- parent reason ; and what confirms this, is, that the Dentes Sapientice in both jaws are more alike than the other grinders ; for this reason, as I apprehend, because the Dens Sipienlice in the upper jaw, does not interfere so much with the maxillary sinus. What makes it still more probable that the two first superior grinders have three fangs on account of the maxillary sinus, is, that JOHN HUNTER. 35 the two grinders on ear-h side of the upper jaw, in the child, have three fangs, and we find thorn underneath the Anhum; but those that succeed them have only one fang, as in the lower jaw ; but by that time the Antrum has passed further back, or rather the arch of the jaw has projected, or shot forwards, as it were, from under the An- tra, so that the alveolar processes that were under the Antrum at one age, are got before it in another. That the edge of every fang is turned towards the circumference of the jaw, in order to counteract the acting power, we shall see when we consider the motion of the jaw, and the use of the teeth. OF THE ARTICULATION OF THE TEETH. The fangs of the teeth are fixed in the gum and alveolar processes by that species of articulation called Gomphosis, which, in some measure, resembles a nail driven into a piece'of wood. They are not, however, firmly united with the processes, for every tooth has some degree of motion ; and in heads which have been boiled or macerated in water, so as to destroy the periosteum and adhesion of the teeth, we find the teeth so loosely connected with their sockets, that all of them are ready to drop out, except the grinders, which remain as it were hooked from the number and shape of their fangs. OF THE GUMS. The alveolar processes are covered by a red vascular substance, called the gums, which has as many perforations as there are teeth ; and the neck of a tooth is covered by, and fixed to this gum. Thence there are fleshy partitions between the teeth, passing between the external and internal gum, and as it were, uniting them ; these par- titions are higher than the other parts of the gum, and thence form an arch between every two adjacent teeth. The thickness of that part which projects beyond the sockets is considerable ; so that when the gum is corroded by disease, by boiling, or otherwise, the teeth appear longer, or less sunk into the jaw. The gum adheres very firmly in a healthful state both to the alveolar process and to the teeth, but its extreme border is naturally loose all around the teeth. The gum, in substance, has something of a cartilaginous hardness and elasticity, and is very vascular, but seems not to have any great degree of sensibility ; for though we often wound it in eating, and in picking our teeth, yet we do not feel much pain upon these occasions; and both in infants and old people, wheie there are no teeth, the gums bear a very considerable pressure, without pain. The advantage arising from this degree of insensibility in the gums is obvious, for till the child cuts its teeth, the gums are to do the business of the teeth, and are therefore formed for this purpose, having a hard ridge running through their whole length. Old peo- ple, who have lost their teeth, have not this ridge. When in a sound 36 JOHN HUNTER. state, the gums are not easily irritated by being wounded, and there. fore are not so liable to inflammation as other parts, and soon heal. The teeth being united to the jaw by the periosteum and gum, have some degree of a yielding motion in the living body. This circum- stance renders them more secure ; it breaks the jar of bony contact, and prevents fractures both of the sockets and of the teeth themselves. OF THE ACTION OF THE TEETH, ARISING FROM THE MOTION OF THE LOWER JAW. The lower jaw may be said to be the only one that has any mo- tion in mastication ; for the upper jaw can only move with the other parts of the head. That the upper jaw and head should be raised in the common act of opening the mouth, or chewing, would seem, at first sight, improbable; and from an attentive view of the mechan- ism of the joints and muscles of those parts, from experiment and observation, we find that they do not sensibly move. We shall only mention one experiment in proof of this, which seems conclusive; let a man place himself near some fixed point, and look over it, to another distant and immoveable object, when he is eating. If his head should rise in the least degree, he would see more of the dis- tant object over the nearest fixed point, which in fact he does not. The nearer the fixed point is, and the more distant the object, the experiment will be more accurate and convincing. The result of the experiment will be the same, if the nearest point has the same motion with the head ; as, when he looks from under the edge of a hat, or any thing else put upon his head, at some distant fixed object. We may conclude then, that the motion is entirely in the lowerjaw : and, as we have already described both the articulation and the mo- tion of the bone, we shall now explain the action of mastication, and, at the same time, consider the use of each class of teeth. With regard to the action of the teeth of both jaws, in mastication, we may observe, once for all, that their action and re-action must be always equal, and that the teeth of the upper and lower jaws are complete, and equal antagonists both in cutting and grinding. When the lower jaw is depressed, the condyles slide forwards on the eminences ; and they return back again into the cavities, when the jaw is completely raised. This simple action produces a grinding motion of the lowerjaw, backwards on the upper, and is used when we divide any thing with our fore teeth, or Incisores. For this purpose, the Incisores are well formed ; as they are higher than the others, their edges must come in contact sooner; and as the upper project over the under, we find in dividing any substance with them, that we first bring them oppo- site to one another, and as they pass through the part to be divided, the lower jaw is brought back, while the incisors of that jaw slide up behind those of the upper jaw, and of course pass by one anoth- er. In this way they complete the division, like a pair of scissors; and at the same time they sharpen one another. There are excep- tions to this; for these teeth in some people meet equally, viz: in JOHN HUNTER. 37 ithose people whose fore-teeth do not project further from the gum, or socket, than the back teeth; and such teeth are not so fit for di- viding ; and in some people the teeth of the lower jaw are so placed, as to come before those of the upper jaw ; this situation is as favour- able for cutting as when the overlapping of the teeth is the reverse, except for this circumstance, that ihe lowerjaw must be longer, and therefore its action weaker. The other motion of the lawer jaw, viz : when the lateral teeth are used, is somewhat different from the former. In opening the mouth, one Condyle slides a little forwards, and the other slides a lit- tle further back into its cavity ; this throws the jaw a little to that side, just enough to bring the lower teeth directly under their corres- ponding teeth in the upper jtw : this is done, either in diving, or hol- ding of substances ; and these are the teeth that are generally used in the last mentioned action. When the true grinding motion is to be performed, a greater degree of this last motion takes place ; that is, the condyle of the opposite side is brought further forwards, and the condyle of the same side is drawn farther back into the cavity of the temporal bone, and the jaw is a little depressed. This is only prepa- ratory for the effect to be produced ; for the moving back of the first mentioned condyle into the socket is what produces the effect in mastication. The lateral teeth in both jaws are adapted to this oblique motion ; in the lower they are turned a little inwards, that they may act more in the direction of their axis ; and here the alveolar process is strong- est upon the outside, being there supported by the ridge at the root of the coronoid process. In the upper jaw, the obliquity of the teeth is the reverse, that is, they are turned outwards, for the same rea- son ; and the longest fang of the grinders is upon the inside, where the socket is strengthened by the bony partition between the antrum and nose. Hence it is, that the teeth of the lower jaw have their outer edges worn down first; and, vice versa, in the upper jaw. GENERAL COMPARISONS BETWEEN THE MOTION OF THE JAW IN YOUNG AND OLD PEOPLE. In Children who have not yet teeth, there does not seem to be a sliding motion in the lowerjaw. The articular eminence of the tem- poral bone is not yet formed, and the cavity is not larger than the condyle ; therefore the centre of motion in such, must be in the con- dyle. In old people who have lost their teeth, the centre of motion appears to be in the condyles, and the motion of their jaw to be only depression and elevation. They never depress the jaw sufficiently to bring the condyle forwards on the eminence, because, in them the mouth is sufficiently opened when the jaw is in its natural position. Hence it is, that in old people, the gums of the two jaws do not meet in the fore-part of the mouth, and they cannot bite at that part so well, as at the side of the jaw ; and instead of the grinding mo- tion which would be useless, where there are no grinders ; they bruise their food rather by a simple motion of the jaw upwards and down- wards. 38 JOHN HUNTER. It is from the want of teeth in both those ages, that the face is shorter in proportion to its breadth. In an old person, after the teeth ;ire gone, the face is shorter, while the mouth is shut, by almost the whole lengths of the teeth in both jaws ; that is, about an inch and a half. From the want of teeth too, at both those ages, the cavity of the mouth is then smaller; and the tongue seems too large and unmanage- able, more especially in old people. In these last we observe also, that the chin projects forwards, in proportion as the mouth is shut; because the basis of the lower jaw (which is all that now remains) describes a wider circle than the alveolar ppocess in younger people. The jaws do not project so much forwards in a child, as in an adult; hence the face is flatter, especially at the lower part. In proportion as the last grinders are produced, the sides of the curve formed by the jaws b-come longer, and push forward the fore-part, none of the additional part passing backwards. The fore-pait also continues nearly of the same size, so that the whole jaw is longer in proportion to its breadth, and projects farther forwards. OF THE FORMATION OF THE ALVEOLAR PROCESS. Having considered the alveolar processes in their adult, or perfect state, we shall next examine and trace them from their beginning. We observe the beginning of the alveolar process at a very early period. In a foetus of three or four months it is only a longitudinal groove, deeper and narrower forwards, and becoming gradually more sh illow and wider backwards: instead of bony pirtitions, di- viding that groove into a number of sockets, there are only slight ridges across the bottom and sides, with intermediate depressions, which mark the future Alneoli. In the lower jaw the vessels and nerves run along the bottom of this alveolar cavity, in a slight groove, which afterwards becomes a complete and distinct bony canal. The alveolar process giows with the teeth, and for sometime keeps the start of them. Thj ridges which are to make the parti- tions shoot from the sides across the canal, at th ■? mouth of the cell, forming hollow arches: this change happens first at the anterior parts of the jaws. As each cell becomes deeper, its mouth also grows narrower and at length is almost, but not quite, closed over the contained tooth. The disposition for contracting the mouth of the cell, is chiefly in the outer plate of the bone, which occasions the contracted orifices of the cells to be nearear the inner edge of the jaw. The reason, perhaps, why the bone shoots over, and almost covers the tooth, is that the gum may be firmly supported before the teeth have come through. The Alveoli which belong to the adult grinders, are formed in an- other manner; in the lower jaw they would seem to be the remains of the root of the coronoid process; for the cells are formed for JOHN HUNTER. 39 those teeth in the root of that, process ; and in proportion as the body of the bone, and the cells alreadv formed, push forwards from under that process, the succeeding cells and their teeth are formed, and pushed forward in the same manner. In the upper jaw there are cells formed in the tubercles for the young grinders, which at first are very shallow, and become deeper and deeper as the teeth grow ; and they grow somewhat faster, so as almost to inclose the whole tooth before it is ready to push its way through that inclosure and gum. There is a succession of these, till the whole three grinders are formed. OF THE FORMATION OF THE TEETH OF THE F03TUS. The depression, or first rudiments of the Alv.oli observable in a foetus of tlnee or four months, is filled with four or five little pulpy substances, which are not very distinct a* this age. About the fifth month both the processes ihemselves and the pulpy substances be- come more distinct: the anterior of which are the most complete. About this age too, the ossifications begin on the enge of the first In- cisores. 'I he Cuspidati are not in the same circular line with the rest, but somewhat on the outside, making a projection there at this age, there not being sufficient room for them. In the sixth, or seventh month, the edges, or tips, of all these five substances are begun to ossify. a*id the first of them is a little ad- vanced ; and besides these, the pulp of the sixth tooth has begun to be formed ; it is situated in the tubercle of the upper jaw, and under and on the inside of the coronoid process in the lowerjaw; so that at this age, in both jaws, there are in all twenty teeth begun to ossily, and the stamina of twenty-lour. They may be divided into the In- cisores, Cuspidwi, and Molares; for at this agt: there are no Bicuspi- des, the two last teeth in each side of both jaws having all the charac- teristics, and answering all the puiposes of the true Molait\ in the adult though when these first Molu esfall out their places are taken by the Bicuspides. The teeth gradually advance in their ossification, and about the seventh, eighth, or nin'h month after birth, the Incisores begin to cut or pass through the gums ; first, generally, in the lowerjaw. Before this time the ossifications in the third grinder, or that which makes the first in the adult, are begun. The Cuspidatus and Moines of the fetus are not formed so fast as the Incisorts; they generally all appear nearly at the same time, viz: about the twentieth, or twenty-fourth month ; however, the first grinder is often more advanced within the socket than the Cuspidatus, and most commonly appears before it. These twenty are the only teeth that are of use to the child from the seventh, eighth, or ninth month, till the twelfth or fourteenth year. These are called the temporary, or milk teeth, because they are all shed between the years of seven and fourteen, and are supplied by others. 40 JOHN HUNTER. OF THE CAUSE OF PAIN IN DENTITION. These twenty teeth, in cutting the gum, give pain, and produced many other symptoms which often prove fatal to children in dentition. It has beengenetally supposed that these symptoms arise from the tooth's pressing upon the inside of the gum,and working its way me- chanically; but the following observations seem to be nearer the truth. The teeth, when they begin to press against the gum, irritate it, and commonly give pain. The gums are then affected with heat, swelling, redness, and the other symptoms of inflammation. The gum is not cut through by simple or mechanical pressure, but the ir- ritation and consequent inflammation produces a thinning, or wasting Of the gum at this part ; for it often happens that when an extrane- ous, or a dead substance, is contained in the body, that it produces a destruction of the part between it, and that part of the skin which is nearest it, and seldom of the other parts, excepting those between it and the surface of a cavity opening externally, and that by no means sO frequently. And in those cases, there is an absorption of the solids, or of the part destroyed, not a melting down, or solution of them in to pus. The teeth are to be looked upon us extraneous bodies, with re- spect to the gum, and as such they irritate the inside of that part in the same manner as the pus of an abscess, an exfoliation of a bone, or any other extraneous body ; and therefore produce the same symp- toms, excepting only the formation of matter. If, therefore, these symptoms attend the cutting of the teeth, < there can be no doubt of the propriety of opening the way for them ; nor is it ever, as far as I have observed, attended with any dangerous consequence. OF THE FORMATION AND PROGRESS OF THE ADULT TEETH. Having now considered the first formation, and the progress of the temporary teeth, we shall next describe the formation of those teeth which are to serve through life. In this enquiry, to avoid confusion, I shall confine the description to the teeth in the lower jaw ; for the only difference between those in the two jaws, is in the time of their appearance, and generally it is later in the upper jaw. Their formation and appearance proceeds not regularly from the first Incisor backwards to the Dens Sapi- enticB, but it begins at two points on each side of both jaws, viz : at the first Incisor, and at the first Moldris. The teeth between these two points make a quicker progress than those behind. The pulp of the first adult Incisor, and of the first adult Molaris begin to appear in a foetus of seven or eight months, and five or six months after birth the ossification begins in them, soon after birth the pulp of the second Incisor and Cuspidatus begin to be formed, and about eight or nine months afterwards they begin to ossify ; about the fifth or sixth year the first Bicuspis appears; about the sixth or seventh the second Bicuspis, and the second Molaris ; and about the JOHN HUNTER. 41 twelfth, the third Molaris or Dens Sapiential. The first five may be called the permanent teeth : they differ from the temporary in hav- ing larger fangs The permanent Incisores and Cuspiaati are much thicker and broader, and the Molares are succeeded by Bicuspides, which are smaller, and have but one fang. All these permanent or succeeding teeth are formed in distinct Ahe- oli of their own ; so that they do not fill up the old sockets of the temporary teeth, but have their new Alveoli formed as the old ones decay. The first Incisor is placed on the inside of the root of the corres- ponding temporary tooth, and deeper in the jaw. The second Incisor and the Cuspidatus begin to be firmed on the inside, and somewhat under the temporary second Incisor and Cuspidatus. These three are all situated much in the same manner, with respect to the first set ; but as they are larger, they are placed somewhat farther back in the circle of the jaw. The first Bicuspis is placed under, and somewhat farther back than the first temporary grinder, or fourth tooth of the child. The second Bicuspis is placed immediately under the second tem- porary grinder. The second Molaris is situated in the lengthening tubercle in the upper jaw, and directly under the coronoid process in the lower. The third Molaris, or Dens Sapiential, begins to form immedi- ately under the coronoid process. The first adult Molaris comes to perfection, and cuts the gum about the twelfth year of age, the second about the eighteenth, and the third, or Dens Sapi-ntia, from the twentieth to the thirtieth : so that the Incisores and Cuspidati require about six or seven years, from their first appearance, to come to perfection ; the Bicuspides about seven or eight; and the Molares about twelve. It sometimes happens that a third set of teeth appears in very old people ; when this does happen, it is in a very irregular manner, some- times only one, at other times more, and now and then a complete set comes in both jaws. I never saw an instance of this kind but once, and there two fore teeth shot up in the lower jaw. I should suppose that a new alveolar process must be also formed in such cases, in the same manner as in the production of the first and second sets of teeth. From what 1 can learn, the age at which this happens is generally about seventy. From this circumstance, and another that sometimes happens to women at this age, it would appear that there is some effort in nature to renew the body at that period. When this set of teeth which happens so late in life, is not com- plete, especially where they come in one jaw, and not in the other, thev'are rather hurtful than useful ; for in that case we are obliged to pull them out, as they only wound the opposite gum. 6 42 JOHN HUNTER. THE MANNER IN WHICH A TOOTH IS FORMED. The body of the tooth is formed first, afterwards the enamel and fangs are added to it. All the teeth are produced from a kind of pulpy substance, which is pretty firm in its texture, transparent, ex- cepting at the surface, where it adheres to the jaw, and has at first the shape of the bodies of the teeth which are to be formed from it. These pulpy substances are very vascular, they adhere only at one part to the jaw, viz. at the bottom of the cavity which is to form the socket; and at that place their vessels enter ; so that they are pro- minent, and somewhat loose in the bony cavity which lodges them. They grow nearly as large as the body of the tooth before the os- sification begins, and increase a little for some time after the ossifica- tion is begun. They are surrounded by a membrane, which is not connected with them, excepting at their root or surface of adhesion. This membrane adheres by its outer surface all around the bony ca- vity in the jaw, and also to the gum where it covers the Alveoli. When the pulp is very young,, as in the Foetus of six or seven months, this membrane itself is pretty thick and gelatinous. We examine it best in a new born child, and we find it made up of two lamella, an external and internal: the external is soft and spongy, without any vessels ; the other is much firmer, and extremely vas- cular, its vessels coming from those that are going to the pulp of the Tooth : it makes a kind of Capsula for the pulp and body of the Tooth. While the Tooth is within the gum, there is always a mu- cilaginous fluid, like the Sinovia in the joints, between this membrane and the pulp of the Tooth. When the Tooth cuts the gum, this membrane likewise is perfora- ted; after which it begins to waste, and is entirely gone by the time the Tooth is fully formed, for the lower part of the membrane contin- ues to adhere to the neck of the Tooth, which has now risen as high as the edge of the gum. OF THE OSSIFICATION OF A TOOTH UPON THE PULP. The beginning of the ossification upon the pulp is by one point, or more, according to the kind of Tooth. In the Incisores it is generally by three points, the middle one being the highest, and the first that begins to ossify. The Cuspidaius begins by one point only ; the Bicuspis by two, one external, which is the first and the highest, and the other internal. The Molares, either in a child, or an adult, begin by four or five ossifications, one on each point, the external always the first. Where the Teeth began to ossify at one point only, that ossification gradually advances till the Tooth is entirely completed ; but if there are more than one point of ossification, each ossification increases till their bases come in contact with one another, and there all unite into one ; after which they advance in growth as one ossifi- cation. JOHN HUNTER. 43 The ossifications in their progress become thicker and thicker Where they first began, but increase faster on the edges of the Teeth ; so as thence to become more and more hollow, and the cavity be- comes deeper. As the ossification advances, it gradually surrounds the Pulp till the whole is covered by bone, excepting the under surface ; and while the ossifications advance, that part of the Pulp which is covered by bone is always more vascular than the part which is not yet covered. The adhesion of the Pulp to the new-formed Tooth, or bone, is very slight, for it can always be separated from it without any appar- ent violence, nor are there any vessels going from the one to the other ; the place, however, where it is most strongly attached is round the edge of the bony part, which is the last part formed. When the bone has covered all the Pulp, it begins to contract a little, and becomes somewhat rounded, making that part of the Tooth which is called the neck ; and from this place the fangs begin. When the fangs form, they push up the bodies of the teeth through the sockets, which waste, and afterwards through the gum, which also wastes, as has been explained upon the cutting of the Teeth ; for before this time the rising of the teeth is scarce observable, as the pulp was at first nearly of the size of the body of the tooth itself, and wasted nearly in proportion to the increase of the whole ossification. The pulp has originally no process answering to the fang ; but as the cavity in the body of the tooth is filled up by the ossification, the pulp is lengthened into a fang. The fang grows in length, and rises higher and higher in the socket, till the whole body of the Tooth is pushed out. The socket, at the same time, contracts at its bottom, and grasps the neck, or beginning of the fang, adheres to it, and rises with it, which contraction is continued through the whole length of the socket as the fang rises ; or the socket which contain- ed the body of the tooth, being too large for the fang, is wasted or absorbed into the constitution, and a new alveolar portion is raised with the fang ; whence in reality the fang does not sink, or descend into the jaw. Both in the body, and in the fang of a growing tooth, the extreme edge of the ossification is so thin, transparent, and flexible, that it would appear rather to be horny than bony, very much like the mouth or edge of the shell of a snail when it is growing : and indeed it would seem to grow much in the same manner, and the ossified part of a tooth would seem to have much the same connection with the pulp as a snail has with its shell. As the tooth grows, its cavity becomes gradually smaller, especi- ally towards the point of the fang. In tracing the formation of the fang of a tooth, we hitherto have been suprosing it to be single, but where there are two, or more, it is somewhat different, and more complicated. . When the body of a molaris is formed, there is but one general cavity in the body of the tooth, from the brim of which the ossifica- tion is t • shoot, so as to form two or three fangs. If two only, then the opposite parts of the brim of the cavity of the tooth shoot across 44 JOHN HUNTER. where the pulp adheres to the jaw, meet in the middle, and thereby divide the mouth of the cavity into two openings ; and from the edges of these two openings the two fangs grow. We often find that a distinct ossification begins in the middle of the general cavity upon the root of the pulp, and two processes coming from the opposite edges of the bony shell join it; which answers the same purpose. When there are three fangs, we see three processes coming from so many points of the brim of the cavity, which meet in the centre, and divide the whole into three openings ; and from these are formed the three fangs. We often find the fangs forked at their points espe- cially in the Bicuspides. In this case, the sidrs of the fang as it grows, come close together in the middle, making a longitudinal groove on the outside; and this union of the opposite sides divides the mouth of the growing fang into two orifices, from which the two points are formed. By the observations which I have made in unravelling the texture of the teeth, when softened by an acid, and from observing the dispo- sition of the red parts in the "tooth of growing animals, interruptedly fed with madder, I find that the bony part of a tooth is formed of Lamellae, placed one within another. The outer Lamella is the first formed, and is the shortest: the more internal Lame/Ice lengthen gra- dually towards the fang, by which means, in proportion as the tooth grows longer, its cavity grows smaller, and its sides grow thicker. How the earthy and animal substance of the tooth is deposited on the surface of the pulp is not perhaps to be explained. OF THE FORMATION OF THE ENAMEL. In speaking of the enamel we postponed treating of its formation, till it could be more clearly understood ; and now we shall previous- ly describe some parts which we apprehend to be subservient to ita formation, much in the same manner as the pulp is to the body of the tooth. From its situation, and from the manner in which the teeth grow, one would imagine that the enamel is first formed ; but the bony part begins first, and very soon after the enamel is formed upon it.— There is another pulpy substance opposite to that which we have de- scribed ; it adheies to the inside of the capsula, where the gum is joined to it, and its opposite surface lies in contact with the basis of the above described pulp, and afterwards with the new formed basis of the tooth : whatever eminences or cavities the one has, the other has the same, but reversed, so that they are moulded exactly to each other. In the Incisores it lies in contact not with the sharper cutting edge of the pulp or tooth, but against the hollowed inside of the tooth; and in the Molares it is placed directly against their base, like a tooth of the opposite jaw. It is thinner than the other pulp, and decreases in proportion as the teeth advance. It does not seem to be very JOHN HUNTER. 45 vascular. The best time for examining it is in a foetus of seven or eight months old. In the granivorous animal, such as the horse, cow, &c. whose teeth have the enamel intermixed with the bony part, and whose teeth, when forming, have as many interstices as there are continuations of the enamel, we find processes from the pulp passing down into those interstices as far as the pulp which the tooth is formed from, and there coming into contact with it. After the points of the first described pulp are begun to ossify, a thin covering of enamel is spread over them, which increases in thickness till some time before the tooth begins to cut the gum The enamel appears to be secreted from the pulp above described, and perhaps from the capsula which incloses the body of the tooth. That it is from the pulp and capsula seems evident.ii. the horse, ass, ox, sheep, &.c, therefore we have litile reason to doubt of it in the human species. It is a calcareous eaith, probably dissolved in the juices of our body, and thrown out from these parts which act here as a gland. After it is secreted, the earth is attracted by the bony part of the tooth, which is already formed ; and upon that surface it crystallizes. The operation is similar to the formation of the shell of the egg, the stone in the kidneys and bladder, and the gall stone- This accounts for the striated crystallized appearance which the enamel has when broken, and also for the direction of these Strice. The enamel is thicker at the points and basis than at the neck of the teeth, which may be easily accounted for from its manner of for- mation ; for if we suppose it to be always secreting, and laid equally over the whole surface, as the tooth grows, the first formed will be the thickest; and the neck of the tooth, which is the last formed part inclosed in this capsula, must have the thinnest coat; and the fang, where the Periosteum adheres, and leaves no vacant space, will have none of the enamel. At its first formation it is not very hard; for by exposing a very young tooth to the air, the enamel cracks, and looks rough ; but by the time that the teeth cut the gum, the enamel seems to be as hard as ever it is afterward; so that the air seems to have no effect in hardening it. OF THE MANNER OF SHEDDING OF TEETH. An opinion has commonly prevailed, that the first set of teeth are pushed out by the second ; this, however, is very far from being the case ; and were it so, it would be attended with a very obvious in- convenience ; for, were a tooth pushed out by one underneath, that tooth must rise in proportion to the growth of the succeeding one, and stand in the same proportion above the rest. But this circum- stance never happens: neither can it; for, the succeeding teeth are formed in new and distinct sockets, and generally the Incisores and the Cuspidati of the second set are situated on the inside of the cor- responding teeth of the first set; and we find, that in proportion to the 46 JOHN HUNTER. growth of the succeeding teeth, the fangs of the first set decay, till the whole of the fang is so far destroyed, thai nothing r emains but the neck, or that part of the fang to which the gum adheres, and then the least force pushes the tooth out. It would be very natural to suppose,that this was owing to a constant pressure from the rising teeth against the fangs or sockets of the first set: but it is not so ; for,the new alveoli rise with the new teeth, and the old alveoli decay in proportion as the fangs of the old teeth decay, and when the first set falls out, the succeeding teeth are so far from having destroyed, by their pressure, the parts against which they might be supposed to push, that they are still in- closed, and covered by a complete bony socket. From this we see, that the change is not produced by a mechanical pressure, but is a particular process in the animal economy. 1 have seen two or three jaws where the second temporary grind- ers were shedding in the common way, without any tooth underneath ; and in one jaw, where both the grinders were shedding, I met with the same circumstance. A remarkable instance of this sort occurred to me in a lady who desired me to look at a loose tooth which I found was the last tem- porary tooth not yet shed. I desired that it might be drawn out, and told her it was of no use, and could not by any art be fixed, as it was one of the teeth that is naturally shed, and that another might come in its place: however she was disappointed. These cases prove evidently, that in shedding, the first teeth are not pushed out by the second set, but that they grow loose, and fall out of their own accord. That the succeeding teeth have some in- fluence on the shedding of the temporary set is proved by those very cases; since in one of the first mentioned the person was above twenty years of age, and in the other the lady was thirty ; and it is reasonable to believe, that the shedding of these teeth was so late in those instances, from the want of the influence, whatever it is, of the new teeth. When the Incisores and Cuspidati of the new set are a little advanced, but long before they appear through their bony sock- ets, there are small holes leading to them on the inside, or behind the temporary sockets and teeth ; and these holes grow larger and larger, till at last the body of the tooth passes quite through them. OF THE GROWTH OF THE TWO JAWS. As a knowledge of the manner in which the two jaws grow, will lead to the better understanding the shedding of the teeth ; and as the jaws seem to differ in their manner of growing, from other bones, and also vary according to the age, it will be here proper to give some account of their growth. In a foetus three or four months old, we have described the marks of four or five teeth, which occupy the whole length of the upper jaw, and all that part of the lower which lies before the coronoid process, for the fifth tooth is somewhat under that process. These five marks become larger, and the jaw bones of course in- crease in all directions, but more considerably backwards ; for in a JOHN HUNTER. 47 foetus of seven or eight months, the marks of six teeth in each side of both jaws are to be observed, and the sixth seems to be in the place where the fifth was ; so that in these last four months the jaw has grown in all directions in proportion to the increased size of the teeth, and besides has lengthened itself at its posterior end as much as the whole breadth of the socket of that sixth tooth. The jaw still increases in all points till twelve months after birth, when the bodies of all the six teeth are pretty well formed ; but it never after increases in length between the symphysis and the sixth tooth ; and from this time too, the alveolar process, which makes the anterior part of the-arches of both jaws, never becomes a section of a larger circle, whence the lower part of a childs face is flatter, or not so projecting forwards as in the adult. After this time the jaws lengthen only at their posterior ends ; so that the sixth tooth, which was under the coronoid process in the lower jaw, and in the tubercles of the upper jaw of the foetus, is at last, viz: in the eighth or ninth year, placed before these parts ; and then the seventh tooth appears in the place which the sixth occupied, with respect to the coronoid process, and tubercle ; and about the twelfth or fourteenth year, the eighth tooth is situated where the seventh was placed. At the age of eighteen, or twenty, the eighth tooth is found before the coronoid process in the lower jaw, and un- der, or somewhat before the tubercle in the upper jaw, which tubercle is no more than a succession of sockets for the teeth till they are completely formed. In a young child the cavity in the temporal bone for the articulation of the jaw, is nearly in a line with the gums of the upper jaw ; and for this reason the condyle of the lower jaw is nearly in the same line ; but afterwards, by the addition of the alveolar process and teeth, the line of the gums in the upper jaw descends considerably below the articular cavity ; and for that reason the condyloid pro- cess is then lengthened in the same proportion. In old people who have lost all their teeth, the articulation comes again into the same line with the gums of the upper jaw ; but in the lower jaw, the condyles cannot be diminished again lor accommoda- ting it to the upper, so that it necessarily projects beyond the gums of the upper jaw at the fore part. When the mouth is shut, the pro- jection of the jaw at the chin, fits the two jaws to each other at that place where the grinders were situated, and where the strength of mastication lies; for if the chin was not further from the centre of motion than the gums of the upper jaw, at the fore part, the jaws, in such people as have lost all their teeth, would meet in a point at the fore part, like a pair of pincers, and be at a considerable distance behind. THE REASON FOR THE SHEDDING OF THE TEETH. As the shedding of the teeth is a very singu'ar process in the ani- mal economy, many reasons have been assigned for it; but these reasons have not carried along with them that conviction which is 48 JOHN HUNTER. desired. Authors have not fully considered the appearances which naturally explain themselves; nor have they considered the advan- tages necessarily arising from the size and construction of only such a number as the first set; nor have they considered fully the disad- vantages that such size and construction would have, if continued when it is necessary to have a greater number, which is the case with the adult. We shall consider these advantages in a child where the shedding teeth are all completely formed, which will be setting them in the clearest point of light; and also, the disadvantages that would occur, if in the adult these were not changed for another set somewhat different. If the child had been so contrived, as not to have required teeth till the time of the second set's appearing, there would have been no occasion for a new set: but the jaw-bones being considerably smaller in children than in adults, and it being necessary that they should have two grinders, there is not room for Incisores and Cuspidati of sufficient size to serve through life; and the first formed grinders having necessarily too small fangs, and the jaw increasing at the back part only, these two grinders would have been protruded too far forwards, and at too great a distance from the centre of motion. This variation in the size of the teeth is likewise a reason why the second set are not formed in the sockets of the first; and why the old sock- ets are destroyed. These circumstances with regard to the shedding of the teeth, contradict the notion of the second set being made broader and thick- er, by the resistance they meet with in pushing out the first. For were we on a partial view of the subject, to admit the supposition, the Bicuspides would effectually overturn our hypothesis ; because here the second set are much smaller than the first, and yet the re- sistance would be greater to them than to the Incisores. From the manner in which the teeth are shed, it is evident that drawing a temporary tooth, for the easier protrusion of the one un- derneath, will be of no great service ; for in general it falls out be- fore the other can touch it. But it is often of much more service to pull out the neighboring or adjacent temporary tooth; for we must be convinced by what has been advanced with regard to the changes in size, that excepting the whole were to shed at the same time, or the order of shedding, viz : from before backwards, were to be in- verted, that the second set of Incisures and Cuspidati must be pinch- ed in room, till the grinders are also shed : and therefore we find it often of use to draw a tempoiaiy moth, that is placed urther back; and it would, perhaps, be right upon the whole, always to draw, at least the first grinder; and, perhaps, some time after, the second grinder also. OF THE CAV1TV FILLING UP AS THE TEETH WEAR DOWN. A tooth very often wears down so low, that its cavity would be exposed, if no other alteration were produced in it. To prevent this, nature has taken care that the bottom part of the cavity should JOHN HUNTER. 49 be filled up by new matter, .in proportion as the surface of the Teeth is worn down. This new matter may be easily known from the old; for when a Tooth has been worn down almost to the neck, a spot may always be seen in the middle, which is more transparent, and at the same time of a darker colour, (occasioned, in some measure, by the dark cavity under it) and is generally softer than the other. Any person may be convinced of the truth of these observations, by taking two Teeth of the same class, but of very different ages, one just com- pletely formed, the other worn down almost to its neck. In the last he will observe the dark spot in the centre ; and if as much is cut off from the complete Tooth as hath been worn off the old one, the cavity of the young Tooth will be found cut through; and on ex- amining the other, its cavity will be found filled up below that sur- face, (d) Now this observation contradicts the idea of the hole leading into the cavity of the Tooth being closed up ; and what is still a fur- ther proof of it, I have been able to inject vessels in the cavities of the Teeth in very old people when the Alveolar Process has been gone, and the Teeth very loose in the Gum. Old people are often found to have very good sets of Teeth, only pretty much worn down. The reason of this is, that such people never had any disorder in their Teeth, or Alveolar Processes,sufficient to occasion the falling of one Tooth. For if by accident one Tooth is lost, the rest will necessarily fail in some degree, even though they are sound, and likely to remain so, had not this accident happened ; and this weakening cause is greater, in proportion to the number that are lost. From this observation, we see that the Teeth support one another. (d) We could in no way account for the filling up of the natural cavity of the teeth as they wear down by mastication, if they were, as many suppose them to be, inorganic bodies, beyond the reach of the circulating fluids or the secretory and excretory vessels. This entire filling up or obliteration of the natural cavi- ty of the teeth is not always, although it may be generally, a consequence of the loss of substance from the surface, as lias been stated. 1 have frequently seen in the teeth of old people the cavity completely filled with new bone, and the tooth solid, entirely divested of sensibility, when no perceptible wearing had taken place. The manner in which this is effected is very satisfactorily explained by Mr. Thomas Bell, whose experience and whose opportunities from having been for twenty years or more lecturer at Guy's Hospital, have undoubtedly made him in his profession, the ablest Physiologist of the present day—and from having long ei;joyed a friendly acquaintance with him, and regarding his views general" ly, as being physiologically and practically correct, I shall unhesitatingly quote his language in support of my own professional views.—Mr. Bell remarks, "as the superstratum of bone becomes thinner by abrasion, the membrane lining the internal cavity, from which, as I have before shown, the bone of the tooth was originally produced, now again resumes its ossific action and produces a fresh layer of bony matter, which in some cases at length fills the socket and oblite- rates the membrane from which it has been secreted. This is particularly the case in sailors who have lived much upon hard biscuits, a circumstance which tends greatly to accelerate the abrasion of the surface, a process perfectly and obviously analagous to that of the wearing of the teeth in graminivorous animals.'* SO' JOHN HUNTER. OF THE CONTINUAL GROWTH OF THE TEETH. It has been asserted that the Teeth are continually growing, and that the abrasion is sufficient to keep them always of the same length ; but we find that they grow at once to their full length, and that they gradually wear down afterwards ; and that there is not even the ap- pearance of their continuing to grow. The Teeth would probably project a little farther out of the Gum, if they were not opposed by those in the opposite Jaw; for in young people, who had lost a Tooth before the rest had come to their full length, I have seen the opposite Tooth project a little beyond the rest, before they were at all worn down. It may be further observed, that when a Tooth is lost, the opposite one may project from the disposition of the Alveolar Process to rise higher, and fill up at the bottom of the sockets ; and the want of that natural pressure seems to give that disposition to these pro- cesses, which is best illustrated in those Teeth which are formed deeper in their sockets than usual. As a proof that the Teeth con- tinue growing, it has been said that the space of a fallen Tooth is al- most filled up by the increased thickness of the two adjacent Teeth, and the lengthening of that which is opposite. There is an evident fallacy in the case; either the observations have been made upon such Jaws as above described, or the appearances have not been examined with sufficient accuracy; for when the space appears to have become narrow by the approximation of the two adjacent Teeth, it is not owing to any increase of their breadth, but to their moving from that side where they are well supported, to the other side, where they are not. For this reason they get an inclined direction ; and I observe it extends to the several adjacent Teeth in a propor- tional less degree, and affects those which are behind, more than those which are before the vacant space. In the Lower-Jaw the back Teeth are not fixed perpendicularly, but all inclined forward; and the depression of the Jaw increases this position ; the action of the Teeth, when thrown out of the per- pendicular, has also a tendency to increase that oblique direction, as a pair of scissars, in cutting, pushes every thing forward, or from the centre of motion : therefore this alteration, I think, is most commonly observable in the Lower-Jaw. And that Teeth are not actually always growing in breadth, must be obvious to every person who considers, that in many people, through life, the Teeth stand so wide from each other, that there are considerable spaces between them; which could not be the case if they were always growing in thickness. We might add too, that according to the hypothesis, the Dens Sapiential should grow to an enormous size backward, because there it has no check from pressure ; and in people where the Dens Sapientice is wanting in one Jaw, which is very common, it should grow to an uncommon length in the opposite Jaw, for the same rea- son. But neither of these things happens. I need hardly take notice, that when a Tooth has lost its opposite JOHN HUNTER. 51 it will in time become really so much longer than the rest, as the others grow shorter by abrasion ; and I observe that the Tooth which is opposite to the empty space, becomes in time not only lon- ger for the above-mentioned reason, but more pointed. The apex falls into the void space, and the two sides are rubbed away against the sides of the two approaching Teeth next to that space. The manner of their formation likewise shews that Teeth cannot grow beyond a certain limited size. To illustrate this I may observe, that I have often, in the dead body of adults, found the left Cuspidatus of the Upper-Jaw, with its points scarcely protruding out of the Al- veolar Process, though the Tooth was completely formed, and longer than the other by the whole point, which in that other was worn away. This Tooth, at its first formation, had been deeper in the Jaw than what is common ; and after it had grown to the ordinarv size, it grew no longer, though it had not the resistance of the oppo'- site Teeth to set bounds to its increase : yet commonly in these cases the Tooth continues to project further and further through the Gum; though this is not owing to its growing longer, but to the socket filling up behind it, and thereby continuing to push it out by slow degrees. OF THE SENSIBILITY OF TEETH. The Teeth would seem to be very sensible; for they appear to be subject to great pain, and are easily and quickly affected by either heat or cold. We may presume that the bony substance itself, is not capable of conveying sensations to the mind, because it is worn down in mas- tication, and occasionally worked upon by operators in living bodies, without giving any sensation of pain in the part itself. In the cavity of a Tooth it is well known that there is exquisite sensibility; and . it is likewise believed, that this is owing to the nerve in that cavity. This nerve would seem to be more sensible than nerves are in common ; as we do not observe the same violent effects from any other nerve in the body being exposed either by wound, or sore, as we do from the exposure of the nerve of a Tooth. Perhaps the reason of the intenseness, as well as the quickness of the sense of heat and cold in the Teeth, may be owing to their commu- nicating these to the nerve sooner than any other part of the body.(E) (e) One of the strongest proofs we have that the bone of the tooth posses- ses life, and is vascular to a nice degree, is the acute sensation which is felt when an instrumeut is passed slightly over a tooth that, has been denuded of its enamel, or when the gum has separated from the enamel and exposes the neck of the tooth. I have, in the course of my practice, had many patients apply to me supposing that their teeth were in a state of decay from the pain felt in brush- ing them, or when they accidentally touched them with an instrument, or with the finger nail. I have for many years believed that the whole sensibility of a tooth did not depend solely on the nerve, within its internal cavity, and every years' observation confirms me more strongly in that belief, which can be easily proved in such cases as I hare named ; notwithstanding, Mr. Hunter very confi- dently asserts, " that the bony substance is not capable of conveying sensations to the mind." 62 JOHN HUNTER1. OF SUPERNUMERARY TEETH. We often meet with Supernumerary 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 Incisores and Cuspidati. I have only met with one instance of this sort, and it was in the Upper-Jaw of a child about nine months old : there were the bodies of two Teeth, in shape like the Cuspidati, placed directly behind the bodies of the two first permanent Incisores ; so that there were three Teeth in a row, placed behind one another, viz. the temporary Inci* sor, the body of the permanent Incisor, and that supernumerary tooth. The most remarkable circumstance was, that these supernumerary teeth were inverted, their points being turned upwards, and bended, by the bone which was above them not giving way to their growth, as the alveolar process does. It often happens that the Incisores and Cuspidati, in the upper jaw especially, are so irregularly placed, as to give the appearance of a double row. I once saw a remarkable instance of this in a boy ; the second Incisor in each side was placed farther back than what is common, and the Cuspidatus and first Incisor closer together, than if the second Incisor had been directly between them ; so that the appearance gave an idea of a second row of teeth. This happens only in the adult set of teeth, and is owing to there not being room in the jaw for this second set, the jaw bone being formed with the first set of teeth, and never increasing afterwards ; so that if the adult set does riot pass further back, they must over-lap each other, and give the appearance of a second row. (f) OF THE USE OF THE TEETH SO FAR AS THEY AFFECT THE VOICE. The teeth serve principally for mastication ; and that use need not be farther explained. They serve likewise a secondary, or subordinate purpose ; giving strength and clearness to the sound of the voice, as is evident from the alteration produced in speaking, when the teeth are lost. This alteration, however, may not depend entirely upon the teeth, but, in some measure, on the other organs of the voice having been (f) 1 have very frequently found these supernumerary teeth, and have seen them in all parts of the mouth, on the sides, and as far back as the wisdom teeth in the upper jaw — but most frequently among the superior incisores, and are generally of the shape described by Mr. Hunter. I do not remember having seen one of this kind in the lower jaw. I have at this time two patients who have five beautifully formed lower incisores instead of four ; and some years ago, had one patient who had five beautifully formed upper incisores instead of four.with perfect arrangement in both cases. I have also a patient whose canine tooth in the right side adjoins the central incisor with a perfect lateral incisor standing between the canine and first bicuspis, in perfect arrangement. In relation to the irregula- rity spoken of here, I shall have occasion to speak at considerable lengthen a subsequent number,when the operations spoken of by Mr. Hunter are considered. JOHN HUNTER. 53 accustomed to them ; and therefore when they are gone, those other organs may be put out of their common play, and may not be able to adapt themselves so well to this new instrument. Yet I believe that habit in this case has no great effect; for those people seldom or never get the better of the defect; and young children, who are shedding their teeth, and are, perhaps, without any fore teeth for half a year or more, always have that defect in their voice, till the new teeth come , and as these grow the voice becomes clear again. This use seems to be entirely in the fore teeth ; for the loss of one of these makes a great alteration, and the loss of two or three grinders seems to have no sensible effect. As an argument for the use of the teeth in modifying the sound of the voice, we may observe, that the fore teeth come at a time when the child begins to articulate sounds, and at that time they are so loose in the gums, that they can be of very little service in mastication. Every defect in speech, arising from this defect in the organ, is generally attended with what we call a lisp, People who have lost all their teeth, and most old people for that reason, lose, in a great measure, their voice. This arises partly from the loss of the fore teeth, but principally from the loss of all the teeth, and of the alveo- lar processes of both jaws, by which means the mouth becomes too small for the tongue, and the lips and cheeks become flaccid ; inso- much that the nicer movements of these parts, in the articulation of sounds, are obstructed and thence the words and syllables are indis- tinctly pronounced, and slurred, or run into one another. UNDER WHAT CLASS DO THE HUMAN TEETH COME. Natural historians have been at great pains to prove from the teeth, that man is not a carnivorous animal; but in this, as in many other things, they have not been accurate in their definitions ; nor have they determined what a carnivorous animal is. If they mean an animal that catches and kills his prey with his teeth, and eats that flesh of the prey just as it is killed, they are in the right; man is not in this sense a carnivorous animal, and there- fore he has not teeth like those of a lion ; and this, I presume, is what they mean. But if there meaning were that the human teeth are not fitted for eating meat that has been catched, killed, and dressed by art, in all the various ways that the superiority of the human mind can invent, they are in the wrong. Indeed, from this confined way of thinking it would be hard to say what the human teeth are fitted for ; because, by the same reasoning man is not a graminivorous animal, as his teeth are not fitted for pulling vegetable food, &c. They are not made like those of cows or horses, for example. The light in which we ought to view this subject is, that man is a more perfect or complicated animal than any other; and is not made like others, to come at his food by his teeth, but by his hands, directed 54 JOHN HUNTER. by his superior ingenuity; the teeth being given only for the purpose of chewing the food, in order to its more easy digestion: and they, as well as his other organs of digestion, are fitted for the conversion of both animal and vegetable substances into blood ; and thence he is able to live in a much greater variety of circumstances than any other animal, and has more opportunities of exercising the faculties of his mind. He ought, therefore, to be considered as a compound, fitted equally to live upon flesh and upon vegetables. OF THE DISEASES OF THE TEETH. The teeth are subject to diseases as well as other parts of the body. Whatever the disorder is that affects them, it is generally at- tended with pain ; and from this indeed we commonly first know that they are affected. Pain in the teeth proceeds, I believe, in a great measure, from the air coming into contact with the nerve in the cavity of the tooth ; for we seldom see people affected with the tooth-ache, but when the cavity is exposed to the air. It is not easy to say by what means the cavity comes to be exposed. The most common disease to which the teeth are subject, begins with a small, dark colored speck, generally on the side of the tooth where it is not exposed to pressure ; from what cause this arises is hitherto unknown. The substance of the tooth thus discolored, gradually decays, and an opening is made into the cavity. As soon as the air is thereby admitted, a considerable degree of pain arises, which is probably owing to the admission of the air, as it may be prevented by filling the cavity with lead, wax, &c. This pain is not always present; the food, and other substances, perhaps fill up the hole occasionally, and prevent the access of the air, and of consequence the pain, during the time they remain in it. When an opening is made into the cavity of the tooth, the inside begins to decay, the cavity becomes larger, the breath at the same time often acquires a putrid Factor, the bone continues to decay till it is no longer able to support the pressure of the opposite tooth, it breaks and lays the cavity open. We have not as yet found any means of preventing this disease, or of curing it; all that can be done,is to fill the hole with lead, which prevents the pain, and retards the decay ; but after the tooth is bro- ken, this is not practicable ; and for that reason it is then best to ex- tract it. It would be best of all to attempt the extraction of a tooth by drawing it in the direction of its axis : but that not being practicable by the instruments at present in use, which pull latterally, it is the next best to draw a tooth to that side where the alveolar process is weakest; which is the inside, in the two last grinders on each side of the lower jaw, and the outside in all the others. m It generally happens in drawing a tooth, that the alveolar process is broken, particularly when the grinders are extracted ; but this is JOHN HUNTER. 55 attended with no bad consequences, as that part of the alveolar pro- cess from which the tooth was extracted always decays. In drawing a tooth, the patient complains of a disagreeable jarring noise, which always happens when any thing grates against the bones of the head. OF CLEANING THE TEETH. From what was said of the nature and use of the enamel, it is evi- dent, that whatever is capable of destroying it, must be hurtful; therefore all acids, gritty powders, and injudicious methods of scaling the teeth are prejudicial : but simply scaling the teeth, that is, clear- ing them of the stony concretions which frequently collect about their necks, while nothing is scraped off but that adventitious sub- stance, is proper and useful. If not removed by art, the quantity of the stony matter is apt to increase, and to affect the gum. This mat- ter first begins to form on the tooth near to the gum ; but not in the very angle, because the motion of the gum commonly prevents the accumulation of it at this part. I have seen it cover not only the whole tqoth, but a great part of the gum : in this case there is al- ways an accumulation of a very putrid matter, frequently considera- ble tenderness and ulceration of the gum, and scaling becomes abso- lutely necessary, (g) OF TRANSPLANTING THE TEETH. From considering the almost constant variety of the sire and shape of the same class of teeth in different people, it would appear almost (e.) The animal fluids, when out of the course of the general circulation, es- pecially when they stagnate in cavities, are apt to deposit an absorbent earth, and form concretions. This earth is sometimes contained in the fluids ; and is only deposited, as in the formation of the stone in the urinary passages: in some cases, perhaps, the fluids undergo a change, by which the earth is first formed, and afterwards deposited. This deposition takes place particularly in weakened parts, or where the circulation is languid, or where there are few arteries, such as about joints and tendons ; as if it were intended to strengthen these parts, if they should at any time give way ; for if an artery, for instance, is overcome by the action of the heart, and unnaturally dilated, its coats have commonly these concretions formed every where in their interstices. The same thing happens also in the coats of incysted turners, whicli are constantly distended ; in cases of distensions of the tunica vaginalis testis, &c. It is also apt to take place in parts which have lost their natural functions : as in the coats of the eye in cases- of blindness, and in diseased lymphatic glands, &c. and where the living power is diminished in the system, as in the arteries, membranes, &c. of old people ; and in some particular habits, as in those who are affected by the gout. The same sort of deposition takes place likewise, where there is any substance with such properties as render it a fit basis for crystallization ; as when extra- neous bodies are lodged in the bladder : whence such bodies are bo often found to form the nucleus of a stone. The same thing happens in the bowels of many animals • whence the nucleus of intestinal concretions, or bezoars, is commonly a nail or some indigestible substance which had been swallowed. Tne crust, which collects upon the teeth, seems to be a crystallization of the same nature. HUNTER. 56 JOHN HUNTER. impossible to find the tooth of one person that should fit, with any degree of exactness, the socket of another; and this observation is supported, and indeed would seem to be proved by observing the teeth in skeletons. Yet we can actually transplant a tooth from one person to another, without great difficulty, nature assisting the ope- ration, it is done in such a way that she can assist; and the only way in which nature can assist, with respect either to size or shape, is by having the fang of the transplanted tooth rather smaller than the sock- et. The socket in this case grows to the tooth. If the fang is too large, it is impossible indeed to insert it at all in that state ; however, if the fang should be originally too large, it may be made less ; and this seems to answer the purpose as well. The success of this operation is founded on a disposition in all liv- ing substances, to unite when brought into contact with one another ; although they are of a different structure ; and even although the circulation is only carried on in one of them. This disposition is not so considerable in the more perfect or com- plex animals, such as quadrupeds, as it is in the more simple or im- perfect ; nor in old animals, as in young : for the living principle in young animals, and those of simple construction, is not so much con- fined to, or derived from one part of the body ; so that it continues longer in a part separated from their bodies, and even would appear to be generated in it for a time ; while a part separated from an older, or more perfect animal, dies sooner, and would appear to have its life entirely dependent on the body from which it was taken. Taking off the young spur of a cock, and fixing it to his comb, is an old and well known experiment. I have also frequently taken out the Testis of a cock and replaced it in his belly, where it was adhered, and has been nourished ; nay, I have put the Testis of a cock into the belly of a hen with the same effect. In like manner a fresh tooth, when transplanted from one socket to another, becomes to all appearance a part of that body to which it is now attached, as much as it was of the one from which it was taken ; while a tooth which has been extracted for some time, so as to lose the whole of its life, will never become firm or fixed ; the sockets will also in this case acquire the disposition to fill up, which they do not in the case of the insertion of a fresh tooth. These appearances show that the living principle exists in the seve- ral parts of the body, independent of the influences of the brain, or circulation, and that it subsists by these, or is indebted to them for its continuance ; and in proportion as animals have less of brain and circulation, the living power has less dependence on them, and be- comes a more active principle in itself: and in many animals there is no brain nor circulation, so that this power is capable of being con- tinued equally by all the parts themselves, such animals being nearlv similar in this respect to vegetables. EXPLANATION OF PLATES. PLATE I. Fig. 1. A front view of the upper and lower-jaws of an adult, with a full set of teeth, a a a, the upper-jaw. b- b, the lower-jaw. c its ascending process, d the root of the coronoid process. M. D. Columbia, S. C. 1 Blake El.hu, N. Y. 1 Baldwin James Oscar. Newark, N. J. 1 Bancroft T. L , Granville, Ohio, 1 Cook Doctor, Brooklyn, 1 Brown B B St. Louis, Mo, 2 ; Clute Nicholas, Louisville Ky. 2 Backus G. Nashville, Tenn. 1 i Chandler James, Schenec. N. Y. 1 Briscoe A W., -Baltimore, 1 j Cobb B. C, M. D. Clarkstore, Mar- Baretow Wm. H., M. D., George- | tins Co. N. C 1 town, K. Y. l Cox A. L., M. D. New York, 1 SUBSCRIBERS NAMES. 47 Cleveland J. A., Charleston, S. C Crocker Fred'k, Sagharbour, L. i'. Clark F. H., Baltimore, Comegys,---Baltimore, Cutler Wm. Daily, Baltimore, Cutler Sam'l Jackson, Baltimore, Coleman, R. K. Baltimore, Cauling& Edmunds, Bait. Cobb An^on, Brooklyn, Clark C, Jacksonville, 111. Clark James, Springfield, 111. (Jassill J. F., Upper Marion, Col. Mo. Chewning F. B., Rich. Va. Clark James, Lebanon, O. Coppel Chas. Preston, Eng. Crane (). P- Geneva, N. Y. Chevalier J. D., N. Y. Crofoot E., E. Muddletown Con. Dexter, Doctor, Brooklyn, Dunning H. H. Buffalo, Davis W. H. H. Cassville, Oneida Co., N. Y. Duncan Archibald, N. Y. Davesson Frederick A., M. D. Hills- boro, Loudon Co. Va. Dodge Ezra, N. Y. Dunlap Joseph, Chilco'he, O. Dunbar J. R. H., M. D. Bait. Desha John R., M. D. Little Rock, Ark. De Loude Le Chas. Wolverhampton, England, Esterly D., f.l. D. Troy, N. Y. Early---, Doctor, Lynchburg, Va. Elmendorf Joseph, I'ennyan, N. Y. Ellery E. Baltimore, Evans J. N.,M. D. Cynthiana, Ky. Elliott Joseph D. Leicester, Mass. Ensor — Dentist, 4 Seal-st. Liver- pool, Fenn Horatio N., M. D. Rochester, 2 Foster J. 11., M. D. New-York, 2 Fla.ug Josiah F., M. D. Boston, 1 Fmzer, Doctor, Cynthiana, Harrison Co. Ky. 1 Frink J. N. Portland, 1 Foote George, Vernon, N. Y. 1 Faulkner & Pierpont, Man. England, 1 Fundenberg G. B. Dentist Pittsburg, Pa. 1 Gilfiland, Doctor, Brooklyn, 1 Gaines Kich. W. Charlotte C. II. Va. 1 Garrison, Doctor, Brooklyn, 1 Gallop L. F. Newport, R. I. 1 GardeUe E. B-, Philadel. 2 Greenwood Isaac J., New-York, 1 Green L. T., Nashville, Tenn. 1 Goddard W. 11., Louisville, Ky. 1 Gill Brygon, Baltimore, 1 j Gunnel!, M. D. Washington, 1 Griffith S. & E. Louisville, Ky. 1 Gcer—Rev. John A., Maryland, 1 Grandhomme M. P. Paris, France, 1 Gidney Eleazar, Man. England 1 Herd, Doctor, Brooklyn, 1 Harris Chapin A., M. D. Bait. 40 Hawes Arnold, Pawtucket, R. 1. 1 Hulihen J. P. Wheeling, Va. 1 Hawes & Allen, New-York, 1 Hou&ton P., N. Y. and Charleston, 1 Hartness Thos. L. New-York, 1 Hewlet J. W., Greensbo, N. C. 1 Holmes Oliver, Baltimore, 1 Howard F., Washington City, 1 Harris John, M. D. Georgetown, Ky. 2 Hall A. S., M.D.Scotland Neck, N.C. 1 Hubbard, E. K., Newbern, N. C. 1 Harper Sam'l, Kent Island, Md. 1 liar d G. C, l\as'on, Pa. 1 Humphreys Geo.W.,Winchester,Va. 1 Hodgson, Doctor, Whiteplains, N. Y. 1 Harrison R.II , M.D. Huntsville, Ala. 1 Irnrie—Dentist. Man. England, 1 Johnson Wm., Hagerstown, Md. 2 Jenks W. D., Fredrickstown, Md. 2 King, Doctor, Brooklyn, 1 Kelley Elbridge G., Newbury port, Mass. 2 Knower Daniel, N. Y. 1 Keene Benjamin F., Hills. Ga. 1 Knapp, F. H. Baltimore, 1 Latham Hiram, Brooklyn, 1 Lum John Patterson, N. J. 1 Levett M., New York, 1 Lovejoy John, New-York, 1 Lossing B. J. New York, 1 Laroque Edward, Baltimore, 1 Lapham B. B., Baliimore, 1 Lawrence J- M. D., Taiboro, N. C. 1 Leadbetter John, Alexan. D.C. 1 Lyon S. K , N. Orleans, 4 Lloyd T. B., Manchester, Eng. 1 Lloyd Rich., Liv. Eng. 1 Laird O. P., Columbus, Ga. 1 Lamphire Wm., Alexan. D. C. I Marvin, Doctor, Brooklyn 1 Miller Seth I1., Worcester, Mass. 1 Maynard E. —. M. D Washington City 20 Martin Chas. F., Norfolk, Va. 1 M'Kinney W.N.,Fredericksburg,Va.20 Milhau John, New York, 1 Munson W. G. New Haven, 1 Manly Horace, Catianda. N. Y. 1 Macall Leon-ird, M. D., Bait. 1 Miller J. H. Professor, &.c. Baltimore 1 Merry man Geo. Baltimore, 1 Manning M. E., Tarborough, N. C. 2 iS SUBSCRIBERS JNAMJbjy. M'Cabe James D., Richmond, Va. 2 McDonald G., M. D. Macon, Ga. 2 Macey Wm SI., M. D. Georgetown, Ky. 1 McAllister J. M. Albany, 1 McNaughton M. A. Albany, 1 Mason, Doctor, Brooklyn, 1 Merritt C, Bndgport, Con. 1 Nelson Alexander, Albany, 1 Norman S. P., Little Rock, Ark. 4 Overfield M. Winche.-tur, Va. 2 Parker, Doctor, Brooklvn, 1 Parmly L. S., N. Orleans, 20 Parmly Jahial, New-York, 20 Parmly Jahial Savannah, 1 Parmly Geo. W., N. Orleans. 1 Parmly David, New York, 1 Parmly Eleazar, New York 40 Parmly Ludolph, Mobile, 1 Parmly W. Samuel, New York, 1 Patello Wm. H., Charlotte C.H. Va. 1 Park David N., A. M. New-York, 1 Paruhurst Wm. H., New York, 1 Peak J. M. Cooperstown, N. Y. 1 Plant Eleazar, Willimantic, Conn. 1 Pritchard P. C, Jackson, N. C. 1 Plough.A. L , New Orleans, 1 Parsons J, H , Liverpool, England, 1 Palmer W. A., New Haven, Conn. 1 Pleasants Charles, Painesville, O. 1 Royce W. A. Poughkeepsie, N. Y. 3 Robinson E. C Norfolk, Va. 1 Roper Lewis, M- D. Philad. 20 Rowell Chas., N. Y. 2 Roe Early, M. D. Hillsborough, Ga. 1 Rodriguez B. A., Charles. S- C. 1 Ritter — Washington City, 1 Robinson E. M. D. Leesburg, Ky. 1 Reynolds Wm., M. D. Camden, S. C. Strickland Benj. Cleveland, O. 1 Snow R. J., Buffalo, 1 Smith & Thackston, Farmville, Va. 1 ' Scott W. R., Raleigh, N. C. Shuff P. L , M. D , Leesburg, Ky. Smeds, M. D., Frankfort, Ky. Stringfeilow S. L. Baltimore, 20 Stratton Cha's, Keene N. H. Sanders M., London, • Sanborn E,, Andover, Mass. Smith Wm., Liverpool, Eng. Minkley B. D., Albany, Smith G. W., N. Orleans, Stuart R., Knoxville, E- T. Smith J. W. Amherst, Mass. Searles F., Springfield, Mass. StocktonS. W., Phila. 20 Taylor Edward,M.D., Bainbridge, O. 2 Tucker E. G., M. D. N. Y. 2 Trenor John, M. D. N. Y. Trenor James, M. D„ N. Y. Tilyard H. W., Baltimore. Taliaferro T.S., M.D.,Maysville, Ky, Thompson — Doctor, Colum. O. Thorn, Doctor, Brookyln, Tyler Nah'l S. Mass. Chicapee Falls, Taylor James, Crawfordville, la. Teter G. T., Dentist, Greenfield, Highland Co. Ohio, Van Praag A. S., N. Y. Vincent Ezra, N. Y. Van Camp, Louisville, Ky. Van Patten C. H. Vanboskirk L. E., St. John, N. B. Willard M. T. Concord, N. H. Weed J.Sacket,W.Greenfield, N. Y. White Geo. H., N. Y. Walker & Jones, N. Y. 20 Wanzer N. C, Auburn, N. Y. Wayt John G., Ricmond Va. Wilson J. 1). Richmond, Va. Ware W., M. D. Wilmington, N. C. Wheat J. B., N. Haven, Young H„ Troy, N. Y. If each of our subscribers would obtain an additional name to be inserted in this catalogue, the permanency of this Journal would be amply secured. As it is, the Publishing Committee assure the profession, that the first vol- ume of twelve numbers, shall be fully completed without any unnecessary delay. The long interim between the present and the last number, has been occasioned by the difficulty of transmitting available funds from re- mote parts of the country. 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