S' Zoi TRANSACTIONS ODONTOLOGICAL SOCIETY OF LONDON, VOL. II. 1857-1860. LONDON: PUBLISHED BY THE SOCIETY. MDCCCLXI. LONDON : COX ANT> WYMAN, PBINTBBS, GBBAT QUEEN STREKT, i,incot.n's-inn fields. mnx Iresiknts. 1856-7.— SAMUEL CARTWRIGHT, F.R.S. 1858.— JOHN H. PARKINSON, L.D.S., R.C.S.Eng. 1859.— ARNOLD ROGERS, F.R.C.S.Eng., & L.D.S. 1860.— WILLIAM A. HARRISON, F. R.C.S.Eng., L.D.S. , &c. a 2 MEMBERS ODONTOLOGICAL SOCIETY OF LONDON. >t«i, J. J. 14, Surrey Street. BROMLEY, CHARLES, L.D.S., R.C.S.Eng. 1, Portland Terrace. (V.P. 1857, V.P. 1858, V.P. 1859, V.P. 1860.) RANSOME, ROBERT, L.D.S., R.C.S.Eng., Dentist to the Hastings Infirmary. 3, Verulam Place. KOLLIKER, PAUL ALFRED. 12, Stadelhofen, Zurich. {Corresponding.) LIST OF MEMBERS. XIX Swansea- Torquay wolverhamp- ") TON ) Worcester York Elected. 1857 1856 1860 1858 1857 1856 SCOTT, niEDERICK JAMES CLOUSTON, L D.S., R.C.S.Eng., Dental Surgeon to the Cambrian Institution for the Deaf and Dumb. 9, Fisher Street. RODWAY, HENRY BARRON. Park Place. RODWAY, C. A., L.D.S., R.C.S.Eng. Park Placj. DE LESSERT, CHARLES GRIERSON,L.D.S., R.C.S.Eng. 10, Waterloo Road. ROBERTSON, JAMES. 47, Foregate Street. KING, JOSEPH, L.D.S., R.C.S.Eng. 33, Coney Street. GENERAL MONTHLY MEETING. Monday y November 2, 1857. ARNOLD KOGERS, Esq., V.P., in the Chaib. The following Gentleman was duly elected a Member of the Society ; — Simon N. Dentz Amsterdam {Honorary). The following Gentleman was proposed for the Membership of the Society : — John B. Lindsey Dover. Mr. Edwin Sercombe exhibited specimens of Irregular Develop- ment of the Teeth. Mr. Dupp made the following communication on the "Materials used by Dentists" The materials used in the manufacture of arti- ficial teeth, some twenty-five years ago, were either metallic or animal, with the occasional use of a mineral substance. The metallic were gold, silver, or platina. Gold then, as now, held the first place among the metals, because of its duc- tility, purity, and unoxidisable character in the mouth. Silver was objectionable from too readily oxidising ; and platina, from its great specific gravity, extreme softness, and being difficult to obtain commercially, was little used. Of the animal substances, the tusk of the Hippopotamus Z ^ ON THE MATERIALS had the priority, although the Walrus tusk. Whale teeth, and Elephant ivory were severally used for dental purposes. The Hippopotamus ivory more nearly resembles in character human dentine than any other substance used by dentists* The oleaginous character of Walrus ivory renders it capable of resisting, to a considerable degree, the action of the acids in the mouth. It also admits of a high degree of polish ; but, on account of its softness, is readily worn down by mastication. Whale teeth are objectionable on account of their offensive odour and bad colour. Natural teeth could only be considered by comparing them with the mineral teeth of the present day. The author enumerated various combinations of these mate- rials as dental substitutes, and passed encomiums upon the artistic excellence of some amongst the early practitioners in dentistry. He considered the introduction of mineral teeth as a step in the right direction, and contrasted the French manu- facture with those at present in use. These were considered as far from perfect, being wanting in strength. The liability of mineral teeth to frac- ture was a cause of great annoyance, which the exercise of skill could not obviate. Mineral teeth had been puffed by quacks and charlatans as indestructible and incorrodible, and thus was introduced into the profession an ele- ment of competition more or less destructive to its dignity. The introduction of palladium, dental USED BY DENTISTS. 6 alloy, and other white metals as substitutes for gold and silver, was considered unjustifiable even where economy was a consideration. Gutta- percha as a base on which to construct artificial teeth, had not realized the sanguine expectations of those who introduced it, and was only applicable under certain temporary circumstances. B 2 GENERAL MONTHLY MEETING. Monday^ December 7, 1857. JOHN H. PARKINSON, Esq., V.P., in the Chair. The following Gentlemen were duly elected Members of the Society : — Mr. Charles William Dunn Florence {Konorary). Mr. George Gregson Harley Street, London. The following Gentleman was proposed for the Membership of the Society : — Mr. Egbert Norman Adelaide, Australia. Mr. R. Thomson exhibited and described an apparatus for making Spiral Springs, and demonstrated its use. Messrs. Betjeman, of Oxford Street, exliibited an improved Dental Chair, and Dental-Instrument Cabinet. Mr. Edwin SeRcombe then read a paper " On the Method of taking Impressiotis of Cases of Cleft Palate.^^ It will be unnecessary to preface what I am about to say on the subject of " taking impressions of the mouth" by any remarks to enforce the importance of a correct model as a first step in all cases where an apparatus is to be made for wear- ing in the mouth, either for the purpose of carrying upon it artificial teeth, or of obliterating a fissure in the palate. It must be obvious that, if the model is incorrect, the apparatus made upon it will be incorrect also, and just in proportion to b METHOD OF TAKING IMPRESSIONS its incorrectness will it fail to secure to the person for whom it is made those delicate advantages which constitute the great value and merit of such work. The failure in remedying indistinct enun- ciation that follows the introduction of an artificial palate into a mouth of which an imperfect model had been obtained, or the pain inflicted by artificial teeth when constructed upon an incorrect model, is too well known to all upon whom it devolves to adapt these contrivances, not to make the question, — How can we most easily and certainly secure a correct model of the mouth ? — ^worthy the attention of this Society. Perhaps the diflftculties I have sometimes expe- rienced in obtaining a satisfactory impression have arisen principally from my own awkwardness, and would not have been felt by another ; but whether it has been so or not, I presume it will not be denied that there are cases which offer great diffi- culties, even to the most expert manipulator ; and if in these instances the plan I have adopted, with much advantage, should render the task of taking an impression more easy, I shall feel that the subject has not been brought before you in vain. The class of cases in which I have experienced great difficulty in obtaining a correct impression of the mouth has been that in which the roof has been preternaturally high, and the ruga3 have been strongly marked. But the most difficult cases are generally congenital cleft palates, where, in addi- OF CASES OF CLEFT PALATE. 7 tion to a lofty arch, there is a fissure through which, to some extent at least, it is necessary that the wax should pass. There are of course other cases yet more difficult, arising from accident or disease, where, from contractions without or within the mouth, nothing but much patience and ingenuity will triumph ; but as these are exceptional cases, it will be useless to advert to them on the present occasion. The necessity of modifying the ordinary form of tray for cases where the vault is high, and the ruga3 strongly developed, was forced on my atten- tion by a case where a plate, which was fitted with great fidelity to the model upon which it had been made, stood off considerably at its inner edge from the mouth. After repeated attempts, I failed to improve upon my first model : thinking the tray might be at fault, I made a longitudinal section of the model, and a similar section of the tray, and then I soon saw sufficient reason for my previous failures. The interval between the inner surface of the impression tray and the roof of the mouth, when the tray was carried as near to the latter as the upper incisores would allow, was so great that it was necessary to employ a large body of wax to even reach the roof. The desirableness of using as small a quantity as possible for the comfort of the patient^ for the convenience of the manipulator, and for the success of the result, is 8 METHOD OF TAKING IMPEESSIONS well known to us all. I therefore constructed a tray, wliich, while it secured these points, gained another of considerable importance ; viz. that of forcing the wax not only upwards, but forwards into the intervals between the rugae. The diffi- culty, I may say impossibility, of efiecting this by the ordinary tray must be evident to every one accustomed to its use ; with it the wax is merely driven upwards, whereas it is necessary that it should have also a forward direction. It first struck me that a tray, nearly similar to those generally used for the lower jaw, with its inner border nearly perpendicular, would answer the purpose, so that when the wax rose above the inner border, as it would do when pressed against the alveolar ridge, it could be pressed upwards and forwards with the index finger, and thus be forced firmly into the interstices of the rug^ and against the roof of the mouth ; but I found that the point of my finger was not broad enough to make the pressure equal on all sides at once, and that when I pressed on one side, the wax rose at the expense of the other, and that when I with- drew my finger before removing the impression from the mouth, the wax was sucked down a little by the finger. These objections were immediately overcome by substituting a piece of metal rather broader than the interval left in the tray for the tongue, which I attached by a hinge to the inner border of the tray behind the incisor teeth. After OF CASES OF CLEFT PALATE. 9 the tray, armed with softened wax, had been pressed upwards against the alveolar ridge as far as possible, the finger was introduced into the mouth, and the moveable piece of metal was pressed upwards and forwards, carrying the wax before it. Thus a quantity of wax, so small as to be easily removed from the mouth, was sufficient to reach the highest part of the arch, and even to extend some way into the fissure of a cleft palate. This plan will be found to answer well in all such cases as those I have referred to, provided the lower jaw can be extended wide enough to allow the tray to be removed from the mouth without the front teeth scraping the upper surface of the wax. But instances will occasionally arise in which this cannot be accomplished, in which the oral opening will be so small as not to allow of even such a body being withdra^vn from it without sustaining some damage. In these cases I have found the following plan succeed. I take the best impression I can with an ordinary form of tray, from which I obtain a metal model, and strike up a Britannia-metal plate, placing between the model and the plate several layers of thick brown paper, so that the plate shall fit the mouth very loosely. I sometimes solder to this plate a handle, to render its removal from the mouth more easy. On this plate I lay a sheet of softened wax about a quarter of an inch in thickness, which, as the tray nearly fits the mouth it is used for, is suffi- 10 METHOD OF TAKING IMPRESSIONS cient to secure a perfect impression of every part. As the whole affair scarcely exceeds a quarter of an inch in thickness, it is easily removed from the smallest mouth. The cases next in difficulty to those I have just referred to are those of the lower jaw, where one or two of the molar teeth are absent on both sides, together with two or three of the front teeth, allowing the wisdom teeth to incline for- wards and inwards, and the other teeth that remain to fall towards each other ; the difficulty in such case is often considerably increased by the superior molar teeth, by having become elon- gated by the loss of their antagonists of the lower jaw, and so preventing the impression being lifted up sufficiently to clear the lower teeth. In such cases, the advantage to be derived from fitting a plate to the mouth in the way I have just de- scribed, and substituting a thin sheet of gutta- percha for wax, is sufficient to compensate fully for the extra trouble it involves. Indeed, I am doubtful whether it is extra trouble, whether the greater accuracy thus obtained does not more than compensate for the first trouble in the fewer visits paid by the patient for alterations. The difficulty of obtaining satisfactory impres- sions of such cases has been felt by every one, and has given rise to the employment of various substitutes for wax, which, however, upon being OF CASES OP CLEFT PALATE. 11 removed from the mouth, are dragged away by the inclining teeth, often to so great an extent as to render the impression worthless. Of all sub- stances, gutta-percha appears the one best adapted for the purpose ; but, until I had recourse to the fitted plate instead of the ordinary metal tray, I found the impressions taken in this material very indistinct and unsatisfactory. The heat required to soften a thick roll is too great to be endured patiently in the mouth ; yet, if employed less heated, the impression is very defective ; but, by using a thin sheet a quarter of an inch, or even less, in thickness, on a plate previously fitted to the mouth, it proves itself to be a most valuable agent. It is scarcely necessary to describe the way it should be used. A piece is cut to fit the plate, which should be roughened on the surface on which the gutta-percha is to rest; and when thoroughly softened in water, it is laid in the plate which has been previously warmed, and both are carried into the mouth. The plate should be pressed steadily into its place, and retained there by a finger on either side of the jaw : in about a minute the whole may be removed. The gutta-percha will be found to have yielded to the inclining teeth as it passed over them in coming out, but to have returned to the shape it first received in the mouth. A new material has recently been introduced 12 CASES OF CLEFT PALATE. by Mr. Stent for taking impressions, whicli ap- pears likely to be very useful in those cases in whicli the teeth do not incline towards each other ; but in such cases I fear it will be useless, as it must be allowed to become hard before it is removed from the mouth. But I have had no opportunity yet of testing it in such cases. In bringing these suggestions to a close, I feel bound to say that the idea of presenting them to this Society did not emanate with myself, but was suggested to me by others, who thought they would form a useful addition to the few remarks on cleft palate given on a former occa- sion. ^Tiether I have done wisely in thus yielding to the wish expressed or not, it is not for me to say, or whether the difficulties I have described have been felt by others, I cannot knoAV, as, until the recent date at which this Society was formed, we knew little of one another's difficulties and resources, and since its origin we have had other and perhaps more important subjects to occupy our attention ; but if you have listened on the present occasion to suggestions for which you have no need, you will, T doubt not, allow the motive to clothe the deed. ANNUAL GENERAL MEETING. Monday t January 4, 1858. W. A. HARRISON, Esq., V.P., in the Chair. The following Gentleman was duly elected a Member of this Society : — Mr. J. B. Lindsay Dover. The following Gentleman was proposed for the Membership of the Society : — Mr. Andrew Brae Leeds. The following Donations were made to the Society :— Mr. Arnold Rogers, an improved Ballot-box ; Dr. Arthur, his work on the Use of Adhesive Gold ; Mr. R. Brookhouse, a series of works on Dental Surgery ; Mr. Purland, a collection of Advertisements on Dental Subjects, principally of the last century. The following Gentlemen were elected by ballot as Officers and Council for the ensuing year : — T resident. — John H. Parkinson, Esq. Vice-Presidents.— 'kix^^W Rogers, Esq., F.R.C.S. ; W. A. Harrison, Esq., M.R.C.S. ; Robert Nasymih, Esq., F.R.C.S.Edin. ; W. Robert- son, Esq. ; William M. Bigg, Esq. ; C. Bromley, Esq. Treasurer. --Yi. Saunders, Esq., E.R.C.S. Honorary Secretaries. — Samuel Cartwright, Esq., Jun., M.K.C.S. ; John Tomes, Esq., F.R.S. ; Thomas A. Rogers, Esq., M.R.C.S. Council.— R. J. Barrett, Esq., M.R.C.S.; Alfred Canton, Esq., M.R.C.S. ; G. A. Ibbetson, Esq., F.R.C.S. ; John Martin, Esq. ; James Parkinson, Esq.; T. G. Palmer, Esq. ; John Parkinson, Esq , M.R.C.S. ; Hubert Shelley, Esq., M.B., M.R.C.S. ; Thomas Sheffield, Esq. GENERAL MONTHLY MEETING. Monday, February 1, 1858. J. H. PARKINSON, Esq., President, in the Chair. The following Gentleman was duly elected a Member of the Society : — Mr. Robert Norman Adelaide, Australia. The following Gentlemen were proposed for the Membership of the Society : — Mr. J. N. Manton 2, North Crescent, Bedford Square, Mr. Robert Ransom St. Leonard's. Mr. Cattlin read the following case : — At 3 P.M., Nov. 27th, 1857, Mr. C. applied to have a first upper molar of the left side ex- tracted. He stated that his teeth were fixed in an unusual manner, and that those which had been removed were extracted with considerable difficulty. The second bicuspis of the same side had been lost. The forceps were carefully adapted and applied low upon the neck of the tooth ; but, notwith- standing that cautious efforts were made for its removal, it was displaced with difficulty, and the anterior buccal fang broke off* low in the alveolus. It was found to be loose, and could be easily moved to and fro by a tenaculum. On a slight 16 EXTRACTION OF AN UPPER MOLAR. effort being made to extract, it slipped into the antrnm. A consultation was at once held with Mr. Stanley, and as the patient's father had died from malignant disease of the lower jaw, it was agreed that the fang should be removed from the antrum on the following day. 28th. — The soft parts being reflected, the bone in the situation of the stump was removed obliquely by a small trephine. The cavity was carefully explored and injected, but no trace of the missing fang could be discovered. A larger trephine was now used, and the antrum opened in a more depending situation ; but still, after repeated explorations and injections, we failed to extract the object of our search, and Mr. Stanley suggested that it was possible that the stump might have escaped through the opening during the night. Mr. Callender and myself thought we could feel it in a deep fossa, at the posterior part of the antrum ; but ridges of bone, and the fangs of other teeth which projected into the cavity, made the result of the examination very uncertain. On the 29th I visited the patient at Edmonton. He stated that he had had some pain during the night, but being now comfortable, he objected to further interference. Being certain, in my own mind, that the fang was not removed, I persuaded him to allow me to inject the cavity, and three pints of warm water were forcibly poured into it EXTRACTION OF AN UlTEB MOLAR. 17 by an enema syringe through an elastic tube (the head depending), but without effect. On the 30th I constructed a small gutta-percha scoop at the end of a probe, which was bent at such an angle as to command a sweep of any fossa in the antrum. In a few seconds the fang was removed by means of this instrument. 31st. — Has had occasional slight lancinating pains, but the parts are surprisingly free from inflammation. Ordered to foment and take an aperient if the pain increased, but otherwise merely to wash out the cavity gently with warm water twice daily. Dec. 4th. — Has had very little pain. Discharge rather foetid, but trifling in amount. 11th. — No pain, and scarcely any discharge. The communication between the antrum and the mouth is nearly closed, and air can only be forced through it by an effort. 21st. — A small quantity of air passes through the opening into the cavity. No pain, and scarcely any discharge. Jan. 18th, 1858. — A very small quantity of air still passes. No discharge nor pain. The adjacent parts look remarkably healthy, and free from inflammation. The opening is closing rapidly by granulation. 28th. — The opening in the gum in not larger than a pea, and is fast filling up. No air passes into the mouth upon blowing the nose. The c 18 ON PLATE-CASTING. parts look perfectly healthy, and cause the patient no inconvenience. This case is useful to show the amount of irritation which the bone and lining membrane of the antrum suffered, without exciting more inflammation than is necessary for the healing process. The communication through the nose was at no time obstructed, neither was there any collection of secretion in the cavity after the fis- tulous opening made in the bone had closed, so far as we have had an opportunity of observing. I have always used the trephine instead of the usual perforating instruments, with the advan- tages of exciting less inflammation and giving more space for washing out irritating matter from deep fossae, which are often present in the floor of the antrum, prior to curative treatment by injection. In a similar case in which I operated some years ago, I observe that the front and side teeth have separated very much, owing to the patient having neglected to wear a mechanical con- trivance which was supplied to keep them in situ, and assist mastication. Mr. J. N. Statham then read a paper ou " Flate-casiing ^ After alluding to the possibility of forming plates by the electric battery, by packing crystal- line or adhesive metal, or by layers of foil and solder, the author said : — " To scientific and prac- ON PLATE-CASTING. ' 19 tical men I feel assured that the specimens I have the honour to lay before you will need but little explanation. They are cast in loam. A core or mould of loam or sand, with plaster of Paris, hitherto presenting an objectionable roughness on the surface of the metal, I am now endeavouring to cast in a composition of blacklead, somewhat in the same way that small iron articles are cast ; and I hope to be able to compensate more thoroughly for the contraction of the metal. The plates appear to me sufficiently hard and tough." The plates exhibited were — Nos. 1, 2, and 3, of different thicknesses. No. 4, cast with bands, the burr cleared away to fit it to the plaster model. No. 5, suction-plate. No. 6, strong plate with bands. No. 7, upper plate, with bands and caps for decayed teeth. All of these were cast in silver. No. 8 was a plate cast in 18-carat gold. " They were cast by Mr. Corbett, of Denmark- street, Soho. A wax model of the plate is fitted to the plaster cast by means of a slight heat, produced either by dipping the sheet of wax in warm water, or directly by holding it to the fire and effecting any joining necessary with a heated wire ; the impression of the whole is taken in sand or loam. The mould is sprinkled and slightly dried, and the wax plate being replaced, c 2 20 ON PLATE-CASTING. the reverse impression taken. The moulds are then separated (channels for the molten gold cut), again dried and adjusted, and the gold poured, a much larger amount of metal being melted than the actual weight required for the plate ; the proportion being twenty times the weight of the wax plate, the weight of the column of gold being of essential service in forcing the metal into every crevice of the mould, and in pre- venting air-bubbles. The rough edges are now taken off, and the plate fitted down to the model, much in the same way as an ordinary ivory piece. I have also used a hard plaster-and-sand model to burnish the plate on, and to assist in correct- ing irregularities. Lacing the plate will be also found useful. From the approximate results of several measurements, I assume that the contrac- tion of 18 -carat gold is one- sixtieth of the mean breadth of the plate ; hence, scraping the model with a sculptor or graver evenly over its surface before the wax plate is made will compensate for the contraction of the metal on cooling. I am not acquainted with any solvent that will answer equally well. " Nos. 1, 2, and 3 were some of the first plates cast to ascertain how thinly they could be pro- duced, and also, in the event of their requiring much finish, the advantage of having a thick plate, to be reduced in fine fitting. " No. 4. A piece fitted to the model with bands. ON PLATE-CASTING. 21 This has been burnished on a hard plaster-and- sand model. " No. 5. The same piece cast on a plaster-and- sand model as a core, showing a well-defined internal surface. " No. 6. A plate cast from a scraped model, with wax plate and plaster model. " No. 7. Lower piece in the rough state, with wax and plaster models. " The aforementioned are in silver. " No. 8. Strip of 18-carat cast gold. "Also, specimens of casting sand, and of the thin sheet- wax used.* " The gold casting is now in my mouth, and I am happy to say that, after a month's wear, and although only roughly fitted in before a mirror, I have found it from the first as comfortable as an ivory piece, and more so than one in gold made in the usual way, resting firmly in its place, without springing or annoying the remaining teeth. The strip No. 8 is part of the same plate (cut off to reduce its size, and leave as Httle in the mouth as possible consistent with strength). One end has been struck between zinc and lead, and the result shows increased hardness and con- sequent capability of receiving a higher polish ; but I am not prepared to say that it would be * This is the white wax employed for making artificial flowers, and was procured from Mrs. Peachy and from Mr. Kcenig, of Rathbone Place. 22 ON PLATE-CASTING. beneficial to * strike up ' the plates, as the im- mense power obtained under the point of the burnisher seems to do all that is necessary. I may mention that the only compensation for con- traction in this piece occurred in drying the sand moulds, and the only solder used attaches the pins to the plate." GENERAL MONTHLY MEETING. Monday^ March 1, 1858. J. H. PARKINSON, Esq., President, in the Chair. The following Gentleman was duly elected a ^ Member of the Society : — Mr. Andrew Brae Leeds. The following Gentlemen were proposed for the Membership of the Society : — Mr. G. W. Smith, M.R.C.S.Eng., 6, Aytoun Street, Manchester. Mr. G. Ash, 15, Great Marlborough Street, London. Mr. E. E. Brand, 14, Berners Street, London. Mr. N. Stevenson, M.R.C.S.Eng., 62, Cleveland Square, London. Mr. C. G. De Lessert, 10, Waterloo Road, Wolverhampton. Mr. S. G. Hugo, 15, Allez Street, Guernsey. Mr. Buchanan exhibited the model of a child's mouth, in which one of the upper central incisors was standing diagonally. Mr. WooDHOUSE described a mode of treating these cases by torsion, which he had seen employed by Mr. Sheffield, of Exeter. - Mr. Tomes presented the following statistics compiled by Mr. Manton. A Statistical Account of 1,500 permanent Teeth removed, from various causes, at the Middlesex Hospital, hetiveen October 1866 and December 1857. By J. N. Manton. The relative loss of the several kinds of teeth both from the upper and lower jaw, and from the right and left side of the mouth, will be seen in the following Tables. 24 RELATIVE LOSS OP TEETH UPPER JAW. BIGHT SIDE. Centrals 9 Laterals 14 Canines 14 1st Bicuspid 70 2nd Bicuspid 68 1st Molar 97 2nd Molar 56 3rdMolar 37 Total. 365 LEFT SIDE. Centrals 9 Laterals 22 Canines 14 1st Bicuspid 60 2nd Bicuspid 60 1st Molar 114 2nd Molar 40 3rdMolar 25 Total. 344 LOWER JAW. RIGHT SIDE. Centrals 6 Laterals 5 Canines 10 1st Bicuspid 21 2nd Bicuspid 39 1st Molar 194 2ndMolar 80 3rdMolar 31 Total .386 Centrals Laterals Canines LEFT SIDE. 1st Bicuspid 22 2nd Bicuspid 42 1st Molar 197 2ndMolar 93 3rdMolar 36 Total. 406 Comparison between Manton's 1,500 and 1,500 from " Tomes's Dental Surgery." manton's. tomes's. Centrals 27 36 Laterals 48 58^ Canines 43 39 1st Bicuspid 173 136^ 2nd Bicuspid 209 217 1st Molar 602 562 2nd Molar 269 318^ 3rd Molar 129 132i Total 1,500 1,500 OF THE UPPER AND LOWER JAW. 25 Of 1,500 temporary Teeth removed in twelve months. This table gives the number of each kind of temporary teeth that were removed ; the cause of removal, of at least two-thirds, was to give room for the permanent teeth. UPPER JAW. BIGHT SIDE. Centrals 51 Laterals 57 Canines 89 1st Molar 98 2nd Molar 66 Total. 411 LEFT SIDE. Centrals 51 Laterals 50 Canines 65 1st Molar 97 2nd Molar 70 Total, 333 LOWER JAW. RIGHT StDB. Centrals 89 Laterals 70 Canines 84 1st Molar 97 2nd Molar 84 Total. 374 LEFT SIDE. Centrals 34 Laterals 65 Canines 78 1st Molar Ill 2ndMolar 96 Total. 411 333 374 384 Grand Total L502 The extensive opportunities of practice afforded in the hospital necessarily bring before the stu- dent many highly interesting cases, which, in the 26 CASES IN MIDDLESEX HOSPITAL. more limited range of private practice, would be less frequently seen. The following cases came under treatment in the Dental department of the Middlesex Hospital during the past year, and, although destitute of novel features, are yet sufficiently rare to justify me in bringing them before the Society. There have been five cases of haemorrhage from the dental periosteum. Case 1. — A first lower molar was removed on the Tuesday morning from a female aged forty. She returned on the following Saturday in a very weak state from the bleeding, which had continued up to that time. The reason of her not returning to the hospital before, was that her medical man had been en- deavouring to stop the haemorrhage, but had not succeeded. The cavity from which the tooth was removed was cleared, and matico-leaf, rolled into a ball, was placed in it, and the bleeding ceased in a few minutes. Case 2. — A young woman, aged twenty years, had the first lower molar extracted on Thursday. She returned on the following Saturday, and stated that a slight amount of bleeding had con- tinued ever since the tooth was removed. The haemorrhage was stopped in a short time by applying a little wool, saturated with muriated tincture of iron. CASES IN MIDDLP]SEX HOSPITAL. 27 Case 3.- — A man, twenty-five years of age : he had the first left upper molar stump removed, the first right upper bicuspid, and also two supernumeraries, which were situated behind .the upper central incisors. He returned on the second day after the operation. The bleeding did not continue long after the teeth were extracted, but the following afternoon blood flowed from the alveolar cavities, from which the molar and supernumerary teeth had been removed. In this case there was some little difficulty in arresting the haemorrhage from the sockets of the supernumerary teeth; but by persevering in the use of matico-leaf, with a compress of lint, and a bandage round the head and chin, it ceased in about forty minutes. The other two cases were treated by the house surgeon. There have been three cases of injury to the alveolar process. Case 1. — A middle-aged man sought advice under the following circumstances : He had applied to a dentist about a week previously, to have the first lower molar on the right side removed. The operation was performed with the key instrument. Upon examining his mouth, it was found that the alveolar process on the buccal side of the first, second, and third lower molares was firactured, and the second and third molares much loosened. 28 CASES IN MIDBLESEX HOSPITAL. The patient seemed to be suffering very much, but the fractured bone was not sufficiently detached to render its removal expedient ; neither was it con- sidered advisable to extract the loosened teeth. The patient returned at intervals, and in about two months from the time of the injuries the dead bone had become sufficiently detached from the living to be readily removed. The loose teeth had in the mean time become firm and useful. Case 2. — In this instance a man came to the hospital in consequence of injuries he had received six months previously, in the removal of the second upper right bicuspid with the key instrument. The alveolar process was very much broken, and the first bicuspid loosened to such an extent that its removal became necessary. The fractured alveolar process was removed at the same time. In the third case a large piece of alveolar process was removed from where, four months previously, a second lower temporary molar had been extracted. The key instrument had been used in this as in a preceding instance. Supernumerary Teeth, Six supernumerary teeth have been extracted during the past year. A man, aged twenty-five, had two removed, which were situated behind the upper central incisores. The impression of this case is now on the table. CASES IN MIDDLESEX HOSPITAL. 29 In tlie second case, the teeth were situated on the right side of the upper jaw of a girl aged sixteen, and consisted of two perfectly formed supernumerary lateral incisores, placed imme- diately behind the normal lateral incisores. The posterior teeth were removed. The impression of this case is also before you. In the third case, a supernumerary tooth was removed from behind the left lateral incisor in the lower jaw of a girl twelve years of age. In the fourth case, a girl, aged seventeen, had a supernumerary tooth placed between the central incisores of the upper jaw. In the fifth case, the supernumerary tooth was situated between the lateral and canine, on the left side of the upper jaw, of a girl aged six- teen years. A Persistent Temjporary Tooth, A man, aged twenty-five, applied for advice for the relief of pain situated in the lower bicuspides on the right side. The teeth, to all appearance, were quite sound and healthy ; but, as he imagined they had been the source of annoyance to him for upwards of two years, he wished them removed. Upon examination, a very small opening, from which pus escaped, was discovered. The opening was situated at a point corre- sponding to the extremity and between the two 30 CASES IN MIDDLESEX HOSPITAL. fangs of the first and second bicuspides above mentioned. A small probe was passed, and what appeared to be dead bone was felt. The opening was then enlarged, and the supposed dead bone removed, which, upon removal, was found to be the crown of a second lower temporary molar tooth. It was removed with some difficulty. A PAPER ON THE FORM AND SIZE OF THE ADULT ANTRUM, AND ON THE DIAGNOSIS AND TREATMENT OF INFLAMMATION OF THE LINING MEMBRANE, Was read hy W. A. N. Cattlin, F.E.C.S. Eng. Since the time of Galen, the Maxillary Sinus has attracted the particular attention of surgeons, on account of the many serious maladies to which it is liable. Highmore described the antrum as " conical and somewhat oblong," and wrote a Latin treatise upon its diseases. He also illus- trated the shape of the cavity by plates (Figs. 1,2). Fig. 2 Fig. 1. ^ ' Shape of Antrum copied from Shape of Antrum, copied from Highmore, half size. Highmore, half size. He refers to the operation of tapping, which he appears to have practised for the relief of accu- mulated fluid. Holden, one of the best of modern authors, more correctly compares it to "a trian- gular pyramid, with the base towards the nose, and the apex towards the malar bone," and refers to " thin plates of bone which are often found 32 ON THE FOEM AND SIZE extending across tlie antrum." It would be difficult to describe every variety of form and size wliicli may be seen in the human antrum at adult age, and such knowledge can only be obtained by the personal examination of nume- rous specimens. As a general rule, it is larger in the male than in the female, and perhaps diminishes in size with extreme age. It is lined by a muco-serous membrane, which, in the healthy state, allows air to enter the sinus through an opening in the upper part of the posterior wall. In the young subject the cavity is small, and its walls comparatively thick. The roots of the molar and bicuspid teeth, if fully developed, often perforate the floor, but more frequently they are covered by a very thin layer of the inferior wall. The specimens (Figs. 3, 4, 5) have been selected from a hundred bones taken indiscriminately. Fig. 3. Common shape and size of the Adult Antrum, capable of containing 2.J drams of fluid {transverse section). OF THE ADULT ANTRUM. 3a Fig. 4. Large Adult Antrum, capable of containing 8 drams of fluid {transverse section). [-^ Fig. 5. Small Adult Antrum, capable of containing 1 dram of fluid {transverse section). There is often a great difference in the size and shape of the cavity, and in the elevation of its floor I) 34 ON THE FORM AND SIZE in the two sides of the same individual (Fig. 6). Fig. 6. Antnim differing in the size and elevation of the floor in the two sides {transverse seetion). Occasionally the antrum extends into the body of the malar bone (Fig. 7), Antrum extending into the Malar hone {posterior view). OF THE ADULT ANTRUM. 35 or is divided into compartments by thin plates or thick ridges of bone (Figs. 8, 9, 10). Fjg. 8. Antnnn divided by a thin plate of bone, with a deep fossa on each side {posterior view). Fig. 9. Antrum divided by a thick ridge of bone {anterior view). Fig. 10. Antrum divided hini -ntn'hj . with cells exten^ng beneatlt the orbital plate (jtosterior view.) D 2 36 ON THE FORM AND SIZE More frequently dee/p 'pockets, or fossce, are formed in various parts of tlie cavity, particu- larly at the anterior or posterior corners of the floor (Fig. 11), and along the upper part of the Fig. 11. Antrum with pockets in the anterior and posterior corners of the floor, perforated by alveolar abscess, in the possession of Mr. Tomes {transverse section). anterior wall immediately beneath the orbital plate (Fig. 10). Sometimes a bony canal ter- minates in a cul-de-sac beneath the orbital plate in the nasal corner of the anterior wall (Fig. 12). An intimate knowledge of irregular formations of the antrum will contribute to the diagnosis and treatment of those maladies which are usually OP THE ADULT ANTRUM. 37 Fig. 12. Fossa extending along the upper part of the anterior wall heneuth the orbital plate. Bony canal ending in a cul-de-sac {posterior view). included in dental surgery. The accidents and diseases to which this part is peculiarly liable are also worthy of passing notice. Where the cavity is divided by a plate or ridge of bone (Figs. 8, 9) in the operation of tapping, fluid may be removed from one compartment, and remain in the other, or the instrument may impinge upon the bony septum. In the former case the treatment would be ineffectual, and in the latter the septum might be mistaken for an osseous growth. Foreign bodies, such as musket-balls and fangs of teetli, often pass into the antrum, 38 ON THE FORM AND SIZE and may become impacted in some compartment of tlie sinus. As a general rule, they do not cause sufficient inconvenience to warrant surgical inter- ference; but should the case be otherwise, in ordinary shapes of the cavity they can readily be extracted by an enlargement of the opening through which they have entered. Loose teeth have been found in solid and encysted tumours (Fig. 13) ; it is a question of surgery whether such foreign bodies should be allowed to remain within the sinus in persons pre- disposed to malignant disease. The following case occurred in the writer's practice. The fang of a first molar tooth, during an attempt to extract it, passed at once into the antrum ; the patient being a gen- tleman whose father had died of secondary malignant disease of the jatv. A consultation was held with an eminent hos- pital surgeon, and it was thought advisable, under the circumstances, to trephine the antrum. Two large openings were made, — one in the anterior, and the other in the inferior wall. The cavity was repeatedly explored and injected, but, after Fig. 13. An unique specimen of osseotts cyst con- taining a loose tooth, in the possession of Mr. S. Cartwright (posterior view). OP THE ADULT ANTEUM. 39 considerable search, we failed to remove the fang. On the second day three pints of warm water were forcibly injected through the upper opening by means of a syringe, but with no better success. The writer being convinced that he had felt the fang, and that it was impacted in a pocket at the posterior part of the floor, constructed a small gutta-percha scoop, and attached it to a gold probe capable of being bent to such an angle as might be necessary to sweep any irregularity in the floor of the antrum. With the aid of this simple instrument (Fig. 14) the foreign body was at once dislodged and extracted. Very little pain was experienced after the first operation, the patient soon pursued his ordinary business, and, at the end of three months, the parts were restored, apparently by bone, and looked perfectly natural. A small quan- tity of healthy mucus could, however, be forced through a minute opening in the ffum at the end of the fourth month, O ' Half size. but very little inconvenience of any kind was suffered after the first few days. This case is of interest to show the great amount of irritation which the lining membrane of the antrum will sometimes bear without taking on active inflam- mation; and the rapidity with which the walls were restored, contrasts strongly with the lack of 40 INFLAMMATION OF THE reparation which generally obtains after any part of the maxillae has been lost by necrosis. Morbid growths dilate the antrum, and may be mistaken for accumulated fluid. They are either Osseous, Cartilaginous, Fibrous, Encepha- loid. Fatty, or Erectile. Epulis has also been known to penetrate into and distend the cavity. They occur at all ages. As a general rule, the malignant kinds are soft and of rapid growth, while the non-malignant are hard and of slow growth. The lining membrane is also liable to cancerous ulceration. Membranous cysts and efiusions of blood, serum, or pus into the cheek, occasionally compress the anterior wall, and some- times simulate dilatation of the antrum. A careful inquiry into the history of the case, and a judicious use of the grooved ne^edle, will, in most instances, lead to a correct diagnosis* , Inflammation of the lining Membrane. Inflammation of the lining membrane of the maxillary sinus is not confined to any age ; it is, however, most frequently met with in middle-aged persons of weak or strumous constitutions. Mild forms of the disease, produced by local irritation or catarrh, are by no means uncommon ; but its most severe form, accompanied by efiusion, is comparatively rare. Cannes.— it will be remembered that the fangs %t m LINING MEMBRANE. 41 of the superior molares, bicuspides, and cuspi- dati often protrude through the inferior wall of the antrum, or are covered only by a very thin layer of its substance : hence it follows, that diseased teeth are the most common cause of inflammation of the lining membrane. Occasionally, part of the floor is brought away with a tooth in the operation of extraction f^^- 15. /t:i' -• ^'\ n J* 1 Part of the floor of the Antrum nttufhed (Fig, 1 5) . Sometimes al- tv the fangs of a molar Tooth. veolar abscess produces absorption, and its secretion passes into the antrum (Fig. 11). Inflammation may also be produced by blows, foreign bodies, obstructions of the proper open- ing by tumours, &c. ; syphilis, necrosis, irregular dentition, pressure during parturition, &c. It may assume the catarrhal, rheumatic, stru- mous, phlegmonous, or erysipelatous forms. An interesting case in an infant only two weeks old, where the disease was caused by pressure of the face upon the arch of the pubis during delivery, has been published by the late Dr. Gr. A. Rees. {Medical Gazette, vol. iv., N.S., p. 860.) Another, arising from irregular dentition, is recorded by M. Gensoul, of " a child aged thirteen, whose antrum was distended with a large collection of yellow fluid, caused by a canine tooth which was found at the bottom of the cavity adhering to 42 INFLAMMATION OF THE its walls." He was about to operate upon this patient for the removal of a morbid growth. Sijm'ptoms. — In acute inflammation of the antrum there is a deejp^ dull, heavy pain, accom- panied by a sense of weight and fulness in the side affected. Occasionally lancinating pains pass to the frontal sinus, orbit, and various parts of the face; the cheek is swollen, red in patches, and tender to the touch : there is feverishness, with or without rigors. If the symptoms be not subdued, the cavity may become dilated by fluid, the cheek and palate enlarged, the superior wall pressed upwards, the nostril contracted, and its secretion diminished. The anterior wall has even been known to ex- foliate, and to allow fluid to escape into the cheek. Chronic inflammation is attended by less severe pain, which is either dull or of a grinding rheu- matic character. The walls of the antrum are more gradually dilated, and are said to have become so thin as to crepitate upon pressure. Occasionally they are hypertrophied. In some cases the pain is altogether inconsiderable, and a discharge passes into the mouth or nostril, for years unheeded by the patient. Character of the fluid. — If we remember that the lining membrane of the antrum is continuous and identical in structure with the Schneiderian membrane, and call to mind the morbid changes which take place in the secretions of other air- LINING MEMBRANE. 43 passages, we shall be prepared to understand how fluids detained in the antrum will vary with the causes and circumstances under which they shall have been produced, and the length of time they may have been confined within the cavity. Hence we see the sinus at one time distended by its own proper secretion, unaccom- panied by pain or inconvenience until its walls have been greatly dilated {dropsy of the antrum) ; and at another time the effusion is the result of acute inflammation, and takes on the appearance of healthy pus {abscess of the antrum). When the disease has been of long standing in strumous patients, the secretion is of a dirty, curdy, or flocculent appearance, and in some instances a thin watery fluid escapes, and leaves the cavity dilated by a firmly-clotted mass of most offensive odour. A case is recorded by Mr. W. Ferguson in which the fluid was of a " yellow, viscid charac- ter, containing brilliant particles of cholesterine." {Medical Times, May 18th, 1850.) Treatment, — It is of the highest importance to remove, without delay, any diseased teeth or necrosed bone which may be found in or beneath the floor of the antrum, and at the same time to examine whether pus be discharged into the mouth, and whether dentition has been com- pleted. If the jaws be closed, they should be separated, for the purpose of examination, by means of the speculum, or some other appropriate 44 INFLAMMATION OF THE instrument. The practice of refusing to operate for the extraction of teeth until inflammation of the soft parts has subsided, caanot be too strongly condemned. Patients' often suffer for weeks, and even for life, from the effects of such injurious surgery. In recent cases of inflamed antrum, and under favourable circumstances, it will be sufiicient to remove the exciting cause, and leave Nature to complete the cure. If the inflammation be acute, and attended with painful tumefaction, feverishness, or rigors, it will be necessary to draw blood from the gums and palate by means oi free incisions, or the repeated application of leeches, and to bathe the face with warm narcotic fomentations. Purgative, sedative, and saline medicines should be administered, and an antiphlo- gistic treatment pursued to an extent consistent with the severity of the attack and the powers of the patient. Should active symptoms continue, and the cavity become greatly distended by fluid, it will be advisable to extract the first or second upper molar tooth, and to perforate the antrum with a large trocar or small trephine. The opening which is usually made by the ordinary instrument is by far too small, either to allow the escape of clotted mucus, or to admit of successful injection. The lining membrane may now be gently fomented with warm decoction of poppies or infusion of conium ; and if the pain be severe, twenty or thirty minims of the sedative solution LINING MEMBRANE. 45 of opium in a small quantity of warm mucilage may be injected, and detained for the purpose of absorption. In chronic inflammation, when 'the membrane has become altered in character, or when the patient is debilitated, it will be requisite to improve the general health by country air, sea- bathing, generous diet, quinine, the salts of iron or iodine, cod-liver oil, &c. Bearing in mind that acrid discharges may be retained in partictdar compartments of the antrum, or adhere to the membrane, it is important that the cavity should be carefully washed with warm water in eveiij instance prior to the application of an injection. The instrument used for this purpose should be bent and perforated in such a manner as to insure the effectual transmission of its contents to every part of the cavity. A variety of stimulating or astringent injections will be necessary in the treat- ment of. chronic inflammation, and the amount of benefit derived from their use will greatly depend upon the skill with which they are varied and applied. It will be found that parts covered by mucous membrane often become accustomed to any particular remedy, and after a time fail to be affected by its use. This is especially the case with the lining membrane of the antrum, and it is advisable to change the injection, or to increase its strength, directly the discharge ceases to im- prove. In very chronic forms of the disease, the patient should be directed to lie down, and to 46 INFLAMMATION OF THE LINING MEMBRANE. detain the lotion within the cavity until slight pain be produced. One or two grains of the nitrate of silver dis- solved in an ounce of distilled water, and gradually- increased in strength, is perhaps the best injec- tion to begin with. It should be administered with a glass or India-rubber syringe, after the cavity has been freely washed, and may be changed in turn for solutions of the Sulphate of Copper, Alum, Chloride of Zinc, Biborate of Soda, Sulphate of Zinc, Iodide of Potassium, Tannin, Bichloride of Mercury, Sesquichloride of Iron, Chloride of Lime, Permanganate of Potass, &c. The two latter remedies are particularly indicated when the discharge is fetid. Individual expe- rience of comparatively rare diseases must of necessity be limited. The chief object of the foregoing observations has been to suggest a more cautious application of remedies in the treatment of inflammation of the lining membrane of the antrum by injection, and to call attention to some irregular formations of this cavity, which it is beheved are not generally known. GENERAL MONTHLY MEETING. Monday, April 5, 1858. J. H. PARKINSON, Esq., President, in the Chair. The following Gentlemen were duly elected Members of the Society : — Mr. J. N. Manton London. Mr. Robert Ransom St. Leonards. The following Gentleman was proposed for the Membership of the Society : — Mr. George Owen 1, Bedford Row, Islington. Mr. James Parkinson exhibited a model showing a crowded con- dition of the upper and lower jaw of a child ten years old, owing to the presence of permanent teeth before the temporary teeth had been shed. Mr. Tomes exhibited to the Meeting an expedient for determining the forms of Dental Instruments, more especially Stopping Instruments. They had all no doubt felt at times the want of an instrument quite suited to the purpose for which it was required ; and in order to meet that difficulty, he had mounted two or three block-tin instruments in handles corresponding to those he had in ordinary use. They were capable of being bent into any form that might be required while the patient was present, and any maker could supply a steel instrument from the pattern. The following communication was received from Dr. Phaser, of St. John's, Newfoundland. On the 14tli of October, 1848, William Roberts (of Brigus, Nfld.), aged 30 years, by occupation a fisherman, of large frame and robust constitution, sustained (whilst at Labrador) a very serious injury 48 INJURY OF THE FACE. of the face by the bursting of a gun. His nose and right cheek were severely cut and contused, and the whole face completely blackened. Yiolent inflammation, with great swelling, supervened, and he continued in a state of insensibility for three days. When restored to consciousness, he complained of most excruciating pain in the face, which continued unabated for three weeks, and great noise in the head, which lasted for six months. Three weeks after the injury, he arrived at Brigus, and then, for the first time, consulted a medical gentleman, who, however, from the inflamed and oedematous condition of the whole face, could not possibly form a decided opinion as to the precise nature of the injury. The patient was put under medical treatment, and was unable to leave his house until March, 1849, and was then only able to walk a short distance : a constant fetid puru- lent discharge escaped from the right cheek and nostril. In May, 1849, the wound of the cheek completely healed over, but the discharge con- tinued from the nose. In June he went to the summer fishery, but from his debilitated state could work but little. The wound in the face remained closed until November, 1854, when an opening formed near the right ala nasi, through which a purulent dis- charge, with a quantity ofpoivder and rust, escaped. On the 2nd of January, 1855, he was suddenly seized with alarming haemorrhage from the right INJURY OP THE FACE. 49 nostril, the blood being quite florid, and escaping in a full stream, when another medical gentleman was sent for. The bleeding continued, moi*e or less, from one until four o'clock p.m., when it ceased ; but recurred every eight or ten days until April of the same year. Since then there has been little or no haemorrhage. During the whole of the foregoing period the patient suffered from severe headaches, sometimes complained of dimness of vision in the right eye, and occasionally of pain in that organ. The sense of smell was completely lost ; his appetite varied, sometimes being very good, at other times ex- tremely bad; he subsisted almost entirely on fluids ; altogether his general health became seriously impaired. In May, 1855, he came to reside in St. John's, and consulted several medical gentlemen, but ob- tained no relief. In August following, the pain in the face became much more intense than it had been since the occurrence of the accident. An abscess formed in the right cheek, and a copious discharge of purulent and sanious matter, together with more powder and rust, followed ; after which the pain only occurred occasionally. He applied to me for advice on Tuesday, the 17th June, 1856, stating that his face had been injured nearly eight years previously by the blast- ing of gunpowder, and made no mention of a gun having burst in his hands until after the operation B 50 INJURY OF THE FAOe! (about to be described) was performed. He in- formed me that he had undergone different kinds of treatment, and applied various remedies to the face, without deriving the slightest benefit there- from. On examination I found the right malar bone considerably enlarged, the right side of the face a little swollen, and a cloaca existed in the right cheek, situated nearly opposite the upper border of the ala nasi. Having passed a probe into this opening, I detected what I at first sup- posed to be a large piece of necrosed bone, which could be slightly moved. As he could not open his mouth more than a quarter of an inch, I failed in ascertaining the state of its interior. I examined the nasal cavity with the speculum, but discovered nothing abnormal. As the man's health was rapidly giving way under the irritation and constant discharges to which he was subjected, I advised him to submit to an operation, to which he most willingly as- sented. On Thursday, June 19th (two days after I first saw him), I proceeded to operate, assisted by Dr. W. C. Simms. The patient having been put under the influence of chloroform, I made one incision from the upper border of the right ala nasi, extending across the cheek towards the prominence of the malar bone, and a second, beginning at the commencement of the first, and extending downwards towards the angle of the mouth, and retracted the flap thus formed, when INJURY OF THE FACE. 51 it became obvious that the cause of so much suffering was not diseased bone, but metal. After considerable difficulty I succeeded in extracting (what is almost incredible) the breech of a gun! the presence of which had never been suspected. The patient was only sensible of the last two or three efforts at extraction, and although there was no haemorrhage of any consequence during the operation, we did not, during its latter part, induce complete anaesthesia, fearing that blood might find its way into the trachea, and cause suffocation. The piece of metal weighed a little more than four ounces^ and was quite oxydized. The trans- verse portion measured in length one inch and a half, in breadth five-eighths of an inch at one part, and half an inch at its narrowest part; its thickest portion measured five-eighths of an inch. That portion of the breech, which is screwed on to the stock measured in length two inches and six- eighths, and in breadth five-eighths of an inch. The screw measured in circumference two inches and five-eighths. It now only remains for me to state, so far as I can, the position occupied by this foreign sub- stance, and the subsequent progress of the case. The superior maxilla was evidently fractured over the antrum Highmori ; the transverse portion of the breech, with the greater part of the screw, passing into that cavity, became embedded there, E 2 52 INJURY OF THE FACE. and a large opening was formed between the antrum and right nasal fossa. The long part of the breech, or that portion which is screwed on to the back of the stock, passed backwards between the zygomatic arch and the coronoid process of the inferior maxilla, its edge resting on the alveolar process of the superior maxilla, and its extremity extending nearly as far backwards, I imagine, as the lower part of the temporal surface of the great wing of the sphenoid bone, its edge, near the ex- tremity, being in close contact with the external plate of the pterygoid process of that bone. Such I think must have been pretty nearly the position occupied by this singular intrusion. No inflammation followed the operation, and since its performance the patient has been almost wholly free from pain. On removing the breech, the cavity appeared quite black, and for a few days a dark purulent discharge, together with small pieces of rust, escaped. Healthy granulations then sprang up, and the parts rapidly contracted. Now (July 4th) the cavity is nearly filled up, and the external wound almost closed. The action of the lower maxilla is slowly improving, and he has quite recovered the sense of smell. The only after- treatment consisted in the administration of one or two doses of aperient medicine, and the con- stant application to the sore of pledgets of lint, moistened with cold water. In a few days the CASE OP TRISMUS* 53 man will, I think, be quite able to resume his usual calling. Mr. Seecombe communicated the following Case : — A lady in the lying-in chamber suffered violently from toothache. Her medical attendant did not extract the tooth — the wisdom tooth on the right side. The pain increased, and shortly afterwards a great swelling appeared underneath the jaw. He thought an abscess had formed, and made an opening about the angle of the jaw to let out the pus, but none escaped, and within a short time the abscess burst into the throat. The swelling was so great that the patient could not open her mouth. It was presumed, however, that as the abscess healed, she would be able to do so ; but when the abscess did heal, after a considerable time, the mouth was quite fixed. It was indeed a case of trismus, and the patient was unable to take solid food. After recovering from her accouchement, efforts were made to extend the jaw, but in vain ; for, with the greatest possible amount of force that could be exerted safely, the jaw could only be opened three- sixteenths of an inch. Under those circumstances it was thought desirable to extract the wisdom tooth, if possible. The patient was taken to York, but the dentist said it was impossible to tp,ke out the tooth, as the jaw could only be opened so slightly. The lady afterwards came under my care. At first I 54 DESCRIPTION OF AN INVERTED TOOTH. thought that the case might be one of hysteria, and that it would be desirable to administer chlo- roform, hoping that the jaw would then become relaxed. Chloroform was accordingly administered by Dr. Snow, and a screw applied for expanding the jaw, but the opening did not exceed three- sixteenths of an inch. I then had no hesitation in putting in an elevator sideways, cutting through the alveolar process, and bringing out the tooth in that direction. The patient returned to the country as soon as possible, and in three months the jaw had entirely regained its original power of extension and closing. The trismus had lasted nine months, during which time the patient had never been able to take solid food. The tooth was considerably decayed. Mr. Tomes read the following paper : — Descrijpticm of an Inverted Tooth, and the conse- quences ivhich its inversion entailed, considered in relation to certain forms of Tumours of the Jaw, I have been induced to bring before the Society the details of a case, not only on account of the unusual characters which it presents, but also on account of its throwing some light upon a certain class of tumours of the jaw, a characteristic fea- ture of which is, the presence of a tooth concealed within the tumour. It will have been remarked that the eruption DESCEIPTION OF AN INVERTED TOOTH. 55 of a temporary tooth is not very uncommonly preceded by the appearance of a vesicle upon the surface of the gum, and that if a lancet be employed, a small quantity of transparent fluid escapes, and leaves the enamel of the coming tooth uncovered. The surface of the enamel, when the formation is completed, becomes de- tached from the investing soft tissue, although the contact of the surface is preserved. But imder certain circumstances the two surfaces may become separated by the interposition of fluid, which, when collected to an appreciable amount, produces that condition described as a vesicle. In unhealthy children the fluid, instead of being transparent, like serum, may become purulent; and the vesicle, which in the one case is productive of no inconvenience, may in the other pass into a painful ulcer, and occasion great suffering to the patient, as well as] injury to the subjacent teeth. But in cases of the foregoing description the collection of fluid, whether serous or purulent, being situated near the surface of the gum, readily escapes without involving the more deeply seated parts of the jaw in disease. In the case I will now relate, fluid collected, as I believe, under similar circumstances, except as regards the posi- tion of the tooth, around the crown of which the disease arose. A girl, 16 years of age, the daughter of a tradesman, was sent to me by Mr. Franklin, nnd 56 DESCRIPTION OF AN INVERTED TOOTH. gave tlie following history of her case. Nine months since, a swelling appeared on the lower jaw, around the unplanted portion of the second molar tooth, and was supposed to be consequent upon the formation of a gum-boil. At first the pain in the enlarged part of the jaw was slight and intermittent ; but with a gradual increase in the size of the swelling, the amount of discomfort became greater, although it was at no time very severe. I saw her for the first time on December 15th, 1856. There was very considerable enlarge- ment of the alveolar portion of the lower jaw, around the second molar of the right side of the mouth ; the tooth itself was, however, perfectly sound, and although slightly tender when pressed upon by the antagonistic teeth,, yet it was not considered by the patient to be the seat of pain. The colour of the tooth was perfectly natural, and the implantation firm — indeed, there was a total absence of any indications which would induce a belief that disease had arisen first in the tooth and subsequently extended to the jaw. The swelling was not confined to the soft parts — the bone was obviously involved in the disease. At one point, however, fluctuation could be felt, but the examination did not appear to produce any considerable amount of pain in the part. The absence of active inflammatory symptoms, and the comparative freedom from tenderness on })ressure, coupled with the large amount of local DESCRIPTION OP AN INVERTED TOOTH. 57 swelling, rendered the nature of the disease very obscure. Mr. Amott was kind enough to see the case. He introduced a grooved needle : several drachms of clear yellow fluid escaped, and the swelling of the soft parts to a certain extent subsided, leaving the outline of the en- largement of the bone comparatively distinct to the finger. The patient felt relieved by the operation from the sense of tension and weight, which had latterly become distressing. I saw her again on the 26th of January. The swelHng she stated had gradually returned, and with it a dull aching pain. The involved tooth I found had in the interval become slightly loose, and was turned a little inwards towards the tongue. The swelling was again punctured with a needle, and with results similar to those already described. On the 5th of February the patient returned. She stated that after the last operation she suffered great pain, accompanied with constant throbbing in the tumour, and that pus had sub- sequently been discharged from the orifice made by the needle. The amount of constitutional disturbance which accompanied these symptoms was sufficient to confine the patient to her room for some days. Upon examination, I found that the tooth had become much more displaced than formerly, that it was quite loose, and that the surrounding gums were greatly inflamed. Under these circumstances I determined to remove the 58 DESCRIPTION OF AN INVERTED TOOTH. tooth, althougli it was by no means clear that it was the primary cause of the mischief. On re- moval, a most unusual state of things was mani- fested. Instead of possessing the two compressed fangs common to second molars of the lower jaw, the unplanted portion of the tooth was dilated into one large concavity or cup, in which was placed the crown of the second tooth, perfectly invested with well- developed enamel, and with the masticating surface directed downwards towards the lower border of the jaw. The two teeth appear to be united by dentine at one point, and to have one common pulp-cavity. The pain from the operation quickly subsided, and within a fortnight all swelling and pain in the soft parts had disappeared; the enlargement in the bone had also sensibly diminished. The result of the operation leaves but little room to doubt that the inverted tooth was the primary source of mischief, and that the strumous diathesis of the patient favoured the development of the disease. But the question as to the manner in which the morbid conditions were developed, re- mains to be answered. That answer will, I think, be found by referring to the cases alluded to at the commencement of this paper. In them we have an opportunity of examining the conditions as they gradually arise, and can see that the fluid collects between the enamel and that portion of the dental sac which surrounds the enamel. Now, DESCRIPTION OP AN INVERTED TOOTH. 59 in the case under consideration, I believe the early conditions to have been similar to those which obtain in the vesicular enlargement con- nected with the eruption of the temporary teeth. The fluid which collected was similar in character; but while, in the one case, a ready means of escape was afforded by irruption through the gum, in the other, the collection was bounded by the tooth above and the jaw below, and its escape conse- quently prevented. As the fluid increased in quantity, the adjacent bone was absorbed, and thus made way for the increasing cyst. Coin- cident with the absorption within, new bone was developed on the outer surface of the jaw, until the jaw at the point corresponding to the disease became greatly enlarged. The fluid was let out by a minute puncture, which rapidly healed; it was again let out by a similarly small aperture; the cyst inflamed and secreted pus, which oozed out through the opening; the tooth was then removed, and free egress given to the pus, and the patiently rapidly recovered. The case, in fact, passed through similar conditions to those which accompany the formation of vesicular swell- ing in connection with temporary teeth subsequent to the development of the enamel, the differences consisting rather in the severity than in the character of the symptoms. But had these con- ditions arisen in connection with a tooth buried deep within the substance of the jaw, and un- 60 PESCEIPTION OF AN INVERTED -TOOTH. connected with either of the teeth which had taken their position in the series, the bone would have enlarged much in the manner it is seen to do in certain forms of malignant disease, and this too without the presence of a tooth as a cause of the disease being suspected. I am indebted to Mr. Underwood for a model of a case which was exhibited at one of the earlier meetings of this Society. In this instance the jaw was enlarged by the gradual expansion of a cyst, within which a canine tooth hes horizontally near the lower border of the jaw. A portion of the jaw was removed, no doubt, under the impression that the disease was malignant in character, and I am not in a position to prove that such was not the nature of the malady. But judging from the appearance presented by the bone, the position occupied by the tooth, and the presence of what appeared to be a lining membrane within the cavity upon the floor of which the tooth was placed, I should be strongly disposed to think that the disease resembles in its origin and pro- gress that which has formed the subject of this paper, and that it would have subsided had a free opening been made into the cyst, and the tooth removed without having recourse to so serious an operation as that of excising a large portion of the jaw. GENERAL MONTHLY MEETING. Monday^ May 3, 1858. JOHN H. PARKINSON, Esq., President, in the Chair. The following Gentlemen were duly elected Members of the Society : — Mr. G. W. Smith Manchester. Mr. George Asir London. Mr. S. G. Hugo Guernsey. Mr. E. E. Brand London. Mr. N. Stevenson ..: London. Mr. C. G, De Lessert Wolverhampton. Mr. S. Cartwright, r.K.S., was elected an Honorary Member. The following Gentlemen were proposed for the Membership of the Society : — Mr. James Anderson, 14, Margaret Street, Cavendish Square. Mr. Harper R. Hugo, St. Heliers, Jersey. Mr. Tomes related a case which he said had occurred in his own practice. A patient complained to him of great pain- in the second molar of the upper jaw. The tooth appeared to be perfectly sound as far as the crown was concerned, but was somewhat discoloured. On looking further back, he found the wisdom tooth, instead of occupying its usual position, pressed forward, the crown being directed towards the posterior part of the second molar. On examining the latter more carefully, he found a small orifice in the neck. He then removed it, 62 A NEW FORCEPS FOR REMOVING and found that the wisdom tooth, in pressing forward, had produced absorption in the neck to such an extent as to open the pulp-cavity. The pulp had inflamed and suppurated, and thus pro- duced the symptoms exhibited. Since seeing the case, Mr. Catlin had sent him (Mr. Tomes) a drawing of a tooth, in which absorption had taken place in the second molar of the lower jaw by the pressure of the wisdom tooth ; also a specimen in which absorption of an anterior tooth had been produced by a pressure forward of a posterior one. A similar case had been forwarded by Mr. Canton, in which a wisdom tooth of the lower jaw had occasioned absorption. Mr. Coleman, on exhibiting a new forceps for removing the stumps of upper molars, said, — "It is with some feelings of diffidence that I venture to bring under the notice of the Society a new form of forceps for extracting the stumps of upper molar teeth ; for so much has already been effected by many leading members of the profession in bringing this class of instruments to perfection, that it appears presumptuous in one young in the profession to suggest any improvement; and, again, as the instrument I am about to submit to your notice was constructed to supply a want felt by myself, I am not at all sure that that want has been felt by others. Still, during the last eighteen months it has proved so useful in my hands that I THE STUMPS OP UPPER MOLARS. 63 think it right to offer a short description of it. The difficulty I just mentioned was in removing the stumps of upper molar teeth when the palatine surface, and frequently a portion of the palatine fang, had been lost by caries, while the fangs still remained firmly attached to each other. Such a stump may be compared with an inverted cone, the base being represented by the distal extremities of the fangs, and the apex by the neck of the tooth, or remaining portion of the buccal surface. In applying the ordinary form of adjusted forceps to such a stump — the blades of which may be also compared to a cone, but having its apex upwards and base downwards, — ^we shall obviously meet with considerable resistance in attempting to force the blades between the fangs and the alveolar process. To obviate this evil, I placed a model in the hands of Mr. Evrard, who soon supplied me with an instrument, constructed with his usual skill and finish, of the following form: — The buccal, or external blade, is somewhat similar to that of the ordinary adjusted forceps, only about half as broad, rather longer, especially in the hooked portion at the extremity, and sufficiently slight to permit it to be readily passed between the external fangs and the alveolar process; the palatine, or internal blade, instead of converging towards the former, as is usual in I think all forceps, diverges slightly, is a little longer, and about as broad as the blade of an ordinary stump- 64 THE llE-UNION OP TEETH forceps, but a little stouter : of course a right and left pair is required. I have found such an in- strument to pass readily between the fangs and their sockets ; and by applying the force in an inward direction, so as to make a fulcrum of the palatine fang, have generally succeeded in either removing the stump at once, or, if caries have proceeded far into the neck of the tooth, the two external fangs; or, sometimes merely separating the fangs, rendering the succeeding operations simple enough. '' Most persons who use the key would be satis- fied with such an instrument for these cases, and for these it is probably better adapted than for any other. " The description of forceps introduced I believe by Mr. Snell, the external blade of which passes through the alveolar process, has not in my hands proved a successful instrument. " Many practitioners would of course rest satis- fied with the elevator for such cases." Mr. WooDHOUSE read a paper upon " The Be-union. of Teeth with the Alveolus" Having lately met with a case of the re-union of a tooth with the alveolar periosteum, after it had been dislocated for three hours, I considered it would be interesting to the members of the Odontological Society to bring the particulars under their notice. I am induced to do so in WITH THE ALVEOLUS. 6b order to arrive at the individual experience of members, as, on referring to the records of dental surgery, I have not met with any case where a similar interval had elapsed between the dislocation and replacement of a tooth. I will now proceed to give the details of the case in question, with some particulars of similar cases of interest communicated to me by pro- fessional friends, together with some which I have fovmd recorded in works on dentistry. A year since, a young man, in the act of jumping over a brook, slipped, and fell forward upon a stone, by which one of his upper central incisors was knocked out without in any way injuring the alveolar process. He picked up the tooth and put it into his waistcoat pocket. Three hours elapsed before his return home, during the ivhole of which time the bleeding continued. His uncle, being somewhat of an amateur in surgery, hearing what had happened, asked to see the tooth, washed it in tepid water, replaced it care- fully in the socket, directing him to hold cold water in his mouth for two hours. Beyond the simple act of replacement there was no further interference, and the tooth was not tied or in any way supported. There was local tenderness for a fortnight ; at the termination of which time it was apparently restored to its ordinary condition ; for, to use his own words, " he was then able to eat 66 THE RE-UNION OF TEETH the toughest beefsteak he had ever put his teeth into." Ten months after the accident I carefully examined the tooth : beyond the fact of its edge being slightly below that of the other central, there was no manifest difference between them ; but on a very close comparison the slightest differ- ence of tint was discernible. The union of the replaced tooth with the gum was so perfect, that the most rigid examination with a probe betrayed no evidence of what had taken place ; indeed, the perfect uniformity of the two teeth was most remarkable, and exhibited, in a striking manner, the extraordinary reparative power of nature. This proof of the tenacity of life in separated parts is an illustration of how far we are justified in relying on the capabilities of the system to repair its injuries, beyond what has usually been considered probable. Through the kindness of Mr. Parkinson I am enabled to lay before you the particulars of a case which, with the exception of a greater exercise of care, has many features in common with the above, especially that of the time which elapsed before its replacement. Some thirty years since, before railways were introduced, a lady, residing in the country, fell down stairs and knocked out the two central incisors ; they were at once picked up, placed in tepid water, post-horses immediately ordered, WITH THE ALVEOLUS. 67 and the lady and teeth conveyed as quickly as possible to town ; the ter was renewed at each stage, to keep up the temperature of the teeth, and on arriving at Mr. Parkinson's, they were replaced by him, and remained firmly in their positions. Mr. Parkinson saw them twenty years afterwards, when they were still good serviceable teeth, and only sHghtly darker than their neigh- bours. The operation of turning the centrals of chil- dren, which I described a few evenings since, depends for its success upon the perfect reunion of the dental periosteum with the alveolar. So uni- formly does this take place, that such cases may be cited as the most perfect illustrations of re- union to be met with ; the conditions are, however, most favourable to that end ; for, although the tooth is completely detached from the alveolar process, it is not removed from it ; the operation also being performed before the end of the root is fully developed, the danger of rupturing the vessels supplying the pulp is avoided, and thus circulation is kept up throughout the tooth, while that of the periosteum is for a time suspended. Although the imperfection of the root contri- butes materially to the successful re-union in cases of torsion, the replacement of such teeth which have been entirely dislocated, is generally unsuccessful ; for, the pulp-vessels being ruptured, the ossification of the dentine cannot be com-* F 2 68 THE EE-UNION OF TEETH pleted, nor can the alveolar periosteum unite with that part of the tooth : irritation and suppuration are the necessary consequence. As an illustra- tion of these remarks, I would refer you to a case which Dr. Cushman describes in the American Journal of Dental Science , vol. xiii. p. 228. The probability of success is of course greatest when the tooth is replaced immediately after its removal. Some years since, I was removing a lower wisdom tooth, the crown of which leaned forward, and dipped down against the neck of the second molar. Thinking that it was possible to remove the offending tooth without disturbing the second molar, I attempted to do so ; but as soon as the one yielded, the other was raised from its socket : I put my finger upon the second molar, so as to prevent its entire displacement, and immediately the wisdom tooth was out, re- turned it to its place, telling the lady to close her teeth firmly. After a few minutes she felt no pain about the replaced tooth, and she told me a year afterwards, when I saw her, that she had expe- rienced no inconvenience whatever from it. Dr. Cushman gives a similar case, to which I would refer you, as it encourages us to hope for the re-union of any tooth that may have been accidentally displaced (vol. xiii. p. 597). If half the stories that our patients tell us of such accidents be true, there must be many opportunities for such experiments. AVITH THE ALVEOLUS. 69 As it is interesting to have the experience of different authors, I will refer you to a case given by Dr. Harris in his work on Dental Surgery (p. 405). Mr. Bell in writing on this subject, remarks, *' The cases are so rare in which any degree of comfort will succeed the replacement of a tooth which has been even slightly dislodged from its attachment to the alveolus, that no decided pro- spect of a cure ought ever to be held out to the patient.*' He then describes a case in which he replaced a tooth which had been partially dis- lodged ; a year afterwards it was perfectly firm, but continued to be tender. Subsequently the gum and alveolar process were considerably absorbed, and the removal of the tooth became necessary. Mr. Tomes takes a much more hopeful view of the operation than the authors just quoted. The success which attended Hunter's well- known experiment of placing a newly- extracted tooth in a slit cut in the comb of a cock, induced some dentists in his time to attempt the trans- planting teeth from the mouth of one person to that of another ; and although I am assured that the operation was successfully performed by Talma in many instances, the well-known variations in the size and form of roots of teeth in different individuals must alone at all times make success exceedingly doubtful. This, together with the risk of inoculation, and the moral wrong done to 70 THE I^E-UNION OF TEETH the person giving up his sound tooth, to my mind renders the operation at all times unjusti- fiable; the improvement in the manufacture of artificial teeth since those days certainly makes the attempt unnecessary. In conclusion, I will say a few words on the treatment I should recommend where it is de- sirable to replace a dislocated tooth. If a tooth be still in the socket, but consi- derably below its normal position, a coagulum having formed above it, and the bleeding stopped, I should remove the tooth entirely, place it in warm water, and then clear the alveolar cavity of the clotted blood, with a syringe and probe covered with lint. Should this operation not in- duce bleeding of the periosteum, I think it might be desirable to scarify it, and then replace the tooth, pressing it firmly to its original position. By this means, the tooth will be brought into more per- fect contact with the alveolar surface than could have been effected had the coagulum not been removed; and the circulation being restored in the periosteum, there is more probability of its being commimicated to the tooth. After holding it in its position for half an hour at least, fine silk should be laced betweeen the adjoining teeth, passing both on the outside and inside of the replaced tooth. "Warm water should be held in the mouth occasionally during two or three hours ; the patient be kept in a passive ^tate, all excite- WITH THE ALVEOLUS. 71 ment avoided ; in fact, for a few days, treated as a patient would be who had a broken limb; If much inflammation supervenes, leeches should be applied ; should excessive irritation continue, it will not be wise to persevere beyond ten days or a fortnight in trying to promote union. Teeth which have been entirely displaced require much the same treatment, only they should be carefully washed in warm water, and all foreign matter removed. Having now presented to you the case which first led me to think particularly on this subject, together with similar cases which have occurred to other men, and given you their opinions, I hope that I may ehcit from you your experience in such cases ; for one of the great advantages of this Society is the interchange of the know- ledge resulting from the practice of its difierent members. GENERAL MONTHLY MEETING. Monday^ June 7, 1858. J. H. PARKINSON, Esq., President, iif the Chair. The following Gentleman was duly elected a Member of tiie Society : — Mr. George Owen *. London. The following Gentlemen were proposed for tbe Membership of the Society : — Mr, Joseph Sn APE Chester. Mr. W. E. Jameson 39, New Bond Street, London. Mr. F. A. Sass Manchester Square. Mr. Arnold Rogers exhibited a supernumerary tooth projecting in the mesial line directly against the lip ; and also an upper wisdom tooth, in which necrosis and absorption of the fang had taken place below the edge of the gum, the gum being adherent, and not exhibiting any sign of disease. Mr. R. Thomson read a communication upon " Striking up Plates," and exhibited a great variety of hammers and other implements that he was aware were used in different establish- ments, and some that he had used himself; the object of which was to show that the more solid the blow given in striking up plates, the better effect could be produced. Mr. Thomson next 74 STRIKING UP PLATES. exhibited a machine, upon the principle of the guillotine, or pile-driver, the pedestal or base of which is two feet high, of cast-iron, weighing 3f cwt. It has two upright pillars of wrought iron, four feet high ; at the top of these there is a cross plate, upon which is mounted a pulley; from the bottom of the base to the top of the pulley is about seven feet high. Between the two uprights there is a hammer of 31^ lbs. weight, which slides up or down at pleasure : with it a very solid blow can be given. But for this machine to be serviceable for stamping gold plates, the bottom of the lead, or counter-model, must be fiat, and the upper surface of the zinc model must be perfectly even with the face of the hammer. To provide for this, there is a cast-iron ring, which has four screws, one to fix the ring to the bottom of the hammer ; the other three point inward to the centre : they can be arranged so as to secure the model in any position required. By fixing the model so that the top of it is perfectly flat upon the face of the hammer, the ladle with the lead in a fluid state is placed upon the top of the pedestal directly under the model; the hammer with model attached is let down till the model is sunk in the lead to the depth re- quired; then there is a slide upon one of the uprights, with a set screw, with which the hammer is supported till the lead sets. The ring is un- fastened and removed when the face of the hammer MODE OF CASTING BEDS AND PALATES. 76 and the top of the model are in perfect opposition, and to keep the models in their central position upon the top of the pedestal there is an iron plate, with two screws to keep it fast ; and to make up for the thickness of the ladle when the lead is taken out of it, there is an iron ring inserted, which makes up for the vacant space. By these means the models cannot possibly shift, so that every stroke of the hammer must be true, and thus very satisfactory results are obtained. Mr. F. G. Harrington made the following com- munication " On a mode of casting Beds and Palates for Artificial Teeth in the new metal, Aluminium ; also on improvements in Flat Mineral Teeth." After stating that the new metal is the basis of common clay, he said, — '* Like gold, aluminium possesses the property of resisting the action of all such acids as are likely to come in contact with it in the mouth. Nitric and sulphuric acids, or melted sulphur, do not appear to affect it in the least!" In addition to which he exhibited a piece which he had worn in his mouth night and day for six months without its having under- gone the least apparent change. These tests had fully satisfied him that it could be placed in the mouth with the most perfect confidence respecting its durability^ freedom from taste, and everything offensive. 76 ON THE USK OP ALUMINIUM > " But that which renders aluminium pecu- liarly adapted for artificial teeth, is its extreme lightness, its specific gravity being only 2*60, whilst silver is 10'47, and gold 19*26. Conse- quently, silver is about four times heavier, and gold more than seven times the weight of alumi- nium." Three masses of solid metal, each about the size and shape of a pigeon's egg, one of gold, another of silver, and a third of aluminium, were exhibited, and when taken in the hand they pro- duced a very striking and decided idea of the great difference between the relative weights of the three metals. But for the information of those who had not an opportunity of handling them, it was stated that if a medal were made of alumi- nium exactly the size and thickness of a crown or five-shilling piece, it would be lighter than a sovereign. The appearance of aluminium was also stated to be greatly in its favour. In colour it is a silvery lead, and where gold would be instantly and distinctly seen in the mouth, the new metal would escape detection under the same circum- stances. Mr. Harrington considered a gold found- ation to be far inferior to aluminium, except for such artificial teeth as are intended to he exhibited for ornamental display at shop doors, to attract the eye of the casual passer by their shoivy appearance ; but wjiere utility and comfort are required, he considers a set made of aluminium to be worth FOE BEDS AND PALATES. 77 more than double the value of any set that has ever yet been made of gold. ^ Mr. Harrington stated that many dentists have attempted to use aluminium by soldering pieces of it together, on the principle of gold- work, but they have failed, because no suitable solder has yet been discovered, that will connect pieces of it together. By his plan, a piece can be made of any form, size, or thickness that can be required for the mouth, without the necessity of any kind of solder whatever, either for making the beds or palates, or attaching the teeth. On account of the extreme lightness of the metal, molar teeth can be made entirely of it, including their mas- ticating surfaces. He uses flat mineral teeth, and his improvements consist, first, in making them with only one instead of two or more pieces of platina; and, secondly in taking the strain, during mastication, off the platina, by applying an aluminium support at the base of each tooth. By his plan, " the soft ^arts of the mouth can at all times be met by round, instead of sharp cutting edges ; a perfect fit will be insured, which has never before been attained, either in gold or bone ; cleanliness will be preserved, because there will be no cavities in which food can lodge ; and, added to these advantages, the teeth will combine lightness, firmness, efficiency, and durability, at less expense, greater certainty of arrangement and fit, with simplicity of construction. All sol- 78 ON THE USE OF ALUMINIUM. dering and cement will be avoided, and alterations that may be found necessary to relieve the tender parts of the mouth may be easily made, as the plate being thick, can be safely cut away where required ; the metal is more easy and pleasant to work than gold ; its expense is below that of bone ; and the saving of time in making a set of teeth on the new, compared with the old system, will be quite half.'' Several specimens were exhibited to the members. GENERAL MONTHLY MEETING. Saturday y November 6, 1858. J. H. PARKINSON, Esq., President, in the Chair. The following Gentlemen were duly elected Members of the Society :— Mr. James Anderson London. Mr. Harper R. Hugo Jersey. The following (Jentlemen were proposed for the Membership of the Society : — Mr. W. A. Roberts, 30, Queen Street, Edinburgh. Mr. E. R. Randell, Carshalton. Mr. H. A. Woolfryes, 1, Gloucester Street, Portman Square. Mr. John Littlewood, 14, Lower Eaton Street, Pimlico. Mr. James E. Palmer, Priest Gate, Peterborough. Mr. William Cattlin, Jun., M.R.C.S.Eng., 1, Highbury Place, Islington. Mr. Peter Orphoot, 113, George Street, Edinburgh. Mr. Cartwright presented the Society with his Portrait. Mr. C. J. Fox presented a photographic Portrait of the lafe Dr. Townsend, of the United States. Mr. Statham exhibited a modification of Jacob's Drill. Mr. Ash exhibited machines for Electro-Anaesthetic purposes. Mr. Coleman exhibited a skull with two supernumerary teeth in the upper jaw. Mr. Hearder read the following paper. 80 EMriOYMENT OF ELECTEICTTY A few Practical Hints on the Employment of Elec- tricity in Dental Operations, with a description of an improved Apparatus for the purpose. By J. N. Heaeder, Electrician, Plymouth. The object of the present paper is to endeavour to remove some of the practical difficulties which may be in the way of the efficient application of an agent, comparatively new, perhaps, to some who may have to employ it. Electricity involves such a variety of contrivances to enable it to accomplish specific objects, the success of which depends so much upon the electrical knowledge of the operator, that it is not at all surprising, without the least disparagement, if all do not obtain the same amount of success. Hence it is, that in the late employment of electricity to alle- viate the pain of the extraction of teeth, there has been so much difference of opinion as to its real efficiency for this purpose. Different operators, apparently employing the same means and under apparently the same circumstances, have obtained widely differing results, leading to opposite con- clusions. It is with a view to reconcile these apparent anomalies, by pointing out the various sources of failure, and the difficulties likely to be met with by those who are unskilled in electrical science, that the present communication is ad- dressed to the Society. l^N DENTAL OPERATIONS. 81 Without discussing the various opinions which have been broached upon the subject, or attempt- ing here to offer a rationale of elpctro-anassthetic action, it will be sufficient to take up at once the practical matters connected with it, the action of the instruments employed, and the most effica- cious mode of applying them. Hitherto, the greatest amount of success has attended the use of the instrument called the galvanic coil machine, in one or other of its forms. The action of this instrument depends upon the repetition of a great number of ver}^ minute shocks, in such rapid succession as to approximate the character of a continuous cur- rent. These shocks, although individually very feeble, give rise to accumulated sensations, which increase in power, generally in proportion to the rapidity with which they succeed each other, the total effect being of course also modified by the absolute strength of each individual shock. The force of the single shock depends, first, upon the quantity of wire contained in the secondary coil ; secondly, upon the amount of magnetism in the iron core, inducing upon the secondary coil ; and this magnetism again depends upon the relation which the primary coil and battery bear to each other. As there is no standard assumed for the construction of these instruments, each manufac- turer follows his own inclinations, often without being guided by any definite electrical laws : hence 82 EMPLOYMENT OF ELECTRKJITY it is, that scarcely any two instruments of different manufacturers correspond precisely in their phy- siological effects. Some machines have no means of modifying their electrical effects : it is needless to say that these are most objectionable, since they afford no facilities either for adapting the power to the constitution or temperament of the patient, or other circumstances of the case, — other machines have the power of modifying the action of the inducing magnetism by the partial withdrawal of the iron core. This plan is open to the objection that it affords no means of pro- ducing a series of delicate and equal increments of power, and it involves also the use of a second magnet for actuating the vibrating spring, and this requires generally the employment of a large battery, thereby increasing the bulk and complex- ity of the machine. A third mode of moderating the shock, is by employing the whole coil on all occasions, but modifying the amount of effect, by causing the shocks to pass through variable lengths of an imperfect conductor, such as water contained in a tube. The contrivance is ingenious, but still it does not admit of that definite and accurate degree of graduation which is desirable when accurate comparisons of experiments are to be made ; for the conducting power of water not only varies with its chemical character, but with its temperature. IN DENTAL OPERATIONS. 83 Having been for more than thirty years engaged in researches in magnetism, electricity, and elec- tro-physiology, as well as in the application of electricity as a therapeutic agent, I have been enabled from time to time to avail myself of the experience derived in the study of one branch of the science, to increase the facilities for investi- gating the other branches ; thus discoveries of the relation of certain laws to each other in the phenomena of electro-magnetism led to the im- provement of the apparatus employed for electro- physiology and therapeutics, as the requirements for such increased appliances suggested them- selves. About sixteen years ago, I introduced a new mode of graduating the force of the shock, by dividing the secondary coil into equal and known portions, and I subsequently still further increased the accuracy and delicacy of this graduation, by introducing a contrivance for subdividing each of these degrees of power again into quarters, so that by this means I was enabled to obtain a range of power over 50 or more equal and minute degrees. I was honoured by the Royal Cornwall Polytechnic Society with their silver medal for this invention. At the same time, by carefiil attention to the arrangement of different parts, I succeeded in reducing the size of the exciting battery so as to be able to include the whole of the apparatus in a very small box, and my humble 84 EMPLOYMENT OF ELECTRICITY exertions received the kind and flattering appro- bation of the Edinburgh Review, Lancet, the late Dr. Pereira, and others of the profession ; and the able suggestions of Dr. Barnes led ultimately to a still further reduction in the size of the instrument, for the sake of rendering it more portable and efficient for general as well as for specific purposes, which improvement is again most gratifyingly acknowledged by the scientific world. I have the honour of exhibiting one of these instruments to the Society this evening, as modified to suit the requirements of the den- tal profession ; but whilst it may appear to me to combine every requisite, the experience of others may suggest modifications and appliances to which it will afford me great pleasure to listen. I may explain that the chief scientific features, and if I may be allowed the term, I will say, the chief advantages of the instrument, are as follows : — 1st. The exciting battery (Smee's) is, I believe, smaller than any yet used, the silver plate being only three inches long, and about one inch wide, and the quantity of dilute acid required to excite it little more than a wine-glassful. Small as this battery is, the magnetism produced by it in the iron core is sufficient to sustain several pounds' weight at one end. 2nd. The amount of magnetism thus produced IN DENTAL OPERATIONS. 85 not only enables me to use a shorter secondary coil, and thereby increase the compactness of the instrument, but it also affords an opportunity of using very strong interrupting springs which insure better contacts and more uniform action, and which vibrate with immense rapidity, causing the shocks to follow each other with correspond- ing velocity. 3rd. The secondary coil is so arranged as to take up the whole of the electricity induced by the core, and is subdivided, by means of an index and graduated buttons, into four equal degrees of power, each of which, by means of a second index, is again subdivided into quarters, thus giving a range of 16 equal and delicate increments of force, perfectly under the control of the operator. The advantage of this arrangement is, that the unit of force being extremely small, the rate of increase can be always accurately measured, and no more electricity is by any' accident capable of passing than the precise quantity excited in the portion of secondary coil embraced between the terminals. 4th. All these graduations being of precisely the same value, different operators have accurate means of comparing their results; since, if the apparatus be kept' in proper working order, the corresponding degrees of each machine will be found to be equal. 5th. The battery being connected with the machine in one determinate manner only, the 86 EMPLOYMENT OF ELECTEICITY uniform direction of the current, as marked on the indices Pos. and Neg., is always insured ; a desideratum of considerable importance, since the effects or rather the sensations produced by the negative terminal are much more pungent than those of the positive. 6th. The whole of the apparatus, including coil, battery, stoppered bottle to contain dilute acid, shock-handle, insulated wires, and spring foot- board, are contained in the little box six inches long, six inches high, five inches wide, and the battery and coil- work, without being taken out of the box. In the spring footboard which I employ, I sus- pend the current by the depression of the spring, and cause it to pass by removing the foot, the elasticity of the spring making its own contact. The spring not being in connection with the machine when depressed, the foot which is placed upon it does not become a conductor to the shock, as is the case frequently, if this precaution be not observed. Having naw described the machine, which I trust will be found as efficient and free from objections as may be desired, I proceed to notice its employment and connection with dental in- struments. The main object to be obtained is the trans- mission of a current of electricity, or a rapid succession of minute vibratory shocks, through IN DENTAL OPERATIONS. 87 the nerve of the tooth during the operation of extraction ; and this is most readily accomplished by making the forceps, or instrument in contact with the tooth, form one terminal of the conductor, and completing the circuit by a brass handle held by the patient. To accomplish this, the following particulars must be attended to. It is absolutely necessary that the wire from the battery which ia connected with the instrument to be applied, should be in perfect contact with the clean sur- face of the metal terminating on the tooth. Too much importance cannot be attached to this. It may be accomplished in the following modes. A piece of vulcanized India-rubber tubing about one inch long may be slipped on over one of the handles, and under this, the end of one of the conducting wires may be thrust. Or a piece of flattened brass wire, about two inches long, terminating in a small binding screw, may be used to slip under the India-rubber clip; and to this binding screw the wire from the machine may be attached. If the handles be covered with silk ribbon for the purpose of insulation, then the wire may be thrust under the ribbon ; but this is not likely to secure so good a contact as when the India-rubber is employed. Again, a hole may be drilled in the handle of the forceps, &c., into which the end of the con- ducting wire may be hooked. In this case the touching surfaces must be clean, or the cmTent 88 EMPLOYMENT OF ELECTRICITY may be impeded, and failure be the consequence. The plan which I have heard mentioned, of making contact by the simple action of closing the forceps, appears to be open to objections, since the current must necessarily pass through the tooth before the instrument has perfectly closed upon it, or can be satisfactorily adjusted, and the patient may be alarmed or inconvenienced by the electrical sensations preceding the operation. It is necessary also that the operator should be insulated either from the forceps or the patient. If it were possible to operate with one hand with- out touching the patient with the other, this would be of no consequence, but if the forceps held by the operator be not insulated, a current would pass through him to the patient whenever he touches the individual with the other hand. The simplest way of insulating is to wear a silk, cotton, or thread glove on either hand, taking care to keep it dry. JSTone of these substances have sufficient conducting power to transmit a shock of the strength requisite for dental purposes. As some, however, object to operate with a glove, the same end will be accomplished by covering the forceps with silk ribbon or velvet, or even cotton tape, or by slipping India-rubber tube over each handle of the forceps, covering the portions of the metal which the tube would not cover, with ribbon, &c. If the operator be an electrician, however, he will see, that by the employment of the spring board IN DENTAL OPERATIONS. 89 which I have described, no electricity can pass until the circuit is completely adjusted through the patient; and a very small amount of insulation will thus prevent the current from dividing and passing, partly through the patient, and partly through the operator when the circuit is closed. For this reason, if the forceps or other instruments be well covered with shellac varnish, except in the portions which come into immediate contact with the tooth, preserving always a clean portion for perfect metallic communication with the wire of the machine on the inside of the handle, this is all the insulation that is really necessary; and I venture to affirm that if the operator understands the subject, he will need no other protection than this. With regard to the amqunt of power required for the most satisfactory results, operators vary in their evidence according to their views of the effect which they desire to produce. Those who act upon the principle that the electric current should produce an absence of all pain or sensation, employ exceedingly small degrees of power, vary- ing from 1^ to 2 degrees of the scale of my in- strument ; whilst others, who look to the effect of the benumbing influence of the current in masking or disguising the character of the sensation felt, employ stronger powers. I have known a case in which eighteen teeth were extracted under the influence of a strong 90 EMPLOYMENT OF ELECTRICITY current, with the exception of two, one of which, for the sake of contrast, was extracted without the employment of the machine, and with the other, the current accidentally failed to pass ; and the whole of the operations, with the exception of those two, one of which was very painful, were perfectly satisfactory. There is a great advan- tage in varnishing the portions of the forceps which come in contact with the gums, and inside of the mouth, since the whole of the action is thus confined to the tooth. It must be borne in mind also, that various portions of the tooth have various conducting powers ; the lower and softer portions conducting best. The nerve is the best conductor of all ; consequently, the introduction of a conducting wire into a deeply -excavated tooth in which the nerve is exposed, or the con- tact of a conducting wire with the amalgam filling of a tooth, causes intense pain. It is the practice of some operators not to let on the current of electricity until the moment of extraction, whilst Mr. Spence Bate rather advo- cates the plan of first ascertaining the strongest amount of current which the patient can bear through the tooth, and allowing it to pass until it has begun to exert a benumbing influ- ence, and he then, and not till then, extracts the tooth. These variations of process must, however, be still left to experience. Operators will do well to tabulate their results, noticing age. IN DENTAL OPEEATIONS. 91 sex, constitution, condition of the teeth, gums, &c., and the amount of power employed, and effect produced, discriminating, however, care- fully between effects attributable to the operation itself or to the sensations derived from the electric shocks. As an electrician of more than thirty years' experience, I have not failed to discover that it is not yet possible either to prognose or diagnose with certainty. Abnormal conditions, apparently identical in external symptoms, originate in very different causes, and the treatment which is per- fectly successful in one case not unfrequently turns out quite the reverse in another, apparently similar in all respects. Up to a certain point, then, experience derived from patient investigation will be found to be the safest guide^ GENERAL MONTHLY MEETING. Saturday y December 4, 1858. J. H. PARKINSON, Esq., President, in the Chair. The following Gentlemen were duly elected Members of the Society : — Mr. Joseph Snape Chester. Mr. F. A. Sass London. Mr. W. E. Jameson London. The following Gentlemen were proposed for the Membership of the Society : — Mr. Charles Hampson, 7, Dorset Square, London. Mr. Henry Andrew Dewar, M.D., 181, Union Street, Aberdeen. Mr. Cattlin exhibited a case of ulceration arising from a wisdom tooth. Although the disease had occurred twelve years ago, its course could now be readily traced by cicatrices from the angle of the mouth along the cheek and gums through the soft palate into the pharynx. This patient, when she applied for assistance, was suffering from great prostration of strength; the jaws were closed, and the sepa- ration necessary for a minute examination caused considerable pain. Independently of the ulcer- ation, small fistulous openings were observed in the left side of the pharynx, and the polished sur- face of a tooth was detected deeply imbedded in 94 CASE OF ULCERATION. the soft parts. This was extracted with a lever, and the first and second lower molares being diseased, were also removed. After the bleeding (which was considerable) had ceased, chloride of zinc was freely applied to the whole of the ulcer- ated surface, and the patient was recommended to become an in-patient of St. Bartholomew's Hospital, where she remained seven weeks, and her health was much improved by generous diet and tonic medicines. From the contraction of the cicatrices, the jaws became again locked ; but by the daily use of the mouth- speculum which has lately been exhibited to the Society, sufficient motion has been obtained for all useful purposes. The points of practice connected with the case are — 1st, the importance of a careful diagnosis ; 2ndly, the danger of refusing to operate on account of inflammation of the soft parts, or any pain or difficulty experienced in separating the jaws. Had a superficial examination been made, the wisdom tooth would probably have escaped notice, and the diseased molar teeth of the lower jaw might have been mistaken for the real cause of the mischief. If the operation had been delayed, in all probability the ulceration (which had been rapid in its progress) would in a very short time have reached the carotid artery through the pharynx. The patient was then brought in and examined by various members. INFLUENCE OF SYPHILIS ON THE TEETH. 95 Mr. Hutchinson read the following paper On the influence of Hereditary Syphilis on the Teeth, By Jonathan Hutchinson, M.R.C.S. Eng., Surgeon to tlie Metropolitan Free Hos- pital, &c. Mr. President and Gentlemen, — The type of malformed and dwarfed teeth, which the casts, portraits, &c., before the meeting exemplify, are, I believe, quite peculiar to those who during infancy have suffered hereditary syphilis. This conclusion is based upon so large a series of observations, that I place the utmost confidence in it, and I am now accustomed to make use of the teeth as a means of diagnosis as to the syphi- litic nature of certain symptoms. In order to understand rightly the manner in which the disease in question influences the for- mation of the teeth, it is necessary to bear in mind two general propositions. The first of these is, that as a rule, no specific inflammations occur during inter-uterine life. Almost all obser- vers agree that the majority of infants who suffer from hereditary syphilis are born healthy. The second is, that this disease does not, by any means, generally impair the development of the whole frame. Its effects upon the physiognomy and upon various structures (the bones, eyes, &c.) are always to be explained by reference to some inflammation which has occurred previously, and 96 ON THE INFLUENCE OF HEREDITARY not to any. occult influence of the morbid poison. In many instances I have seen the subjects of inherited taint well grown and of good develop- ment. The proposition, then, with which I set out is, that whatever effects may be traceable in the teeth, are due directly to inflammation of the gums, periosteum, and dental pulps, occurring diiring the first few months of life. The fre- quency of general stomatitis as a symptom of syphilis in infants, is universally recog- nized. Let us ask, then, what effects upon the teeth, should we, a priori, expect in an infant, exposed, say at the age of six weeks, to an inflam- mation involving parts in which those structures are imbedded ? In giving an answer, we must bear in mind what is their exact state at that period of life. The temporary teeth are already formed, calcified, and beyond the reach of damage as regards their shape ; but the others exist as yet as mere pulps. The effect, then, which we must expect would not be so much upon the temporary teeth as upon their successors ; and exactly so does it appear to be in practice. The first set show no peculiarities of form, but are liable to le- sions of nutrition by which their premature decay (see Figs. 2 and 3, Plate II.), or even exfoliation, is caused, whilst the permanent ones, cut many years after all morbid action has ceased, exhibit its effects in peculiarity of shape, size, and colour. I have remarked that the temporary teeth are SYPHILIS ON THE TEETH. 97 now and then exfoliated by the acuteness of the inflammation. This is a rare occurrence, but it' is important when it does happen, as a proof that the stomatitis does really involve the alveolar structures. Another instance on this point to which I will ask your attention, is that of an infant seven weeks old. In this case four teeth came away. This infant was at the time under my care at the Ophthalmic Hospital for inflammation of the eyes, attended with the usual symptoms of syphilis. A rapid, too early, and very irregular evolution of the first set of teeth, must also be enumerated as one of the results of syphilitic periostitis during the first few months of life. I have already re- marked, that as the periostitis referred to, occurs subsequently to the complete calcification of the temporary teeth, the only effect it can have upon them is to impair their nutrition. On the per- manent set its influence is altogether different. Existing as yet as mere soft pulps, they receive fi'om it an inflammation, which affects the very capsules in which they are moulded, and which contributes to their development an in- delible stamp. Becoming subsequently hard and changeless, they bear throughout the patient' s^ whole subsequent life the footprints of his in- herited disease. (It is in proof of this assertion I beg to adduce the portraits and casts now before you.) In regard to the diagnosis of the H 98 ON THE INFLUENCE OF HEREDITARY disease in those patients from whom they were taken, I may speak most confidently; and the more so, because, in almost every instance, it has been made at a pubHc hospital, and subject to the correction and criticism of other observers. My plan has been to take only those cases in which no one felt any doubt as to the fact of the patient being subject to hereditary syphilis. Mr. Cole- man, from whom I have received invaluable assistance during the inquiry, examined the patients' mouths, and made casts of their teeth. I may appeal to the casts on the table, apart from any description I may offer, as being accurate models of the teeth of a number of patients who have suffered in infancy from inherited syphilis. I may safely leave it to you to decide whether they do not exhibit a remarkable similarity of type amongst themselves, and at the same time special features of difference from all others. Amongst these peculiarities is, first, their small- ness ; the teeth, especially those of the lower jaw, stand apart, with interspaces ; are rounded and peg-like in form, instead of being flat. This is exhibited in Fig. 1, Plate II. But the most im- portant characteristics are to be found in the upper incisors, especially the two central ones : they are of a much more conical form than these teeth normally present (see Figs. 1, 2, 3, 4, and 8, Plate I.). Well- formed incisor teeth are harder at their cutting surface than at their necks ; the syphi- SYPHILIS ON THE TEETH. 99 litic teeth present the reverse conditions. The ver- tical notching of the incisors is perhaps the most remarkable and trustworthy characteristic (see Figs. 6 and 8, Plate I.). I do not mean that serrate condition of the edges of the teeth which usually occurs in the most healthy subjects. The syphilitic notch is a single, deep, and broad one, including almost the entire width of the tooth's crown. In the normal serrations there are two shallow notches, and consequently three tubercles ; both notches and tubercles being on a much smaller scale than those characteristic of the syphilitic tooth. The upper central incisors when cut, in these patients, not unfrequently present the characters seen in the upper central incisor shown in Figs. 1 and 2, Plate I. ; the prominent portion in the centre of the cutting edge of the tooth is very thin, and soon worn down by masticating, leaving a central notch and tubercles on either side of it. Thin-edged teeth often present a central vertical notch ; but this is the result of fracture, as in Fig. 7, Plate II., and is easily distinguished from that produced by inherited syphilis. In many cases, the canine teeth exhibit a peculiar circumferential notch near the cutting point ; it is not due to caries, but exists when the tooth is cut (see Fig. 8, Plate I.). A somewhat similar condition is seen in the temporary canines (Fig. 4, Plat« II.), which I suspect has here arisen from a circumferential H 2 100 ON THE INFLUENCE OF HEREDTTAKY wearing of one tooth upon the other. A very remarkable instance of the first kind occurred in a patient under my care at the Ophthalmic Hos- pital for chronic keratitis, a disease which I hold to be always of specific origin. A process of horizontal growing of the teeth has been described by dental authors, which differs from that I have described, by being situated nearer the neck of the tooth. It is often associated with other imperfections in the enamel, and is very well shown in Fig. 6, Plate II., which represents those teeth termed craggy teeth. Softness is another* peculiar condition of these teeth. They do not appear especially liable to caries, but wear down remarkably early, a pro- cess of eburnation preventing their decay. Very frequently, the characteristic notch of which I have spoken, is obliterated by this process of premature wearing down. The colour of these teeth is almost always altered, aad they present a dead greyish-white tint, instead of being clear and ivory-like. I should like, at this place, to make the obser- vation, that we do not consider what are called " bad teeth " as in any special manner associated with syphilis. The first set undoubtedly decay early, but the permanent teeth do not appear to be unusually liable to caries. I shall be asked whether strumous patients do not shoAY teeth presenting the appearance I have SYPHILIS ON THE TEETH. 101 described. I have made very extensive obser- vations upon this point, and will venture a very confident opinion in the negative. It must, how- ever, be remembered, that, under the denomina- *tion " strumous," a vast number of patients who are really syphilitic are constantly classed. In those cases in which there is no reason to suspect liereditary syphilis, strumous patients often have most excellent teeth. Here is a cast from a patient who came to me at the Ophthalmic Hospital, which will do for illustration. He was florid, presenting tumid alee nasi, and a thick upper lip ; he had enlarged glands in the neck, and ulcers on the cornece. He presented, indeed, a very ideal of tumid florid struma, where there was not the slightest resemblance to the physio- gnomy of hereditary syphilis. The cast shows his teeth large, and of perfectly good arid regular formation, contrasting most strongly with the others now before you. Setting aside two or three cases in which I could not ask questions, I may aver I have never yet met with an instance in which the teeth were strongly characterized, in which subsequent inquiry did not completely confirm the suspicion of hereditary syphilis. I there- fore believe that these observations are of exceed- ingly great value in the diagnosis of this disease. They are especially so after the age of puberty, when it is possible the patients may have con- tracted the disease themselves. Of course, no 102 ON THE INFLUENCE OF HEREDITARY acquired disease could alter the form of the permanent teeth. The question may naturally be asked whether these conditions may not be due to the adminis- tration of mercury. My reasons for giving a* decided opinion that they are not due to mercury, are, that although I have given mercury for here- ditary syphilis, and other affections, to a vast number of infants, I have never seen it in one single instance cause exfoliation of the crowns of the teeth. That syphilis in infants does undoubt- edly cause inflammation of the periosteum of the dental structures, is proved; and it seems, men, far more logical to attribute to it any effects which may ensue, than to a remedy against which there is little or no evidence. We must remember, besides, that mercury subdues the very conditions which are likely to cause inflammation of the teeth. I look upon it, therefore, as preventing the full development of those peculiarities, and not as itself causing them. Another reason I have for thinking that the use of mercury rather counteracts the development of these conditions is, that I have had several cases in which I have inquired from the mother, and I have found that the patients have never been sub- jected to any mercurial course, yet the type was even more marked in them than in others. The administration of mercury in large quantities during infancy has, I believe, some influence upon SYPHILIS ON THE TEETH. 103 the development and future condition of the teeth ; and Fig. 8, Plate II., shows the teeth of a patient, not syphiUtic, who had taken much mer- cury during infancy. The teeth are bad-coloured, marked with shallow horizontal grooves, and slightly pitted near their edges. Fig. 5, Plate II., are also, probably, of the same type. I shall conclude this paper with a short report of the observations made by my friend Mr. Coleman, quite independently of my own. 1. " The period of the first dentition. — Although the time of cutting the first teeth varies consider- ably, yet, fi:*om the calculations of writers upon the subject, it appears that the central incisors may be looked for about seven months after birth. Out of eleven of these syphilitic cases, in which I was able to obtain information on this point, two had their teeth at birth ; one when a few weeks old ; two about two months after birth ; two about the usual time ; the remainder very late. 2. " The form of the permanent teeth. — They are universally small; for although the alveolar arches are decidedly below the average size, there are in most instances considerable spaces between the teeth : the latter are also more round in form, resembling little pegs projecting from the gum. The upper central incisors of most have a deep notch in their cutting surface, giving this portion of the tooth a tuberculated appearance. In many cases the teeth are much worn, from mastication, 104 INFLUENCE OF SYPHILIS ON THE TEETH. the enamel being very soft, and probably contain- ing a smaller proportion of calcareous salts than the normal quantity. From this circumstance the notch is not so marked in some cases, though its commencement may be observed. *' In nearly every case there is a deficiency in the superior alveolar arch, at the anterior portion so great in some patients that the upper and lower incisors are a considerable distance from each other when the mouth is shut. In these latter, the notched appearance is well marked, the teeth not having been worn by mastication. " Teeth (incisors) having a notched appearance are not very uncommon, but they are rarely so marked as with these patients. The upper central incisors, instead of having their internal or mesial borders slightly everted, as in every well-developed arch, have them, in these patients, slightly inverted towards the palate. 3. *' Colour, — This is very characteristic, being of a dirty, translucent shade, not perhaps unlike the size frequently seen in the oil- shops, and therefore somewhat difficult to describe, but, when once seen, is readily recognized again." DESCRIPTION OF PLATE I. The Figures illustrate Mr. Hutchinson^ s Report on iS^pAilitie Malforma- tions of the Permanent Teeth. Eig. 1. An upper permanent central incisor of a boy, the subject of inherited syphilis. The tooth has been very recently cut, and shows a broad vertical notch, in which are several small projecting spines (the sole remains of the atrophied mid-lobe^. Eig. 2. Two upper and four lower incisors (permanent) of a girl, the subject of inherited syphilis, all but recently cut. The upper teeth are narrow from side to side, at their edges, and show a thin middle lobe, bounded above by a crescentic line. The lower teeth are rounded, and show foliated extremities. All the teeth are small, and spaces occur between the adjacent ones. In the upper ones, the crescentic thin mid-lobe, and in the lower ones the foliated extremities, will before long break away, and leave the teeth in the state shown in Fig. 3, Plate IX., and Eig. 1, Plate VIII. respectively. Eig. 3. The central upper incisors of a lad aged 15, the subject of inherited syphilis. The teeth are short, convergent, narrow from side to side at their edges, and show in each a vertical notch. Eig. 4. In these teeth, almost similar characters as in Eig. 3 are seen. The notches are, however, less deep, whilst the narrowing from side to side is very marked. Eig. 5. The upper incisors of. a girl of 17, the subject of inherited syphilis. There is a wide space between the central ones ; and both these teeth, although of nearly normal length, are narrow, and show deep vertical notches. The lateral incisors are, as is usual, of normal size and form. These teeth are much less typical of hereditary syphilis than those in Eigs. 3 and 4. Eig. 6. The upper incisors and canines of a girl of 12, the subject of hereditary syphilis. The right canine is a temporary tooth ; all the others are permanent. The incisors are remarkable for great inequality of size and difference of form. The right central incisor is very small and notched. The right lateral incisor is of normal size ; all the others much below it. Eig. 7. The upper permanent incisors of a boy of 12 (syphilitic). This sketch shows a condition of extreme dwarfing of the central ones, which, although cut four years ago, liave never grown higher than a line or two above the gum. Eig. 8. An exceedingly well-characterized set of syphilitic teeth (upper and permanent), from a girl aged 16. The central incisors are dwarfed, narrow, and notched ; the lateral ones of normal size ; and of the right canine, the apex is replaced by a notch, in the centre of which is a small tubercle. DESCRIPTION OF PLATE II. The Figures illustrate Mr. Ilutchinsotis lieport on Malformations^ Si/i)hilitic and otherwise^ of the Teeth. Fig. 1. The lower incisors of a girl aged 15, the subject of inherited syphilis. The teeth are very short, rounded, and peg-like, with wide inte^p)aces. This sketch shows the most typical condition ever exhibited by the lower set. Fig. 2. The milk-teeth (upper set) of a syphilitic child aged nearly 3. The necks of the four incisors have been attacked by circular caries, which has wholly spared the canines. The extremities of the lateral incisors have already fallen away, and those of the centrals will soon follow. Fig. 3. The milk-teeth (upper set) of a girl of 5, the subject of inhe- rited syphilis. The central" incisors have been destroyed by caries, and their stumps exfoliated ; and of the laterals, only the stumps remain. The canines are perfect. The sketch shows a further stage of progress of the changes illustrated in Fig. 2. Fig. 4. The temporary canines (upper and lower) of a boy aged 9, the subject of inherited syphilis. They are remarkably symmetrical, and all of them show a central tusk-like projection, the result of a peculiar circumferential wearing away (not caries). Fig. 5. The upper permanent teeth of a boy aged 11, not syphilitic. The teeth are somewhat honeycombed, of bad yellow colour, and have peculiarly thin and narrow edges. They differ from the syphilitic type, in all possessing, in greater or less degree, the same features, instead of each pair having its own peculiarities. Possibly the result of a mercurial course in infancy. Fig. 6. Two upper permanent central incisors, not syphilitic, but of the type known as " craggy teeth." They are larger and wider than syphilitic teeth, not notched, and of much harder structure. Fig. 7. Thin-edged and broken teeth, not syphilitic, from a woman aged 20. In these they result not so much from the softness and original malformation of the teeth, as frond their preternatural thinness and brittleness. Near the edges of the lower set a horizontal line or notch is seen to extend. Fig. 8. The permanent front teeth of a boy aged 15, who had taken much mercury in infancy. The teeth are all of them of yellow colour, somewhat pitted in their surfaces, and very thickly coated with tartar. Near the edges of the lower set, a horizontal line extends, similar to that adverted to in FigSB^^^H?^<^^^* • •■ '■ Kg 8. Ag7 ^JM0 ^ i lens Aldous del. Tuffen West sc. 'AITest ahromciiEi) PLATE II Pl61. Fi|3. -^r^ ,||/ii^^^||^^gM^ Fi^.Z. r'^^-.M^ s^0% Fig 4. Kg- 6. ^ UaJuU> R|7. R6,8..' .A^ YTWest nhromoiaip. ADJUSTIVE OPEEATING CHAIR. 107 Mr. Owen exhibited a new form of Adjustive Operating Chair, and made the following observations : — ' When a patient seats himself in the operating chair, the first thing the dentist naturally pro- ceeds to do, is to raise or to lower the seat of the chair, if necessary, in order that the head may rest at that level at which he can most easily and most effectively perform his task. Of late years this has been accomplished by mechanical arrange- ments of various kinds, instead of with loose cushions, as formerly; but in all the chairs that have come under my observation, having the advantage of a rising and falling seat, there is a serious defect, which renders a certain amount of complication indispensable. I allude -to the fact that ivhen their seats are placed at the lowest points, they are still so. high that the head of a tall patient stands far above its proper resting-place, and out of the reach of the dentist of average stature. Now, as the w^ant of depression in the seat, referred to above, and the several contrivances by which it is counteracted, appeared to be dependent upon the apparatus for elevating and lowering the seat being placed under it, it oc- curred to me that if a chair could be constructed in which this should not be the case, — i.e., in which the machinery should, for example, be placed in the back, — ^we might be able not only to raise, bvit also to depress the seat to any extent, and thus to dispense with some complexity. In 108 A NEW FOEM OF ADJUSTIVE the cliair before you, and to wliicli I will now very briefly direct your attention, this condition is at- tained. There is, as you perceive, a total absence of machinery, and I might say of legs also, below the seat. The seat and arms are connected, and move together in a direction not purely vertical, but in that corresponding with the inclination of the hach of the chair. An advantage is thus gained which is not unimportant; viz., that while the vertical range of motion in the seat is itself but thirteen inches, the true and available space between the highest and lowest positions of the seat, measured in the line of motion, is not less than sixteen inches, a range seven inches greater than has hitherto been realized. The great advantages of a practical nature arising out of this form of operating chair are, — First, that it admits of the headpiece being fixed as to height, the level of it being the extreme height of the chair, which is determined in the ordering or selection of it. Secondly, that hy one movement alone, viz., the elevation or depression of the seat, the patient, how^ever tall or otherwise he may be, can with facility be placed in the position required. The mechanism by which the seat is raised and lowered is very simple, and the seat may be ad- justed to the three- sixteenths of an inch, provided such nicety should be considered desirable. There is no noise whatever connected necessarily with the working, and the patient can be raised or OPERATING CHAIR. 109 lowered while seated. The headpiece, although attached to the chair, and fixed as to height, is nevertheless moyshle forwards and backwards, and it has a ratchet-frame behind, by which the head may be easily and instantly placed, and supported for a considerable period without fatigue to the patient, either with the face parallel to the ceiling, as is necessary in operations upon the upper molars, for example, or in any other position between that and the erect posture required in operations upon the teeth of the lower maxilla. The extreme facility with which the movement of the headpiece is effected, and the security with which it fixes itself, however placed, are, I think, deserving of your particular notice. One hand only is required to move the headpiece, and its position can be changed at any moment during an operation, without the removal of the other hand of the operator from the patient's mouth. Another peculiarity of the headpiece is, that it has hvo depressions for the head to rest in, according to the side of the patient on which the operator may require to place himself. I have employed one of these chairs since May of this year, and have found this double resting-place for the head to be extremely convenient. In conclu- sion, I will only remark upon the general aspect of this chair, that there is nothing formidable in it, no machinery is visible, nor anything that is suggestive of the concealment of any. ANNUAL GENERAL MEETING*. Saturday, January 8, 1859, J. 11. PARKINSON, Esq., President, in the Chair. The following Gentlemen were duly elected Members of the Society : — Mr. E. B. Randell Carshalton. Mr. W. A. Roberts Edinburgh. Mr. H. A. WooLFRYES London. Mr. John Littlewood ....London. Mr. William Cattlin, Jun., M.R.C.S., London. Mr. J. E. Palmer Peterborougli. Mr. Peter Orphoot .Edinburgh. The following Gentlemen were proposed for the Membership of the Society : — Mr. Thomas Underwood .......7, Gower Street, London. Mr. JasEPH Rogers, M.R.C.S....16, Hanover Square, London. Mr. Alfred O'Meara 18, Queen-Anne Street, London. Mr. R. J, H. Pratt 15, Piccadilly, London. Mr.E. Barton Bartlett 10, Cambridge Terrace, Hyde Park. The following Gentlemen were elected by ballot as Officers and Council for the ensuing year : — President, — Arnold Rogers, Esq., E.R.C.S. Vice-Presidents. — W. A. Harrison, Esq., M.R.C.S. ; Robert Nasmyt h, Esq., M.R.C.S. ; William M. Bigg, Esq. ; C. Bromley, Esq. ; J. Tomes, Esq., F.R.S. ; J. Martin, Esq. Treasurer.—!^. Saunders, Esq., E.R.C.S. Honorary Secretaries. — Samuel Cartwrighf, Esq., Jun., M.R.C.S.; Thomas A. Rogers, Esq., M.R.C.S. ; Alfred Canton, Esq., M.R.C.S. Cotmcil.—Zo\m H. Parkinson, Esq ; J. B. Eletcher, Esq. ; G. A. Ibbet- son, Esq., E.R.C.S. ; Robert Brookhouse, Esq. ; James Parkinson,Esq. ; T. G. Palmer, Esq. ; C. Spcnce Bate, Esq. j Edwin Sercombe, Esq., M.R.C.S. GENERAL MONTHLY MEETING. Saturday^ Februari/ 5, 1859. ARNOLD ROGERS, Esq., President, in the Cuaik. The following Gentlemen were duly elected Members of the Society : — H. A. Dewab, M.D Aberdeen. Mr. C. Hampson London. The following Gentlemen were proposed for the Membership of the Society : — Mr. Samuel Ghrimes 65, Gloucester Place, London. Mr. Chas. Stokes, M.R.C.S. 65, Brook Street, London. Mr. G. Bartlett 15, Caroline Street, Bedford Square. Mr. W. G. Bennett 47, Poland Street, London. Mr. Robert Hepburn 8, Davies Street, Berkeley Square. Mr. D. D. Hepburn Pavement, Nottingham. Mr. David Hepburn 7, Abercrombie Place, Edinburgh. Mr. M. J. Watt 13, South Charlotte Street, Edinburgh. Mr. J. K. Chisholm 33, Queen Street, Edinburgh. Mr. James Orrock 7, Abercrombie Place, Edinburgh. Mr. J. A. Baker, E.R.C.S. ...4, Clare Street, Dublin. Mr. J. Murphy Derby. Mr. C. D. Roberts Ramsgate. Mr. T. A. Rogers read the following paper, — " On some of the Caustics used in Dental Surgery" Caustics, from xaico, I hum, may be defined to be local agents, wliich effect chemical changes in the parts to which they are applied. They may be conveniently divided, according to their niuduii o^jcrandi, into two classes : — I 114 ON SOME OF THE CAUSTICS 1st. Those which act by the complete destruc- tion of the tissues with which they come in contact. 2nd. Those which act by entering into chemical combinations with the components of the tissues. In the first class are comprised the mineral acids, which exert a powerful affinity for the water which constitutes four-fifths of the weight of the animal tissues ; the caustic alkalies, which dissolve albumen, fibrin, and gelatine; and the actual cautery. Under the second head are included the metallic compounds which act as caustics; such as sulphate of copper, bichloride of mercury, nitrate of silver, chloride of zinc, chloride of antimony, arsenious acid, &c. In the practice of dental surgery, caustics are employed in two classes of cases : — I. — In the treatment of various unhealthy conditions of the mucous membrane of the mouth. These conditions, however, so generally arise from constitutional causes, that they come more into the province of the surgeon, and I propose, there- fore, to confine myself to, — II. — The treatment of diseased conditions of the dental tissues themselves. We may subdivide this class into, — 1st. Those cases where it is only required to lessen the sensitiveness of the dentine or cemen- tum ; and, — USED IN DENTAL SUEGERY. 115 2nd. Those cases where the pulp is exposed, and is either to be entirely destroyed or brought into a condition to bear further operations. 1st. As regards the action upon, sensitive den- tine or cementum. For this purpose the most appropriate caustics are either chloride of zinc or arsenious acid, in accordance with the locality of the tender tissue, or other circumstances. If the cementum be exposed by the receding of the gums, from constitutional or mechanical causes, or if there be a very sensitive surface of exposed dentine after filing or cutting operations, or from accidents to the teeth, the apphcation of chloride of zinc seems peculiarly efiectual. The surface of the tissue to be acted upon should be thoroughly dried (for this salt, though under the second class of caustic substances, somewhat re- sembles the first in its attraction for water, being highly deliquescent), and precautions taken to prevent the chloride from spreading about the mouth. A small crystal is to be placed in contact with the bone, and immediately covered over with firmly-compacted wool, or some other substance, to exclude all excess of moist air. In most cases, considerable pain comes on, lasting from five to twenty minutes : when this has ceased, the tooth may be exposed again by the removal of the wool, «&c., and probably the tenderness will be found to luive disa])pcarcd, or at least to be materially I 2 N 116 ON SOME OF THE CAUSTICS lessened. It not nnfrequently happens, however, that several applications are necessary; and I have observed that if pain does not occur during the action of the chloride, the benefit is seldom so great. This caustic is peculiarly useful in cases where the friction of artificial work has set up great irritability about the necks of the teeth. We have next to consider arsenious acid as an agent in reducing the sensitiveness of dentine. There can be no question but that this is by far the most efficacious substance for this purpose. If it can only be thoroughly kept in contact for a certain length of time with the part to be acted upon, it will, I believe, scarcely ever fail in bring- ing about the desired effect. It is, however, much slower in its operation than chloride of zinc, and cannot, therefore, for obvious reasons, be em- ployed in mere surface cases, as the latter can ; but it is far superior to it where there is a cavity into which it can be inserted and leffc without dis- turbance for a given time. The mode of applying arsenious acid is too well known to render it necessary that I should enter much into that part of the subject. The preparation I use is the common one, I believe, of arsenious acid, creosote, and morphia, and I leave it in the cavity, covered in with wool moistened in gum mastic, for a length of time, in proportion to the nature of the case, the age and constitution of the patient, &c. But there is one serious objection to the use of USED IN DENTAL SURGERY. 117 arsenic, which is its absorbability, and the conse- quent inflammation and death of the pulp, and irritation and inflammation of the peridental mem- brane. I confess that I have not found this to occur to such an extent as some practitioners record ; but it is, undoubtedly, too often the case, and must make us regard arsenic as occupying its present position in our list of remedies only till a safer preparation shall be discovered. Some years ago. Dr. Arthur brought into notice the ore of cobalt, the escharotic properties of which are due to the presence of large quantities of arsenic in it. The cobalt being insoluble, the arsenic is not so likely to be absorbed by the tooth. Dr. Arthur places the one-twentieth part of a grain in the cavity of decay, covering it in with wool moistened with a solution of gum sandarach in alcohol, and leaves it there from twenty-four to forty-eight hours, according to the depth of the cavity ; and after removing it, 'he waits for about the same length of time before commencing to operate. He seems to have obtained great advan- tages from its use ; but I cannot speak so highly of it from my own experience. I did not, in- deed, find that any inflammation of the pulp or peridental membrane followed its employment; neither, however, did the sensibility of the dentine appear to be at all lessened. In comparing chloride of zinc with arsenious acid, therefore, the former is quicker in its effect ; 118 ON SOME OF THE CAUSTICS it can be safely applied on flat surfaces, where arsenic, by escaping and lodging abont the mu- cous membrane, might cause extensive ulceration ; and there is no liability to injury of the adjacent tissues by ulceration. On the other hand, arsenic is more certain in its effect, and in most cases does not cause such severe pain as does the zinc. Nitrate of silver is frequently used in stick or in solution, to diminish the sensibility of dentine, especially when that occurs after filing ; but it is not so effectual as chloride of zinc. When placed in the cavity of decay of a tooth, it gives rise to discoloration very difficult to remove. The actual cautery has lately been employed by dentists — ^by Mr. Waite, Mr. Harding, and others — with the view to remove the tenderness of ex- posed dentine. I have no experience of its avail- ability for this purpose ; but its good qualities are highly spoken of by these gentlemen. We will now proceed to consider, — 2nd. Those cases where the pulp is exposed, and is either to be entirely destroyed or brought into a condition to bear further operations. The caustics most commonly used in this class of cases are nitric acid, arsenious acid, chloride of antimony, and the actual cautery. The two latter are those employed for the purpose of inducing a healthy surface to an ex- posed pulp, where it is deemed advisable to endeavour to preserve that organ. The chloride USED IN DENTAL SURGERY. 119 of antimony I have used with this view on many occasions, and after waiting a few days for the eschar to come away, I have capped the pulp and filled the tooth. I am indebted to my friend Mr. Woodhouse for several valuable hints on this point. Of the actual cautery for this purpose I cannot speak from my own experience ; but the writings of many dentists bear testimony to its utility in this class of cases. For the complete destruction of the pulp, the actual cautery, nitric and arse- nious acids, are commonly employed. Previous to the application of electricity to dental purposes, the difl&culty of carrying a very fine wire, at a sufficient temperature to act efficiently, up the canal of the fang, was so great that the so-called actual cautery had almost become obsolete in dental surgery. Now, however, that electricity is being brought more under control, I entertain sanguine expectations of the results to be ob- tained by its employment in this class of cases. The advantages conferred by it would appear to be that the operation of destroying the pulp is rendered much less painful, is more speedily and thoroughly accomplished, and with less chance of the after-occurrence of mischief than by any other method. We have all heard of — and perhaps some of us may have practised — the operation of the destruction of the nerve by nitric acid. It causes 120 ON SOME OF THE CAUSTICS great pain Avhilst its action is going on, extending usually over several hours, and it is apt to cause injury to other teeth, even with the greatest care in its application. But we constantly meet with cases where it has been perfectly successful ; and though of late years it has been superseded by arsenic, it is, I think, worthy of further trial. Arsenic is, however, now almost exclusively employed for this purpose, and is very effectual. Applied in the manner before mentioned, it combines with the albumen of the animal matter, causing the pulp to shrivel and become detached from the bone, so that it can be easily brought away from the whole length of the fang or fangs. I have alluded to the absorbability of this sub- stance, as being the chief objection to its use in diminishing the tenderness of dentine. This objec- tion appHes equally in the present case ; and though I think the danger has been exaggerated, there is still no doubt that the ill effects of the arsenic may show themselves even after the interval of many months, and that such cases are less amenable to treatment than the ordinary inflam- mations of the roots of teeth. Whilst I am penning these remarks, the thought occurs to me that the danger of absorption might possibly be lessened by the incorporation of the arsenious acid with gutta percha, and its application in that state in the form of small pills or masses. As there is no time to try this, however, I throw USED IN DENTAL SURGERY. 121 it out as a mere idea, which may or may not possess any practical value. I have now passed in review most of the caustics employed in our practice, — very hastily, it is true, but not so much so, I hope, but that discussion may be provoked. I must appeal to the charity of my audience for the sketchy nature of my communication ; but the expected paper for this evening was not forthcoming, owing to cir- cumstances over which the writer had no control, and I have had only a few hours to draw up these few remarks to place before the Society. The French have a proverb, " Who excuses, accuses himself." By doing so, however, I hope to disarm the criticism of my friends ; and I trust they will be so kind as to keep up a good supply of papers for our meetings, and so save themselves any more inflictions of " papers on caustics." GENERAL MONTHLY MEETING. Saturday^ March 5, 1859. ARNOLD ROGERS, Esq., Peesident, in the Chair. The following Gentlemen were duly elected Members of the Society : — Mr. Joseph Rogers, M.R.C.S. Eng London. Mr. Thomas Underwood London. Mr. Alfred O'Meara London. Mr. R. J. H. Pratt London. Mr. E. B. Bartlett London. The following Grentleraen were proposed for the Membership of the Society r— Mr. Robert H. Moore, F.R.C.S.L Dublin. Mr. Walter Brown Nottingham. M r. Thomas W. Evans Paris (corresponding). Mr. L. S. Burridge Rome (corresponding). Mr. A. J. L. Talma Brussels (corresponding). Mr. E. Parmly New York (corresponding). Mr. Chapin Harris Baltimore (corresponding). Mr. Thomas E. Bond Baltimore (corresponding). Mr. A. S. PiGOTT Baltimore (corresponding). Mr. Robert A rthur Philadelphia (corresponding) . Mr. J. D. White Philadelphia (corresponding). Mr. J. Tucker Boston (corresponding). Mr. Cattlin exhibited models which represented the positions of the teeth of a patient at the age of 78 : a true canine tooth could be seen in the 124 MODELS OF THE TEETH. palate beliind the right upper lateral incisor. The new tooth gradually protruded, and in about twelve months loosened and removed the lateral incisor, the place of which it now occupied. The patient was at the present time 81 years of age, and the canine tooth which had been cut so late in life, was the only one decayed. The second model also represented a right upper cuspidatus, which was cut at the age of 49. Four of the neighbouring front teeth had been knocked out by concussion in a railroad accident, and had been replaced by artificial means. The large canine tooth attached by wax to this model was extracted about two years after the accident, in consequence of the impediment it offered to the free use of the artificial teeth. Probably but for the pressure of the plate and the accidental loss of the adjoining teeth, the eruption of the canine tooth in this case might have been delayed for a still longer time. A third model exhibited a second right upper bicuspid tooth, which was cut at the age of 70. The upper jaw was, with this exception, edentulous. He remarked that these three models were taken from male patients ; the teeth were all well formed, and could not be mistaken for supernumerary teeth. The large right upper central incisor tooth, represented in the fourth model, was interesting only on account of its peculiar shape, the crown being half an inch wide. The left central, and the right and left CUTTING TEETH AT AN ADVANCED AGE. 125 lateral incisors, were well-formed teeth of the second set ; therefore the great width of the right central incisor did not arise from osseous union with any ordinary tooth, although it might have united with a supernumerary. The President read the following letter, in reference to the case mentioned in the newspapers, of an old lady in the West of England cutting two teeth at 103 years of age : — " Wells, Somerset, February 4, 1859. *' Dear Sir, — Mr. Brodrick has put into my hand this morning a note from a friend of his, in which he mentions that you are anxious to ascer- tain some particulars relating to the case of Mrs. Oxley, of this town. I have made a call upon her this afternoon, with the view of learning, if pos- sible, the real facts of the case. '' It appears that Mrs. Oxley is 95 years of age; that twenty years ago she cut a tooth at the back of the lower jaw, which, being very painful, she had extracted shortly afterwards. On examining her mouth with my finger, I found a small tooth in the upper jaw, about a quarter of an inch farther back than the seat of the left central incisor : this she and her daughter agree in saying that she cut three years ago. She persists in saying that others are coming; but I see no reason for thinking this to be the case, from the appearance of the mouth. 126 REMOVAL OF THE SUPERIOR MAXILLA. " I may add that tliis old person has been bed- ridden for the last two years. " Believe me to be, dear Sir, " Faithfully yours, "John French. " Arnold Rogers, Esq." Mr. Sercombe exhibited a portion of the su- perior maxilla which he had removed from a child at St. Mary's Hospital a fortnight ago, containing the shedding canine and the first and second shed- ding molars, together with the permanent lateral incisor, the first bicuspid, and probably in the body of the mass the permanent canine. This extensive loss of bone was the result of ulcerative stomatitis, which had been neglected by the parents until the swelled face, fetid breath, and other symptoms of severe suffering, led them to the hospital. The child, who was eight years old, could with great difl&culty, when she first came under his care, open her mouth a quarter of an inch, and the fetor was so perfectly intolerable that he was quite unable to make an examination of the parts. A wash, consisting of three drops of creosote, half an ounce of glycerine, half an ounce of brandy and six of water, succeeded in entirely removing the fetor in a day or two. He gave the patient bark and chlorate of potash, and in a fortnight from this time was enabled DEPOSITION OF TARTAE UPON TEETH. 127 to remove the mass now exhibited. Since its removal, the general health of the child had im- proved, and the parts were heaUng kindly by granulation. The origin of the case was obscm'e, and it was remarkable, from the absence of those exciting causes which usually exist; there were no carious and aching • teeth, and the child was well fed, having animal food always once a day. She was living in a room on the first floor, but her person was very far from clean. A communication was read from Mr. Hutchins, respecting a " Large Deposition of Tartar upon Teeth:" — "The subject is a girl 18 to 19 years of age, who was sent to me the latter part of last year by Dr. Henry Davies. Her mother, who accompanied her, brought in her hand the mass of tartar marked 1, and the girl was suffering dreadfully from extensive ulceration at the frae- nimi and reflected membrane under the tongue. As this condition clearly arose from the irritation caused by the projecting angles of the remaining portions of tartar, I immediately removed the piece marked 2, which indeed was quite loose, and in succession that marked 3 : these came away entire and with great ease. The portion of plaster marked 4 represents another mass of tartar, which, however, was firm : this was taken away in smaller detachments, which are inclosed in paper with the specimen. All the teeth of 128 DEPOSITION OF TAKTAll UPON TEETH. both jaws were more or less covered with tartar, which at the- moment I simply smoothed from all irritating angles. I saw the patient four days afterwards, when the ulceration was completely healed, and as she was free from all pain, I did nothing further, but sent her to the Dental Hos- pital, that the gentlemen there might see the case as it was; and I found subsequently that they had, very properly, gradually cleared the teeth of the tartar that had been left. The girl's mother declared that, until the first portion came away, she had never complained of any suffering; the tartar had accumulated so gradually and so smoothly, as to its surface, that the parts were not offended; but immediately the first piece gave way, two sharp angles were left, and rapidly brought on the ulceration. There is in the Col- lege of Dentists even a larger mass aggregated upon an artificial piece in the lower jaw; and I remember, during the first ten years of my prac- tice, I received a visit every six months from a lady who wore six artificial teeth, made of the hippopotamus's tooth, and tied to the adjoining bicuspids by silkworm gut: these had been put in five years before I saw the lady, and they con- tinued quite sound and hard ten years afterwards, when she died. This piece collected on its inside next the tongue, within every six months, more than double its mass of tartar, and only required removal and retying, on account of the substance fJHEOPLASTIC METHOD OF MOUNTING TEETH. 129 intruding on the tongue, as it seldom became loose at all, the tartar actually cementing it to the teeth. Dr. Blandy, of New York, then read a paper " On the Cheoplastic Method of Mounting Artificial Teeth" — The necessity for a more accurately fitting denture than has been used is one that has always existed, and perhaps ever will exist, until a pro- cess shall be made known by which the principle of atmospheric pressure shall be perfectly applied in the retention of artificial teeth in the mouth. This principle gives a power of fifteen pounds to the square inch; and it follows that the pro- cess which best accommodates all its require- ments, is the one which should be adopted in the construction of all pieces for the mouth, being equally desirable in pieces of greater or lesser size, with clasps and springs, or without either, the former being required in proportion as the means used enables the manipulator to bring to bear this principle of atmospheric pressure. A plate that is struck between two dies is, of necessity, a rude fit to the mouth at best; as, admitting that the impression has been correct, and the casts from this impression carefully taken, you encounter the change invariably following from the shrinkage of these dies, as well as the perhaps minute differences resulting from even the most correct manipulation : added to these, is the change of surface of dies from pressure used in 130 ON THE CHEOPLASTIC METHOD swaging up the plate, wliix?li can only be partially avoided by using a number of dies, and even this attended by the possibility of considerable varia- tion in the dies as compared with each other. The difficulties consequent upon soldering, &c. such pieces are too well known to require repe- tition, but which increase the obstacles found in obtaining a correctly fitting denture from a struck plate. The great skill and beauty displayed in the carving of bone pieces do not, from limited observation, obviate the objections to struck plates in this particular, besides having other more serious objections, such as perishability and want of perfect cleanliness. The process known as hard rubber, and intro- duced to the American practice by a Mr. Wheat, is a better process for this end, although not by any means perfect, as in the manipulation the delicate corrugations of the cast are often rubbed down, and the pressure of the screw used to force the one part down in the other, is often attended by a displacement or injury of surface, in spite of the greatest care, as also the great tendency of this material to spring and warp from slight heat and small pressure, must greatly mar and inter- fere with a perfect result, if it were even attended by all other perfections. The process which is now about to be intro- duced to your consideration has been denominated cheoplasty, or a means by pouring, being a OF MOUNTING ARTIFTCIAL TEETH. 131 method of casting a plate, at the same time se- curing the teeth properly adjusted. It is proposed to you as at once securing the best-fitting plate, the most reliable attachment for holding the teeth, the least expensive and the most rapidly executed, although not employing the least skill ; and it may be said not to lack real beauty in comparison with the most received processes for beauty, and is also the most cleanly in wear as well as safely and reliably repaired when broken or injured. It is the best-fitting because the plate is obtained without change or injury from manipulation, an exact counterpart of the impression. The cast from the impression, usually known as the plaster, being formed of a composition which undergoes no perceptible change in working, that is, it is not injured by pressure or too much friction, is free from perceptible shrinkage and warping whilst subjected to the heat of a common oven, say 400°. The metal being cast upon this, it possesses sufii- cient strength to resist the little tendency of shrinkage in the metal, which may be stated at g^th of an inch; so that the palatal surface of the plate must be the exact counterpart of the impression, and this being correctly taken from the mouth in plaster, or by other means, must be the palate's facsimile, and requires but little exer- cise of reason to accord to it the claim of a nearly perfect adaptation. K 2 132 ON THE CHEOPLASTIC METHOD The teetli used for it and best adapted, althongli all teetli can be well mounted by it, are so formed by means of grooves, dovetails, and holes, that the metal runs into and about them in such a manner as to render their removal impossible, except by remelting or breaking; permitting teeth to be remounted any number of times, care being used in regulating the comparative equality of heat of the teeth and metal, when pouring the metal into them. It is least expensive, as costing about one eighth of gold, the same character of teeth rating at the same value as for old processes ; the metal costing but 5s. per ounce, and being capable of remelting any number of times, not necessarily attended by any material loss. The time required in mounting depends greatly upon the facility of the practitioner, but can be safely stated as not employing one eighth of the time used in gold, five to eight hours being sufl&cient to mount any ordinary set of teeth; as sets have been made in much less time, as well as much longer, de- pending upon peculiar difficulties in the grinding, as well as the perfection of finish. Suffice it, that this statement of time is a liberal one, as all partial pieces require much less time pro- portionally than full, which is not so in other methods. The piece when completed represents a solid mass, free from all apertures or open joints, and OF MOUNTING ARTIFICIAL TEETH. 133 of necessity must be cleanly, never becoming offensive from wear ; which qualities last through its use. It is repaired or altered with great readiness, and being done by pouring or soldering, accord- ing to circumstances hereafter to be described, and as the metal unites perfectly with the plate repaired, it leaves no trace of such repair or alteration. In this particular it will be found to possess especial advantages, as in the case of altering a temporary set to become a permanent, or in case an error has been made in the first impression, and found only in trying the piece in the mouth, a correct change can be made in a very short time, by cutting out the entire inner or outer surface, and recasting it upon a better impression without disturbing the teeth that have been found to suit in all particulars. Again, in mounting pieces in which the teeth are scattered, you find one or more have not the desired posi- tion,— it is but the work of a few moments to cut such teeth off, and solder them on again exactly adjusted. For all cases of regulating, this power of ready alteration is one peculiarly valuable, and has not its equivalent in these particulars in any other process, and done without waste of material or time, as well as the smallest amount of additional expense. It is a matter of but little moment in what 134 ON THE CHEOPLASTIO METHOD direction the tooth or teeth to be regulated re- quire to be drawn, as a few minutes will enable you to alter the position of the pin, if the power is applied from the palate surface, or to perforate the band passing in front, if it is from the labial portion; or should it require a new means by addition of metal, it is soldered so accurately and with such expedition as to command in these par- ticulars the whole field of mechanics in regulating. This will be readily understood when the principle is comprehended of obtaining the plate or band. Having a good impression, you model your plate to rest in a certain position, holding it by as many points of attachment as you think proper to grasp by clasps or ligatures, as may be preferred, securing at the same time the substance of metal upon the grinding surfaces of the molars necessary to keep the teeth from antagonizing during the reduction of the irregularity, and of course the piece is delivered precisely as you have modelled it, with the greatest opportunities for any subse- quent alteration.' If cheoplasty had no other especial advantage, its superior use in regulating would command from you, gentlemen, its adoption for such pur- poses. But it commends itself in many other directions, none greater, however, than the un- qualified superiority of adaptation to any given surface. In all pieces in which springs or clasps are used, the small size of the plate which may be OP MOUNTING ARTIFICIAL TEETH. 135 employed, at the same time securing a greater approximation to the original form of the ab- sorbed parts, is of peculiar import, presenting as it does to the tongue and lips the most acceptable surface, at once strong, natural, and most cleanly. For single or detached teeth in the lower jaw, nothing can be more perfect, if at all equal to it. In the great majority of such pieces, struck plates are inadmissible, and bone in others only avail- able ; but with this process all cases can be accommodated; even in some of those where a correct impression could not be obtained, owing to the peculiar position of the teeth, by the facility of soldering they have been made successful. In inserting pieces when the teeth are single or separated, it often happens that one or more of the teeth are found on completion to have been misplaced or disturbed, so as to be out of their desired situation in the mouth. For all processes this is always a serious mistake; yet by this method it is safely and perfectly corrected by cutting off and soldering on again, requiring cer- tainly not more than fifteen minutes, and this done so neatly as to defy detection, without im- pairing in the slightest degree its usefulness. The great advantage it has, also, in lower sets, where the alveolus is exceedingly narrow, is at times quite indispensable, as it may occupy but a few lines in breadth of the surface, and yet possess as much or little weight as required with 136 ON THE CHEOPLASTIC METHOD greatest strength, as well as the most comfort- able surface for the gums, the tongue, and the cheek. This is, of course, peculiar to cheoplasty, and of the most desirable character, as there can be nothing more unpleasant to the patient or more unfortunate to the dentist than the move- ment of the plate in the mouth, sometimes noticed in bone pieces, resulting from insufficient weight when admitting only a very small base. Again, it is especially valuable for such lower pieces as are required to sustain two or more teeth upon either side, connected by a delicate band passing behind and below the front teeth. These commonly inflict great pain, or want much usefulness, as well as being necessarily clumsily made. These troubles are almost wholly over- come, as, by this means, they can be made perfect in their fit as well as free from bulk, yet pos- sessing all required strength and usefulness, as well as presenting the round edges so admirably formed in bone. From the great perfection in its fitting the parts so accurately, a smaller amount of the surface of the mouth may be employed, at the same time possessing more strength, and, from this close adaptation, much less liable to break or to give way in the mouth ; because the plate itself is called upon to bear but little pressure, as the gums, being in absolute contact at each particular point, sustain directly the pressure applied by use. OF MOUNTING ARTIFICIAL TEETH. 137 This is, of course, in reference to plates made with springs and clasps ; for when atmospheric pressure is employed, it is a rule to occupy as much of the superior jaw as possible. These are points which should not be forgotten, because in England the practice requires the use of springs and clasps, and of course the great facility of their application in this process is one which should claim particular attention. When two or more teeth are to be sustained by pivots passing into the natural fangs, which for comfort or choice requires a small plate, nothing can exceed the facility, beauty, or strength of this method ; because the impression can be made to give you positive indication of the desired direc- tion of the pivots which are cast with the plate, and thus lessen the difficulties commonly expe- rienced in positioning these pivots, as well as obtaining the exact situation of the teeth. In this process breakages never occur from use, but from accident only out of the mouth, and much less frequently, from its superior strength, than is generally experienced, and when broken is rapidly and effectually repaired, without affecting in the slightest degree its former usefalness or appearance. Having secured a beautiful stock of block and single teeth, known to some of you as those im- properly used for hard rubber, as they were made for this process and belong to this patent, a 138 CHEOPLASTIC METHOD OF MOUNTING TEETH. facsimile of tlie piece broken can be obtained, ground to its position, and fastened by pouring the metal ^bout it hot enough to unite with the plate, a point always easily secured. It is then dressed down so as to leave no indication of the repair. To give some indication of the extent of the use of this process in America, I would state that there have been sold between 300 and 400 rights, and that, during the year 1858, over 300 lb. of the metal was sold by the agents. This year, thus far, the increase has been much greater, and will no doubt reach 600. However, this statement you have doubtless seen made by others, as found in the last edition of Harris's '' Principles and Practice," in his trea- tise on cheoplasty. The very small amount charged for the right of use, the inexpensive character of everything employed, the entire absence of new implements or machinery of any kind, the liberal and unquali- fied indorsement of its advantageous use by men whom we all know and respect ; and also the fact that its adoption will save to its users several times its cost the first year, are, with those named, a few of the leading advantages of this process, expressed within the exact limits of facts from experience. GENERAL MONTHLY MEETING. Saturday, April 2, 1859. ARNOLD ROGERS, Esq., President, in the Chair. The following Gentlemen were duly elected Members of the Society : — Mr. Samuel Ghrimes London. Mr. Charles Stokes, M.R.C.S London. Mr. G. Bartlett London. Mr. W. G. Bennett London. Mr. Robert Hepburn London. Mr. Duncan D. Hepburn Nottingham. Mr. David Hepburn Edinburgh. Mr. J. Watt Edinburgh. Mr. J. K. Chisholm Edinburgh. Mr. J. Orrock Edinburgh. Mr. J. A. Baker, M.R.C.S Dublin. Mr. J. Murphy Derby. Mr. C. D. Roberts Ramsgate. The following Gentlemen were proposed for the Membership of the ;iety : — Mr. J. FiNNiE Alexandria, Egypt (corresponding). Mr. George Allcard ...35, Carlton Villas, Maida Vale, London. Mr.JoHNCALDCLEUGH.,.32, Claypath, Durham. Mr. L. Dreschfeld 229, Belgrave Place, Oxford Road, Man- chester. Mr. Spence Bate communicated a method for constructing Lower Plates :— The piece is made as usual, and the teeth are fitted on and completed, all but being fixed. A plate of thin gold is struck upon the model and soldered beneath the piece of work; the edges 140 ON THE VULCANITE BASE are turned up where they can be conveniently so done ; in other positions strips of gold must be soldered on and the margin let in flush with the surface of the teeth, which now may be fixed on and completed. It appears to me that in this way every requi- site is obtainable — a good fit, smooth and round edges, and work of great strength and durability combined with lightness. The work can, more- over, be readily taken to pieces for repair; and, from what I have seen and read, combines all the advantages of either of the new methods, except that of economy in money, time, and sldll, I would also draw attention to the swivels which I have for some time made and used, as having advantages over those in common use. Mr. Putnam, of New York, read the following paper — On the Vulcanite Base as applied to Dentistry, its history and progress to the present time. Mr. President and Gentlemen, — In appearing before you to-night to read this paper, in com- pliance with the expressed wish of several of your members (and by the permission of your Council), I feel considerable difficulty, coming among you, as I do, a comparative stranger, and proposing a system of artificial dentistry, which, in a mea- sure, is opposed to your preconceived ideas in this branch of our profession. AS APPLIED TO DENTISTRY. 141 Moreover, my name is so intimately known in connection with this subject from the commence- ment, that it is difficult to avoid an egotistical dissertation. Again, in my desire to confine myself to the simple statement of facts, which will bear sub- sequent investigation, I may fail in imparting that kind of information which you expect from me. And, thirdly, because I am desirous of not even appearing to claim to myself any credit to which others are justly entitled. I beg, however, to state, first, that in the year 1855, Mr. Goodyear brought to my office in New York samples of " hard vulcanite," in sheets of an ebony black, requesting experiments for its application to artificial dentistry. According to his statement, several dentists had previously been induced by him to make the attempt, but invariably failed, for the want of some specific system which had yet to be discovered. Among those names he mentioned were Mr. Cummings, of Boston, and also a Mr. Wheat, of Philadelphia, with whom I have no acquaintance, and to whom special reference was made in a paper read before you on the 5th of March last. Mr. Evans, of Paris, has recently informed me that he made some experiments for Mr. Goodyear as far back as 1851 or 1852, and that he beheves himself to be one of the first, if not the first, who 142 ON THE VULCANITE BASE ever made a practical piece ; also, tliat he saw but recently a piece wliich he succeeded in making at that time, and which had been worn until the present without change. Others also profess to have made early experi- ments— with what degree of justice I have no means of judging. The experiments previously made and known to Mr. Goodyear prior to his calling upon me, were, in a measure, explained by him, and I commenced as follows : — Instead of the small amount of plaster which is now found sufficient for a single piece, more than four times the quantity was considered ne- cessary. I was told that the plaster investment and piece must be buried in a mass of pulverized soap- stone, and thus remain in a high degree of steam- heat for twelve hours. I therefore prepared work in this manner, and sent it to Goodyear' s extensive works to be steamed. This system was pursued for nearly three months, during which time not more than one piece in five was returned to me in a fit condition to use. The cause of all the failures was wholly un- accounted for by any one at the time. Yet even this small per-centage of success encouraged me to have constructed in my own house an appa- AS APPLTED TO DENTISTBY. 143 ratus similar to theirs, on as small a scale as it could be made to operate, though it was at the cost of over lOOL The size of my steam-chest was about that of a 16-gallon cask, and the boiler of a capacity to hold 150 gallons of water. This supply of water was not sufficient for one heat of vulcanizing, as condensed steam in the chamber had to be constantly drawn off and was lost, while the boiler had to be refilled by a hand force-pump, against a pressure of 70 to 80 lb. to the square inch. I was enabled, however, by a series of ex- periments— in the preparation of material and otherwise — to reduce the time of vulcanizing from twelve hours to six, and also to use less plaster in investments. But the successful pieces were even now only about three in five, resulting in part from the improtected condition of the plaster while steaming ; for occasionally it would separate into a thousand fragments, caused by imperfect moulding ; also, if an equal amount of plaster was not used for each piece, the work was too hard, or too soft, accordingly. At this period, in 1846, the necessity became imperative for what are now called in America ** Putnam's vulcanizing flasks." And, although they appear simple to those now using them, I have to acknowledge that a long series of experi- ments and repeated alterations were necessary to 144 ON THE VULCANITE BASE obtain the proper form, proportion, and sim- plicity. I was then enabled to dispense with the pul- verized soap-stone, and reduce the time of vul- canizing to three hours. And the result now being that four pieces out of five turned out suc- cessful, I no longer hesitated to adopt the system fully in my practice. An important and reasonable difficulty now arose against its general introduction among dentists in America. The profession shrank from introducing into their workshops so ponderous and expensive an apparatus, and my position as a fellow-prac- titioner naturally deterred many from availing themselves of the offers I made in the way of free access to, and use of, my own apparatus. Another difficulty arose to prevent its general introduction. The parties holding a patent for the '* vulcanite material" were tenacious (and are still so) about having the general vulcanizing process much known, and therefore only consented that a few agents might be employed — one in each of the large cities — to do the vulcanizing for dentists. I need not add the result of such a determina- tion, but trust that I have sufficiently answered the frequent inquiries made in Europe as to '' why the work was not, ere this, more generally adopted in the United States?" AS APPLIED TO DENTISTRY. 145 The result of my visit to London, in 1857, only made the fact more evident, that dentists must have in their own workshops a small and con- venient apparatus, or that the public must be debarred from enjoying the benefits of the system. Members of this Society will remember the promise I made on the eve of my departure from England, to return again in 1858, with an appa- ratus so perfected as to meet their demands ; and they are now my censors if I have not done so. To answer many inquiries relative to the use of dry heat for vulcanizing, I give (by your per- mission) a synopsis of some experiments made immediately after my return to New York from London, in October, 1857. I first constructed two cylinders of sheet iron, one within the other (a model of which I present). A cover upon the small cylinder, in which a ther- mometer was arranged. The flasks containing the work were put into the inner cylinder and surrounded with asbestos to make the heat even. Sand and pulverized soap-stone were also used for the same end. That some moisture might be constantly sur- rounding the work, a reservoir of water was formed upon the top, with an aperture at the bottom to allow a steady supply to a coil of pipe or worm placed over the gas flame. The coil of pipe was kept constantly red hot, and the water forced throusrh it into the small 146 ON THE VULCANITE BASE cylinder, the quantity regulated by a suction- valve, acted upon by pressure from without, and by heat within. After more than one hundred consecutive ex- periments with this. apparatus, and having varied it and the application of heat (with and without the steam made through the red-hot coil), in every possible form which I could imagine, and without obtaining satisfactory results, I turned my attention to the use of an oil-bath. This I had constructed, using two cans, one smaller than the other. The largest, being one-third full of common oil, was placed upon an ordinary stove to heat, and the smaller cylinder or can was then let down into the oil, resting on a flange near the top of it, which made the large can tight. The work was then put into the small cylinder, which closed by an adjustable cover, into which the thermometer was attached. The boiling point of oil being about 500 de- grees, a vulcanizing heat was readily obtained, and before the least ebullition of the oil took place. But the results of this apparatus proved the same as those made with the last one de- scribed; viz., that under certain conditions of the plaster some pieces were made hard, but in all cases having such imperfections as to deter me, for the time, from making further experiments on this point. AS API'LIKl) TO DENTISTRY. 147 Work might appear and look as well as though steam had been employed, yet it was invariably destitute of the requisite solidity and strength. If the plaster moulds were first dried, then the piece would be uniformly burned or porous ; if not dry, then the inner part of the piece was not in the least hardened, while the outer edges were burned to a crisp. Such was my experience in all forms of dry heat ; and it would be interesting to know what success has been obtained by others in this espe- cial point. In January, 1858, I constructed a steam appa- ratus, to work automatically, viz., self-circulating and self -regulating, — the greatest diameter 12 inches, and length 40 inches. It was soon successfully put into operation in the presence of the late Professor Townsend (of whom many of you,' no doubt, have pleasant recol- lections) and Professor Austin, of the Baltimore College of Dental Surgery ; eifecting in two hours better results than were produced by my first extensive steam apparatus in three hours, and which the ponderous machine of Goodyear' s could scarcely accomplish in twelve. The gentlemen just alluded to (though gene- rally adverse to patents) urged me to patent what seemed to them so useful, convenient, and novel an invention, and a copy of the original L 2 148 ON THE VULCANITE BASE drawing, which was thereupon deposited in the Patent Office, is now before you. I soon found, however, that the apparatus was sufficiently perfect to satisfy all demands for dentistry, without the self-regulating attach- ment, and consequently it has been left off en- tirely. So many of your members are now familiar with the working of this apparatus, that I need not detain you Avith the details of its description. I state, however, that its small capacity gives great facility and safety in its use, and that in vulcanizing, the pressure required is only about sixty-six pounds to the square inch ; also that it is, I believe, the opinion of all engineers, that pressure on a square inch by steam is the same, in all respects, as leverage pressure ; therefore, as steam pressure is equal in all parts of a cylinder containing it, we have only to consider its capa- city, and then the strength of the cylinder itself. For instance, steam with a pressure of 200 pounds or more to the square inch, may be used with safety in a very thin pipe of one inch dia- meter, from the fact, that the capacity is so small, very little force is exerted upon it. Machines which I have been permitted to in- troduce to your notice have been subjected to a pressure of over 200 pounds to the square inch, and the manufacturer informs me that they can AS APPLIED TO DENTISTRY. 149 be used with safety at a pressure of 400 pounds to the square inch. In France a law exists, making it a fine to use a steam-boiler for driving machinery before it has been stamped by a chief engineer, and under the direction of the Prefet of Police. I accordingly applied to this functionary, who, on viewing my apparatus, replied, " that government had nothing more to do with it than with every cook's tea- kettle.'* He remarked further, that its small capacity and the great thickness of metal used, would warrant any one in using it under a pressure of 500 pounds to the square inch, and thereupon signified his willingness to attach the ofl&cial stamp to that efiect, if desired. FeeUng, as I now do, that there is a special advantage to every one who uses the vulcanite in practice, to fully comprehend all its peculiarities in manipulation, I beg first to state, that with all the attention which I have thus far been able to give to this part of the subject, there are a few points yet unexplained. For instance, when a mass of material is to be made hard in vulcanite (say one inch square or thick), it is more than probable that it will come out porous and unfit for use, and yet occupy no more apparent space than if it had come out solid. As yet I know of no remedy for this, nor why 150 ON THE VULCANITE EASE it is made porous ; nor can I conceive why a mass made tlius — even like a sponge — should not ne- cessarily occupy more space than the same mass or bulk would if it had been perfectly sound. To make myself more clear, we will take two plaster moulds from an English walnut ; fill both, and vulcanize under an equal degree of tem- perature, observing that the manipulation and conditions are equal throughout the preparatory process. On examination, we find that one is solid, and of the usual weight of vulcanized material, while the other is exceedingly porous, except over the surface, and of much less weight than the sound one, and still both measuring the exact size. The cause of all this is somewhat a mystery, and it is not yet known what properties of the material are lost, to make so great a diminution of weight and solidity. In fact, the chemical change of the material under heat, and under any circumstances, is not, I believe, much under- stood. As regards changing the vulcanite, so as to make it approximate to the natural colour of the gums, I will not tire you by relating the numerous experiments I have made to attain this desirable object. I have found, however. First. That sulphur alone does not change in a vulcanizing heat. AS APPLIED TO DENTISTRY. 151 Second. That pure vermilion, which is the only- suitable colour now used, does not of itself change. Third. That sulphur and vermilion mixed in any proportions do not change. Fourth. That rubber alone does not change. Fifth. That rubber and vermilion mixed do not change. Sixth. That rubber and sulphur, when mixed and hardened, invariably produce a substance jet- black. Seventh. That the three combined, in certain proportions, will change but slightly in colour, at a temperature sufficient to produce a substance in hardness equal to leather. And, Eighth. That gutta-percha used alone, and in the manner just referred to relative to rubber, produces nearly similar results. Therefore we may reasonably infer from these facts, and others, that the chemical change (if it is such) which the rubber itself undergoes to obtain the necessary solidity and strength, im- parts a degree of, or covers up by its own inlcy hlachiess, such colours as do not in themselves change. Again : to those somewhat familiar with the process, there are important queries often arising touching the condition of the water in an appa- ratus after it has been used for a length of time. Whether it receives or not, and retains, any vul- 152 ON THE VULCANITE BASE canizing properties ? Or, if the small amount of iron rust lias any effect in vulcanizing? Or, whether, after using it repeatedly, the water be- comes so charged with sulphur, or other foreign substance, as to make a change of water impera- tive at given periods ? In reply to most of these queries, I acknowledge the courtesy shown me by your worthy President, to whom I am indebted for a chemical analysis of this sediment, which proved it to be wholly oxide of iron ; and we cannot expect anything to be held in a solution which is not detected in its evaporated sediment. To prevent the inner surface of the apparatus from rusting, a little borax may be occasionally mixed with the water. Another point offers a field for investigation ; viz., the use of loose mercury surrounding the bulb of the thermometer. It is now used as a medium to give a correct indication on the scale of the thermometer, of the heat within, thereby dispensing with the neces- sity of having the glass bulb come in direct contact with the steam, and it is generally ac- knowledged, I believe, that the result is quite the same. The question now arises — Will it, on being exposed to the atmosphere, and a temperature of heat required, deteriorate, and become after a time less sensitive than at first ? AS APPLIED TO DENTISTRY. 153 It is argued by some, that none but distilled mercury should be used for this purpose; and others maintain that this is not essential. My attention has been called to these points by statements, that when a machine had been some time in use, the same results were pro- duced, at the same indicated temperature, in a shorter period than when the machine was first put up. A certain time, and the use of a certain and even degree of steam heat, seems now to be abso- lutely necessary for good and practical work. Some important facts on this point have been satisfactorily proved by others as well as by myself : — 1st. That an excess of heat will give a darker colour to the material, and render it brittle ; while not enough heat leaves it of a brighter colour and not possessing sufficient solidity to hold the teeth. Any endeavour to substitute increased heat for length of time would be about as reasonable as to expect to bake a loaf of bread or roast a round of beef in ten minutes. For, unless a given time is allowed, one part will be surely crisp and another raw. 2nd. That a piece vulcanized upon a plaster model will afterwards fit its duplicate in tin, or fusible metal, and vice versa. 154 ON THE VULCANITE BASE This, we tliink, answers the inquiry, so often made, — " Will the material shrink ?" 3rd. That the plaster models or moulds should never be dried, and that the material should be packed while the plaster is in its natural condition, one hour or more after casting. 4th. That no moisture should be allowed in contact with the material while packing, and that in removing work from the flasks, it should be first allowed to become perfectly cold. In replacing teeth upon a set which has been worn, by the addition of new material, I find that the original changes to a darker brown, but gene- rally loses none of its strength and solidity. If, however, the same piece had been continued in the heat (at the first time of vulcanizing), the additional time given to it in repairmg , it would have been rendered brittle and wholly unfit for use. This may be accounted for by the condition of new plaster, which had been substituted for that which had already been in the steam. Yet no one doubts, I suppose, but that the heat is as intense in the centre of a flask at the moment it is up to the point of vulcanizing, as when the piece may have remained in double the time neces- sary for making good work. I have made numerous experiments, in com- bining with plaster for moulds proportions of AS APPLIED TO DENTISTRY. 155 soap-stone, feldspar, silex, and asbestos, without being able to perceive any considerable advantage over plain plaster. I have also mixed with it large and small quan- tities of sulphur, with a view of using less in the vulcanite compound, but could never determine that it produced any change whatever in the cha- racter of the piece within. To make the plaster model hard, I have used a solution of alum, at other times a solution of silicate of potash, but with no special effect. To make the plaster separate more cleanly and readily from the piece after vulcanizing, I have used upon the model a solution of silex, glass, gum arabic, gum copal, and almost every other known gum, without practical benefit, and only find sul- phuric acid, simply applied after the work is vulcanized, to act the most effectually. It has been suggested '' that the use of vermi- lion in the material gives us in the piece one of the forms of mercury, and that with those who cavil at trifles, serious objections would arise against its use." We reply, that if the work decomposes, wears away to any extent, or absorbs the fluids of the mouth one jot or tittle — which has yet to be proved, then I submit it for your decision as to what extent of injury can possibly arise to those who wear it ? In conclusion, I beg to state that these and 156 ON THE VULCANITE BASE many other facts and experiments have no doubt been made a study by many of those present, and some have no doubt drawn different conclusions. To several I am happy in according thanks for valuable suggestions in furthering the process. As the system is one of no mushroom growth, depending on no recommendation except its own intrinsic merit, and not so easily comprehended as the casting of toy-metal or modelling gutta- percha on silver and gold plates (yet possessing peculiar advantages), it is, I trust, fully appreciated by those dentists who have adopted it exclusively in their practice, and doubly so by such of their patients as have had other styles of work replaced by it. I therefore now feel that the sacrifices made by others as well as by myself have not been wholly lost. But while we have some cause for congratula- tion that the method has attained a certain degree of perfection, we feel free to state that the field of research and experiment is still open and broad. And looking to members of this Society, may we not expect, nay, even hope, that ere long the pro- cess will be so improved that what we are now doing will then look antiquarian, and that every dentist will be still prouder of what he can furnish for its neatness, beauty, and strength, while from its use he daily receives the increasing gratitude of his patients. AS APPLIED TO DENTISTRY. 157 Gentlemen, for this token of your respect in listening to my remarks, you have my thanks. If acceptable to your members, I now take plea- sure in presenting to the Society the model I have alluded to, with the drawings, and a few samples of the material, as further illustrating the subject of my paper. GENERAL MONTHLY MEETING. Saturday, May 7, 1859. ARNOLD ROGERS, Esq., President, in the Chair. The following Gentlemen were duly elected Members of tlie Society : — Mr. Robert H. Moore, r.R.C.S.I.... Dublin. Mr. Walter Browne Nottingham. Mr. Thomas W. Evans Paris (corresponding) . Mr. L. S. BuRRiDGE Rome (corresponding). Mr. A. J. L. Talma Brussels (corresponding). Mr. E. Parmly New York (corresponding). Mr. Chapin Harris Baltimore (corresponding). Mr. Thomas E. Bond Baltimore (corresponding). Mr. A . Snowden Pigott Baltimore (corresponding). Mr. Robert Arthur Philadelphia (corresponding). Mr. J. D. White Philadelphia (corresponding). Mr. J. Tucker .Boston, U.S. (corresponding). The following Gentlemen were proposed for the Membership of the Society : — Mr. James J. Sherwin Sheffield. Mr. S. Gill Liverpool. Mr. J. H. M'QuiLLEN Philadelphia (corresponding). Dr. Ballard New York (corresponding). Mr, Maclean Dublin (Honorary). Mr. W. R. Ballard London. Mr. Tomes exhibited a small Mouth-mirror. Mr. Childs exhibited a Vulcanizing Apparatus. The vulcanizing chamber, to be filled ^vitll an atmosphere of steam, requires to have poured or placed in it, before the lid is screwed down, not 160 ON LATERAL rRESSUEE. more than a quarter of a pint of water. The gas is then to be lighted, and the heat brought up gradually by means of both the gas coils ; when the heat is up to the desired temperature, then the small coil will be found sufficient to keep it at that degree of heat. The lid of the vulcanizing chamber must be always steam-tight when in use — this will prevent the escape of any smell. This is easily done by dusting some French chalk on that part upon which the lid is screwed down each time of vul- canizing. When the time necessary for hardening is com- pleted, the apparatus must be allowed to cool down before opening the lid. Mr. Bridgman read the following paper on "Lateral Pressure:^' — '' Lateral pressure^ ^ is a term usually applied to certain results arising from an abnormal state of the human denture. It is by no means restricted in its application, but is commonly assigned as a cause for any par- ticular effect, either of crowding, or decay in the teeth, or any other deviation from the normal condition. But, although it is thus the assertion of a fact of common occurrence, it does not appear to have been made the subject of especial atten- tion ; nor, so far as I am aware of, has any attempt ever been made to point out its original ON LATERAL PRESSURE. IGl source or manner of being produced, or of the circumstances under which it may arise. The immediate action upon the teeth to which this appellation is commonly applied, is merely the expression of some other and more remote force. There are three separate and distinct sources whence this force may be derived. The first, and most obvious, is that arising from the force of growth — the " vis incrementiy The second is the " vis extensionis,^^ or pressure caused by the muscles of the cheeks and lips upon the outer curve of the dental arch, and by the expansion of the tongue in sucking, &c. within the arch. And, thirdly, the '' ?*i9 occlusionis/^ or under- pressure, caused by an imperfect " bite." In the first division, in which the pressure may arise from the growing teeth, its effects will of course be principally confined to a limited period, and generally terminate with the maturity of the denies sapientice, although in some few instances the retardation of particular teeth may cause it to be delayed for a much longer time. Passing over the deciduous teeth, the crowns of the first per- manent molars are the first to become affected by it ; for when these make their appearance through the gum, immediately beyond the distal surface of the second temporary molar, the bulbous protu- berance of the latter projects over the intermediate transverse septum of the alveolus, and catching M 162 ON LATERAL PRESSURE. the crown of the rising tooth, causes it to recede as it emerges from the gum, and thus produces just so much pressure as will be required to separate the one from the other at their necks when fully formed. The result of this is the sub- sequent decay of one or both at the parts which have thus come in contact. That teeth so crushed together do, sooner or later, decay at the parts injured, I believe to be an indisputable fact, although we may not all agree as to the precise manner in which this decay takes place, or upon the agent by which it is immediately produced. The peculiar distinctive features of the mischief arising from this source may be readily traced in the extent of the injury. When the distal surface of the first or second molar is found to be decayed, the cavity will generally extend down to the edge of the gum, or even below it ; but not so with the mesial surface opposed to it ; for this being the offender and presenting a thickly enamel- coated Fig. 16. surface, receives but a small amount of injury to itself, which is principally confined to its most prominent part, and often es- capes almost unscathed. The above diagram, Fig. 16 (the original of which is in the Society's museum), is a fair illustration of these effects. Here, the second molar, having no opportunity of moving forward out of the way of ON LATERAL PRESSURE. 163 the deris sapientice, and the latter coming up at a considerable angle to the former, and having caught the overhanging enamel, has literally crushed its way into and embedded a portion of its crown within it, the molar having been kept down in its socket by the antagonism of the upper teeth consequent upon the closure of the mouth. The molars of the lower jaw are more especially calculated to produce this injurious pressure through their line of growth being forwards as well as upwards, owing to the curvature of their fangs. And wherever one tooth in its eruptive stage has to come up between two others which are too close together, and have not left room between them for it, it will have to force its way to its place, or else to the inside or outside of the arch, according to circumstances ; and any pressure upon the fang or fangs in the way, will only lead to a portion of the latter being absorbed, while any part of the crowns or the necks so circum- stanced almost invariably ends in the decay of of one or both. This effect of lateral pressure, however, must be strictly confined to the period prior to the teeth having attained their full eleva- tion and become antagonized with their opponents. Any pressure subsequent to this stage will belong to one or other of the following sections. In the second division, lateral pressure is pro- duced by the tension of the muscles of the lips M 2 164 ON LATERAL PRESSURE. and cheeks when the jaws are distended. This has been termed the vis extensionis, because it exists principally during the action of these muscles. We are all conversant with the effects of applied pressure upon a misplaced tooth, and constantly have opportunities of witnessing how readily a tooth may be moved in almost any direction, and that too with but a very small amount of force. We also frequently see the anterior portion of the upper denture rendered unnaturally prominent by sucking the finger or thumb, or by biting the lower lip ; and therefore it may be fairly inferred that should any other part of the mouth, under any particular circumstances, be in a position to exert a pressure upon the teeth, it would be fol- lowed by corresponding results. That such an effect does in reality occur, and that the form of the palate, in combination with the size and shape of the tongue, is the means of producing the particular form of the dental arch by which they are accompanied, has, to me, long ceased to be a matter of doubt. In his work on the '' Anatomy, Physiology, and Diseases of the Teeth," Professor Bell states, in the chapter headed "Observations on the pretended Prevention of Irregularity," pp. 89, 90, that " a favourable prognosis may, with tolerable certainty, be formed of the ultimate regularity of the teeth, as far as it depends upon the relative proportions ON LATERAL PRESSURE. 165 between them and the maxillary bones, where the following circumstances are found to exist at the period when the second dentition commences : "1st. If the maxillary arch be well formed, suffi- ciently expanded, and of a semicircular form rather than elliptical. " 2nd. If the temporary teeth, although broad, are a little separated from each other ; especially if, having been originally somewhat crowded, they have been gradually acquiring more room during the last year or two; as this indicates a disposition in the jaws to expand,** The preceding passages, together Avith others of a similar character, in which peculiar effects are alluded to without reference being made to any particular cause from which they would be likely to result, many years since arrested my attention, and led to a closer examination of the subject, with a view to determine the primary source whence these deviations are produced. That there should be a disposition in the jaws to expand in some cases and not in others, was too significant a hint to be lost sight of; as it affords a clear indi- cation of the existence of some peculiarity which is not common to all. Therefore, when we find that the semicircular form of denture, the form which gives rise to a separation of the temporary teeth by the " expansion of the jaws," is invariably accompanied by a broad and shallow palate, this would naturally suggest itself as in some measure 166 ON LATERAL PEESSUEE. allied to the former peculiarity. But when it can be shown, that with this particular form of the palate vault, the tongue in sucking or in mastica- tion, by its pressure is capable of producing the expansion of the jaws, and that when the palatal vault is differently formed, so that no pressure can be exerted by it upon the teeth during mastica- tion, &c., the expansion of the jaws does not take place, it will scarcely be doubted but that they are in reality to each other as cause and effect. It is, moreover, in the absence of the possibility of this pressure by the tongue within the arch, that nearly all cases of irregularity occur. Fig. 17. The above diagram. Fig. 17, is a life-size outline of the section of a cast between the first and second bicuspides on each side. The dotted line is an imaginary section of the tongue at the same part in the position assumed when in the act of sucking or of deglutition. The muscular side of the tongue coming thus in contact with the lingual surface of the teeth, has a ten- dency to press them outwards, and which, as the result of the tongue growing with the increasing age of the child, fully explains the " disjwsition of ON LATERAL PEESSUBE. 167 the jaws to exjpand^^^ and the consequent separation of the temporary teeth which they contain. But if we take a similar section of a case of irregu- larity, we shall find a very different state of things. Fig. 18. The form of the palate in Fig. 18 will at once indicate the absence of any support on the teeth, being derived from the pressure of the sides of the tongue ; and wanting this, it leaves them, as regards the position they assume, at the mercy of some other force which then regulates the forma- tion of the dental arch. If a lower incisor be removed on account of irregularity, or if a bicuspid be extracted from the upper jaw to make room for the cuspid, what is the power which causes the teeth to fill up the space in the one case, and brings the cuspid into the vacancy in the other ? It will not be the force of growth in the case of the lower incisors, because these teeth will be fully grown before such a pro- ceeding would be Seemed necessary. In the case of the cuspid, it might be supposed, on a super- ficial view of the matter, to be capable of effecting it. But were the upper lip to be held up and prevented from touching the cuspid, I have no 168 ON LATERAL PRESSUEE. hesitation in saying it would never reach its in- tended destination without assistance. And also, that were the tongue and the lower lip to be pre- vented from touching the lower incisors, these would never assume that degree of regularity which they are usually found to do after such operation. An incisor within the arch in the lower, is always much sooner restored to its proper position than an outlying one ; and it is this force, the pressure of the tongue, which, as the permanent incisors come up behind their tem- porary predecessors, pushes them forward into their places. In cases of crowded dentures, it is well known that the greatest amount of irregularity almost invariably occurs at the angles of the mouth, in the neighbourhood of the bicuspids, and it is just at this part that the pressure of the muscles of the face is exerted with its greatest force. If the mouth be distended to its utmost, a considerable amount of pressure will be felt upon the teeth in this region, from the tension of the m'bicularis oris and anterior portions of the buccinator connected with it. If the palate be broad and shallow, the more frequent action will have the preponderance, and the teeth will have becorae arranged . at the sides and extremity of the tongue when at its greatest point of expansion ; and the exterior pressure will then only have the effect of crushing the teeth together, and causing them to decay. ON LATERAL PBESSUllE. 169 In the act of sucking, in mastication, and in de- glutition, tlie tongue and the palate are as much dependent upon each other for the proper per- formance of their functions as are the two rows of teeth upon each other in eating; and therefore, when the tongue is pressed against the palate, either to produce the vacuum for sucking, or to compress portions of food, the very act of pressing it forcibly upwards tends to its expansion, and the corresponding expansion of the jaws previously alluded to as a favourable prognosis of the ulti- mate regularity of the teeth. In every variety of form of the dental arch, a particular shape of the palate will invariably exist in connection with some few other peculiarities which are corresponding accompaniments. Thus, where the palate is broad and shallow, the palate processes of the upper maxillse presenting a con- siderable area of horizontal surface, and gradually shelving off to the alveolus at an angle of about 45°, the tongue large and broad, the teeth are com- paratively small and wanting in boldness of outline, and rarely or never irregular in position, although occasionally producing supernumerary or " pin" teeth among the upper incisors. But in the opposite extreme, we shall find the palatal vault deep, narrow, and angular; the tongue thick, narrow, and tapering ; the alveolar ridge thick, prominent, and almost perpendicular; the teeth large, and fully developed, thickly but unevenly 170 QN LATERAL PEESSURE. coated with enamel, and bold in outline, but almost invariably more or less irregular in posi- tion. Under these conditions, in the act of sucking (which becomes extremely difficult, and sometimes almost impossible in the case of a very deep and pointed arch), there will be 7io lateral expansion of the tongue. All the effort will be required to reach the apex of the vault, and the tongue will be drawn up and thickened vertically. Hence the action of the muscles external to the arch will be to press the teeth inwards, and to cause them to assume an irregular line and to overlap one another; the two upper maxillae in extreme cases having the appearance of being compressed together inwards. It is under these circumstances that the con- traction of the jaws will be found to follow the extraction of a tooth; and it is more especially desirable in this form of mouth to retain the crowns of the temporary teeth in the mouth as long as possible, — as close up to the period of their successors coming up to replace them as possible, and not to remove them unless under the most urgent necessity. In all cases of re- moving one tooth to make room for another, it is most essential to notice the stage of the latter, and not to attempt the operation until after the period of its maturity, or the space may be filled up in a way not intended. In the shallow palate there is no fear of the arch contracting through ON LATERAL PRESSURE. 171 the premature removal of a tooth ; and although desirable not to sacrifice a temporary tooth need- lessly, there can be no worse evil resulting from it; and beyond the removal of an aching tooth, perhaps, this form of mouth seldom needs the interference of the dentist, and certainly not on account of irregularity. These peculiarities of the oral cavity are strongly marked at an early age — long before that period in the stage of dentition which usually commands the notice of the dentist, — and afford an unerring prognosis for our guidance in the treatment of the growing mouth. They have been made the basis of my own practice in this respect for many years past, and I can assert with confidence that I have never been once disappointed in any of its anticipated results. At a later period, however, but often before the dentine has arrived at completion, other results begin to arise. The pressure from the cheeks, which in Fig. 17 had no share in the ar- rangement of the teeth, now begins to show its effects in a different form. Force applied upon the outer curve of an arch, causes a thrust against its buttresses, but at the same time has a crushing tendency upon the sides of each of its component parts (if it be constructed in several portions), through the tendency of the curve to become flattened. Thus, the tension of the muscles upon the outer curve of the dental arch, produces a 172 ON LATERAL PRESSURE. degree of lateral pressure among tlie crowns of the teeth, which causes them to decay at their sides in contact. This is more especially felt among the upper bicuspides, as well as the upper incisors ; and it is a rare circumstance to find the former in a perfect state, under these conditions, long after they have become fully developed. The entire absence of lateral pressure from this source in the extreme forms of Fig. 18, renders the teeth much less liable to decay upon their mesial and distal surfaces. But they are more especially the victims of destruction in another way. The absence of pressure during the period of the crown of the tooth being formed and its being covered with enamel, has a marked effect upon the character and outline of the tooth. Begin- ning to form simultaneously at a number of centres, the enamel continues to increase greatly in thicJcness, but fails to be spread out sufficiently to become thoroughly united at the sides and angles, where two or more plates meet ; the con- sequence of this is, that these imperfections are the origin of that decay which so constantly ac- companies this form of the mouth, in the fissures upon the grinding surface of the molars, as also the medial depression on their buccal surface, as well as the division between the two cusps of the bicuspides. In the form Fig. 1 7 these circumstances rarely. ON LATERAL TRESSURE. 173 if ever, occur. The pressure of the tongue upon the alveolus not only causes the plates of the latter to be very thin, but also produces a more even distribution of the enamel upon the surface of the dentine. This renders the tooth less bold in outline, more uniformly coated with enamel, and causes the edges of the several plates to meet and be thoroughly united. It is not improbable but that the pressure thus exerted upon the crown of the tooth during the period of its being formed within its cell, has much to do with the first permanent molar being so commonly incapable of resisting decay. When within the cell, its much greater thickness than the temporary molars causes the alveolus to form a considerable projection inwards, and thus places it more in the way of the contiguous parts. This is not the case with the second molar, because the increased width of the alveolus at the first molar forms a protecting screen. That the latter condition constitutes by very far the largest proportion of the causes for the teeth being re- moved, is universally admitted, and by these teeth mostly decaying in many places simultaneously, there can be little doubt but that a large portion, or perhaps the whole, of the crown of the tooth has been subject to some detrimental influence in the early stage of its being formed ; and although it may be possible that the effect may arise constitu- tionally, or from irritation, or some other causes 174 ON LATERAL PRESSURE. connected with dentition generally, I am more disposed to attribute it to the above cause. The first molar is in some respects analogous to the dens sajpientice ; it stands in pretty much the same relation to the deciduous teeth that the wisdom- tooth does to the first and second molars ; and we know how very generally the wisdom-teeth, when cut late, or even at the accustomed age, are soft, friable, and rapidly decaying, but which is not the case when the early removal of one of the molars has caused it to make its appearance within a short time afterwards. Its more rapid growth, and the absence of any particular pressure from confinement within its cell, by the other molars coming forward, and thus enabling it to effect its own liberation, are correlative with its being a healthy and well-formed tooth ; therefore, there is some reason to suppose that its being in an imperfect state is the result of pressure during its protracted formation, and that the first molar may be similarly affected. In the correction of irregularity by the expan- sion of the arch (and which is extremely easy by pressure applied within the arch), it becomes a question how far this extension can be carried with safety ; for if the teeth be placed much within the influence of lateral pressure from the action of the muscles of the face, we run great risk in having them made to decay. The amount of it must therefore be guided by circumstances ; for ON LATERAL PRESSURE. 175 although we have hitherto contrasted only the extremity of both forms, others will be found merging from one into the other in every stage of gradation, with more or less difference in their relative proportions. In the third and remaining source of lateral pressure, its occurrence may be attributed to accidental circumstances producing imperfect an- tagonism of the teeth. In a perfect " bite," we have everywhere a series of inclined planes in opposition. This is espe- cially apparent in the bicuspides, the point of one cusp fitting in between the oblique sides of the two opposed to it. The "stop" which pre- vents the mouth closing beyond a certain point, is effected by the molars, and when these have become so arranged, by the loss of some of them, that there are none remaining in antagonism, the bicuspides have a tendency to separate, and exert a destructive amount of lateral pressure against their neighbours, if such there happen to be. Or it will sometimes be seen that the bicuspides, as well as the cuspids and incisors, have become pro- jected forwards, and the former will then press upon each other, so as to decay at the parts in contact, while the latter — the cuspids and in- cisors, especially in the upper jaw — ultimately become excessively prominent, and either loosen from the absorption of the socket, and fall out of themselves, or require removal. 176 SOLDEEING APPAllATUS. The proper antagonism of the teeth is of the very utmost importance ; for if any of the *' cusps" be out of place, they disturb the equal distribution of the force in biting, and tend to produce mischief at the points holding those cusps in their assumed position. In regulating the mouths of children, it is of far more consequence to secure correctness in this respect, than as to the actual number of teeth remaining, provided the symmetry of the anterior portion of the denture be not interfered with. In thus noticing the reverse sources of lateral pressure the short limits of a paper like the present necessitate its being confined to a mere summary of the general features. To have par- ticularized many of the various peculiarities assumed under the different forms, would have added greatly to its length, and rendered it too voluminous, although it might have tended ma- terially to strengthen the position I have assumed. Still, I trust sufficient has been pointed out to show the importance of the subject, and to obtain for it that consideration it deserves. Mr. Mather exhibited a Soldering Apparatus, and made the fol- lowing commnnication : — That which I wish first to direct your attention to is my gas and steam blowpipe. This will be recognized as an adaptation of the old spirit self- acting blowpipe; but the great heating power, SOLDERING APPARATUS. 177 economy of, and complete control to be had over gas, in comparison with spirit, gives it an advan- tage which all will at once concede. I have here a boiler containing water, which is converted into steam by a small Bunsen's burner, and is the blowing power ; the force of the jet of steam is increased or decreased instantaneously by turning on more or less gas, as required in soldering. The burner for operating with is in the front part of the apparatus, and is regulated by a separate stopcock, and receives the steam-jet in its centre, like a DanieU's blowpipe ; by bringing the steam-pipe through the gas flame below the boiler, the steam is thoroughly dried, and also superheated ; thereby causing a considerable addi- tion of heat in the flame. By regulating the gas-burner under the boiler, either a powerful deflagrating flame or a fine- pointed one may be had at pleasure. The self-sus- taining power of this apparatus must recommend it as far preferable to the mouth blowpipe; and also, being so exceedingly portable, in addition to not being one half the cost of any bellows arrange- ment, it could be supplied to each workman, in order that one man may not have to wait while others are using the bulky bellows or forge, as is too often unavoidably the case. A very important peculiarity of the gas and steam flame is, that its heat is found to be sufficient to run the hard sol- 178 SOLDERINa APPARATUS. ders easily without injuring the surface of the metal soldered. The bowl at the top is intended to be used as a reservoir while the blowpipe is in use, the heat from below making the water in it so hot, that when emptied into the boiler, by turning the stopcock, it immediately gives off steam, and prevents any loss of time. The boiler would not require replenishing more than once an hour, or perhaps not so often, as it would of course depend upon the power employed. This method of replenishing will be found much better than any self-acting arrangement, being incapable of derangement. As a matter of necessity, a little experience is required to develop its powers ; but I venture to express the confident belief that it will save a great amount of time when worked against any other form of blowpipe. (See Fig. 19.) Another apparatus of mine is for melting down gold or silver in crucibles, by the action of a stream of air blown into a gas flame, and directed upon the bottom of the crucible. This is an exceedingly valuable apparatus for melting down scraps and alloying-metals. Another is the application of a series of power- ful Bunsen's burners to melt the softer metals in large quantities (as shown in action), capable of melting a quarter of a cwt. of lead in fifteen minutes. I have also a Bunsen's burner, to which I have SOLDERING APPARATUS. 179 attached a blowpipe, and which is very highly approved by operative chemists, and will be found of equal value in the dental profession. In conclusion, I beg to thank you for the favour allowed me, and shall be most happy to put my apparatus to any test required by you. Mr. Mather then exhibited liis apparatus in action. Fig. 19. A. The boiler in which the steam is generated tty a Bunsen's burner C, which burner superheats steam as it passes through pipe H, to soldering burner D. B is a reserroir to supply boiler, which is done by turning stopcock E when required. The stopcock F regulates the supply of gas under boiler, increasing or decreasing pns- ture at will. That marked G regulates the soldering burner. N 2 GENERAL MONTHLY MEETING. Saturday y June 4, 1859. ARNOLD llOGERS, Esq., President, in the Cuaie. The following Gentlemen were duly elected Members of the Society : — Mr. J. FiNNiE Alexandria (corresponding) . Mr. George Allcard London. Mr. John Caldcleugh Durham. The following Gentlemen were proposed for the Membership of the Society : — Mr. John Howard Kyan Preston. Dr. Daniel Harwood Boston, U.S. (corresponding). Mr. Lindsay exhibited the model of a New Drill. Messrs. Ash exhibited specimens of Mineral Teeth and Vulcanite. Mr. Maclean exhibited a cast of a Tumour, which was connected with the external fang of the anterior superior-bicuspid. This was removed, and in about three weeks or a month the enlargement had completely subsided. Mr. Pinnie presented to the Society the Skull of a Hippopotamus. Mr. Childs read the following paper on Superheated Steam : — In undertaking to read a paper on superheated steam, it was entirely upon the solicitation of your respected President, and an assurance from him that anything I might say would be received in no hypercritical spirit, but with candour, as it was a subject for the most part, in which members of 182 ON SUPEIMIEATED STEAM. jour Society had had no experience. It is this beHef that has induced me to travel so far out of my own particular pursuits as I have done, to present this paper to the notice of the Odontolo- gical Society ; and if, from the varied experience of my life, I can bring to bear upon this subject any useful fact, and can offer any practical sug- gestion, I shall esteem my present attempt to do so a very happy and a very grateful task. I have, however, been urged by so many of the profession not to confine myself to superheated steam, but to give my observations a wider and more practical range, embracing, as far as I am able, the whole subject and application of steam, steam-boilers, dry heat, the hardening and nature of the dental rubber compound. I will, therefore, with your permission, enter upon the subject in a general manner, and from a dentist's point of view ; and in all this which relates to steam, I do so without any feeling of presumption, knowing, as I do, that there is yet much unknown and untold, in all that relat^ to the economy of steam-heat, and the causes which produce explosions in steam-boilers. It is said by one who has written much upon the subject, " that the rule which connects the tem- peratures or elasticities, or volumes of steam (one or all), with the expenditures of heat in producing it — a question affecting even the resources of nations — remains to be settled ; and it has been truly said, that the imperfect knowledge of it must ON SUrERHEATED STEAM. 183 still occasion the waste of more thousands yearly than it would cost pounds to set it at rest for ever, by a series of the most elaborate experiments, conducted on the most expensive scale. To this end, however, a new thermometric scale, graduated to equal additions of heat, and not of expansion, seems one indispensable requisite, even before all else ; and more exact determinations of the specific heats of steam and air, compared to water, are loudly called for, the discrepancies between the numbers obtained for these by Crawford, De la Roche, and Berard, the authorities commonly followed, being such as to destroy all confidence in calculations founded on either." To enter, therefore, first, upon the considera- tion of steam-boilers of high-pressure-saturated Steam, we will now refer to the diagram of one, Fig. 20, in which the relative positions of the water Fig. 20. and steam will be obvious to all : the steam, as it is generated, is carried away from thence to its uses. Now I do not intend to touch upon the questions of latent heat, consumption of fuel,, horse-power, shapes of boilers, &c. : those wha 184 ON SUPERHEATED STEAM. are curious in such matters, I must refer to ele- mentary works on tlie subject; and tlieir name is legion. My essay, first of all, is rather upon the practical, theoretical, and dangerous operation of boiling the usual water under high pressure, and also the effects produced upon the material of the boilers. Water, then, is the first body with which we have to deal. And indeed a wonderful and mighty agent it is ! Who can tell of all its wonderful, its beneficent, its mighty agency ? — no one but the all- wise Creator of the universe. We have here to do with only one of its manifold elements of power. This water, then, in the boiler, is a liquid which expands with heat into seventeen hundred times its volume, and forms steam, the lightest of all vapours. Up to a certain point, the increase and pressure are nearly uniform, and very safe and controllable : this point of safety is at about 50 lbs., or rather more than three additional atmospheres — 15 lbs., or one atmosphere, always being upon it in its first condition. Now beyond this point of pressure, I venture to call it pre- sumption to carry it, except as a matter of necessity, as the laws which regulate its pace upwards are unknown. A steam-boiler is like a horse which is well under control and manage- ment up to ten miles an hour ; but once let it go faster, or run away, and no one can tell at what moment an accident may happen. The Table of ON SUPERHEATED STEAM. 185 Increase of Pressure is here represented, and you will perceive how rapidly the ratio of pressure increases with the heat. Table I. Saturated Steam, or Steam in contact with Water. Atmospheres. Pressure. Corresponding Temperature. 1 15 lbs. 212° 2 30 „ 251° 3 45 „ 275° 4 60 „ 294° 5 75 „ 308° 6 90 „ 320° 7 102 „ 332° 8 117 „ 342° 9 131 „ 351° 10 146 „ 359° 12 175 „ 374° 14 205 „ 387° 16 233 „ 398° 18 263 „ 409° 20 292 „ 418° 22 321 „ 427° 24 350 „ 436° 30 438 „ 457° 40 584 „ 487° 50 730,, 511° 56,000 „ 1170° At 21 2° it is equal to the pressure of the atmo- sphere ; at 250° it is 28 lbs. to the inch : let the temperature increase to 280°, it becomes 56 lbs. ; and it is said that at 1170° of heat, the pressure of steam and water is 56,000 lbs. to the square inch ! Now there are some people who try to account for the explosion of boilers, by supposing the generation of gases ; but surely the known ex- 186 ON SUPERHEATED STEAM. pansion of steam- water, such as here mentioned, is sufficient to account for any amount of explosions. Let us refer again to the diagram of the boiler ; the pressure we will suppose at 100 lbs. ; the fire to be at its full intensity (''for the consumers of steam are always crying out for more"). Whilst the engine and works are in full operation, the danger of the boiler bursting is not so great, for the whole mass is pretty nearly of equal tempera- ture, and all inside is in boiling agitation. But dinner-time comes ; the engine is stopped ; the water then is in a comparative state of rest, and does not boil or agitate, in obedience to the law of not doing so under pressure if the outlet be stopped ; the water is a slow conductor ; the lower stratum is somewhat hotter, the deposit and bottom of the boiler, perhaps, nearly red-hot as the time approaches to start the engine. Suddenly, the communication is opened, and the pressure is lessened at the top by the steam passing off ; the whole mass opens, and heaves to rush out at the opening, and is then lifted up from the bottom along with a large mass, perhaps, of red-hot earthy deposit ; in a moment, a great mass of water flashes into 1,700 times its volume, for it is a noticeable fact that explosions take place mostly when steam-engines or works are started. When a boiler bursts, it is invariably found to have done so at the side or ends, being weakened there by the water mechanically, as well as chemically, ON SUPERHEATED STEAM. 187 wearing away that part, and also because there are two degrees of temperature there, where the water and steam divide, and which is due to the different heat-conducting properties of steam and water ; the fire in the flue acting partly on steam and partly on water, which weakens the metal rapidly. In passing, I would observe, another element of danger is the pumping-in of cold water : this might be avoided. Another cause of explosion may be found in the earthy deposit alone, which, from being a bad conductor of heat, is not pre- vented by the water from getting red hot, which thus repels the water ; but steam will pass to it and be the medium to enable it to act upon the water at a moment when a sudden alteration of pressure takes place, and which is assisted also by some of the impurities of the water, to send it into steam Avithout regard to apparent pressure. Boilers are found to burst in a variety of ways : I once saw a boiler that burst from its place, and passed through the side of the building, falling outside, eighty yards off. I incidentally mentioned that water mechanically wore away the iron of the boilers, and this is a point not oflen alluded to ; but that it does so, a very Httle reflection will convince any one of the fact ; and be it remembered also, that the friction ofthe constant boiling of water on the iron is greatly more, in consequence of the earthy impuri- ties which it contains. 188 ON SUPERHEATED STEAM. If water were always pure, no doubt many elements of danger would be removed, as it would take up tlie heat and generate steam in a more uniform manner, and not decompose or weaken the iron ; but as it is not only not always pure, but always impure, every drop of the water carries with it into the boiler an extraordinary mixture of substances ; in fact, I believe that if you were to take some water from four boilers, each boiler being one from the four separate quarters of the globe, and mix the water together, you would find something of everything that is in and on the earth. You would find all the gases, all the metals, and all the earths so called ; and this is the mixture which people boil up together under a great pressure and at a great heat, and are then sur- prised they cannot get uniform results. Of course not ; for at high temperatures the organic matter has influences, the nitrogen of the aerated water has influences ; the lime, the metallic oxides, the silicates, the sulphur, the potash, all have influ- ences. A steam-boiler may be likened, with great truth, to a man's digester, which has to deal with multifarious substances, and gives the human doctor as much difficulty as the boiler does the steam doctor. If both were fed with jpure ma- terials, less danger and less wearing would be found in both cases. Havinof considered as well as I am able in the I ON SUPERHEATED STEAM. 189 limits of my paper, the nature and working of high-pressure steam-boilers, we will enter upon the consideration of superheated steam, or, more properly speaking, sub-saturated steam, and its generation. Now, the difference between the nature of saturated and sub-saturated steam is fully ex- pressed by the words used; but words, I am aware, do not always convey a knowledge of what is, or may be, correctly expressed, and therefore I shall endeavour to explain what sub- saturated steam is. Steam is saturated which is in contact with water, and cannot be anything else, no matter what heat is applied and what pressure is attained, as long as it is in contact with water. This step is, I trust, perfectly under- standable. Steam which is not in contact with water, and which is heated ever so little or ever so much, is superheated or sub- saturated steam. This differ- ence is clear between the two kinds of steam, and cannot tax the memory much to retain it — satu- rated steam is wet steam, sub-saturated is dry steam. Having clearly in your minds the many dangers and difficulties to contend with in high-pressure steam-boilers, you will be prepared, I hope, to see and understand that there is an absence of them in the use of superheated steam-chambers. 190 ON STTPRUHEATEI) STEAM. To enable you to see the more readily the nature and formation of superheated or sub- saturated steam, as distinguished from the ordinary or satu- rated steam, we will at once refer to the expe- riment of the two chambers before us, which are now in operation. You will not, I am sure, find fault with me for giving you the experiment in so working and practical a form : for persons who are to be amused only, something in glass or silver would have done better. In the vessel to the left you have the ordi- nary or saturated steam as a boiler; in the vessel to the right you have sub-saturated steam, or steam only. The vessels, are connected with a pipe, and both are consequently of the same pressure, but both are not consequently of the same heat ; for you will perceive that the thermometer in the vessel with water is not so high (although of the same pressure) as the thermometer in the vessel with steam only. If the steam-pipe which connects the two vessels be closed and the communication shut off, with the heat continued equally under both vessels, the saturated steam of the boiler will increase rapidly to a great pressure, and in an increasing ratio the higher it goes ; but the sub- saturated of the other vessel will only increase in ON SUPPIEHEATED STEAM. 101 a slow and uniform degree. This table represents the pressures at corresponding temperatures : Table II. Sub-iaturated or Superheated Steam. Increase of Expan- fncrease of Tempe- Increase of Expan- Increase r f Tempe- sion—pounds. rature above 212°. sion—pounds. rature above 212°, 1- 32° 8-5 272° 1-5 48° 9- 288° 2- 64° 9-5 304° 2-5 80° 10- 320° 3- 96° 10-5 336° 35 112° 11- 352° 4- 128° 11-5 368° 4-5 144° 12- 384° 5- 160° 12-5 400° 5-5 176° 13- 416° 6- 192° 13-5 432° 6-5 208° 14- ■448° 7- 224° 14-5 464° 7-5 240° 15- 480° 8- . 256° this (the boiler) is the lion, this (steam- chamber), on the other hand, is the lamb ; this sub-saturated steam will increase only in a uniform pressure with its temperature (the reason of which will be explained further on). The Table No. II. gives the figures of its increase of heat and temperature, which you will perceive is uniform ; and so little is the increased expansion of sub- saturated steam, that by increasing the temperature 230°, you only get an additional expansion of half its volume, or *7\ lbs. additional pressure to the square inch ! What do we find in the case of the saturated 192 ON SUPERHEATED STEAM. Tig. 21. steam or steam-boiler? Why, that 230° of in- creased temperature gives or causes an expansion of force equal to twenty-five atmospheres, or 360 lbs. to the square inch ! A further illustration of the formation of sub-saturated steam will be shown on reference to the diagram, Fig. 21. In it let it be supposed that one cubic inch of water is gene- rated into one cubic foot, or 1,700 cubic inches under the ordinary pressure of the atmosphere; if heat be applied, it is the next EiG. 22. moment sub-saturated, as it would take up more water if present; if 15 lbs. pressure be added, as in Fig. 22, it will evap- orate one cubic inch more water with heat in the same space ; if another 15 lbs. pressure be added, another cubic inch of water will be evaporated ; if a fourth cubic inch of water, and about 45 lbs. pressure, it also will be evaporated into the same space of a cubic foot; or, further, the cubic foot of steam could be compressed by 15 lbs. weight into half its space, or 850 cubic inches, as shown in Fig. 23. And if the heat be continued, it immediately be- Fig. 23. ON SUPERHEATED STEAM. 193 Fig. 24. comes sub-saturated steam, no matter what the pressure, for superheated or sub-saturated steam is such when it will take up more water. The formation of sub-saturated steam may- be formed, by illustration, with the next diagram of a larger vessel (Fig. 24). Suppose half the space to be filled with 1,700 measures of steam, and then allowed to expand into the whole space, or 3,400 measures of steam, it would have only half its elasticity ; but it would not then be saturated steam, but sub- saturated steam, and capable of taking up its own weight of additional water. In other words, it would be superheated steam, having a temper- ature of 212°, but only a pressure of saturated steam at 180°. It would be a dry or drying steam, in which water would evaporate or wet things dry; but 180° would be its dew-point, below which it would condense partly into water, and would become saturated steam. The morn- ing dew or fog is saturated steam, which be- comes sub- saturated with the rising sun, and bodies wet will rapidly dry. Nature is always generating steam and sub- saturating it, and vice versa. We now come to the explanation of ''the 0 194 ox SUPERHEATED STEAM. table" (No. II.) of heat and pressure of the sub- saturated steam. All aeriform bodies, according to Dalton, when insulated from liquids, expand in a uniform manner and by the same increase of temperature. Gay-Lussac, whose researches on the subject of vapours, made with very refined and accurate apparatus, states also, that all vapours, when insulated from their liquids, obey the same laws as gases. The four following propositions exhibit at a view the principal facts of the case : 1. All gases expand alike for equal increments of heat ; and all vapours, when remote from their condensing points, follow the same law. 2. The rate of expansion is not altered by a change in the state of compression or elastic force of the vapour or steam itself. 3. The rate of expansion is uniform for all degrees of heat, 4. The actual amount of expansion is equal to 4^^h part of the volume of the vapour at 0° Pahr. for each degree of the same scale. The rate of expansion near enough for our pur- pose is shown by table No. II. We thus have in an atmosphere of steam, when being superheated, a safe and manageable medium to deal with, which expands in a known and uniform manner with heat ; and this is a knowledge of great prac- tical importance to the chemist. Of the various modes of heating steam, it will be necessary, I think, for the perfect under- ON" SUPERHEATED STEAM. 195 standing of the subject, to explain two or three. One mode is shown by the diagram Fig. 20, in which the steam is superheated in a mass of pipes, placed in the flue between the boiler and the shaft. Another is the conducting the steam from the boiler through pipes arched over the fire. A third is by conducting it through a set of pipes fixed in a separate furnace ; and it is by the latter mode which I have chiefly gained my experience. A fourth mode is according to a patent of my brother, Mr. S. Childs, viz., by double or cased vessels with a fire underneath, which is a very excellent plan for heating or distilling fluids. The steam may be also heated in a separate chamber, as in the case of the vulcanizer, or with a coil of gas pipe underneath the top chamber (Fig. 25). Fig. 25. 196 ON SUPERHEATED STEAM. Apart from the safety of using sub-saturated steam, is the avoidance of the deposits which result from water, and the consequent less injury to the material of the vessels. When steam only is used, and at too high an expansion for the strength of the vessel, it is not so liable as saturated steam is to burst it, but bends or tears the metal only, and the moment of escape lessens the force behind. I have had slight-made malleable vessels bend and twist out to all kinds of shapes and tear open, but never burst. I have seen steam passed through red- hot pipes for years, but never knew of explosions therefrom. We will now in a few words enter upon the chemical formation of rubber and its change by being hardened with heat. Faraday and Brande have both written and experimented upon the subject, the result of which may be told in two or three words; viz., that india-rubber is a carbo- hydrogen — Cgo, Hjo; but Ure, who has also written upon the subject, states that it contains a small amount of oxygen, less than 1 per cent. I incline to the latter as the correct formula. If I may be permitted to express a theory upon the subject, not founded upon actual analysis, but founded upon the observation of appearances in my experiments, which are analogous to changes and appearances in other carbo-hydrogens of which I have a correct knowledge, I am decidedly ON SUPERHEATED STEAM. 197 of opinion that the whole change in the hardening by heat and sulphur arises from the evolution of hydrogen and the absorption of a small amount of oxygen. As the heating and hardening progress, the substance becomes darker in colour, one evidence of its being richer in carbon; it also gives out at the same time a great deal of sul- phuretted hydrogen, that is, the hydrogen leaves the carbon and takes to the sulphur, forming a gas; and it is the formation of this gas which makes a certain amount of pressure necessary to prevent this gas forming globules in the rubber, which it will without pressure; and hence the porosity which is so often found in sulphur and ru"bber hardened by dry heat. Without pressure,, a greater amount of this sulphuretted gas is formed, and the hardened material is of a darker coloiu' and not so strong, as will be found by making an inch bar of the vulcanite, about a foot long, and subjecting it to a breaking force in the centre, with its ends on supports. I have also found that more sulphuretted hydrogen is evolved with the presence of saturated steam, when under pressure, than with sub-saturated steam, which is accounted for by the rubber compound being slightly porous, and thus enabling a greater amount of moisture to act upon the rubber and carry away more of the sulphur and hydrogen than is necessary ; for water exerts the . power, in an Extraordinary manner, of decomposing all 198 ON SUPERHEATED STEAM. organic substances under heat and pressure, and further, also, as the pressure of saturated steam requires, to be greater than in the case of sub- saturated steam. If the heat be carried too far, a substance like charcoal is produced, very porous ; if the pressure be carried forward uniformly, with greater heat, then a substance like jet is formed; but the clear and distinct change is the evolution of hydrogen ; but in the case of the jet-like substance it is partly 'displaced by oxygen. If impurities or adulterations form part of the rubber compound, then of course totally different results obtain ; and it is well to state, that there is nothing which will take up such a variety of im- purities, or will admit of so much adulteration, as india-rubber, and yet appear the same to the eye ; but the action of the chemical agents, such as the gastric fluids or the saliva, soon makes them evident. I have learnt, upon the authority of Messrs. Macintosh and Co., confirmed by my own experience, and some careful experiments by Mr. Vasey, that rubber will take up, with but little change of bulk, more than half its weight of im- purities ; if these be oxides, acids or caustic alkalies will readily decompose the compound with heat. The various modes of hardening india-rubber may be stated to be three : 1st, by saturated steam heat; 2nd, dry heat; 3rd, sub-saturated iiteam heat. ON SUPERHEATED STEAM. 190 The first mode is the one which has for the most part been adopted, in some cases by cylin- ders from the boiler, in others by side chambers, and in others by top chambers to the boilers (the vessels, as shown in the diagram Fig. 25, by Wright and Fouche, would answer the purpose) ; and most excellent results have been arrived at; but the materials hardened or vulcanized are generally in substance, and not with solutions, when done in this way. When in woven fabrics and with thin layers of rubber, then the mode adopted for vulcanizing is generally by ovens, or dry heat, as it is termed. One advantage of the dry heat insisted upon by some persons, is the power of continuously vulcanizing, as trays of paste or cakes are continuously baked, by putting in and taking out all day, without any unscrewing lids, &c. For neither of these modes, as a principle, can a patent exist, as both have been used and described for more than thirty years. Patents for either the one or other must be for a particular kind of apparatus only. The third mode of hardening and vulcanizing is by superheated or sub-saturated steam. The principle of this is patented by myself. The form of apparatus, which is before you (Fig. 26), and which is called " Childs' Vulcanizer," I must, with your per- mission, now allude to. That it bears my name will arm you against over-estimating what I say of it; but as it contains a new and novel applica- 200 ON SUPERHEATED STEAM. tion of steam to the hardening of rubber, I will proceed to explain its merits, safety, and sim- plicity. The vnlcanizer, Fig. 26, is made very thick. Fig. 26. not fi'om the necessity of so much strength, but because the gas burnt underneath and the sulphur inside both tend to wear it away ; and cast iron has been preferred because it is much less acted upon by gases, water, or acids, than other metals, as copper, malleable or wi'ought iron. The vessel may be filled with an atmosphere of steam, either by putting in as much water as will be vapourized, or by the emission of steam from the plaster or any hydrated solids. I prefer very * Section of Childs' Vulcanizer. ON SUPERHEATED STEAM. 201 much to get the atmosphere of steam from the plaster, as it is beautifully simple and self-regu- lating. If water be used at all, the quantity never should exceed a gill, as the safety of having an atmosphere of steam only to be heated, would not be secured. I do not now advise putting any water at all to get the atmosphere of steam, as it has happened, as I thought it would, that the instructions to put only a certain small quantity of water in are so liable to be neglected, and bad results follow. There is perfect safety if those who use it will clearly bear in mind that an atmosphere of steam only is wanted; this im- portant fact, if once fixed in the mind, will never go out of it. The . use of a boiler requires care, and is like walking along a narrow plank over a fall 1,700 feet from the ground ; the use of a steam-chamber is like walking along a plank one foot from the ground : in the case of a slip, the difference of danger is too evident to require comment. With a chamber filled with steam only, the heat radiates through all parts of it, and is a great advantage, as one part of the vessel cannot get so very much hotter than another, and the bottom cannot be made red-hot with gas coils, as it is liable to be with water and its earthy deposits. With steam only being present, not so much sul- phuretted hydrogen is formed as when water or air is used, as is well known to those who have had practical experience in the matter, but more 202 ON SUPERHEATED STEAM. free sulphur is eliminated. A coating is found of sulphuret of iron, pretty equally in all cases. Where water is used, it is charged with the sul- phuretted hydrogen to a considerable extent ; but where only steam is used, it takes up but a small quantity, and forms with the steam a less elastic vapour, but with equal capacity for heat. I have also found, that with water and heat at high pressure, the plaster of Paris, which is sulphate of lime, becomes changed ; that is, the sulphur of the rubber joins with the sulphuric acid of the plaster, and mixes with the water. Sulphur, of which the rubber contains a portion, is, as you know, next to oxygen, the strongest chemical body, and has, like it, a powerful affinity for all other elements ; and as the rubber has more than it requires, the heat in hardening it sets it free, and its action is more or less active as it is mixed with more or less water, to bridge it over under pressure and heat to its restless combinations. In the vulcanizer, pressure sufficient is procured by the atmosphere of steam, and a certain amount of pressure is necessary, as it prevents the separation of the rubber by means of the gas formed in it by the sulphur and hydrogen, and which, as it forms, distends out the rubber, when there is no pressure, into small holes. With sub-saturated steam only in the vulcanizer, a pressure of 50 or 60 lbs. to the inch, or of higher or lower pressure, is of no consequence, as it ON SUPERHEATED STEAM. 203 expands only in a uniform degree with its incre- ments of heat. Supposing this vulcanizer to be one cubic foot (which it is not), three cubic inches of water would be evaporated at 45 lbs. pressure ; and if one degree only of heat more be applied, it becomes superheated steam. A much larger weight is put on the valve than the required pressure, to prevent the chance of escape, as much as possible, of odour or steam. A pressure of 120 lbs. to the inch, will set free small quantities of steam at 50 lbs., by merely the vibrations on the lever, caused by a person walking across the floor, if it be boarded, or by opening or shutting the door quickly ; and if the steam leaks, it becomes a dry chamber, and the quality of the work is injured. The only care required is, to keep it steam-tight, and this is done with very little atten- tion at first; and surely so simple an apparatus, if it be a good one, deserves that little attention. Many curious and original questions have been asked, which scarcely require to be answered ; such as, Do the mineral teeth dissolve with the heat and pressure used ? But one question has been asked which I will take the opportunity of answer- ing; that is, with respect to the formation of hydrogen. Now, if hydrogen did form, it would combine with the sulphur, and would not be as elastic as steam. Steam will not decompose with red-hot ii'on, and I doubt if it would with white- hot iron, if no air or other body were present ; 204 ON SUPEEHEATED STEAM. and lastly, if hydrogen did form, it would only occupy tlie same space, and have the same force, and obey the same expansive laws as sub- saturated steam. A gentleman who works one of the vul- canizers put on to it a pressure-gauge, thinking I had not done so. He said he found the pressure to be 50 or 60 lbs. to the square inch. I told him to try the experiment with 2 lbs. to the inch. That, he found, spoiled his work. Another gen- tleman said it was not superheated steam if it were 60 lbs. to the inch ; and asked, would it not be just as dangerous as a boiler ? I had to refer him to the fact, that steam could be superheated at high as well as at low pressure, and that, with sub-saturated steam, no explosion of the vul- canizer, as fitted, could take place. It remains to be mentioned, that the thermo- meters should, in all kinds of such apparatus, have their tubes to extend at least one third of their length into the apparatus, and that the tube should be filled with mercury or oil. Thermometers with the bulb inserted a very short length, I have found indicate 15° less than the heat of one inserted a longer length. In conclusion, I would just speak of patents connected with this subject, as dentists, like all other people, prefer to have all the advantage without the drawback, and patents are great drawbacks. I for one, although having had a great deal to do with patents, both of my own and ON SUPERHEATED STEAM. 205 other people's, and having been successful with them, nevertheless wish that there were no patent laws at all, and that there should be no protection by law to inventors. This, I know, is held by the majority to be an unjust and robbing doctrine ; but I believe real talent will always find its own reward, and that the good and advantage of the few must and ought to give way to the good and advantage of the many. I, of course, whilst I have to risk my money to pay for patents, will take all the protection the laws give. My own patent claims in the vulcanizer are for the use of an atmosphere of steam, sub-saturated, however formed ; and also for the use of steam generated from plaster or hydrated solids alone. The patent of Thomas Hancock for moulding the vulcanite, of which I have the sole license for its application to dentistry, is one of the first and best patents ; and I wish publicly to state before this Society, and I do so with respect, that any dentist forming the bases of teeth as they are now formed, is working under that patent. A notice of the same, with the date and title of the patent, has been inserted in the dental journals. I will add here, that both my own patent and my possession of the Hancock patent, shall be worked quite as much as it is possible for the interests of the profession as for my own. In consequence of the great adulterations prac- tised (and which I before have shown the india- 20G ON SUrERHEATED STEAM. rubber is so capable of), and which are so easily practised and are so dangerous in their ultimate results, I must impress upon dentists, for their own benefit, the necessity of procuring the best and purest rubber compound ; and no surer way of doing so can be, than by purchasing it of a house of such high standing as Messrs. Macintosh and Co., and who are not only the first manufacturers in the world in position, but were the first to commence the manufacture of india-rubber in this or any other country. I can speak, further, personally of their scientific and advanced know- ledge on all subjects connected with their business. The patent of Charles Groodyear, dated 1855, but which has lapsed, is one which deserves un- questioned credit, as it, there is no doubt, has paved the way for all that is now done by dentists; for the present details and manner of working up the rubber into bases of teeth is identically the same as he describes, and no other. Others have done as much, there is no doubt ; but not, if I may so describe it, in first principles, as Thomas Hancock in a general view, and as C. Goodyear, jun., in his special view for teeth. GENERAL MONTHLY MEETING. Monday, November 7, 1859. ARNOLD ROGERS, Esq., President, in the CiiiHR. The following Gentlemen were duly elected Members of the Society : — Mr. James Shebwin Sheffield. Mr. S. Gill Liverpool. Mr. W. R. Ballard London. Mr. J. H. M'Quillen Philadelphia (corresponding) . Dr. Ballard New York (corresponding). Mr. M. Maclean ..^ Dublin (Honorary). The following Gentlemen were proposed for the Membership of the Society : — Mr. G.Parkinson, M.R.C.S.,Eng. 10, Hereford Street, Park Lane, London. Mr. Edwin Lowe, M.R.C.S.,Eng., George Street, Hanover Square, London. Mr. W. B. Swanson Edinburgh. Mr. James Bell 1, Blackfriars Street, Perth . Mr. S.A.Rogers Manchester. Mr. R. C. Pilling Blackburn, Lancashire. Mr. E. A. Sayles Lincoln. Mr. J. H. Parkinson, the late President, presented his Portrait to the Society. Mr. Henry Rogers exhibited specimens of coloured Vulcanite. Mr. Patrick exhibited a machine for Vulcanizing with Dry Heat, and made the following communication : — The apparatus which I here produce, is for the purpose of vulcanizing by dry heat, and has 208 MACHINE FOR VULCANIZING been patented by me. It is very simple in its construction, and entirely free from danger. The air rises from the bottom, or may descend by a down draught, which is the better process, and it becomes rarefied and gradually heated through the apparatus. This, in point of fact, is the true automatic principle. The air, being perfectly equalized, will not singe or burn 'anything. There is not that process which is called torrefaction, taking place. The heat is gradual, and the moisture of the atmosphere is taken up with it, and the consequence is, that when the heat has been brought up to 300° or to 310°, a paper label placed in the apparatus has not been so much as singed, and yet the vulcanite piece made has been perfectly vulcanized. So far as the application of heat, therefore, is concerned, I believe that dry heat is virtually the best. I don't say it because I produce these apparatus, and I wish that to be distinctly understood. Nor do I speak of any particular machine, but of the principle of the combined action of hydrogen with the sulphur in india-rubber ; and it is an acknowledged principle, that in the process where the cellular condition is produced in the rubber, that it is owing to the presence of hydrogen in combination with the sulphur. But with my application of dry heat, only the moisture of the atmosphere is taken up in sufficient quantity to obtain the heat necessary to produce a sound base. I have always found. \ WITH DRY HEAT. 209 SO far as my experience has gone, that porosity is produced from three causes — defect in packing, the bad quality of the rubber, or excessive heat with hydrogen ; and I believe it will be generally found that these are the principal causes of defect. As touching my apparatus, I would observe, that there is only sufficient moisture to prevent singe- ing, and not sufficient to produce the sulphurous hydrogen gas which causes the porosity of the rubber. Where the generation of that gas is pre- vented, whether by this patent or by any other process, the process of vulcanization is extremely simple ; but the statement that was first promul- gated, that high pressure only was necessary, I pronounce to be a fallacy. There is only one way of producing pressure, in even a high-pressure or a steam apparatus of any kind, and that is by attaching a spring as I have done here [exhibiting his improved patent flask]. Here is a small cap, and by attaching a spring we then have a gradual pressure during the fusion of the rubber. You take one of my flasks, and we thus have a pressure which can be regulated by a screw. Now one would really think that a heat of 300°, or even 350°, in this apparatus, would soften this spring, but as it is not sufficient to singe paper, it certainly will not destroy the temper of the spring. In the early stages of the process of vulcanizing, you have an immense pressure while the rubber is yet partially fluid ; and when the 210 MACHINE FOR VULCANIZING rubber is first fused by heat, we know that there is a most eccentric property in connection with the sulphur, viz., that at a certain heat it fuses perfectly, but increase that heat ten, twenty, or thirty degrees, and it becomes viscid, and to render it fluid again it is necessary to carry it to a much higher temperature, and at this you bum the rubber. Still, if you have a proper tempe- rature, and if you regulate your heat — and that is the difl&culty, as I said before, with every ap- paratus— ^you will then have something like mathematical accuracy, which has not been obtained hitherto by any process. I don't care whether you take a saucepan, a gluepot, or any- thing else, if you have not a regular and steady supply of gas, the heat produced will not vulcanize with certainty. Now, with my regulator we can regulate this supply, so that if you were to turn the gas on in the morning, or at mid- day, you might leave it till that hour twelvemonth hence, and, no matter what the pressure was, it would burn steadily, and give no greater degree of heat or light. This regulator is so constructed as to act perfectly with the thermometer. By this simple arrangement in the apparatus, you have a steady supply during the whole twelvemonth, and it will register 250°, 270°, 300°, or any fraction of a degree to a mathematical exactness. It is thus self-regulating, and this thermometrical gauge is WITH DRY HEAT. 211 capable of being adapted to high pressure or any other form of apparatus whatever. By the use of this invention there is no fear of danger, and I have been surprised, considering the objections which have been raised to various apph cations of steam, and the frequent instances of explosions^ even when boilers have been pro- nounced by Government inspectors perfectly safe, that an apparatus operating so perfectly as the one I exhibit should be so misunderstood. On the contrary, with any application of steam there is a presence of danger, and I may say the fact is made notorious by the accidents daily occurring in the use of steam in every form ; were it not so, how is it that with thermometers registering a degree of heat which indicates perfect safety, and even the safety-valves themselves, known to be perfectly free from any additional weight what' ever, that explosions under such favourable auspices continually take place ? Engineers, though unable to explain this melancholy phe- nomenon, have resorted to a beautiful but not wholly harmless expedient, that of placing plugs of lead at the bottom of the boiler, so that when the supply of water should be below the working point, the heat, coming up to 500° or 600°, melts out the lead, which allows the steam to pass off without exploding or doing any material damage. But with this apparatus there is no pressure. You may put your hand within a few inches of p 2 212 MACHINE FOE VULCANIZING the funnel, and neither burn nor scald yourself, even when the apparatus is working at 300°. In fact the apparatus will wear till it is as thin as tissue-paper. This is one of a series of my patents. I have also steam-baths attached, and I am at present bringing out a patent for self- paclcing boxes, and hoped to have been able to produce one before you this evening, had the maker not disappointed me. By means of such a contrivance, no packing is required beyond what is done by the apparatus itself This, with two or three other things, forms a supplementary patent, which I have found it necessary to take out in order to protect my interests. This will also be capable of being used in connection with high pressure. It is just possible to overpack a piece, and to bestow too much trouble and labour upon it. I may say, in conclusion, that vulca- nizing in connection with this apparatus is a com- paratively easy process. I had almost forgotten to refer to a little boiler which I have here for generating steam, and which may be used in connection with my apparatus. These apparatuses were made more particularly with a view to the working of my new base — the Osteoplastic base. [Mr. Patrick then exhibited a small test-piece of his new base, which very closely and beautifully resembled a piece of bony sub- stance.] A ring above the burners, pierced hori- zontally, traverses the bottom of the apparatus. WITH DBY HEAT. 213 A small piece of india-rubber tubing is then brought from this ring to the boiler, which throws a jet of steam through the flame of these burners, and this gives an atmosphere heated, moist, and beau- tifully equal in every respect. This is intended more particularly for the working out of the base I referred to. As soon as my hands are more at liberty, I purpose having this base either with or without sulphur. Dry heat is often a failure in a confined form, but in an open form it is most successful, and in proof of which I have brought these specimens of vulcanite and my apparatus here to-night. Mr. Fletcher read the following paper : — In introducing to your notice this evening some remarks on the mechanical contrivances we at present possess for reducing irregularity in the growth of the permanent teeth, I intend to allude more particularly to the means required in the treatment of those cases which are most com- monly met with in our practice. Much must necessarily be left to the judgment of the operator, in selecting those means best suited to the particular case, and in which he has the greatest confidence; and as many are frequently found following one system in almost every case where success has attended its use in some, simply for the reason that they have not seen any others offering greater advantages. 214 MECHANICAL APPLIANCES It is for this reason I have ventured to select from that interesting and rather comprehensive subject — irregularities in the growth of the per- manent teeth, some of the mechanical appliances which have hitherto been used for the purpose of drawing and forcing the teeth into their proper line on the alveolar ridge, and directing them to their proper approximation, conducing to their utility as well as appearance. Perhaps it will not be quite out of place here to allude to the age when any attempt at correction by mechanical means should be undertaken. I believe that some practitioners prefer leaving it until all the permanent teeth are through, ex- cepting the third molars. For my own part, I prefer getting the teeth into position at as early an age as I possibly can : although frequently attended with much greater difficulty, the advan- tage of the teeth being directed into the proper position, whilst the process of the new formation is in vigorous operation, fully compensates for any extra trouble the case may possibly have given ; but it most frequently occurs that we have not this choice given us, and besides, cases have been most successfully treated up to twenty-five, and even thirty years of age. Formerly, when the position of a tooth was required to be moved, recourse was had to a gold plate, or bone-piece fitted to the mouth, which was used for drawing the teeth inwards by means FOR REDUCING IRREGULARITY. 215 of silk ligatures passed through holes made in the plate, and tied over the teeth ; or by means of a spiral spring, one end of which was attached to the plate, and the other, by means of a ligature, tied to the tooth, whereby a constant tension was kept up. For the purpose of drawing a tooth forward, a stout gold bar was made, and kept some little distance in front of the tooth, to be brought for- ward ; the ends of the bar being tied to the back teeth, silk ligatures were passed round the tooth, and through holes in the bars, drawing the tooth forward. Occasionally, a piece of Ijone was riveted to the bar, resting on the molar teeth, in order to keep the opposing teeth from impeding the moving of the misplaced tooth ; or a gold cap was fitted over the molar tooth for the same purpose, made, independently of the bar, similar to one Mr. Har- rison has most kindly lent me ; then the bar was united to caps on both sides of the mouth, which had the advantage of keeping it much more steady. These methods were pursued for some time with occasional modifications, until a plan was brought out for forcing a tooth forward, by the occlusion of the jaw on an inclined plate of gold soldered to a piece capping the opposing teeth. This plan appears to have come into use, together with other methods ; and we occasionally see bars or plates similar to these fitted to the palate or the 216 MECHANICAL APPLIANCES backs of the teeth with small incline strips of gold resting on the edges of the misplaced teeth, and holes in the bars for ligatures or elastic bands operating on the other teeth at the same time. A modification of these plans I made use of some few years since, in a case where the under- teeth projected before the upper: in this I capped with gold the back teeth of the under jaw, uniting the caps on both sides of the mouth by a narrow, stout, gold band, passing in front and resting against the anterior teeth, to the buccal sides of the caps ; to the side of the cap from about the second bicuspid to the first half of thQ first molar, was soldered a stout piece of gold plate, projecting upwards about half an inch, cut at about an angle of sixty degrees, sloping upwards from the bicuspid to a parallel line from the middle of the molar. The upper plate was made capping the back teeth, and cover- ing a portion of the lingual surfaces of the anterior teeth. A small thick piece of gold was soldered to the buccal sides of the caps, into which was screwed a strong gold pin, which, on any effort to close the mouth, rubbed against the inclined edge of the under piece, forcing the under jaw back. As the caps came into contact, the points were filed away, until the teeth themselves nearly met. In the course of about three weeks, the under teeth were, on closing the mouth when the apparatus was out, fully one eighth of an inch Foil REDUCING IRREGULARITY. 217 within the upper, being previously more than double that distance beyond the upper teeth. This I adopted in preference to the strap on the chin and strong elastic bands carried to the back of the head, which I had found considerably increased the inconvenience to the patient, and was much less effective in its operation. Another plan is sometimes used for the upper central incisors, where, from the persistence of the temporary teeth, the permanent have made their appearance considerably on the lingual side of the alveolar ridge. This is very simply remedied by means of a piece of bone fitted against and rather beyond the edges of the growing teeth, which, as they descend, the thicker part of the teeth rubbing against the bone, forces them forward into their proper line. Nature might possibly correct this state, if the under teeth did not interfere on closing the mouth. A case in illustration of this method has been kindly lent me by Mr. Harrison. A very useful and efiective method of sus- taining pressure on any part of a tooth is frequently resorted to, especially for the pur- pose of turning it, by means of a piece of flat gold spring soldered to a gold plate. A specimen has kindly been lent me, showing how the pressure has been directed on the edge of the central incisor. It is likewise of use for pressing the teeth apart to obtain space. A case of this description will be found most ably described in 218 MECHANICAL APPLIANCES Mr. Tomes's " Manual." Or for the purpose of drawing back a bicuspid, the spring is brought round to the anterior portion of the tooth, and the end bent, so as to bear tightly on the median sur- face. It is occasionally very useful, and has the advantages of being clean and easily removed. Some models, with the instruments used by Mr. Sercombe, to whom I am indebted for their loan, illustrate the plans he adopted for expanding the arch of the mouth, somewhat, I believe, after that described in one of the American journals. By means of two gold plates fitted to the grinding sur- faces of the bicuspids and first molars, and con- nected by a spiral spring keeping up a constant pressure outwards, he afterwards fitted a bone plate to the hard palate; on to the bone was riveted a piece of metal, to which was soldered four grooved pieces, for the purpose of carrying- compressed hiccory in order to force the anterior teeth forward. And another case, in which he succeeded in drawing into line a lateral incisor and cuspid by means of a bone-piece, to which he attached elastic bands, one passing through a hole cut in the bone for the purpose of keeping the band on the cuspid, which was only partially erupted. Another illustration Mr. Sercombe has kindly favoured me with, for drawing the central incisors back. It consists of capping the two first molars, and connecting the caps by means of a gold bar FOR REDUCING IRREGULARITY. 219 across the palate. On the buccal sides of the caps is attached a strong elastic band, which passed in front of the central incisors, and was attended with complete success in the case in which it was used. * I have now the pleasure of endeavouring to explain to you what I consider the greatest ad- vance we have yet made in moving misplaced teeth, and it is to Mr. Harrison we are indebted for this result of skill and ingenuity. By using, in his peculiar way, compressed wood, he has obtained success in some of the most difficult cases, very simply and effectually. The manner in which compressed wood has mostly been used, has been by first drawing a round stick of wood (generally hiccory) through the holes of a draw-plate. By this process the fibre of the wood is pressed together, and if not very dry, elongated as much as possible. This is mostly used by drilling a hole in the bone-piece, and inserting a piece of the wood endways. Very little elongation takes place on the wood absorbing moisture; but there is a considerable effort to expand laterally, as you may frequently have found on endeavouring to take out one of these pegs after it has been in the bone and subjected to moisture for a very short time. * The band is occasionally made to press against the lingual sides of the molars and bicuspids, for the purpose of expanding the arch of the mouth, and which I have used most successfully in some of the most difTicult cases. 220 MECHANICAL APPLIANCES The way in whicli Mr. Harrison makes use of compressed wood, is by taking a piece of dry willow, or any fine-grained wood, that is as free from resin as possible, and compressing it, by screwing it up between the jaws of a parallel vice for about forty-eight hours, occasionally, as it becomes compressed, screwing the vice up more. A bone-piece is fitted to the mouth, and behind the tooth to be brought forward is cut a slot, or groove, the width of the tooth ; the edges of the groove are slightly undercut, to retain the wood in position ; that end of the groove which approxi- mates to the gum is cut somewhat deeper : con- sequently, when a piece of compressed wood of equal thickness is slid into the groove, with the fibre of the wood parallel with the tooth, on absorbing moisture it expands, and the pressure comes first on the edge of the tooth, where it can exert the greatest amount of power. When it has pressed the tooth out as far as it possibly can, another and thicker piece of wood is substituted, and so on, until it may be found requisite to fit another bone-piece to the retreating tooth, and continuing the same plan. The way in which the compressed wood is used for drawing a tooth back, is by cutting a small recess on the lingual surface of the bone-piece behind the tooth to be drawn back. Into the recess is placed the wood, the fibre parallel with the tooth, and over the wood a small FOR REDUCING IRREGULARITY. 221 piece of gold plate, and over the plate a liga- ture, passing throngli holes on either side of the recess. The ligature is then made fast over the tooth, on which the expanding wood now acts. The bone may be left sufficiently deep to prevent the antagonistic teeth from being obstructive, and at the same time mastication is but little impeded, and the incumbrance to the mouth is much less than when spiral springs are used, and more con- venient and less unsightly than when gold bars are brought in front of the teeth. Wood compressed in the above way will be found most useful in dividing the teeth ; a very thin shaving placed between two teeth may in a very few hours be made to produce a division equal to the sixteenth of an inch. Lately, the use of vulcanite for forming the plate has been most successfully used. The com- pressed wood, on Mr. Harrison's plan, can be placed in it very readily, or it can be used for carrying ligatures or elastic bands. Its perfect fitting has very great advantages in enabling the plate to keep its position, and remain firm without the use of ligatures, and for the counteracting pressure which is distributed so equally over the other parts of the mouth. We are sometimes obliged, in order to keep an instrument secure in the mouth, to make use of ligatures. For that purpose I have found the fine, hand-spun, hempen thread, in many cases 222 APPLIANCES FOR REDUCING IRREGULARITY. very superior to silk ; the knot is much less liable to slip, and the moisture in the mouth causes it slightly to shrink, and become tighter. And in many cases where the teeth are very firm it ivill be found superior to the elastic bands, and for that purpose a much stronger thread is used. GENERAL MONTHLY MEETING. Monday, December 5, 1859. W. A. HARRISON, Esq., V.P., in the Chair. Tlie following Gentlemen were duly elected Members of the Society : — Mr. John H. Kyan Preston. Dr. Harwood Boston, U.S. (corresponding). The following Gentlemen were proposed for the Membership of the Society : — Mr. W. F. Forsyth ...225, Piccadilly, London. Mr. W. J. Parks 27, Newington Crescent, Kennington-road. Mr. C. G. Kempe 37, Gallow Tree Gate, Leicester. Mr. Thos. Howkins ...24, Waterloo Street, Birmingham. Mr. P. A. K0LLIKER...I2, Stadelhofen, Zurich (corresponding). Mr. Albert E.Ollive, 47, Smith Street, Chelsea. Mr. W. D. Saunder presented a preparation of Epulis. Mr. Palmer presented to the library, " Fox on the Teeth;" Parmly's " Treatise," and Waite's " Treatise on the Teeth." Mr. Parsons presented to the museum Dr. Snow's Chloroform Appa- ratus ; a fine specimen of an under Jaw from Italy ; a curious specimen of Whale's Tooth; and an instrument for extracting Stumps used by Dubois, of Paris, from 1780 to 1809. Mr. Mummery read the following paper :— " On the Structure and Adaptation of the Teeth in the lower Animals, and their relation to the Human Dentition!'' The dentition of the lower animals, being almost co-extensive with the entire series of the animate creation, embraces so wide a field of study that I have found considerable difficulty in so treating 224 STRUCTURE AND ADAPTATION OF TEETH the subject as to bring it within the allotted limits of the present paper. Viewed merely as a recrea- tion, no pursuit offers more exuberant variety of intellectual enjoyment than that of Natural History. Many an hour may thus be profitably occupied when the mind and body are wearied with daily toil, and many a solitary walk is beguiled by the new and lively interest which invests the most common objects. JSTor are these studies incompatible with diligent application to important duty, while the habits of minute observation which are cultivated cannot fail to be beneficial to any one engaged in a profession like our own. Mr. Abernethy has a remark in one of his lectures which, though de- signed to have a still wider signification, appears in its degree not inapplicable to onr own special department. He says — '' The man who confines his attention to a single object will have a mind as contracted as the object he contemplates. Knowledge of various kinds is requisite to form the true surgeon : it serves like light shining ficom various sources to illuminate the object of his researches." As there is no deficiency in the works of the all- wise Creator, so there is no superfluity; and the importance of the teeth in the animal economy is evident from the fact, that the great majority of animals are furnished with these organs in some form or other ; and that, where the teeth are not present, some efl&cient substitute is provided, as in IN THE LOWER ANIMALS, ETC. 225 the powerful beak of the carnivorous birds, and the strong, muscular gizzard of the graminivorous tribes. This latter arrangement is also found in some of the microscopic moss corals : animals so minute, that a group of fifty are scarcely larger than a good-sized pin's head ; and yet each indi- vidual is furnished with a gizzard wherewith to grind down the shelly coverings of the still more minute creatures that constitute its food. We may, therefore, reasonably infer that the teeth are de- signed to fulfil a most important ofl&ce, and that no animal can be deprived of them without serious derangement of all the bodily functions. Fossils have been appropriately termed the Medals of Creation, and the title is emphatically applicable to the teeth. From their durability, they furnish a guide to the forms of long extinct races, when few other relics are discoverable, and the comparative ana- tomist is thus enabled to assign claws to one animal, or hoofs to another, with the digestive, nervous, and muscular organization appropriate to the habits and necessities of each. Admirable examples of the application of this principle are seen in the restoration of extinct animals in the gardens of the Crystal Palace. It was considered a wonderful achievement of inductive science, when Baron Cuvier thus led the way to the reconstruction of long lost races, and the repeopling of the ancient earth with its con- iilrO STRUCTURE AND ADAPTATION OF TEETH temporary inhabitants,; but the science of histology (or the knowledge of tissues) proceeds still farther, and the accomplished comparative anatomists of our own country are now enabled, by applying the microscope to the examination of the minute frag- ment of a tooth, to identify the family and even the genus of an animal. If we examine a polished section of human den- tine by the unassisted eye, it presents a satin-like, opalescent appearance, arising from the presence of innumerable fine tubes penetrating the entire structure, — an organization so clearly elucidated by Mr. Tomes, in his " Dental Physiology," that I need only refer you to the earlier chapters of that invaluable work. The microscope shows that there are distinguishing characteristics in the forms and arrangements of these tubes, in each of the various tribes : supplying a key whereby their true place in the scale of creation may be recognised. ARRANGEMENT OF DENTINAL TUBULI. Fig. ^1 .—Human. IN THE LOWER ANIMALS, ETC. 227 Fig. 2^.—J)olphm. Fig. 'i^.—Boa Constrictor. Fig. m.—])off-Fhh. The teeth of the invertebrate classes present an endless variety of remarkable contrivances, ex- actly adapted to the particular requirements of each species. Did time permit, we might notice the curiously formed teeth and jaws of the sea-urchin, among the radiates (one of the lowest types of animal life), or the diversified forms presented by the horny teeth of insects. The gastric teeth of the Q 2 228 STRUCTURE AND ADAPTATION OF TEETH Crustacea, as in the lobster, might claim our atten- tion ; or the formidable apparatus of lancet and saw-like teeth with which the Annelides, especially the marine genera, are furnished. But, perhaps, we should find still greater cause for admiration, in the multitudinous lingual teeth of the Mollusca, whether adapted for rasping vegetable food, as in the periwinkle, or for drilling holes in the hardest shells, as in the whelk and other carnivorous molluscs. In this great division — the animals destitute of either skull or vertebral column, — the arrange- ment of the teeth is as strange as their forms. The organs supplying the place of jaws are arranged circularly, as in the sea-urchin ; vertically, as in the insects ; triangularly, as in the leech ; or forming a long flexible riband, as in the mollusc, with many other variations to which we cannot make even a passiag reference. But when we turn to the higher or vartebrate division, we per- ceive that the jaws of fishes, reptiles, and mammals, and the bills of birds, are invariably arranged in the horizontal plane, and never exceed two in number. It was originally my intention to take a cursory view of the teeth in the several orders of mammals, passing in the ascending series, fi:*om the horny teeth of that strange paradox, the ornithorhyn- chus, with its duck-like mandibles and webbed feet, to the more perfect teeth of the higher orders ; IN THE LOWER ANIMALS, ETC. 220 but as I wish to stow their relations to the human dentition, I shall restrict my remarks mainly to the teeth of those animals which respectively ex- hibit, in greatest perfection, the three distinct types of teeth in the human species : viz., incisors, canines, and molars. As the teeth determine the nature of the food, there is a necessary connection between their structure and the development of the organs of touch, on which the degree of abihty and address of the animal so much depends. The amount of perfection in these organs is to be measured by the number and flexibility of the digits, and the extent to which the nail or hoof encases the extremities. In the ungulated animals the hoof (entire or divided, as seen in the horse and ox respectively), envelopes the foot, limiting its sensibility, and rendering it incapable of seizing a living prey. Hoofed animals are, therefore, of necessity herbivorous, and they are provided with flat-crowned grinding teeth, adapted to the bruising of roots, seeds, or grass. Animals with unguicu- lated digits exhibit much greater variety in their habits, and in the nature of their food, and they differ greatly in the amount of flexibiUty and sensibility bestowed on their extremities. The carnivorous tribes are furnished with claws adapted for securing their prey, an organization which has its highest development in the cat family, — whose hooked talons being retractile, are 230 STRUCTURE AND ADAPTATION OF TEETH preserved from injury, until witli unerring force they are plunged into the flesh of the victim. These claws are associated with powerful canine teeth ; and instead of flat molars, we find laniary or trenchant teeth, which are capable of cutting flesh after the manner of shears. In the rodents, the claws differ but little from those of the carnivora; but these animals are destitute of canine teeth, while the incisors are more fully developed, and are adapted for a pecu- liar office, that of gnawing, as in the rat and beaver. The form of the condyle is necessarily modified, to admit of the diverse movements required for the efficient use of these several classes of teeth. The digestive organs are equally connected with the character of the teeth. In the carnivorous mammalia, from the highly nutritious quality of their food, the alimentary apparatus is very simple in form, and limited in extent ; the entire intes- tinal canal being not more than three or four times the length of the body. But in the vegetable feeders, the digestive organs exhibit much greater complexity, especially in the ruminants, and the alimentary canal is from twenty to thirty times the length of the body. The upper incisor teeth of the lower animals, with the exception of some of the quadrumana, are implanted in the intermaxillary bones, which in man are only found in the foetal stage of exist- IN THE LOWEE ANIMALS, ETC. 231 ence. The canines, when they exist, are almost invariably longer than the other teeth, and there is a space between the lateral incisor and the upper canine, permitting the lower canine to shut up closely in front of the upper ; thus greatly increasing the efficiency of these teeth, whether employed, as in the camivora, for securing their prey, or, as in the monkey-tribe, for self-defence. The molar teeth, which are succeeded by others in the vertical direction, as in the replacement of the human temporary molars by the bicuspides, are called premolars or false molars; while the teeth which are developed in the horizontal plane, and succeed each other from behind, corresponding with the himaan permanent molars, are called true molars. Among all the animals of the order camivora, the organs of destruction reach their highest development in the cat family : I will therefore take the Bengal tiger as an illustration. Fig. 'ih—SkuH of Tiger. 232 STRUCTURE AND ADAPTATION OF TEETH The incisor teetli are six in number in eacli jaw, the outer pair being much larger than the two front pairs, and conical in form, to assist the action of the canines in seizing prey. In conse- quence of the space between the third or outer incisor, and the canine, the effective power of these teeth is greatly increased, the canines being thus permitted freely to pass each other, and very con- siderably to overlap the gum, in the opposing jaws, when closed. These canines, conical and incurved, are most formidable weapons, implanted in very deep sockets, which impart great breadth to the face. The molars are four in the upper, and three in the lower jaw, on each side, of which the last in each series is the only true molar. The first upper premolar is of very insignificant size, with a blunt crown and a single fang. The second premolar is much larger, of somewhat conical form, flattened laterally, with one or two small lobes, and having two powerful fangs. The third is the true flesh- cutting tooth ; it is deeply notched, and has sharp, flattened cutting edges. (See Fig. 35.) The crushing, or tubercular true molar is represented in the Felidae, by a small oblong tooth placed transversely, but which ob- tains a far greater development in some other genera of carnivorous animals. In the lower jaw, the premolars are of a compressed conical form, with an anteiior and posterior tubercle. The third TN THE LOWER ANIMALS, ETC. 233 is the true molar tooth ; its crown consists of a sharp blade divided into two lobes, and is the true sectorial tooth, corresponding with the last upper premolar. Tlie teeth are so arranged, that when the jaws are closed, the lower teeth shut within the upper row, and their conical points fit into the tri- angular spaces between the crowns of their antagonists. The articulation of the condyles of the lower jaw is so contrived as to set this formidable apparatus in action in the most eflficient manner. These processes are both situated in the same horizontal line; they are cylindrical in form, and are firmly locked in the transversely elongated glenoid cavities, the margins of which are so ex- tended before and behind the condyles, that all lateral motion is impossible. t I'JG. '62. — Jiiff/U Cot/d^/e, Tiger. Fig. ZZ.^ Glenoid Cavity^ right side, 'JHger, 234 STRUCTURE AND ADAPTATION OF TEETH The crowns of these molars, or rather lacerating teeth, are, like the rest, thickly covered with enamel, and when brought into operation, they act like the antagonizing blades of a pair of metal shears upon the substance submitted to their cutting edges. The flesh of their victims is swallowed without much division, and is not truly masticated ; the food, already animalized, not requiring such pre- paration. . If we carefully examine a tiger's cranium, we readily see the machinery by which this terrific apparatus is set in motion. The occipital crest is a sharp and prominent long ridge, rising from the occipital portion of the skull, and continued along the junction of the parietal bones, its chief use being for the attachment of the immense temporal muscles, which would almost entirely cover the cranium, but for their separation by the bony ridge. Fig. 34. — Skull of Tiger ^ showhtfi occipilnl crest rit/d zi/gomatic arch. IN THE LOWER ANIMALS, ETC. 235 These muscles have an extensive surface for insertion in the large coronoid process, which forms the entire vertical ramus of the lower jaw. (See Fig. 32.) To admit of the free action of the muscles, the temporal fossa is continuous with the orbit, the frontal and malar bones not being united as in many other animals ; and the zygomatic process extends very widely at a right angle from the temporal bone, in order to give room for the tem- poral muscle, and to form the long transverse glenoid cavity to receive the condyle, constituting a perfectly hinge-like articulation. The zygomatic arch being very large and power- ftil, and convex above, is carried forward beneath the orbit, the condyle being situated very far back, and in a direct line with the cutting surface of the teeth. This arrangement enables the masseter muscle to act with immense force, its place of insertion being, like that of the temporal muscle, so far in advance of the articulation of the jaw. (See Fig. 31.) Not only is the muscular power of these ani- mals proportioned to their active habits, but, in accordance with the greater intelligence required, the cranial cavity is large, as compared, for instance, with that of the sheep, while the face is shorter and broader. The infra-orbital foramen is very large, supply- ing nervous energy to the powerful levator muscles 236 STRUCTURE AND ADAPTATION OF TEETH of the upper lip, wliicli is thus preserved from injury in seizing the prey, while the uncovered array of teeth strikes the victim with a mortal terror. Conscious of their powers, they instinctively aim at some vital part, as the large blood-vessels t)f the neck, and are thus enabled quickly to over- power animals otherwise capable of effective Iresistance. There is, however, a principle of compensation iseen throughout all nature ; and, while in the vegetable feeders we find numerous examples in which incisors, canines, or molars, as they become worn, are constantly renewed by the agency of their persistent pulps, there is no such provision made for the carnivorous animals. The teeth are subjected to much violence, and are not endowed with a reparative power ; there- fore the lion or tiger, as old age advances, is compelled to seek for prey less able to resist the attack. Unhappily for our species, the animals are consequently induced to prowl about the abodes of man ; and it has been observed, that the man- eater in India invariably proves to be an old tiger, whose teeth have been extensively worn or broken. The dentition of the carnivorous mammalia presents several modifications, adapted to the special requirements of certain genera. IN THE LOWER ANIMALS, ETC. 237 The hyena furnishes an admirable example of peculiar adaptation. In this genus the canines are much smaller than in the Felidas, while the molars are- exactly designed for grinding and crushing bones; the base of each crown being furnished with a power- ful ridge, which serves to protect the gum from being injured by the splinters and angular frag- ments. The tiger or lion pounces on living prey, 9,nd rapidly cuts away and devours the softer and more nutritious parts, leaving the bones and less tempting portions ; whereas the hyena is a sca- venger that watches for the rejected carcasses, and no animal substance is too repulsive for these creatures. The whole cranial structure appears formed for bringing into the most available action a most powerful natural instrument for breaking the hardest bones into shivers. Dr. Buckland has well compared this action to that of a miner's crushing-mill. The lion will gnaw the cartilage from a bone, and strip off the periosteum with his hook-covered tongue, but the hyena will snap asunder and swallow bones in large fragments. As bone forms so large a constituent of their food, the faeces of the hyena are composed princi- pally of phosphate and carbonate of lime, and that eminent geologist, the late Dr. Buckland, success- fully availed himself of this fact, to explain the cause 238 STRUCTURE AND ADAPTATION OF TEETH of the large collection of bones in the remarkable cavern of Kirkdale. During a comparatively recent geological period, when our native land was tenanted by the ele- phant, hippopotamus, and rhinoceros, the tiger, bear, and hyena, this cave had been made the depository of a great quantity of the bones of these and other animals, which were afterwards imbedded in a calcareous deposit or stalagmite. On carefully examining the crushed and splintered fragments, which bore marks of the action of powerful teeth, that acute observer formed an opinion, which was confirmed by the analysis of the coprolites, or fossil excreta, found mingled with the bones, viz., that the cave had been, through a long succession of years, the den of hyenas. In the tiger and hyena, we have seen that the true molar is represented in the upper jaw by a tooth of insignificant size, but in the badger, it is Fig, 2>h.— Tiger's upper Jaw, left side, the small tooth on the extreme right being the Tubercular Molar, the largest tooth in the jaw. It has three tuber- cles, or prominences on its outer edge, and its TN TrrE LOWER ANIMALS, ETC. 239 broad horizontal surface is traversed by two low ridges, the lower molars being similarly modified. Fig. 3G. — Badger's upper Jaw, left side, showing the great development of the Tubercular Molar. This dentition is evidently adapted for an admix- ture of vegetable with animal food ; and the badger is said to live on roots, fruit, and honey, with small birds and frogs. It is remarkable, however, that the hinge-like articulation we have noticed in the tiger, is so much more perfect in the badger, that the condyle is retained in the glenoid cavity, after the soft parts have been removed by macera- tion. The cranial ridge is not seen in the young badger ; the lower jaw is easily disarticulated, and the sutures of the skull are visible : but in the adult animal, the ridge receives an extraor- dinary development for the attachment of the temporal muscles ; the sutures disappear, and the margins of the glenoid cavity are so extended as to enclose the transverse condyle to a degree that renders dislocation impossible. It would appear, however, that these provisions are made rather for defensive than for aggressive purposes. It 240 STRUCTUlv'K AND ADAPTATION oF TKimi Fig. ZK .Skull of Badger. chooses the most soHtary woods for its residence, and is quiet and inoffensive in its manners.; but when attacked, it defends itself with a courage and resolution which few dogs of double its size can overcome. It bites angrily, and holds on with great tenacity, which it is the better enabled to do from the peculiar organization to which we have referred. We will now turn our Fig. 2,%.— Skull of Badger, showing attention to SOme of cranial ridge. ^^^^^ animals in which the molar teeth attain their greatest perfec- tion. Among these, the ruminants, although charac- terized by great deficiencies in the other teeth, occupy a conspicuous place. On comparing the skull of the sheep with that of the tiger, we see evident marks of inferiority in the small compara- FiG. 39. — Skull of Sheep, showing large projwrlionale size of the bones of the face, and small development of the zygoma. IN THE LOWER ANIMALS, ETC. 241 tive size of the cranial cavity, and the propor- tionally greater length of the bones forming the face. The orbits, instead of the forward direction, are widely separated, occupying the sides of the head, and are entirely surrounded by a bony ring, its continuity being completed by the extension of the malar process to the zygomatic arch; which presents a striking contrast, in its smaller size, to the corresponding widely-arched bone in the carnivora. (See Fig. 34.) The long, slender, intermaxillary bones, are destitute of teeth ; but, in place of incisors, the upper jaw is provided with a callous rim, which meets the lower incisors. The cuspidati are absent in the upper jaw, and the lower cuspidati so nearly resemble incisors, that they have sometimes been described as such ; but the alveolar processes are very deep and fully developed for the reception of the long molar teeth ; of which class there are three premolars, and three true molars on each side of both jaws. Fig. 40. — Skull of iiheeit, shuwi/iy absence of incisors and cuspidati in upper Jaw. B 242 sTRUoTtmE and adai'tation of teeth The lower jaw is so much narrower than the upper, that the surfaces of the molars are not in apposition when the jaws are closed, and at rest ; and their crowns are all placed obliquely ; the grinding surfaces of the upper teeth sloping in- wards, while in the lower jaw they incline out- w^ards and downwards. As the crescentiform layers oi*^ enamel in the compound molar teeth assume a longitudinal direction, they are thus brought into efficient service by the great lateral action of the lower jaw. If we watch the sheep or ox when ruminating, the jaw is seen to take a protruding position, describing the segment of a circle as it is alternately swept from side to side. Instead of the transverse hinge-like condyles of the cat tribe, admitting of motion in the vertical plane only, the condyles of the ruminants are flattened at their articular surfaces, and the glenoid cavities are very flat and shallow, and are much wider than the apposed surface of the condyles ; rendering them capable of free horizontal motion, whether laterally or in the antero-posterior direc- tion. As we have noticed, the temporal bone and the zygomatic arch are remarkably small, when compared with the corresponding parts in the camivora, and the deep excavations in the lower jaw for the insertion of the temporal and masseter muscles are not observed, those muscles being very feebly developed. But to meet the very different requirements of the animal, the angle of the lower IN THE LOWER ANIMALS, ETC. 243 jaw is greatly developed, to give space on its in- ternal surface for the insertion of the internal pterygoid muscle, while the external pterygoid is inserted nearer to the condyle ; their united forces supplying the powerful lateral and oblicpie motions referred to. The human teeth present us with a simple arrangement of the three substances of which mammalian teeth are composed, the greater por- tion of the tooth consists of dense nonvascular dentine, the crown being covered by a simple cap of enamel, which is conformed in every part to the contour of the crown; and the enamel fibres are arranged at nearly a right angle to the surface on which they rest, the enamel possessing greater density and hardness, and a lower degree of vita- lity than any other animal tissue. The roots of the human teeth, and, in a very minute degree, the crowns also, are invested with a layer of cementum ; a structure showing a close affinity to true bone, and which, endowed with a far higher amount of vitality than either enamel or dentine, has also the least density. Perhaps the structure of the teeth of gramini- vorous mammals could not be better illustrated, than by our conceiving the idea of a number of such simple teeth, modified in outline and soldered together by the greatly increased proportion of cementum, not only to the surface of the roots, but of the crowns also ; thus forming a compound n 2 244 STRUCTURE AND ADAPTATION OF TEETH tooth, in which the vertical layers of dentine, enamel, and cementum, are intermi:xed. The various patterns in which the folds are arranged, serve to distinguish the several genera of animals in which these compound teeth occur. We see a beautiful example of design in this arrangement. It is evident that this interfolding of parts differing so much in hardness, must produce a constantly roughened surface, which is maintained by the unequal wearing down of the elements of the tooth. The cementum is worn into deep depressions, while the dentine is more moderately wasted, and supports the ridges of enamel, which always retain their sharpness. The folds are arranged in the ruminants in two double cres- cents, the convexity of which is turned inwards in the upper, and outwards in the lower jaw : the object of which is to enable them reciprocally to act on each other in the most effective manner. A peculiar kind of stone is selected for the con- struction of millstones, and is valuable on account of the harder particles disseminated throughout its softer constituents. The miller is obliged fre- quently to dismantle and pick or dress the cutting surface of the stone, to ensure its efficiency ; but in the teeth of the gramnivorous animals, we see the equivalent of a self-dressing millstone. The solitary row of front teeth is more perfectly adapted to its purpose than would at first appear. IN THE LOWER ANIMALS, ETC. 245 If we watch a sheep grazing, we may see how admirably the whole mechanism works together. I "SiqAI.— Molar Teeth of Sheep. A. Grinding surf ace of upper Teeth, left side, showing the convexity of enamel folds directed inwards. B. Showing external and grinding surfaces of lower Teeth {left side), the enu/nel folds being directed outwards. The prolonged upper lip aids the tongue in sweep- ing a tuft of grass into the vice formed by the cutting teeth of the lower, and the unarmed front of the upper jaw, while the upward jerk helps to sever the herbage from the roots. The process of ruminating also supplies an in teresting subject for observation, when the sheep are lying down in the fold, in the act of masti- cating the food previously cropped, and stored in their first stomach. The low murmur of so many sets of animated millstones, when listened to in the stillness of a 246 STRUCTUEE AND ADAFIATION OF TEETH summer twilight, has a very peculiar effect. A brief reference to this function may be desirable. The term ruminant indicates the remarkable faculty possessed by these animals, of re-mastica- ting their food, which they return to the mouth after previous deglutition, a power which results from the structure of their stomachs, with four of which they are always provided. The first three of these stomachs are so arranged, that at the will of the animal the food can be directed into either of the three ; the oesophagus terminating at the point of communication. The first stomach or paunch, is much the largest, and serves as a reservoir for the masses of herbage, rudely broken up by the first mastication. These animals often gather their food in great haste, and very greedily devour rank growing herbage, a propensity which frequently endangers the life of sheep and oxen, when tempted by a luxuriant crop of green corn. They eat so voraciously, that the first stomach becomes over distended by the quantity of food and the carbonic acid gas evolved from the vege- table mass, and the animals, if not speedily relieved, die of suffocation. Some special adaptations in the non-ruminant ungulates will next demand our notice. In the horse, the incisors are present in both jaws, and are slightly curved inwards ; the canines, small in size, are developed in the male, and in the upper jaw stand isolated in the wide gap IN THE LOWEK AN1M*ALS, ETC. 247 between the incisors and molars, but the lower canines are close to the incisors. These teeth are only rudimentary in the female. (Fig. 42.) Fig. 42. — Skull of Horse {female). The premolars and true molars are of equal size and complexity. Fig. 43. — l/tcisoi- Teeth of Horse. A. Verlica' i'cction. B. C. D., shuwhi^ trrudunl oblitertitioii nf l/ir innt-r Jh/il of enamel. 248 STRUCTURE AND ADAPTATION OF TEETH The front teetli of the horse are remarkable for furnishing a test whereby the age of the animal may for several years be determined. (Fig 43.) The " mark," as it is popularly called, is caused by an oblong fold of enamel which dips down into the crown of the tooth, from the cutting surface to the commencement of the fang. This fold of enamel encloses a column of cementum, the surface of which, from its softer nature, is always worn below the ring of enamel, and becomes stained by the food. As the horse advances in age, the constant attrition wears out the mark from the incisors, commencing from the central pair, proceeding in the second and third pairs, successively, and still later in the upper incisors also, until, in an aged horse, the entire depth of enamel is worn away. The true " mark " has now disappeared, a spot of the dark underlying cement alone indicating its former position. The molar teeth, which in their compound Fig. 44. — DeciJuons and perwanetd Molars. JJjiper Jaw of two-year old Colt. {From Professoi' Oicen.) IN THE LOWEE ANIMALS, ETC. 249 character resemble those of the ruminants, differ from them in their great length before dividing into roots. (Fig. 44.) This division does not commence until the crown is considerably worn down, consequently the horse never possesses a perfect crown, with perfect roots, which latter are only found in old horses. Fig. 45. — Grinding Surface of Molar of adult Horse, slowing arrange- ment of folds. The coronoid process of the lower jaw offers, as in ruminants, a very limited surface for the inser- tion of the temporal muscle ; and its attachment to the temporal muscle is equally circumscribed ; but this is amply compensated by the large surface provided for the insertion of the pterygoid muscles in the broad angle of the lower jaw, supplying powerful lateral motion. The condyle is more rounded at its margins than in ruminants, and the glenoid cavity is more con- tracted, hence the masticating action is from side to side, instead of the circular motion observed in the sheep. The horse is much more delicate in the selec- 250 • STEUCTURE AND ADxVPTATlON OF TEETH tion of food than the ruminants, whose cloven hoofs, by their expansion in soft ground, enable them to feed on the rank herbage in marshy places, where the horse would be inevitably pre- vented from grazing. The horse selects the more tender grasses, eating them down to the very roots and leaving the coarser herbage untouched. As the food is swallowed but once, it is masticated thoroughly ; and I have been informed by an intel- ligent farmer, that he never knew of an instance of a horse being similarly affected with the ox or sheep, after indulging in a feast of green corn. In the hog tribe, we have an example of the true tusk of the ungulated animals ; a tooth of conical shape, with a persistent formative pulp, a charac- teristic which receives its fullest development in the canines of the hippopotamus and the incisors of the elephant. The teeth of the common hog are the same in number as in the horse, w4th the addition of one premolar in each row ; and among other distinguishing features may be noticed the progressive increase in size from the first molar to the last. The wild boar, the stock from which our domestic breed is derived, usually harbours in the most secluded recesses of the forest ; and if aroused to combat, employs the tusks with terrific force, as it rushes past its assailant, inflicting fearful wounds, and sometimes ripping open the abdomen. The incisors are levelled forwards and are IN THE LOWER ANIMALS, ETC. 251 admirably adapted to aid the truncated snout in turning up the earth. The sense of smelling is very acute in these animals, and as it is omnivorous, not a root, insect, or worm, escapes the olfactory sense — a faculty which is turned to valuable account by the truffle-himters of the Continent, who train the hog to discover that delicate underground fungus. In the babyroussa, an animal closely allied to the wild boar, the long and slender upper canines describe a still more remarkable curve, and at a little distance more nearly resemble horns than teeth. They rise almost vertically through the upper lip, and curve backwards until they some- times pierce the skull. Although their use is not positively known, they are not unreasonably supposed to be designed as a defence for the eyes, when the animal forces his way through the luxuriant undergrowth of the tropical forests he inhabits. The air is admitted from the frontal sinuses over a large portion of the diploe, or cellular osseous tissue, between the inner and outer plates of the cranium. The external surface is thus extended, without increasing the weight of the head, a structure which is still more extensively developed in the enormous head of the elephant. In the hippopotamus the four upper incisor teeth curve downwards, meeting the sides and 252 STRUCTURE AND ADAPTATION OF TEETH extremities of the lower incisors, which are straight, and, as in the hog, project directly for- wards. The powerful upper canines are compa- ratively short, and are worn obliquely in front, in consequence of their abrasion against their antagonists in the lower jaw. The lower canines are still more massive, and form the segment of a circle, the extremity being worn away on the inner or concave side ; and as the convex outer sides are furnished with thick enamel, which is not present on the inner, a cutting-edge of irresistible power is constantly maintained. Unlike the teeth of the ox or horse, there is in these no distinction of root or crown, but the tooth is of equal diameter throughout. The hollow implanted extremity is occupied by a per- sistent formative pulp, which undergoes progres- sive calcification, and the tooth glides forward in its curvilinear alveolus, to compensate for the wearing down of the free extremity. This mode of growth, however advantageous in some respects it may appear, is occasionally productive of unfortunate results. In the specimens on the table we have examples of the wrong direction taken by the tooth in describing an arc of too small a circle. In one case the apex has returned upon its base, pressing on the outside of the thin wall of the pulp cavity ; and in another it has entered the formative pulp itself, forming a complete ring; IN THE LOWER ANIMALS, ETC. 253 a condition which must have inflicted great suffer- ing upon the unfortunate animal. The jaws and teeth seem to be constructed for rudely tearing and dividing, but not for commi- nuting the tough vegetables which form the staple food of the animal. It is a most voracious feeder, and the enormous stomach is said to be capable of containing five or six bushels. The articulation of the jaws is peculiar, admitting of their wider separation than in any other mammal, and no one who has ever seen the animal yawn, could possibly forget that astonishing performance. ANNUAL GENERAL MEETING. Monday y January 9, 1860. W. A. HARRISON, Esq., V.P., in the Chaie. The following Gentlemen were duly elected Members of the Society : — Mr. G. Parkinson, M.R.C.S. Eng London. Mr.E.LowE, M.K.C.^. Eng London. Mr. W. B. SwANsoN , Edinburgh. Mr. James Bell Perth. Mr. S. A. Rogers Manchester. Mr. R. C. Pilling Lancashire. The following Gentlemen were proposed for the Membership of the Society : — Mr. J. Belisario, D.D.S.... Sydney (corresponding). Mr. H. Jordan Queensland, New South Wales (cor- responding). Mr. Tomes presented to the Library a complete edition of Hunter's Works, by Palmer. Mr. Edwin Saunders presented to the Library " Dictionary of Dental Science," by C. Harris ; Alexander Nasmyth's " Researches on the Teeth;" Hunter's "Anatomy" (IZ^S) ; Bunon's "Essai sur les Maladies des Dents" (1713); Jourdain "On the Diseases of the Maxillary Sinus " (1700) ; Bunon's " Second Essai ; " " American Journal." Mr. R. Parsons presented to the Library " Delabarre on the Teetb,'* 2 vols. ; Fattore " On the Teeth." Mr. W. A. Harrison presented to the Library, Hunter's Works " On the Teeth ;'* Blake " On the Teeth ;" Snell "On the Teeth," and " On Artificial Palates;" Koecker's "Dental Surgery." The following Gentlemen were elected by ballot as Officers and Council for the ensuing year : — 256 President.— 'W. A. Harrison, Esq., F.R.C.S. Vice-Presidents. — William M. Bigg, Esq.; C. Bromley, Esq.; J. Tomes, Esq., F.R.S. ; J. Martin, Esq. ; S. Cartwright, Jun., Esq., M.KC.S. ; T. G. Palmer, Esq. Treasurer. — Edwin Saunders, Esq., E.R.C.S, Honorary Secretaries. — Thomas A. Eogers, Esq., M.ll.C.S. (for Foreign Correspondence) ; Alfred Canton, Esq., M.R.C.S. ; G. A. Ibbet- son, Esq., F.R.C.S., F.G.S. (Ordinary). Co^^/^tf^7.—H. J. Barrett, Esq., M.K.C.S. ; Samuel S. Berend, Esq.; Robert Brookhouse, Esq. ; W. A. N. Cattlin, Esq., F.R.C.S. ; T. R. M. English, Esq. ; J. B. Fletcher, Esq. ; J. Heath, Esq. ; Edwin Sercombe, Esq., M.R.C.S. ; J. Underwood, Esq. GENERAL MONTHLY MEETING. Monday y February 6, 1860. W. A. HARRISON, Esq., President, in the Chair. The following Gentlemen were duly elected Members of the Society : — Mr. C. G. Kemp Leicester. Mr. T. Hawkins Birmingham. Mr. W. J. Parks London. Mr. W. r. Forsyth London. The following Gentleman was proposed for the Membership of the Society : — H. A. Dewar, M.D Aberdeen. Mr. D. D. Hepburn presented to the Museum some preparations: — No. 1. Curious case of exostosis, in which a second tooth is enclosed. 2. Three molars (one with four fangs). 3. Three peculiarly-shaped supernumerary teeth. 4. Three teeth. 5. Osseous union of two temporary incisors, small bicuspids, and case of union after fracture. Mr, R. Hepburn presented to the Museum the following prepara- tions : — No. 1. Pair long-fanged canines, and one other ditto. 2. Three-fanged bicuspid, two ditto, front incisors, and one other. 3. Two inferior front incisors enclosed in tartar, and piece of dittor 4. Three peculiar-shaped molars. 5. Ditto. 6. Lower jaw, containing five permanent teeth between the canines. 7. Upper jaw, containing six front teeth, the right central incisor being of an extraordinary size. Also a few models of No. 7, for any of the members who may wish to possess one. IS 258 HEREDITARY SYPHILIS. Mr. Coleman exhibited models of Teeth illustrative of Mr. Hutchin- son's paper on Hereditary Syphilis, and made the following communi- cation : — The patient, a young woman twenty-two years of age, came to St. Bartholomew's Hospital about the latter end of last summer, with a large indolent ulcer over the middle of the tibia ; and, as is the case sometimes with these ulcers at her period of life, it was vicarious in its functions with the uterus. After being in the hospital some time, with good treatment, the ulcer ceased to discharge at the catamenial period, the uterus resuming its proper office. The case was interesting because the diagnosis was made entirely through the teeth, by Mr. Paget, who has often informed me that he has found this symptom very serviceable in assist- ing him to arrive at a correct diagnosis. I should state that various methods were adopted to cause the ulcer to heal ; viz., by incisions round the ulcer, followed by attempts to draw its margins together, but without success ; and the limb was eventually amputated. Being anxious to ascer- tain the correctness of the diagnosis, I took an opportunity of seeing the patient's mother, who informed me that the child had always been very delicate ; that during her infancy she had suffered from a rash upon the buttocks, and severe snuffles ; that she (the mother), had been married twice, and had had seven children by the first marriage, and six by the second ; and that of the issue of HEREDITARY SYPHILIS. 259 the first marriage the patient was the only child living. This was, of course, a circumstance very probable in a case of a syphilitic taint. I put several other questions with a view of eliciting further history. I asked her if her first husband ever had any rash or sores on his body ? *' No." In fact I could not get any information, though I had very little doubt as to what was the real state of the case. As a last resource I made the remark, " Well, you seem to be a very lucky woman to have had two good husbands, whereas many wives don't get one good one." She then admitted that her first husband was not nearly so attentive to her as the second. This led me to make further inquiries ; and then, for the first time, she stated that she recollected very well her first husband having a suppurating abscess in the groin, and that the medical man who attended him would not allow him to come to her bed for a period of three months — a strong corroboration of the correctness of the diagnosis. My object in bringing this case under the notice of the Society is, to show that the offspring may suffer from hereditary syphilis where the maternal parent has never had any symptoms of syphilis, and may, as in this case, be even ignorant of her husband having ever been affected with it — cases by no means rare, but adding greatly to the difficulty of obtaining a history. The casts now before the meeting are not so 260 ANCHYLOSIS OF THE JAW. well marked as some that were brought under the notice of the Society upon a former occasion, but are still sufficiently so to point out their peculiari- ties. 'No doubt we do find occasionally non- syphilitic teeth approaching more or less to this type ; but on this account we should no more reject the aid the latter lend to forming a correct dia- gnosis, than we should in the case of the syphilitic cutaneous eruptions, which still more closely re- semble some of their non- syphilitic congeners. Dr. Lewison read a paper on Anchylosis of the Jaw, of which the following is an abstract : — Some years ago, while on a visit in Cheltenham, I was consulted by a married lady about forty years of age, who was suffering from rigid closure of her jaws. I found on th^ left side of her mouth, situated about an inch from the angle, a strong semi-cartilaginous band, which was evidently con- nected with the buccinator and masseter muscles of the same side. The probable connections of this jpsett^o-growth were indicated by the restrained actions of the before-named muscles. The sufferer was unable to masticate food, and consequently had to live on slops ; in addition to this evil, her pronunciation of words was seriously affected : indeed, she spoke precisely like a person who has a fissure of the palatine bones, owing apparently to her efforts to overcome the incon- venience of her present condition. To lessen the ANCHYLOSIS OF THE JAW. 261 difficulty experienced in getting food into the mouth, two teeth, the superior and inferior anterior molars of the opposite side of the mouth to that on which the band was situated, were extracted, but little advantage actually resulted from this opera- tion. I experienced great difficulty in under- standing Mrs. , as she spoke with a constant snuffle, and with the wings of the nose so com- pressed as to impart an unpleasant appearance to her otherwise agreeable features. Had it not been so, I should have made a more searching examina- tion, in order to have elicited some information from her as to what she considered the original cause of the formation of the band ; but under the circumstance of her imperfect utterance, she either could not, or would not, assist me in forming any- thing like a correct diagnosis. Nevertheless, being satisfied that the band might be safely separated, I suggested that she should visit Brighton where I then resided. If I could have operated at the time I first saw her, she would have submitted most cheerfully; but my engagements prevented my remaining a suf- ficient time either to do her or myself justice. However, prior to my leaving Cheltenham, she made a definite engagement to pay me a visit, but she did not keep her word; and I was sub- sequently told that this arose from her being influenced by the dentist who had previously at- tended her, and that she had been persuaded by 262 ANCHYLOSIS OP THE JAW. him to see once more a resident surgeon. The gentleman she consented to consult had previously attended her, and I am not aware whether he did or did not object to an operation ; but he did not seem much inclined to undertake to remove the band, probably because the patient herself was at the time in a very highly nervous condition ; so he substituted a mechanical contrivance, but for what object I cannot opine, as any force which could be applied without immediate danger would not have cured the anchylosis, so long as the resisting cartilaginous band remained. This instrument I subsequently inspected. It was of a wedge-form, being made of two steel por- tions, graduated so as to be flat and thinnest at the edges. These flat ends were perforated with holes for the purpose of being covered with white kid leather. A screw was placed so as to pass through the upper half of the wedge, to terminate into a cup'like female screw afiixed to the inner part of the lower half of it, and so contrived that the space between the edges of the wedge could be enlarged at the will of the patient, the edges of which were inserted or rather forced between the front teeth. (See drawing.) Mrs. persevered for two months in using this instrument, until she experienced great agony, and not finding the slightest improvement, she abandoned its use altogether ; and when the effect of the strong resisting band is taken into coii- ANCHYLOSIS OF THE JAW. 263 sideration, viz., that it utterly prevented the action of the temporales and masseters, no other result could have been anticipated. It seems to me not improbable that the wedge was intended to gradually separate the jaws ; and it may be presumed- that the prolonged use of the instrument had induced a chronic inflammation of the integuments and muscles of the buccal cavity, causing the latter to become thickened, judging from her subsequent symptoms and the results. I saw her again about two years after the wedge experiment and my first examination (now six years since), and found the band, instead of being separated from the inner portion of the cheek, so as to admit the finger passing freely between it and the band, perfectly united with the cheek, so that it had now become impossible to do any good by attempting to separate it ; and it could only be removed by dissecting it away from the cheek with which it was incorporated. This last spring, having occasion to visit Chel- tenham, I took the opportunity of once more examining the patient, and now feel assured that any operation would be attended with some danger. The jaws are perfectly immovable, and the anchylosis is complete ; she lives altogether on suction, yet she looks better in health than I had anticipated. There is, however, every proba- bility that she may ultimately die from actual inanition. 264 ANCHYLOSIS OF THE JAAV. As my object in giving publicity to this unique case is for the purpose of obtaining some infor- mation on its probable origin, I shall conclude this paper with a summary of an article " On Anchylosis of the Alveolar Arch," in '' Oppen- heim's Zeitschrift," Band xliv. page 376, as given in the seventeenth number of the '' Medico- Chirurgical Review," for January, ]852. The writer says, " Anchylosis of the lower jaw may occur in three localities : 1st. The head of the condyle may become fixed in the glenoid cavity. This is the most frequent form, examples of which are recorded by Sandifort, Blandon, Cru- veilhier, Howship, Holcher, Hyrtle, and others. 2nd. The coronoid process may become attached to the zygomatic arch. Of this, but two cases are recorded. 3rd. The alveolar process may become conjoined. Of this, there are examples besides the one recorded by Dr. Werner, which is now cited. *' S. R — , aet. 26 ; when three years old un- derwent a severe salivation, after which the jaw remained in a fixed state. Notwithstanding the absence of masticatory power, he was well nourished. The jaw was quite immovable, firm pressure or traction exerting no efiect upon the condition of the teeth. The incisors and molars were, indeed, for the most part wanting ; the roots of those which did exist projecting beyond the alveoli of the diminutive jaw-bone. The jaws were ANOHJLOSIS OF. THE JAW. 265 only so far separated, that, with some trouble, the little finger could be introduced in front. " Speech much resembled that which takes place with the mouth closed ; and food which did not require mastication was introduced between the defective teeth. ** To remedy this state of things, the gums were separated by an incision from the cheeks to the lips, and a broad portion of the connecting arch on either side removed by a small saw. The jaws could now be expanded by the aid of the mouth- speculum to the extent of half an inch, some painful stretching of the muscles being induced. The patient was, however, enabled to voluntarily close the mouth again, proving that twenty-three years of inactivity had not destroyed the functions of the joints and muscles. After several weeks' perseverance in gradual dilatation, a still wider expansion was obtained, enabling the patient to chew food that was not too hard, -which, indeed, the loose state of the teeth rendered impossible." {Vide ** Medico- Chirurgical Review.") 31rs. was in all probability more than thirty before the band began to be formed, and hence now, after the lapse of so many years, there is every probability that both the muscles and joints are implicated. As, therefore, anchyloses of the jaws are rare, either when dependent on morbid growth of the alveoli, or the nnion of the coronoid process and 266 ANCHYLOSIS OV THE . JAW. the glenoid cavity, little can be known of their special pathology. In the case of Mrs. , it being altogether an isolated one, the difficulty is still greater. Although w^e cannot say what predisposed the growth of the band, yet we have data to indi- cate the cause which aggravated her condition, inducing greater inconvenience, and destroying all chances of effecting a cure — namely, the pressure and force of the machine which had been used, which, as a natural consequence, induced the now stronger adhesion of the band and its intimate connection with the cheek itself, from which it had been for some years perfectly separated. That the present adhesion of the band with the cheek is attributable to the cause indicated, he (Dr. L.) had no doubt. At the conclusion of the paper. Dr. Levison said, he had heard that very evening that the lady was upon her travels, and would shortly be in London ; and he should certainly make an effort to induce her to see some of our most eminent dentists, with a view of ascertaining if anything could be done on her behalf, as at present her existence was a misery. He exhibited the instru- ment to which he had alluded in his paper ; and said he knew of no society or tribunal to which he should more confidently look for an opinion than the Odontological Society, where the members displayed, not only a knowledge of the anatomy ANCHYLOSIS OF THE JAW. 267 and patliology of the mouth, but also of the mechanical appliances useful in dentistry. He had no doubt light would be thrown upon the case by gentlemen present, whose remarks he should look for with very great interest. GENEEAL MONTHLY MEETING. Monday, March 5, 1860, W. A. HA.RRISON, Esq., President, in the Chair. ITie following Gentlemen were duly elected Members of the Society : — Mr. Albert E. Ollive London. Mr. John Belisario Sydney (corresponding). Mr. Henry Jordan Queensland (corresponding). The following Gentleman was proposed for the Membership of the Society : — Mr. T. Bell, E.R.S., P.L.S., &C....17, New Broad Street, City. Mr. Spencer Cookings presented to the Library " Berdmore's Trea- tise on the Teeth." Mr. Jameson, a collection of Models. Mr. Ash exhibited specimens of Vulcanite. Mr. Blackburn, a machine for holding mineral Teeth whilst fitting or grinding them. Mr. Palmer presented some models illustrating the wasting away of the edges of the upper Incisors. Mr. Maclean exhibited the model of a Mouth, the incisors of which had been lost by a blow from a stone at nine years of age. The model was taken at the age of forty -five, showing that nature had repaired the loss by the approximation of the adjoining teeth. Mr. Sercombe then read the following paper " On Inflammationy as it appears -in the Tissues of the Mouth, and its Treatment:'' — The mouth, though a small region, is made up of many parts, which, when the seat of idiopathic disease, no more fall to our care as dentists, than does the eye or the ear, yet these parts, when 270 INFLAMMATION JN THE TISSUES OF secondarily affected, may, and often do, come under our treatment. It is, therefore, clear that if I keep myself to that part of the subject I am announced to speak of this evening, " Inflam- mation, as it appears in the tissues of the mouth, and its treatment," which concerns us as den- tists, I must pass by in silence many forms of inflammation which are met with in the mouth. For instance, I cannot speak of that idiopathic inflammation of the tongue which often runs its wild course, rapidly carrying its victim to a most miserable death ; nor can I speak of those attacks of idiopathic inflammation of the submucous tissue which are also rapid in their course, and often fatal in their termination ; nor, again, of those attacks of acute inflammation of the glands so often met with; yet each of these parts are obnoxious to attacks of inflammation induced by diseased teeth, and in this manner they may come under our care. We have all of us, probably, had cases of inflammation of the tongue, brought on by the ragged edge of a tooth. I have known a few such cases, in which the swelling of the tongue rapidly became so great as to cause serious alarm to the patient of suffocation. But the inflammatory affections which- most concern us as dentists are those of the dental pulp ; of the membrane lining the alveolar socket and the root of the tooth ; of the cellular tissue of the gum ; and of the mucous membrane. Of these I THE MOUTH, AND ITS TREATMENT. 271 intend to select the periosteal membrane, and the mucous membrane, as they will afford quite matter enough for the time at our command. I trust the days are now over — at least in large towns, where there are a sufficient number of intel- ligent dentists to compel each practitioner, by a wholesome competition, to keep himself well- informed in his profession — when the only treat- ment for the cure of all aches and pains in the mouth is the extraction of a tooth, a carious one if such can be found, but failing that, a soimd one. When T first entered the profession, I not uncommonly witnessed such irrational prac- tice, but, thanks to this Society pre-eminently, and to other agencies of lesser pretensions, such practice has almost, if not altogether, ceased. I do not pretend to say that all cases of toothache can be successfully treated without extraction, but I am quite sure that very large numbers of teeth were, but a few years ago, probably many still are, extracted for affections which are amenable to other and more scientific treatment. I think extraction may be regarded as as much the oppro- brium of the dental art as amputation is that of the surgical ; and just as we advance in accurate medical knowledge will the use of the forceps diminish. Why should not the same general principles which are brought to bear on inflamma- tion in other organs be brought into operation by the dentist, and with the same average amoimt of 272 INFLAiMMATIOX IX THE TISSUES OF success ? The surgeon is compelled, by tlie ter- rible alternative, to treat and, if possible, cure periostitis by internal remedies associated witli local applications. Not so the dentist. The ex- traction of a tooth is not so formidable in the immediate pain it inflicts, and the after apparent consequences that follow, that patients generally obstinately refuse to submit to it when it is recom- mended by their dentist ; it is, therefore, the more necessary that he should have a quick and tender conscience, faithfully to act upon the command, " Do as thou would' st be done by." But I fear it must be confessed that the neglect of a medical education will principally account for the indiscriminate extraction of teeth. Unfamiliar with disease and its treatment — for it is quite impossible for a man to know disease merely by reading about it, yet, unfortunately, hitherto this has been almost the only way the man qualifying himself as a dentist has been able to acquaint him- self with it ; he must have seen it, and educated all his senses by coming in contact with it, to know it to any practical purpose — unfamiliar with disease, I say, and its treatment, he has not known how cases may be dependent upon constitutional vice, and how, if so, they may be treated with a good chance of success ; and thus many an ex- traction is due, not to want of conscientiousness, but really to want of knowledge. I rejoice in the firm belief that this great evil has received its death- THE MOUTH, AND ITS TEEATMENT. 27^ blow. The present race of dentists, by free and friendly intercourse, are daily becoming them- selves better informed on matters a little outside the run of daily practice, and, what is far more important, we are all lending a willing hand to secure for those who shall follow us a more com- plete education. I may illustrate the preceding remark by what has again and again come under my notice. Attacks of acute inflammation of the peridental membrane, give rise to much suffering, especially at night ; robbed of sleep and exhausted by pain, the sufferer goes to the dentist to have his tooth extracted, supposing that to be the only cure for toothache. If the tooth should be carious, the request of the patient is at once complied with ; but should the tooth be quite free of caries, as it sometimes is, the patient is often advised to apply a leech to the gum and take ** some aperient " medicine. I put it to those present, whether they have not often been disappointed at the result; whether they have not often been told that, though while the leech was on there was some abatement of pain, afterwards it became as unbearable as ever, — ay, and even worse, for the leech, by sucking, has caused the blood to flow in increased quanti- ties in the direction of the inflamed membrane, and thus the inflammation has been aggravated rather than lessened. After the failure of this treatment, the tooth has been extracted, as the supposed only alternative. The theory which 274 INFLAMMATION IN THE TISSUES OF leads to this treatment, I suppose, is, that the pain is the result of a cold, which gives rise to inflam- mation of the periosteum, and that therefore anti- phlogistic treatment is correct, and that failing, extraction becomes the only alternative. Such attacks of pain I have found to depend upon very various causes and to need varied treatment, which it will be my endeavour this evening to point out Peeiostitis. Under this head I propose to describe the in- flamatory process as it goes on in the membrane which lines the root of the tooth, the peridental membrane — and its reflection which lines the socket in which the root is retained — the intra- alveolar membrane. For practical purposes, it matters little whether we can discriminate in which of these the attack is. Inflammation of either of these membranes may be the result of external causes ; or internal or constitutional causes ; or of both external and internal causes combined. Of external causes, a blow on the mouth, the sudden and unexpected biting upon some hard body, as a shot, or a splin- ter of bone, or the application of some irritating substance, are among the most common. Of internal causes, syphilis, scrofula, rheumatism, gout, and mercury, may be regarded as among the most frequent. Periostitis may assail one tooth THE MOUTH, AND ITS TREATMENT. 275 or several, or even the entire set. The periosteum, being largely composed of fibrous tissue, is not very prone to take on inflamation, but its situation is most unfavourable to recovery from an attack when it has been set up. The double fold of membrane lies between two bony surfaces, which only yield to the membrane as it thickens (one of the changes it imdergoes during the inflammatory process) in one direction, and that eminently cal- culated to increase the evil. By this thickening the tooth is raised in its socket above its fellows, and consequently first receives the pressure of the opposing jaw. It thus becomes driven back upon the membrane, and so the mischief is greatly increased. During the early stage of this affection, the momentary relief derived fi:'om clenching the jaws together, tempts the individual in whom it occurs fi'equently to do so, until, from the pro- gress of the attack, the membrane becomes so excessively tender that the slightest touch of the tooth gives pain. The symptoms of periostitis are pain, heat, and swelling, confined more or less to the affected part. I say more or less, because sometimes the pain shifts its position, rendering it difficult to decide with confidence where the mischief really is. These symptoms undergo aggravation at night, the reclining posture, the greater warmth of the body in bed, and certain physiological changes which occur at this period of the twenty-four T 2 276 INFLAMMATION IN THE TISSUES OF hours, all tend to this. In addition to these symptoms, which are characteristic of periostitis in every part of the body, we have when this affection assails the dental organs others, peculiar to these parts ; we find the affected tooth raised above the level of its fellows, and slightly loose. In the earliest stage the pain is scarcely at all increased by pressing the tooth firmly into its socket, but in a more advanced stage the pain which follows such an attempt is excessive. When several teeth and sockets are involved in the attack, we find the pulse indicating constitutional irritation, the tongue is covered with a brown fur, the flow of saliva, at first increased, becomes diminished, and much constitutional fever super- venes. In chronic cases the pain greatly diminishes, pus becomes secreted, if not in such quantities as to be visible at all times, yet in such quantities as to be producible at any time upon applying gentle pressure to the gums. The treatment of periostitis will vary with the cause and the stage in which we find it. We seldom have the chance of seeing it in its earliest stage, when probably a saline purge would alone suffice to check it. In the acute form energetic treat- ment must be adopted ; four or five leeches to the part, great diminution of food, entire omission of stimulants, saline purgatives, with fomentations, hot or cold, as the case may indicate, will gene- rally be found beneficial. These attacks are, as THE MOUTH, AND ITS TREATMENT. 277 far as my experience goes, generally confined to young persons of a robust and plethoric habit. All causes of local irritation should at the same time be searched for and, if possible, removed. I have known periostitis of the upper incisor teeth induced by the lower incisors continually striking them behind during the act of mastication, in con- sequence of the absence of molar teeth. In such a case no amount of physic mil avail if the front teeth of the two jaws are not kept from coming into contact by supplying the lost molars. The ex- citing local cause will often be momentary, and' when we see the patient it will not exist ; such, for instance, is a violent blow, which is among the most frequent of the exciting causes of periostitis in the front teeth. But inasmuch as the effects which follow such a cause vary so widely, in one producing little or no after- suffering, whilst in another the most severe symptoms will supervene, it is well to search for any constitutional pecu- liarities of the patient, and to regulate the treat- ment thereby. The following case wiU illustrate this remark. March 3rd, 1859. — I saw a young gentleman who was complaining of an intense pain in his lower front teeth, which for four nights had pre- vented his sleeping at night, the pain being much more severe than by day. I found the parts so sensitive that he could scarcely bear to have the lip withdrawn for the purpose of examination. 278 INFLAMMATION IN THE TISSUES OF The four lower incisors were very loose and in- tensely sensitive, tlie gum. was very red, much swollen, and extremely painful, the submaxilliary glands were enlarged. The pulse quick and irrita- ble. Tongue covered with a brown fur. No local exciting cause present. The patient could not remember having received any blow on the mouth. I ordered two leeches to the part, and two pills, composed of blue pill, colocynth, and henbane, at bedtime. March 5. — No relief; the leeches did their duty well, and the medicine acted freely. My patient informs me to-day that he now remembers receiving a violent blow on the mouth about a month ago from his horse's head while riding, which gave him at the time much pain, but this had so entirely subsided that he could not imagine it had anything to do with his present attack. I found my patient belonged to a rheumatic family, and that he himself was frequently subject to rheumatism; I therefore thought iodine would be likely to be useful, for the exhibition of which tny previous treatment had well prepared the way. I ordered the iodide of sodium, with bicarbonate of soda, in five-grain doses, twice a day. March 9th.— My patient informs me to-day that he has experienced marked relief After he had taken the second dose of the iodide, his sleep was restored. To-day I find his teeth much firmer, and that they will bear to be fingered with- THE MOUTH, AND ITS TREATMENT. 279 out giving pain ; the gums are also free from inflammation and without pain. March 16th. — The teeth are perfectly firm, and the attack quite subdued. I have selected this case as one very charac- teristic of a group. The following will serve to illustrate cases, the result of constitutional causes only. December 6th, 1859. — I was consulted by a gentleman who was sufiering severe pain in the upper right-hand wisdom tooth, which, upon examination, I found very loose and tender when touched. As it had no antagonizing tooth, the jaws could be closed without increasing the pain. An extra glass of wine taken after dinner for the purpose of overcoming the pain, served only, as we should expect, greatly to aggravate it. Taking into consideration the uselessness of the tooth, I wished to extract it, but to this my patient would not consent. There was no local exciting cause to be discovered. The individual was, however, the victim of gout. I, therefore, prescribed the iodide of potassium with the bicarbonate of potash, intending to combine colchicum with it should the iodide prove insufficient alone. The second dose brought perfect relief, but at the same time un- mistakeable evidences that iodine could be very ill tolerated. A greatly-increased flow of saliva showed that ptyahsm was at hand. The medicine was discontinued after the second dose, having 280 INFLAMMATION IN THE TISSUES OF accomplislied that for which it was ordered, and without any contre-temps. The following interesting case is recorded by Dr. Graves, in the Dublin Journal : — *' I recently met in the streets a gentleman of my acquaintance, looking very unhappy, and upon asking the cause of his misery was told that he was suffering severely from pains in his gums and teeth, for which he had already submitted to the extraction of two sound teeth — a bicuspid and a molar — - upon the recommendation of his regular medical attendant, a man of great skill and a dentist of eminence ; and that though the operation was at first attended with some relief, a few days after his sufferings became as agonizing as ever ; and now, as the neighbouring teeth had become loose, he was told that they too must be extracted. Under these circumstances he had had recourse to a celebrated homoeopathic doctor, whose treatment had completely failed. Remembering that he had consulted me the previous year for a periostitic affection of the sternum and ribs, and that the hydriodate of potash was the medicine which, served him best, I recommended him to take ten grains fer in die. I had the satisfaction of per- ceiving a daily improvement, so that pain and in- flammation soon ceased, and in about ten days the teeth were all fastened. The periostitis," adds the doctor, *Ho which this gentleman was liable was of a rheumatic character, otherwise his con- ► THE MOUTH, AND ITS TREATMENT. 281 stitution Avas good. He was about tliirty-four years of age." ♦ About the middle of December of last year I was consulted by a gentleman, who complained of great pain in his gums and teeth, which was much increased when he clenched his teeth together, an act he had a great desire to perform ; and, again, the pain became aggravated when he became warm in bed. I found the mouth and throat presenting a most suspicious appearance, and upon inquiry I learned that lie had recently been troubled with secondary syphilis, from which, however, he was now recovered. Such a case was pre-eminently fitted for the iodide of potassium. I therefore prescribed it, or rather the iodide of sodium, and with the success I anticipated. In such cases, the relief, though almost immediate, is not com- pleted in so short a time as in other and more tractable forms of periostitis. I have never seen any cases of scorbutic periostitis. In strumous children, who often suffer from the effects of irritation of this mem- brane, small doses of the iodide of sodium, of one or two grains, with cod-liver oil, will often prove of great service. I now come to a class of cases extremely diffi- cult to treat with anything hke uniform success. The narration of one case will be sufficient for my purpose on the present occasion. A woman who had been up to her marriage, a domestic 282 INFLAMMATION IN THE TISSUES OF servant, consulted me at the hospital in conse- quence of suffering much pain in her teeth and gums, especially at night, with, on rising in the morning, a " a sense of heat in her teeth." The appearance of the woman was extremely charac- teristic— a heavy, languid look, large and flabby limbs, a full face, with a good deal of very fugitive colour, hair thin, pulse feeble, and expressive of little physical power. The appearances of the mouth were also characteristic — the gums hard, the mucous membrane dry and shining, generally red, but with a band about two lines broad, ex- tending from the necks of the teeth of a much deeper colour ; the upper front teeth had de- scended, and the centrals had separated to the extent of nearly a line, not equally from the mesial line, but by the departure of one (in this case the right central) from it, which tooth had also become the most elongated. This change of position had, according to the woman's testimony, taken place within the year. The teeth were somewhat loose, and upon squeezing them with the finger pus oozed out between the gums and the teeth. I prescribed iodine in this case ; but find- ing on my next visit, after an interval of two days (a period I should say I have found generally sufficiently long to enable me to see whether it is likely to be of service), that no relief whatever had been experienced, my attention became more drawn to the asthenic condition of the patient,' THE MOUTH, AND ITS TEEATMENT. 283 I therefore dropped the use of iodine, and sub- stituted quinine and iron, the citrates of these remedies, and, as a local application, a wash com- posed of the tincture of pellitory, four drachms to the eight ounces* In four days the symptoms had greatly abated, the pain had much diminished, and the general appearance improved ; but as the pus was still formed in considerable quantities, I substituted for the pellitory a chloride of zinc wash, as recommended by Mr. Tomes in his " Manual." In four days from this the secretion of pus ceased, the gums were of a natural colour, the red band having entirely disappeared, and the teeth were firm. In this case there was no local exciting cause. It was one, the cause of which was purely constitutional, and which could only be properly treated by constitutional remedies. The extracting of teeth might have been of tem- porary service, but the pain must inevitably have returned when the cause was deeper than the root, and not to be withdrawn with it. I will bring my remarks on the treatment of periostitis to a close, by giving one case in which local and constitutional causes combined to bring about, or to speak more correctly, as I saw nothing of the case in its earliest stages, to keep up the evil. In such cases it is, as I have already said, clearly our duty to remove all local causes of irritation, while we assail the constitutional. In the following case, however, I postponed all local 284 INFLAMNATION IN THE TISSUES OF treatment, in order that I might test to the very utmost the value of iodine ; and the result which I am about to give, was even beyond my expecta- tion. About five months ago, I was consulted by a man at St. Mary's Hospital, who complained that he was never free from pain in his mouth and teeth ; but that latterly it had greatly increased, and at night became so distressing as often to rob him of sleep. He said he suffered so much, and felt so bad, that he could not keep to his work. Upon examination, I found the teeth all loose, the gums red and swollen, soft and spongy; and upon pressing them with my fingers pus oozed out in every direction. The teeth were much incrusted with tartar. The man had every external appear- ance of a scrofulous tendency ; such as long, weak, light hair, a large head, bright eyes, a fair com- plexion, &c. When I first saw him, there was a good deal of anxious distress expressed in his face. Wishing to test the power of iodine in such a case, I employed no local treatment at first, though the removal of the tartar was so evidently desirable, but contented myself with prescribing the iodide of sodium with the bicarbonate of soda, in five-grain doses. I saw the man in two days ; he said he was not the same man : his appearance had certainly greatly improved. After the second dose he felt himself better, and found he could sleep at night. liittle improvement had, however, tpken place in the gums and teeth, except that THE MOUTH, AND ITS TREATMENT. 285 they were almost entirely free from pain. Pus could be readily produced by pressure. I still postponed the removal of the tartar, contenting myself with the continued use of the iodide of sodium. On my next visit to the hopital, two days later, the man pronounced himself quite well. On examination I found, however, that the teeth, though firmer, were not quite firm, nor had the pus entirely disappeared. I now ordered the tartar to be removed, and a tannin wash to be used, the iodide to be continued as before. In two more days the local symptoms had greatly abated : the man could not ba induced to come again, as he said it was a waste of time, as he was quite cured. In this extreme case, immediate relief and continued improvement was secured by the use of the iodide of sodium, unaided by any local treatment. I have nothing further to say on the constitu- tional treatment of these cases as they come under the care of the dentist. I have given great pro- minence to the employment of iodine, simply because I have found it of such signal service in this most troublesome and intractable afiection. Other remedies doubtless will often be found use- ful, suggested by the constitutional tendencies of the patient ; but as in most cases in which perio- stitis occurs the constitutional taint favours the exhibition of iodine, it will be well to give it a trial ; but after the most skilful treatment, we shall 286 INFLAMMATION IN THE TISSUES OF still sometimes be driven to the forceps to ease our patient of his pain. With reference to the employment of iodine, I may add one word. There are various forms in which it may be given, and in all the effect appears pretty much the same. The most usual form of exhibiting it is the iodide of potassium. In the course of this paper I have spoken of the iodide of sodium. For my knowledge of this preparation I am indebted to Mr. lire, one of my colleagues at St. Mary's. This salt has one striking advantage over the iodide of potassium ; which is, that whilst the latter has a most unpleasant metallic taste, the former is almost tasteless. Mr. Ure states also that it is more readily tolerated. Eecently the iodide of ammonium has been recommended by a French surgeon, but I have had no experience with this salt. There are great differences of opinion as to the dose which should be given. Some advise large doses, of from two drachms to even half an ounce, whilst others state that the dose should seldom exceed five grains twice a day. Some say it should be given in a concen- trated form, and others largely diluted. I have never yet exceeded five-grain doses, which I order twice a day in half a tumbler of water, believing it desirable that the salt should be much diluted. I always combine it with an alkali, and thus I account for my entire escape from all symptoms of gastric irritation, an unfavourable symptom not THE MOUTH, AND ITS TREATMENT. 287 uncommonly showing itself shortly after iodide of potassium has been taken. I believe this irrita- tion due to the decomposition of the iodide by the acid in the stomach, by which pure iodine is set free, a salt we all know to be most irritating, and in some cases even dangerous. The presence of the alkali prevents this decomposition, and thus the mischief is avoided. In three cases I have found unfavourable effects produced by the exhibition of the iodide. The gouty case cited above is one, where I have no doubt ptyalism would have quickly followed a continued use of the medicine ; in this case, however, it had accomplished the object for which it was given before such symptoms became mani- fest. In another case it appeared to produce headache and sleeplessness, with some nausea. And in the third case, there was a good deal of constriction and irritation about the top of the throat. Knowing that such results sometimes, though very rarely follow, I always warn my patients to discontinue the medicine at once, and let me see them, if any of these symptoms appear. I do not wish to be understood as saying that cases do not often come under our notice in which extraction is the proper and only treatment that can be employed with, any prospect of success; such, for instance, are those cases where, from long- continued suppuration, the alveolar process has become absorbed, and the attachment of the tooth 288 INFLAMMATION IN THE TISSUES OF is in consequence very slight. No treatment that I am familiar mtli will cause the alveolar process to be reproduced ; and therefore, as the teeth, from their slight attachment, are annoyingly loose, hey had much better be extracted at once. But in all cases, even where the periosteum has become greatly thickened, if the alveolar process is intact, I think it desirable to try the treatment I have spoken of, if the patient will consent. If the result of the treatment is favourable, the products of inflammation will be absorbed, and the tooth will become firm and useful. We have all, I suppose at times, patients who will submit to any treatment rather than endure the pain of extrac- tion. In such cases I have often been glad to be able to have recourse to a plan of treatment, of the favourable result of which I could express a good hope. Before quitting this subject I must give the pathological condition of the membrane a mo- ment's consideration. If a tooth is extracted in the earlier stage of periostitis, the peridental membrane is found to have undergone a change ; the capillary vessels, w^hich ramify over its entire surface be- come irregularly dilated, so that red globules travel through them; and when the dilatation is at its greatest, they congregate, giving a patchy redness to the membrane, which in a normal condition has few vessels of a diameter THE MOUTH, AND ITS TREATMENT. 289 sufficient to allow the red corpuscle to travel through them. In "a further stage, the membrane is found thickened and much more vascular, and if the attack has been very acute, it is often detached from the root. In many cases lymph is early infiltrated into the fibrous tissue, and gives to the membrane at the apex of the root a saclike appearance. Should the attack have been of slow progress, the membrane is found thick, dense, and firmly adherent to the root. The exuded lymph disappears in either of the following ways. If the membrane is restored to a healthy condition, the lymph becomes absorbed. If not, the lymph may become organized, and small nodes be formed on the root. Or it may pass on to the condition of pus, and then we find, according to the side of the membrane from which the exudation has taken place, pus, either between it and the root, or we have pus between the peri- dental and intra-alveolar membrane. I am not aware that we can diagnose with any certainty from which membrane, or from which side of the membrane, the exudation has taken place, nor am I aware that any practical advantage would accrue from such knowledge. The pus may escape either by oozing out from around the neck of the tooth, or it may travel through the intervening tissues and present either on the gum or on the cheek. u 290 inflammation in the tissues op Stomatitis, Mucous membranes are more prone to inflam- matory attacks tlian serous or fibrous membranes, and hence we find such attacks not unfrequently in the lining membrane of the mouth. Stomatitis, or inflammation of the mucous membrane of the mouth, may be either simple or ulcerative, and in either case it may be confined to a small surface, or spread over the entire region. Ulcerative stomatitis must be preceded by the simple form, and therefore in describing its symptoms I shall describe first, those of simple stomatitis. Symptoms, — They are increased redness, with a sense of heat, and more or less swelling and pain in the gum where the inflammation exists, with at first a diminished, and afterwards an increased secretion of saliva. Causes, — Sometimes stomatitis is excited by constitutional, and at other times by local causes. Among the local causes may be mentioned — want of cleanliness, injuries, the application of irritating agents, diseased teeth and roots, &c. Among the constitutional causes, depressed or exalted vital powers, by whatever cause produced, such as im- proper food, ill-ventilated dwellings, the eruptive and intermittent, or, as the London poor not inaptly call it, intermediate fever, secondary syphi- lis, mercury, &c. Excepting from the two last- THE MOUTH, AND ITS TREATMENT. 291 named causes, constitutional stomatitis appears to commence in the mucous membrane of either the bronchial tubes or of the stomach, and to extend to the mouth. Treatment, — The treatment of simple stomatitis appears to consist in first removing all manifest causes of irritation, such as diseased teeth and roots, bathing the mouth with cooling and demul- cent lotions, and, if the patient be plethoric, temperance in living, calomel, and saline purges ; if the inflammation be of an asthenic character, astringent or stimulating washes, the active prin- ciple of which may be tannin, pellitory, nitrate of silver, or iodine. As an internal remedy, chlorate of potash. Another variety of stomatitis, a case illustrative of which has recently been under my care, is found to follow exhausting discharges. Nursing- women are frequently the victims of it. It occurs only among the debilitated. The • mucous membrane of the tongue is most commonly the situation of this attack. The swelling which follows is sufficient to cause the tongue to be indented along its edges by the teeth ; the edges are exceedingly tender and red, the redness continuing to the under surface of the tongue, and along the floor of the mouth ; the soft palate and the tonsils are generally more or less affected. This variety is of importance, inas- much as the patient will avoid eating to escape u 2 292 INFLAMMATION IN THE TISSUES OP the pain of the operation; and yet her condition is such as to render it most important that she should be well nourished. The case to which I referred above had been treated locally only ; by twenty grains of nitrate of silver to the ounce, and then by blistering-tissue behind the ears — but to no purpose. I ordered ten grains of chlorate of potash, and one ounce of tincture of bark daily. A wash, composed of two drachms of chlorate of potash to half a pint of water, with immediate advantag-e. - But our advice will not often be sought for stomatitis of this simple character. More fre-p quently we shall find it advanced to ulceration in some form. The least important, both in its character and its effects, is that in which we ob- serve some small, circular, aphthous ulcers — one or two, or several— situated most commonly near or at the r-eflection of the mucous membrane, from the cheek to the gum. These ulcers are excessively painful, though very unimportant; if left alone, they generally last from four days to a week, and then heal spontaneously; they may be followed by others, and thus their presence in the mouth may be indefinitely prolonged. In appearance they are circular, with a grey- coloured exudation ; if this is removed, the surface appears a little excavated, and is very irritable. I know of nothing so efficient as a touch of strong nitric acid. There appears to be little or no ten- THE MOUTH, AND ITS TREATMENT. 293 dency to confluence with these ulcers ; nor is the breath rendered fetid by them. Ulcerative stomatitis, or ulcero-membranous stomatitis, is a much more important affection. It occupies that undefined territory which will sometimes be claimed by the dentist, and some- times by the surgeon. It is an affection which as legitimately falls to the care of the one as of the other. In hospital practice it is generally handed over to the dentist, and therefore I think I shall not be going beyond the province of this paper by speaking of it. It is found in this country most frequently in young children of the poorer classes. It also appears to prevail, at times, among the soldiers of the French and Portuguese armies. During the Crimean war, M. Bergeron, a civil physician attached to the Hopital du Roule, was much struck with its prevalence among the garrison of 'Paris, especially among -the recruits ; its character being identical with that which assails the children of this country. From the fact that the privates were more subject to it than the non- commissioned ofiicers, and the latter far more so than the ofl&cers, the doctor attributed the affection to hygienic circumstances. As recently as Saturday evening last, Mr. Arnold Rogers mentioned a case of ulcerative stomatitis, which he met with in the person of a British officer, who had been through the hard- 294 INFLAMMATION IN THE TISSUES OF ships of tlie Crimean campaign, and who was invahded home after the Balaklava charge. Under his care the case speedily recovered. . Symptoms. — Ulcerative stomatitis follows, as I have already said, upon the heels of simple sto- matitis. I am not aware that aphthous ulceration ever degenerates into the. affection now under consideration. In addition to the symptoms which characterize simple stomatitis are others, which indeed generally bring the sufferer for advice. The pain becomes much more urgent, and the breath excessively fetid ; so intensely so in some cases, that I have been quite unable to endure it while making an examination, and have been compelled to order some disinfectant before I could look into the patient's mouth. The saliva is secreted in greatly increased quantities. There is often swelling of the cheek and submaxillary glands on the affected side, but wholly unlike the oedema found with phagedenic stomatitis, which is hard, indolent and waxy, and without much tenderness or pain. The ulcer is not gray, as the aphthous, or exact in outline ; its colour is more that of laudable pus ; its outline is irregular and ragged ; instead of commencing on the cheek, as aphthous 'ulcers often do, it, as far as I have seen it, com- ijaences on the mucous membrane covering the gum : instead of retaining its original form and shape, and manifesting an unwillingness to spread, as is the case with the aphthous ulcer, it spreads THE MOUTH, AND ITS TREATMENT. 295 both in depth and superficies, assailing and de- stroying all tissues alike. Causes, — It is caused by. want of cleanliness, improper food, ill- ventilated, badly-drained, damp dwellings, such hovels, in fact, as the London poor almost alone are acquainted with. It is also fre- quently the sequel of exanthematous and inter- mittent fevers. It is also not uncommonly the result of local irritation, decayed teeth with ex- posed and inflamed pulp. M. Bergeron noticed it frequently among his soldiers in connection with suppuration within the alveolus. Treatment. — It is seldom cured spontaneously, and if neglected, as it too often is, necrosis of more or less of the alveolar plates and even of the maxillary bones themselves may follow* The remedy par excellence for this affection, whether it assail old or young, is the chlorate of potash, used both internally and locally. Opium, which is of so much value in phagedenic ulceration, appears to me to be of no avail in this affection ; but I have never seen a case in which the chlorate of potash has not proved of great value, checking the spread of ulceration, and causing it quickly to heal if the bone has not been implicated. I have seen cases ebb and flow like the tide with the. administration and suspension of this salt. The dose for an infant a year old would be a grain twice a day, for a little child from five to eight grains, and for an adult from ten to twenty grains. 296 INFLAMMATION IN THE TISSUES OP twice a day. It may be used locally witli great benefit, as a wash, from one to three drachms in eight ounces of water. I have never found escha- rotics of any service in this affection. AYhen the disease has advanced so far as to involve the bone, it will of course be necessary that the necrosed portion be removed before the ulceration will heal up ; but during the time the sequestrum is being detached the chlorate appears to keep the ul- ceration in check; and as soon as the bone is removed the parts heal kindly and quickly under the influence of this salt. Such has been my experience with it. There appears a strange tendency to recurrence of the ulceration, but on the opposite side of the mouth, which, however, I believe, may generally be prevented by a prolonged use of the chlorate and an occasional return to it at short intervals during six or twelve months. I have cases which occasionally come under my eye, in which, for some time after the healing of the ulcers, there was a frequent return of simple stomatitis, which was at once checked in its further progress by a recurrence to this salt. I have the opportunity occasionally of seeing the two cases which are represented by the pieces of bone on the table before you, and in neither of them has there ever been a return of the ulceration. One of these followed upon intermittent fever, and the other appeared, as far as I could trace out the case, to . THE MOUTH, AND ITS TREATMENT. 297 be the result of great personal jieglect, and a wretched chamber in which the family lived. .Girls appear to be more obnoxious to this affection than boys, and the lower jaw than the upper. The power of the chlorate of potash in this affection appears not to be confined to the human subject ; some five years ago the serpents in the Zoological Gardens were the victims to a ruinous extent of a disease which manifested itself locally in the mouth, by ulceration of the mucous mem- brane and exfoliations of portions of the alveolus with their teeth. At the time I was a frequent visitor at the serpent-house, investigating a sub- ject, and my attention was drawn by the keeper to the state of their mouths. I sponged the mouth out with a lotion composed of the chlorate, and injected five grains twice a day into the stomach. Synchronously with this treatment the serpents subject to it improved in health. The modus operandi of this salt is disputed, but it is generally believed to owe its power to the great readiness with which it parts with its oxygen. Ulcerative stomatitis, while it destroys the tissues of the mouth remorselessly, never, so far as I know, terminates fatally, but the phagedenic stomatitis not uncommonly does so, especially if neglected in its earliest stages. The general symptoms of phagedenic ulceration, at its com- mencement, are oedema of the affected cheek, of a 298 INFLAMMATION IN TISSUES OF MOUTH. peculiar glossy, waxy appearance, with little or no increase of the mucous membrane, even though an ulcer should be present, and little or no pain. In these respects it is strikingly different to ulcerative stomatitis. The exciting causes appear, however, to be very much the same. GENERAL MONTHLY MEETING. Monday, April 2, 1860. W. A. HARRISON, Esq., President, in the Chaib. The following Gentlemen were duly elected Members of the Society : — H. A. Dewar, M.D. Aberdeen. Mr. Paul A. Kolliker Zurich (corresponding). The following Gentlemen were proposed for the Membership of the Society : — Mr. C.r. Tubes Plymouth. Mr. W. H. May 26, Guildford Street, London. Mr. C. A. RoDWAY Torquay. Mr. J. W. Elliott, M.R.C.S. Eng., Theberton Street, Islington. Mr. W. S. CocKiNGS 17, Gower Place, London. Mr. J. J. Keene 14, Grande Rue, Boulogne sur- Mer (corresponding). Mr. Edwin Sercombe exhibited a specimen showing the destruction of bone wliich sometimes follows ulcerative Stomatitis, and made the following communication : — The case was interesting from the fact that the necrosis had overstepped the usual line of limi- tation, which, SO far as his (Mr. S.'s) observation went, was bounded by the second bicuspid. In this case the first molar was also involved, and was removed, together with the canine of the same side and the intervening teeth. The piece of bone, as would be seen on examination, consisted 300 SELF-PACKING VULCANITE APPARATUS. of tlie principal part of the left superior maxilla. The girl from whom he had removed this bone had had typhus fever seven months previously ; she had been well cared for, but had made a slow recovery. He removed the bone this day week, and this morning the parts were almost entirely healed. Mr. Dewae, read the following paper on " A Self-packing Vulcanite Apparatus : " — The subject to which I have to call your atten- tion this evening, although of some interest in its own department, is so far below that brought before your notice at your last meeting, " that I feel I have good cause for difl&deiice in attempting to interest you. I am aware, however, that any improvement, however trifling, or any light, how- ever feeble, that may be offered to this Society, will be accepted in a liberal spirit, and discussed with impartiality. The application of prepa- rations of India-rubber, and other analogous substances as a basis for artificial teeth, has opened a new field in our profession ; and we all naturally look with interest on every effort towards its further development, as we feel that our knowledge of its application is yet in its infancy. I do not intend this evening to touch either on the composition of the substances to be vulcanized, or on the various modes of effecting this result ; I will confine myself simply to the SELF-PACKING VULCANITE APPARATUS. 301 substitution of vulcanizing material for the tem- porary wax or gutta percha model, and the mode of effecting tlie substitution. Soon after I had adopted the use of this substance, I felt convinced that some better or more certain method of pack- ing might be devised than that in general use. I accordingly entered on a series of experiments, and I will now lay before you the result. As you are all aware, the ordinary mode of packing is attended with two almost unavoidable evils. We must always introduce between the two halves of our flask more than enough of material to fill the vacancy,, trusting to the escape gates, cut ia the plaster, and power- ful pressure combined with a certain amount of heat, to get rid of th^ superfluous material; but never thoroughly accomplishing this object, A diaphragm more or less substantial intervenes between the halves of the flask, and in every case where this diaphragm occurs, the teeth are just exactly the thickness of it distant from the place originally assigned to them. The other inconve- nience occurs where the case still retains some of its original teeth, and our object being to supply the vacancies in such case. . We all know the difficulty attendant on parting the two portions of the flask, the general result being that the plaster last poured retains the plaster teeth of the model as well as the mineral teeth intended to be in- serted, and thereby increasing the difficulty of 302 SELF-PACKING VULCANITE APPARATUS. accurate packing, and liable to produce a still more imperfect adaptation to the moutli tlian where the case is a simple one. I would now proceed to the explanation of the method I have adopted. The apparatus consists essentially, first of all, in a modification of the ordinary form of flask. We have here this form of flask [h and Ic, Fig. A), consisting of three parts, the saucer, the intermediate piece, and the top. The distinctive difference that I have made, and the use of which you will immediately see, is in perforating the lid {g, Fig. A), also having an additional thickness added to it. The bottom saucer may remain exactly as we have been in the habit of using it ; the middle portion of the flask must be pierced with two or more holes — -these holes are to serve for the exit Of the superfluous materials in a manner I will show you immediately. The next point that perhaps it is important to call your attention to, is the abandoning the use of gutta percha as a temporary model, substituting wax, or such a combination. of wax and Canada balsam as will make the wax sufficiently plastic and pliable to try in before submitting it to the process of packing. The next portion of the apparatus consists simply of what I may describe in two words as- a syringe with a steam-jacket. This sjrringe (c. Fig. B), is acted upon by a piston or plunger (d). The latter, instead of being forced by direct action of the hand, is forced SELF-PACKING VULCANITE APPARATUS. 303 into the syringe by a rather powerful screw (e e). We will suppose, then, that the case which I have in my hand is one which is intended to be packed in this new way. The teeth may be ap- plied as usual by soldering on the mineral teeth by means of wax, to the wax model, as we have been in the habit of doing. When the teeth are all in their place, a small piece of tapered brass rod, or what is quite as efficient, a piece of wax about the size of a pencil, is fastened to some central portion of the case, if it is an upper jaw towards the back part of the roof of the mouth. After adjusting the intermediate piece to its place, wires are inserted through the two holes at the side of the flask, and connected to the wax which forms the model to be afterwards made into vulcanite. I may pass this flask round to show the position of the teeth. [The flask was here handed round.] The two wires, you will see, are in contact with the case. The second plaster is then poured into the intermediate division of the flask, the per- forated lid (g) adjusted to its place, the tapered rod of brass or wax appearing through the orifice. The flask is then held together by a clamp (e. Fig. A), consisting of a bottom plate provided with three . arms and screws ; these are adjusted to a top plate (/), of such a form as to leave the orifice in the lid free. This form of clamp retains the two plasters in perfect apposition, and prevents any reasonable 304 SELF-PACKING VULCANITE APPARATUS. force from parting the two halves of the flask. The flask is now heated in a suitable oven (3, yiG. A. g. Lid of flask, perforated. e. Lower piece of clamp, with three jointed arms. f. Upper piece of clamp, with hole in the centre to fit g. « k. Flask, enclosed between the pieces e andf. i. Stopper made to fit orifice in lid g. h. Flask, with stopper i, disconnected from clamp e, f, and held firm by ordinary stirrup clamp. Fig. B), in such a position as to allow the wax to run out ; a suitable vessel (4) of course being placed beneath it to receive the melted wax. In this state it is ready to receive the charge of rubber. I have omitted to mention that as soon as the heat has penetrated the flask, while in the oven, the two side wires must be withdrawn. It is now ready to be adjusted to the apparatus. I will show immediately the mode of heating the SELF-PACKING VULCANITE APPARATUS. 305 cylinder. [The cylinder which was to hold the charge was then passed round.] The object here Fig. B. A B. Iron frame, held in a bench-vice, for holding the various parts of packing apparatus, C. Cylinder with steam-jacket, connected to AB by a swivel joint. D. Plunger, connected to screw EE by a brass joint. F. Handle for forcing-in plunger D into cylinder C. G H. Turn-plate and screw, for holding flask firmly in contact with cylinder C. 1. Copper boiler, connected with steam-jacket of cylinder C by flexible tube. 2. Gas-stand for boiler. 3. Ooen fitting to gas-stand for melting off wax. 4. Receptacle for melted wax running from flask to place within the oven 3. is to syringe in softened vulcanite into the space which was previously occupied by the wax model. Although the importance of saving a little time is not very great, the most important advantage that I find in this process is the non-separation of the flask, the teeth remaining in their relative positions to the surface they are to occupy, and X 306 SELF-PACKING VULCANITE APPARATUS. never being removed from that position from the time they have been tried in the mouth, we may- say, until they are ready for wearing in the mouth. With a certain amount of carelessness we may, even in this mode of packing, have the diaphragm ; but it is the fault of the manipulator in not screwing up the clamp sufficiently. Acci- dents may happen in going through this process as they may in going through any other, if certain points are not attended to ; but the action is exceedingly simple, and my first year's apprentice generally does all the packing .in the work-room. From the time the teeth are modelled in wax, until they come out of the vulcanizing chamber, they do not require, as it were, skilled labour, or, at least, very little of it. The frame of the packing-machine is made exceedingly strong, and in wrought iron, as a great deal more pressure is required to force the rubber into the fine inter- stices than might be generally supposed. The plunger, instead of revolving and turning with the screw, is coupled to the screw by a joint, so that it is pushed straight down into the cylinder. The cylinder has a side motion to enable it to receive a fresh charge of material. The rubber may be made up into blocks suited to the form of the cylinder, not unlike a very large cartridge, so that the cylinder contains enough for eight or nine cases. If we have three or four cases to pack, after the cylinder is once heated, half a minute is SELF-PACKING VULCANITE APPARATUS. 307 the time requisite for each. [Mr. Dewar pro- ceeded to heat the apparatus, by connecting it by means of an elastic tube with a small copper boiler, placed over a suitable gas-burner, preparatory to demonstrating the process which he was explain- ing to the meeting. The apparatus was a very ingenious one, and excited considerable admira- tion amongst the members present.] We ascer- tain that the flask is sufficiently packed by the rubber showing itself at the two side gates. There is one point of interest here which is worthy of attention. The first case which I succeeded in packing was put into the machine to be vul- canized ; on taking it out, after giving it the usual time, I found a long worm coming out of each side from either gate. I consequently feared I should find a cavern, as it were, in the rubber ; so much of it had come out of the gates that I presumed the case must be hollow. On opening it, how- ever, I found it perfectly solid, thereby showing either that I had put in more rubber than was required, or had put it in so condensed a state, that in heating it, it had expanded, packing its own case, as it were, still more thoroughly, and the superfluous rubber had escaped by these two gates. In every subsequent case that I packed by this process I have noticed a great density in the rubber, and uniformity in its appearance; there is no difference in any one portion of it from any other. A question may be asked. Do we get X 2 308 SELF-PACKING VULCANITE APPARATUS. rid of all the wax ? I admit that there is still an appreciable quantity of wax left in the flask, but it has no bad efiFect upon the rubber. What effect it might have when other than steam apparatus is used in vulcanizing I cannot say; but in using the steam process the vulcanite comes out as perfectly where the plaster has absorbed a considerable quantity of wax, as where great care has been taken to render the plaster per- fectly free from wax. Although steam is used here it is simply for heating the rubber suffi- ciently to cause it to soften somewhat to the consistency of plastic sealing-wax. We never get the rubber into a fluid state, it is simply reduced to a plastic condition. [Mr. Dewar here fixed the case on to the cylinder, which was kept filled with steam, and proceeded to manipu- late. After a short interval he succeeded in the operation, and the case was sent round the room for inspection.] He proceeded to observe : — I have succeeded in packing with another form .of machine. The model was so exceedingly rough that it would hardly bear your inspection — it was merely the model for a model ; however, I had a sketch made of it, which I have much pleasure in showing to the meeting. [The sketch was handed to the members for inspection.] It is, you will see, somewhat of an Archimedian screw revolving in a cylinder — in fact, something like a sausage ma- SELF-PACKING VULCANITE APPARATUS. 309 chine, provided, however, with a perfect steam jacket. It is altogether much more compact, and I think quite as effective as this one before you, but it has the disadvantage of being much more expensive in its construction. I GENERAL MONTHLY MEETING. Monday, May 7, 1860. W. A. HARRISON, Esq., President, in the Chaib. The following Gentleman was duly elected a Member of the Society : — Mr. Thomas Bell, F.KS., P.L.S., &c. . Mr. Arnold Rogers presented his Portrait to the Society. Mr. Owen exhibited models of a case of partial edentition. Dr. Levison presented to the Museum some casts of mouths defi- cient in Teeth. Mr. Mummery read the following continuation of his paper — On the Structure and Adajptation of the Teeth in the Lower Animals, and their relation to the Human Dentition, We will now turn our attention to the largest of all existing terrestrial animals, the elephant, a genus which forms the only living type of that extensive family of mammiferous quadrupeds which once peopled a large portion of the earth's surface — the true proboscidians. The dentition of this enormous animal is very remarkable. There are no canines in either maxilla, and the lower incisors are also absent, while the immense tusks (identified as incisors by their implantation in the intermaxillary bones) 312 STRUCTUEE AND ADAPTATION OF TEETH necessarily require alveoli of great size and deptli. The upper jaw is tlius rendered so high, and the nasal bones are so much shortened, that in the skeleton the nostrils are situated in the upper part of the face, although in the living animal they are prolonged into that remarkable organ the proboscis. The tusks are preceded by a deciduous pair not exceeding two inches in length, the bases of which are absorbed toward the end of the second year, and the teeth fall out. The permanent tusks appear a few weeks after- wards ; the immense hollow base being occupied by a persistent formative pulp, supplied abun- dantly with blood-vessels ; and as no antagonists are provided to wear them down, as in the case of the rodents, they attain an immense magnitude and weight. Instances are recorded in which a pair of tusks has weighed more than three hundred pounds ; and the annual importation of ivory into Great Britain alone may be estimated at about one million pounds ; which, taking the average weight of a tusk at sixty pounds, would require the slaughter of 8,333 elephants. Of the two existing species of elephant, the African is provided with the most massive tusks, which are of nearly the same size in both sexes ; while in the Indian species the tusks of the female do not attain equal magnitude to those of the male ; and in the Ceylon variety not one elephant in a hundred is found with tusks, the few that possess them being exclu- IN THE LOWER ANIMALS, ETC. 313 sively males; nearly all, however, are provided with the stunted teeth called tushes, about ten or twelve inches in length, and one or two in dia- meter. The old naturalists maintain that the elephant periodically sheds his tusks, ^lian says he drops them once in ten years ; and Pliny repeats the story, adding that, when dropped, the ele- phants hide them under ground; whence Shaw says, in his ' Zoology,' *' They are frequently found in the woods, and exported from Africa;" and Sir W. Jardine, in the 'Naturalist's Library,' says, " The tusks are shed about the twelfth or thir- teenth year." This is erroneous : after losing the- first pair, or '^ milk tusks " (which drop in conse- quence of the absorption of their roots, when the animal is extremely young), the second pair acquire their full size, and become the permanent tusks, which are never shed. Elephant-tusks are not unfrequently found in which balls of iron or lead are imbedded in the solid ivory, a pheno- menon which is thus explained : '' The ball pro- bably has penetrated the thin parietes of the socket, and the wall of the wide pulp cavity forming the basal extremity of the tusk. If the projectile force be then spent, the ball gravitates to the opposite and lower side of the pulp cavity. The presence of the foreign body exciting inflam- mation of the pulp, an irregular course of calcifi- cation ensues, which results in the deposition around the ball of a certain thickness of osteo- 314 STRUCTURE AND ADAPTATION OF TEETH dentine. The pulp then resuming its healthy- state and functions, coats the surface of the en- closing mass of osteodentine, together with the rest of the conical cavity into which that mass projects, with layers of normal ivory, closing the breach in the thin parietes of the pulp cavity by which the ball entered ; and as the growth of the tusk proceeds, the ball so inclosed is carried forwards into the solidified part of the tusk. The occurrence of a spear-head in an elephant's tusk may be similarly accounted for. The long axis of the weapon corresponding to that of the cavity, and no opening for its admission being discover- able, it is evident that no human strength could have driven such a body through solid ivory." From the highly vascular structure of the pulp, the tusks are slightly movable in the socket, and occasionally, as in the case of the hippopotamus, through irregular pressure on the alveolus, the tusks take a spiral or other distorted form. "We hear people speak of being driven nearly mad with toothache ; but instances are recorded in which the immensely large vascular pulp of the elephant has been the seat of violent inflammation, probably following mechanical injury, and un- governable madness has been the result. A painfully interesting account is given in Hone's Every-Day Book of the destruction of a remark- ably intelligent elephant at Exeter Change, in the year 1826. The animal was attacked by pa- IN THE LOWEli ANIMALS, ETC. 315 roxysms of madness, whicli at length compelled its owner to obtain the aid of a file of riflemen to put it to death. The skeleton of the unfortunate animal is set up in the Hunterian Museum, and the skull bears marks of the many ineffectual attempts to penetrate the brain, owing to the peculiar construction of the skull, to which I shall shortly refer. In an adjoining glass case is seen the hollow basal extremity of the left tusk, which shows by the irregular deposit of osteodentine in the pulp cavity, and the absorption of part of its walls, that the pulp had been the seat of violent and repeated attacks of inflammation ; a condition which must have aggravated, if it did not originate, the uncontrollable state of the animal. The succession of the molar teeth differs greatly from that of the other mammals. We observed that the temporary molars are usually replaced by permanent teeth in the vertical direction, called false molars, corresponding to the human bicus- pids. No such arrangement is found in the elephant; but in the whole of the molar teeth, including those earliest developed, the succession takes places from behind forwards, after the manner of the true molars in the other animals, or the permanent molars in the human subject. The development of these teeth has been so admirably explained by Professor Owen that I shall do well to quote his clear and comprehensive description : — *' The whole series of molar teeth 316 STEUCTUEE AND ADAPTATION OF TEETH succeed each other from behind forwards, moving not in a right line, but in the arc of a circle. The position of the growing tooth in the closed alveolus is almost at right angles with that of the molar in use ; the grinding surface being at first directed backwards in the upper jaw, and forwards in the lower jaw, and brought by the revolving course into a horizontal line in both jaws, so that they oppose each other when developed for use. The bony plate forming the sockets is more than usually distinct from the body of the maxillary, and participates in this revolving course, advan- cing forwards with the teeth. The partition between the tooth in use and its successor is perforated near the middle, and in its progress forward the part next the grinding surface is first absorbed, the rest disappearing with the absorp- tion of the roots of the preceding grinder. From this mode of advance, the upper molars are convex, and the lower concave, from behind for- wards." The first molar, cut a fortnight after birth, is shed at two years old. Previously to this time the second molar has been for some time in use, and is in turn shed at the end of the fifth year. The third molar attains its full growth between the third and sixth, and is shed at the ninth year. Professor Owen regards these three as the re- presentatives of the deciduous molars of the other animals. The fourth, fifth, and sixth molars re- IN THE LOWER ANIMALS, ETC. ' 317 spectively commence to penetrate the gum in the sixth, twentieth, and fiftieth year ; and the two former are shed in the twenty-fifth and sixtieth years ; while the sixth molar is supposed to remain during the continuation of the animal's existence. The perfection of a grinding apparatus is attained in the internal structure of these molar teeth, the three constituent elements, which we have already noticed in the other graminivorous mammals, being developed in a remarkably distinct manner. A molar tooth is composed of a series of transverse perpendicular plates, each of which consists of a central table of dentine, invested by a layer of enamel ; and these separate plates are at length soldered together by the filling-up of the spaces with the cement, which retains the several plates in due relative position, until by the further development of their bases, they unite to form a solid mass of dentine in the more deeply implanted portion of the tooth. Fig. 46. — Molar Teeth of Indian Elephant, showing seven of the transverse plates already in use, the posterior portion of the tooth not yet completely formed. "E. The oblong ring of enamel. H. The enclosed plate uf dentine. C. The cementum uniting the plates. 318 STRUCTURE AND ADAPTATION OF TEETH The appropriate name of cement, bestowed on this third element of the teeth by Baron Cuvier, is thus seen to be peculiarly applicable to the molars of the elephant. Each constituent plate, moreover, consists of a series of slender conical columns, arranged trans- versely across the tooth ; their bases gradually expanding until these columns or denticuli are blended together, and form a flat plate, with wrinkled sides, giving the undulating pattern to the line of enamel when the surface of the tooth is worn. These detached plates, prior to their Fig. 47. — A separate plate, invested with a coating of enamel, D. Dentine exposed in section, E. Enamel. consolidation by the cement, offer a rude resem- blance to a hand, and have been described, when found in a fossil state,. as the petrified hands of a monkey. • As the surface of the teeth is worn in mastica- tion, the processes of enamel, resisting attrition by their superior hardness, form prominent ridges IN THE LOWER ANIMALS, ETC. 319 on the grinding surface, while the dentine, and especially the cement are more rapidly worn away, a structure admirably adapted for bruising and comminuting the woody fibre, and other hard substances which constitute the elephant's food. The molar teeth progressively increase in size and the number of constituent plates ; the first molar consisting of four plates, and the sixth of about twenty-five. From the peculiar mode of dentition, the front portion of a tooth has cut the gum, and is em- ployed in mastication before the back part is com- pletely formed, even before some of the posterior denticles have been consolidated ; and the back part of the tooth does not come into use until the anterior portion has been worn down nearly to the fang. When at length the complex molar has become useless for grinding, the roots are ab- sorbed, and, aided by the pressure of the succeed- ing tooth, it is finally shed. It may therefore be said that the elephant cuts a series of sets of teeth, as the old ones are worn out ; an arrangement which might be considered very convenient by many members of the human family. In the Indian elephant, the grinding surfaces of the dental plates represent flattened ovals placed across the tooth ; but in the African spe- cies these columns form in section a series of lozenges, touching each other along the centre of the tooth. 320 STRUCTURE AND ADAPTATION OF TEETH That wonderful organ, the proboscis, demands a passing notice. From the shortness of the ani- mal's neck, and the enormous weight of the tusks, Fig. 48. — Molar of African Elephattt, showing diffeient form of dentinal plates. E. Enamd. D. Dentine. C. Cementum. the creature would find difficulty in cropping its food were it not for the possession of this specially- adapted organ, composed of multitudes of small muscles (estimated by Baron Cuvier at forty thousand), so variously interlaced as to bestow on it the most complicated powers of mobility, in all the varieties of extension and contraction. It enables the animal at will, to exert the enormous strength of a limb, or to execute the most delicate feats of finger-like touch. Endowed with exquisite sensibility combined with power, this organ, at the will of the animal, will uproot a lofty tree, or crop tender herbage ; will raise heavy cannon, or pick up a pin ; and its great length supplies the place of the long, flexible neck of the ruminants, which would have been incompatible with the support of the large head and weighty tusks. All IN THE LOWER ANIMALS, ETC. 321 the processes of the cervical vertebrae are strongly- developed, and the spinous processes of the dorsal vertebrae are lengthened and powerful. A glance at the head of an elephant will show the thickness and strength of the trunk at its attachment, and the massy, arched bones of the face and thick muscular neck are admirably adapted for support- ing and working this powerful and wonderful instrument. The great development of the diploe, which we noticed in the babyroussa, attains a surprising perfection in the elephant. The external surface of the cranium is enor- mously extended, but the actual cerebral case bears a very small proportion to the skull, the space between the outer and inner table being filled by the extensive mass of vertical cells of the diploe, which are filled with air from the Eusta- chian tubes. By this arrangement the external surface of the cranium is extended for the inser- tion of the powerful muscles and ligaments re- quired to support so heavy a mass of molar teeth, tusks and proboscis, without adding materially to the weight of the head. Many novel and highly interesting details of the habits of the elephant in his native forests are given in Sir J. Emerson Tennent's admirable work on Ceylon;* a book which, in the wide range * In mentioning Sir E. Tennent's book, I am reminded of an amusing suggestion I lately heard, illustrating the different mental characteris- tics exhibited by men of various nations. If an Englishman had the 322 STRUCTURE AND ADAPTATION OF TEETH of its subjects and the vivid character of its descriptions, might serve as a model for other travellers or residents in foreign lands. EiG. 49. — Transverse vertical section of skull of Asiatic Elephant, showing the great developmeut of the dijploe, as compared with the capacity of the brain-case. When we regard the comparatively limited number of existing British mammals, we can lesson given him to write a book about the elephant, he would go to Africa or Ceylon, and would probably join in an elephant-hunt; he would study the animal as closely as he could in his native haunts ; he would get some pretty good sketches of the animal, and would go home and write the book, which would probably be a very faithful description of the elephant. If a Frenchman had the task set him, he would think it a great deal too much trouble to go all the way to Africa. He would accordingly go to the Jardin des Plantes in Paris, and would learn from the keeper what he could about the animal ; that he could fire a gun, ring a bell, and perform other interesting feats. He would hear how much food he ate, and other matters ; and would then go home and IN THE LOWEK ANIMALS, ETC. 323 hardly conceive the idea that the gigantic northern elephant, extinct for untold ages, once forced his way through the tangled forests of our land, and was fitted, with his covering of long hair, and closely-felted wool, to sustain the rigours of a still more northern climate. The teeth of the Elephas primigenius are found scattered throughout nearly the whole of Europe, from the shores of the Mediterranean to those of the Icy Sea. As they are not confined to the continent, but are found in the British islands, and even in Iceland, distant as that island is from the European shores, we may form some faint idea of the immense cycle of geologic changes which must have taken place, since the period when the elephant was a member of the British Fauna. The tusks of the mammoth (as the animal is also called) are not unfrequently dredged up from the tertiary beds of a portion of the British Channel; and specimens have come under my notice, which have been brought into the port of Dover by fishermen who had so ob- tained them. The molar teeth are found in many bunt up all the Encyclopaedias on the article " Elephant." After adorning the description with a few comments of his own, in which his imagina- tion would play a very prominent part, it would pass as a very reliable book upon the elephant. The German would think even the French- man's way too demonstrative. He would not do so ; he would retire to his study, he would put his fingers into his eyes, and his ears too, and there, from the depths of his moral consciousness, he would develop an elephant. And if you say to him, *' Well, that is not like an elephant," he would say, "I cannot help that; that is what the elephant i/rust be. If there is any discrepancy, the fault is in your elephant." V 2 324 STRUCTURE AND ADAPTATION OF TEETH localities; as in tlie superficial beds overlying the chalk on the coast of Kent, and especially in the tertiary strata known as the " Norfolk Crag." The specimens on the table, from the latter forma- tion, supply another illustration of the immea- surably long periods which have elapsed since this comparatively recent geological epoch. One of the teeth, imbedded in a cliff of compact strata, is as sharp in its outlines as at the animaFs death ; while the other specimens have been rolled into boulders by the action of the sea on that more ancient cliff, and yet the gravel bed itself contain- ing these remains was raised, long before the human period, far above the present level of the ocean. The tusks of the extinct European ele- phant are very much more curved than those of the existing species, and sometimes are found with a curvature almost equalling that of the ram's horn. The tusks are so numerous in Siberia, and are in such excellent preservation, that they form an article of extensive commerce as ivory. Per- haps few discoveries of the remains of an extinct animal have equalled in interest the fossil elephant, which was found frozen up in an icy tomb on the coast of Siberia. In the year 1799, a Tungusian fisherman observed a strange, shapeless mass pro- jecting from an ice- cliff, near the mouth of the river Lena, in the north of Siberia, the nature of which he did not understand, and which was so high as to be beyond his reach. In consequence of the IN THE LOWER ANIMALS, ETC. 325 ice melting, he discovered in the following summer that it was the frozen carcass of an enormous animal, which at length became entirely disen- gaged, and fell down from the ice-crag upon a sand-bank. The fisherman carried away and sold the tusks, and more than thirty pounds' weight of the hair and bristles were collected. The head was still covered by the skin ; the pupil of the eye was distinguishable, and the brain remained within the skull ; while a long shaggy mane hung from the neck. But the most striking feature in the accoTmt is the fact, that the fishermen in the neighbourhood carried away large quantities of this elephant's flesh to feed their dogs, probably the only instance on record in which the remains of an animal, extinct long anterior to the creation of man, have been thiis preserved unchanged through so vast a period of time, as to be applied to the sustenance of other animals, contemporary with ourselves. The rodents next claim our consideration, — an order of animals remarkable for the great develop- ment of the pair of incisor teeth in each jaw, which are separated from the molars by a wide space, the canines being always absent. (Fig. 50.) These teeth are hardly adapted for cutting through flesh or other aliments, but rather for reducing them by continual labour into fine particles, — in fact, for gnawing; hence the term rodents, or gnawers. With these weapons they attack the 326 STRUCTURE AND ADAPTATION OF TEETH hardest vegetable substances, and frequently feed on wood or bark. The better to effect this object, Fig. 50. — Skull of Beaver. the incisors are furnished with extremely hard and dense enamel on their anterior surfaces only. Their reciprocal action maintains an oblique sur- face by the more rapid wearing away of the dentine, and the sharp edge of the enamel is thus perpetually maintained, anticipating the ingenious contrivance resorted to in the manufacture of a carpenter's chisel, in which a layer of hard steel is united to a plate of softer iron ; with this supe- rior endowment, that these living chisels keep each other sharp, and never require setting. Like the canines of the hippopotamus, the im- planted fang retains the form of the portion in use, and the hollow base is filled by a persistent formative pulp, the calcification of the dentinal pulp and the deposit from the accompanying enamel organ keeping pace with the abrasion of the extremity. The upper incisor describes a smaller circle than the lower, its basal extremity IN THE LOWEE ANIMALS, ETC. 327 being situated in the beaver immediately anterior to the first molar (Fig. 51, A), while the lower Fig. 51, A. — Section of Beaver's Skull. Upper jaw. E. Enamel indicated by dotted line. D. Dentine. P. Formative pulp at the implanted extremity of the incisor, situated in front of first molar. incisor describes the arc of a wider circle, the implanted extremity extending beyond the last molar ; below the condyloid process. (Fig. 51, B.) Fig. 51, B, — Section of Beaver's Skull. Lower jaw. E. Enamel indicated by dotted line. D. Dentine. P. Formative pulp at the implanted extremity of the incisor situated behind the last molar. So hard is the enamel of the beaver, and so good a cutting instrument is the incisor tooth, that when fixed in a wooden handle, it was, according to Sir John Richardson, used by the 328 STRUCTURE AND ADAPTATION OF TEETH northern Indians to cut bone, and to fashion their horn-tipped spears, &c., till it was siiperseded by the introduction of iron, when tlie beaver-tooth was supplanted by the English file. The power of these natural tools is well de- scribed by Lewis and Clarke, who saw their effects on the banks of the Missouri. " The ravages of the beaver," say they, "are very apparent; in one place the timber was entirely penetrated for a space of three acres in front on the river and one in depth, and great part of it removed, although the trees were in large quantities, and some of them as thick as a man's thigh." Sir John Richardson thus speaks of this part of their operations : '' When the beaver cuts down a tree, it gnaws it all round, cutting it, however, somewhat higher on one side than the other, by which the direction of its fall is determined. The stump is conical, and of such a height as a beaver sitting on its hind quarters could reach." In the specimen upon the table, we see a most interesting example of the effect of the beaver's teeth upon the stem of a tree. In teeth, the growth of which is limited, as in the human jaw, the internal formative pulp gra- dually diminishes in bulk after the crown is com- pleted, and forms by its progressive calcification one or more roots, which are only perforated by minute foramina, through which the blood-vessels and nerves pass to maintain vitality, and the IN THE LOWER ANIMALS, ETC. 329 alveoli are conformed to their conical shape. (Fig. 52.) But when the pulp of the tooth is perpe- tually renewed, to repair by its gradual calcifica- tion the wearing down to which the cutting or Tig. 52. — Human Jaws, showing completed development of roots. grinding surface of the tooth is exposed, the alveolus is of the same diameter throughout its whole length. This perpetual growth of the incisor teeth is sometimes productive of unfortunate results to the poor animal. If either of these teeth is lost by disease of the socket, or is displaced by accident, so that its edge is no longer opposed to that in the corre- sponding jaw, the latter tooth becomes prodigiously 330 STRUCTUEE AND ADAPTATION OF TEETH elongated. In some instances the tooth describes a complete circle, the cutting apex even entering the hollow cavity of the formative pulp ; and many an unfortunate hare, which has survived for a time the injuries received by a charge of shot, is doomed to intense suffering and a lingering death by starvation, resulting from the unnatural growth of the long incisor teeth. In the family Leporidae, including rabbits and hares, we have the only example of a second pair of incisors, and these in the upper jaw only. Instead of being situated laterally, as in other animals, these incisors, which are of small dimen- sions, are placed immediately behind the frontal pair, serving as a kind of anvil to receive the concussion of the lower teeth. An example is seen, in the capybara, of great perfection in the molar teeth of a rodent, and of the apparatus provided for their efficient employ- ment. In the ruminants we observed that the crescentic folds of the enamel were arranged longitudinally, or in the same axis as that of the jaws, in accord- ance with the motion from side to side in mas- tication. There is a great difference in the complexity of structure, and in the reproductive power bestowed on the teeth of the various genera of rodents. In the rats, which are omnivorous, the molar IN THE LOWER ANIMALS, ETC. 331 teeth, owing to the great admixture of animal food, suffer but a moderate amount of abrasion, and they are supplied with roots, as in the human subject. In those rodents which employ their teeth ex- clusively for the comminution of woody fibre and other coarse vegetable matters, as the beaver, the reproductive power of the formative organs is exerted through the greater part of the animal's life, but at length the enamel organ becomes obhterated; and as age advances, roots are developed, supplying an imperfect substitute for the crown, as we observed in the grinders of the horse. But the capybara (Figs. 53 and 54) supplies an Fig. ^'i.— Skull of Capybara, showing the great solidity of the sockets of Teeth. EiG. 54. — Skull of Capybara, showing ante-orbital fossa. example of molar teeth which, like the incisors, have a hollow base and a uniform shape from the 332 STRUCTURE AND ADAPTATION OF TEETH grinding surface to the implanted extremity ; and as these describe a curve in their sockets, the highly vascular pulp is protected, as in the incisors, from the injurious effects of direct pressure. The molars of the capybara consist, like those of the elephant, of an aggregation of dentinal plates, with interposed folds of enamel, and com- pacted together by cementum. They are arranged transversely across the axis of the jaw, and pre- sent another remarkable analogy with those of the elephant, that the number of transverse laminaB increases in each successive tooth as the animal advances in age. (Figs. 55 and 56.) EiGS. 55 & 5G. — Upper and under jaws of Capybara, showing longitu- dinal direction of hinge. In order that these transverse plates may be brought into effective action, the condyloid process IN THE LOWEU ANIMALS, ETC. 333 of the lower jaw is much flattened laterally (Fig. 55, c), and the glenoid cavity is prolonged in the antero-posterior direction, or in the same axis with the jaws; thus limiting the action in mastica- tion to a to-and-fro motion. (Fig. 56, g.) The effect of this longitudinal direction of the glenoid cavity is greatly increased by the position of the condyloid and coronoid processes, which rise very little above the level of the grinding surface of the molars. The jaws, therefore, do not possess the free lateral motion of the sheep, and they present a striking contrast to those of the tiger. (See Figs. 32 and 33.) If the articulation in the latter animal may be compared to a powerful hinge, admitting of vertical motion only, the jaws of the capybara more nearly resemble the sliding action of a bolt in its frame. A beautiful provision for the stability of the transverse plates is seen in the grooved sides of the alveoli ; the projecting transverse plates fitting into these groves, they receive efficient support against the strain to which the antero- posterior motion would otherwise expose them. We may also observe in the form of the skull a special adaptation to set this curious dental apparatus in action. The temporal fossa, as in the Carnivora, is con- tinuous with the orbit, and an elongated process arises from the maxillary bone, connecting it with 334 STRUCTURE AND ADAPTATION OF TEETH the anterior portion of the zygoma, and forming an extensive ante-orbital fossa — an arrangement which is not found in the beaver. The zygomatic arch is thus extended unusually far forward ; and instead of the upward curve, as observed in the Carnivora, the convexity of the arch is directed downwards. Very distant points of attachment are thereby afforded to the variously-directed jfibres of the unusually broad masseter muscle, and the reciprocating antero-posterior or sliding motion of the jaw is provided for. Another peculiarity in the skull of the beaver and hare deserves passing notice. Great timidity and quickness of hearing are remarkable characteristics of these animals ; and to admit of the free posterior movement of the condyloid process of the lower jaw, the long, bony '* meatus auditorius " ascends obliquely backwards, like a projecting trumpet, thus enabling the animal to catch the slightest sound, and receive warning of the approach of its numerous enemiSs. That the beaver was an inhabitant of the British Islands within the historic period there is no doubt. Giraldus Cambrensis gives a short account of their manners in Wales ; but even in his time (he travelled there in 1188) they were only found on the river Teify. " Two or three waters in that principality," says Pennant, " still bear the name in the Welsh lano^uao^e, of the IN THE EOWER ANIMALS, ETC. 335 Beaver Lake. I have seen two of their supposed haunts ; one in the stream that runs through Nant Francon, the other in the river Conwy, a few miles above Llanrwst, and both places in all pro- bability had formerly been crossed by beaver- dams. But they must have been very scarce, even in earlier times, as, by the laws of Howelda, the price of a beaver's skin was fixed at 120 pence, a great sum in those days. Having thus directed your attention to some of the more characteristic forms of dentition in the lower animals, I purpose, on a future occasion, to notice the relations which the several types of teeth bear to the human dentition. The question is not unfrequently asked, ''Does the study of these and kindred subjects tend to any practically beneficial result ?" It may be replied that, apart from the rich store of intellectual gratification to be derived from the study of the infinite variety of special adaptation of structure to function, throughout the world of animal life, it serves an important end in training the observant faculties, which cannot fail to be serviceable in a profession such as our own. That the highest attainments in natural history are not incompatible with professional eminence, I need only cite the example of a gentleman, who, throughout his long and honourable professional career, could yet secure time for the profound cultivation of this science. In addition to his 336 STRUCTITEE AND ADArTATION OF TEETH, ETC. other numerous and varied scientific labours, the " British Mammalia and Reptiles,'* of Professor Bell, have confirmed his position in the foremost rank of naturalists, and will serve as the text- books of future generations. In the cursory view I have taken of this wide field, I feel how inade- quately I have fulfilled the task, especially when I coQsider how efficiently these subjects are treated by distinguished men of science in this country. If I have, been able to offer suggestive hints which may lead some of my younger brethren to pursue these studies, I shall feel that our time this evening has not been altogether vainly spent. GENERAL MONTHLY MEETING. Mondaify June 4, 1860. W. A. HARRISON, Esq., Peesident, in the Chair. The following Gentlemen were duly elected Members of the Society : — Mr. W. S. CocKiNGS London. Mr. John W. Elliott, M.R.C.S. Eng. London. Mr. W. H. May Loudon. Mr. Charles A. Rodway Torquay. Mr. C. F. TuBBS Plymouth. Mr. James J. Keene Boulogne-sur-Mer (corre- sponding). The following Gentlemen were proposed for the Membership of the Society : — Mr. Joseph Walker, M.R.C.S. Eng. ... 13, Holies Street, Caven- dish Square. Mr.S.J.A.SALTER,M.B.,M.R.C.S.Eug.l7, New Broad Street, City. Mr. Adolphus Haet, M.R.C.S. Eng.... Brook Street, Bond Street. Mr. Charles Bygrave Paris. Mr. Joseph Calorie Jamaica. Mr. John Short ^ Madras. Mr, Martin Magor Penzance. Mr. Parsons, of Halifax, presented an instrument called a Pelican, to the Museum, and " Berdmore's Treatise " to the Library. Mr. E. Saunders, a book for the Photographs of the members of the Society. Mr. Pletcher presented an old portable key-instrument. Mr. W. D. Saunder presented a model illustrative of irregularity in the Lower Jaw. Mr. Patrick exhibited a Gas-regulator. Z 338 STRUCTURE AND ADAPTATION OP TEETH Mr. Mummery read the concluding portion of his paper^ On the Structure and Adaptation of the Teeth in the Lower Animals, and their Relations to the Human Dentition. In this, tlie concluding portion of my paper, we will consider the dentition of the Quadrumana, which, of all the lower animals, approach most nearly to the human species in organization. We observe in the several genera a graduated series from the insectivorous modification of the teeth in the lemurs up to the dentition of the orang and chimpanzee, in. which animals the teeth exhibit the same number and general forms as in man. In the lemurine section the number of lower incisors varies from two to six, and they generally slope forward in a nearly horizontal direction; but the upper incisors are four in number. The canines attain different degrees of develop- ment in the various species. There are usually three premolars in each series, which, with the three molars, are furnished with sharp cusps, locking into those of their antagonists, as in the true Insectivora, and the temporal fossa is con- tinuous with the orbit. In the second section, comprehending the broad- nosed American monkeys, we may instance the spider-monkeys, whose long prehensile tail serves as a fifth organ of locomotion. In these animals the dentition approaches nearer to the higher IN THE LOWER ANIMALS, ETC. 339 types, witli the exception of the premolars, which, as in the lower section, are still three in number. But we must dwell more particularly on the third or highest section, comprehending, with other genera, the mandrils and baboons, the orangs, the chimpanzee, and the great gorilla. In all the genera of this great division, the tail-less apes, the teeth exactly correspond in number with those of man. If we compare the skulls of the higher Quad- rumana wdth those of animals lower in the scale of intelligence, we shall observe, many remarkable distinctive characters. The bones of the face are shorter, and constitute a smaller portion of the entire skull, while the cranium is proportion- ally larger. The frontal bone becomes expanded, and the orbits, surrounded by a bony ring, are no longer directed towards the sides of the head, but are much more approximate, and are directed for- wards. The temporal fossa is smaller, and the zygoma shorter and almost straight. The inter- maxillary bones, which in most animals remain distinct through life, are united to the maxillae in a larger proportion and at an earlier period as we approach the highest forms. The jaws become shorter, the vertical ramus of the lower maxilla is more developed, and the coronoid process is smaller than in the Carnivora ; the condyle being nearly flat, admitting of free lateral motion. z 2 340 STEUCTUBE AND ADAPTATION OF TEETH As a result of these modifications, the facial angle is greatly increased; and as the occipital foramen is less obliquely situated, and advances more toward the centre of the skull, the animal is enabled occasionally to assume a nearly erect position. The various species of orang-outang (Pithecus) are all natives of the Indian Archipelago, and are distinguished by their reddish-brown hair. In these enormous apes, the teeth are all very large and powerful ; the central incisors are remarkably solid, and a transverse section of the crown shows them to be square in form, the thickness being nearly equal to the breadth ; the lateral incisors are scarcely half the size of the centrals. The diastema we noticed in the Carnivora is still observable ; a space between the upper lateral and canine permitting the lower canine to close up in front of the upper ; a similar interval exist- ing between the lower canine and first bicuspis, allows the upper canine to overlap the lower alveolar margin. The canines in the female are not more than half the size of those teeth in the male, and rise very little above the plane of the molar teeth. The premolars or bicuspides are furnished in the upper jaw with three roots, and in the lower with two roots, corresponding in arrangement with those of the true molars. Another very striking feature is observable on IN THE LOWER ANIMALS, ETC. 341 comparison with the human maxilla. The molar teeth, instead of being arranged in a gradual curve, are placed in straight and nearly parallel lines ; the incisors forming a line at right angles with the molars in each jaw. In the specimen on the table we have a fine example of the skull of an adult orang, probably aged from forty to fifty years. The tubercles of the molars are greatly worn down, the canines are much abraded, and the incisors have been sub- jected to so severe attrition, that they are truncated to more than half the length of their crowns. Of the genus Troglodytes there are two species, the chimpanzee and gorilla, both natives of Africa, and invariably covered with black hair. The upper central incisors in the chimpanzee are not so disproportionately large compared with the laterals, and the space between the lateral in- cisor and canine is narrower than in the orang. There is also a greater difference in size between the premolars and true molars, and the third molar is smaller than the others, exhibiting a nearer approach to the human dentition. The great gorilla is the most formidable of all the apes. Solitary in its habits, it is so ferocious an antagonist that it has furnished a subject for many a traveller's tale of wonder, from the time of Hanno, the Carthaginian navigator (who records his adventures with wild, fierce men, covered with 342 STRUCTURE AND ADAPTATION OF TEETH hair), down to our own times, altliougli accurately scientific accounts of tlie animal have not until very recently been obtained. The canines of the gorilla are larger and more projecting than in the chimpanzee, and the upper molar series are even inclined somewhat outward, in a direction oppo- site to that of the arch of the human jaw. In the adult orang and chimpanzee the massive jaws are acted upon by muscles which attain a very powerful development, indicated by the wide zygoma and the deeply depressed surface of the skull for the insertion of the large temporal muscle. The sagittal and lambdoidal crests are very high; but these characteristics are still more marked in the gorilla, and the immense projecting supra- orbital ridge bestows a singularly distinctive feature upon the animal's expression. The pro- minence of the crests, and the great development of the muscles, tend greatly to increase the appa- rent size of the skull; but the organs of the senses still bear a very large proportion to the brain cavity, and the faculties of sight, hearing, and smell are remarkably keen. The immature skulls of the chimpanzee and orang, which I here present to your notice, supply a highly interesting opportunity for comparison with the adult skulls. It will be observed that the capacity of the cranium in the young orang, at the age when the first permanent molar is acquired, very nearly equals that of the cranium IN THE LOWER ANIMALS, ETC. 343 in the full-grown animal, the external differences in the size of the skulls being almost entirely due Fig. 57. — Skull of young Orang-outan ; the capacity of brain-case being nearly equal to that of the adult. to the increased thickness of the brain-case, and the very great development of the bony ridges, arising from the long- continued stimulus of the muscles employed in mastication. Tig. 58. — Skull of adult Orang-ouian, showing great development of the bony crests for attachment of the muscles. The contrast is even more striking in the chim- panzees. The brain in these animals attains nearly its full development at an early period of life, and the growth of the bones, muscles, and the general organic structure proceeds rapidly to completion 344 STRUCTURE AND ADAPTATION OF TEETH without a corresponding increase in the vohime of the brain. The striking contrast presented by the larger apes, in their docihty during the earher period of life, and their moroseness and intractability in adult age, is thus easily accounted for; for in proportion as their bodily powers increase, their intelligence degenerates ; and as they attain to years of maturity, the animal powers and propen- sities acquire increased ascendancy over the higher faculties, until at length they are as remarkable for ferocity as formerly for gentleness. In the specimen to which I have referred (the young orang), the whole of the deciduous teeth are present, and the first permanent molar has made its appearance ; the dentition exhibiting an exact correspondence with that of a child in its seventh year, excepting in the exaggerated size, angular forms, and relative position of the several classes of teeth. These animals employ their powerful incisor teeth in tearing open the tough fibrous husk of the cocoa-nut, and in cutting asunder roots and stems; the remarkably "prominent cusps of the molars indicating their fitness for the comminution of such aliment. The presence of large canines does not neces- sarily involve carnivorous habits, unless the molars are ' of the laniary or flesh- cutting type. In the Muntjak deer, for example, a ruminant animal, IN THE LOWER ANIMALS, ETC. 345 the canines attain a large size ; and many exclu- sively graminivorous animals are noted for their ferocity. The alimentary canal in man being six times the length of the body, and in the apes nine or ten times that length, it follows that the food of these animals is more exclusively vege- table; and we may therefore conclude that the canine teeth are bestowed for purposes of de- fence, rather than as indicative of carnivorous instincts. Notwithstanding the many points of resemblance to the human type, in dentition and general struc- ture, there still exists a wide and impassable barrier, and the great gorilla is but a powerful four-handed beast. The thumb is longer and more opposible to the fingers than in other genera ; but it only constitutes a part of a brute paw — a most inefficient organ when compared with that exquisitely constructed instrument, the human hand. Neither are the hinder extremities true feet, but are prehensile, marking the animal's arboreal habits ; the oblique articulation compel- ling it to walk on the sides, instead of the palms of the hands. The pelvis and spinal column are unfitted for the erect position, and the occipital foramen is still placed so far back, that the weight of the skull and ponderous jaws is throAvn for- wards ; and the larger apes can only maintain an upright position for a limited time, by carrying the long arms behind the neck, but soon instinc- 346 STRUCTUEE AND ADAPTATION OF TEETH tively dropping to the more natural position on all fours. Professor Owen has appropriately remarked, in his masterly treatise on this subject, that " no quadrumanous animal, and few other mammals, offer a greater contrast with man in the form and structure of the cranium than does the great male gorilla." We have now taken a discursive review of some of the more prominent types of dentition among the inferior animals, and it remains for us to consider their bearings upon the human dentition. On a subject so familiar to you as the struc- ture of the human teeth, I need only refer to those striking characteristics in form and posi- tion which distinguish them from those of the brute creation. EiG. h^.— Skull of Monkey. The crowns of all the teeth are nearly of equal length, and there is less general dissimilarity of size than in the apes. The incisors are less massive, and more delicate in outline, the late- IN THE LOWER ANIMALS, ETC. 347 rals being larger in proportion to the central pair. The characters of the canine tooth are well marked in its conical shape and the deeper im- plantation of the root, but it rises in a small degree only above the general plane of the teeth. There is a greater difference in form and size between the premolars (bicuspides) and the true molars ; the former are more rounded : and although we may occasionally meet with cases in which the upper bicuspides are furnished with three, and the lower with two fangs, this point of resemblance to the lower type is comparatively rare. The tubercles of the molar teeth are less prominent, and the third molar is not so fully developed. We have observed that even in the highest Quadrumana the space in front of the upper and behind the lower canine is as well marked as in the Carnivora. In man alone the teeth are arranged in an uninterrupted series ; and in the well-formed jaw they exhibit a beautifully regular parabolic curve, in place of the angular dispo- sition of the teeth in the chimpanzee ; and the difference between the sexes is no longer indi- cated by the greater size of the canines in the male. (Fig. 60.) In harmony with the more delicate contour of the human teeth, the jaws and their processes are far less massive than in the higher Quadrumana. 348 STEUCTUEE AND ADAPTATION OF TEETH The masseter and temporal muscles are of moderate size, the parietal bone exhibits no de- rm. %{).— Human Skull. pression for the attachment of the temporal muscle, and the bony intermuscular crests en- tirely disappear. The temporal fossa, the zygoma, and the coronoid process of the lower jaw are smaller : the vertical ramus of the lower jaw is larger, and forms a more acute angle with the base. The condyle is more elevated and convex, and the glenoid cavity is deeper than in the Qua- drumana. The intermaxillary bones have a sepa- rate existence in the foetal condition only. We have observed that even in those animals which approach most nearly to the human form, the bones of the face are larger than the cranium. In striking contrast to these, the conditions are reversed in man ; the skull is larger, its external surface smooth, and its cavity very capacious. The organs of the senses occupy a much dimi- IN THE LOWER ANIMALS, ETC. 349 nished space, and the face is consequently smaller in comparison with the skull. As the volume of the brain increases, the occi- pital portion of the skull is greatly enlarged, and the great foramen advances to the centre of the skull, occupying a nearly horizontal plane. Even in the highest Quadrumana it is placed at nearly twice the distance from the front of the jaws as from the back of the head, and is so inclined in direction, that a line drawn in its plane passes beneath the lower jaw, whereas in man the cor- responding line would pass immediately under the orbit. In all the lower animals, the muzzle, with its projecting front teeth, constitutes the most pro- minent part of the face ; but in man the mouth recedes, and the forehead and chin project. The facial angle is thus greatly increased, the plane of the face being nearly vertical, an arrangement in harmony with all the other parts of the human frame, which is so evidently designed for the erect position, peculiarly distinguishing man from the meaner creatures. We are thus forcibly reminded of the words of our great poet : — " God-like, erect, in native majesty seems lord of all.'* Consistently with these features, the incisor teeth approach nearly to the perpendicular posi- tion, and forming a continuous arch, observable 350 STRUCTURE AND ADAPTATION OF TEETH in no other animal, are perfectly adapted to the exclusively human function of articulate speech. One of the most striking features in the human countenance is the exclusive possession of a chin, not a rudiment of which is found in any of the lower animals. The stuffed specimen of the gorilla, in the British museum, apparently pos- sesses a chin ; but on examining the adjoining skeleton, we find there is no projecting process of the lower jaw whatever : whereas, even in the most degraded varieties of the human family, the chin is distinctly formed; although, from its receding position, its effect on the physiognomy is much diminished. (Fig. 61.) Fig. 61. — Human Idiot. This remarkable fact did not escape the notice of Pliny, who has recorded it in lib. xi. cap. 36, Hist. Nat. As the Romans were thus evidently familiar with the truth that the chin is possessed solely IN THE LOWER ANIMALS, ETC. 351 by the being endowed with mind, it had occurred to me that possibly the word mentum might be traceable to the same root as mens; but I regret that hitherto my own researches, and those of literary men whom I have consulted, have failed to establish positively the common origin of the words in question. It is, however, a curious coincidence, that the nouns mens and mentum should each form mentalis as their adjective. The chin forms a more important element of intellectual expression than is generally imagined; and we are sometimes instinctively conscious of a defect in a countenance in all other respects well formed, but in which the mental process is imper- fectly developed. Time only permits a passing glance at the skull and face in the degraded varieties of the human race. If we compare the Australian skull with the Caucasian, we notice that in the former the forehead is receding, the skull narrow, and the zygoma large and prominent; the alveolar i)ro- cesses are remarkably strong, the incisors pro- jecting, and all the teeth larger than in the higher races. The facial angle is consequently dimi- nished; but the chin, however defective, is still well marked, and the leading characteristics dis- tinguishing man from the Quadrumana are plainly recognizable in the most degraded tribes. The increased development of the zygoma and other bones of the face may be attributed to the harder 352 STRUCTURE AND ADAPTATION OF TEETH nature of their food, the comminution of which tends to develop larger muscles, and these again necessitate more powerful points of insertion and attachment. Many important lessons may be deduced from a comparison of the teeth of man with those of the brute creation. Our incisors are not like those of the rodents, in which progressive calcifi- cation at the base keeps pace with the abrasion of the apex ; and if the teeth are foolishly em- ployed as pincers or chisels, their fracture or luxation is often the result. The canines are not formed for combat, and their diminished size would seem to identify their possessor as a moral agent, amenable to higher principles than the brute instinct of ferocious strife. The molars are endowed with feebler powers than those of the ox or elephant, but are well fitted for the mode- rate work which suitably-prepared food provides for them. Wg have seen that the typical form receives a special adaptation to meet the particular require- ments of every animal ; and if Creative Wisdom has thus endowed the meaner creatures, we may rest assured that the teeth bestowed on us are as exactly suited to the capabilities of our digestive organs. The eminent Dr. William Hunter, when refer- ring in his lectures to the various theories of digestion, was accustomed to caution his pupils IN THE LOWER ANIMALS, ETC. 353 that the stomach was neither a stewpan, a fer- menting-vat, nor a mill, but only a stomach ; an appropriate warning to every one who regards the preservation and effective employment of the molar teeth as a matter of trivial importance. The crab possesses a powerful apparatus of calcareous gastric teeth ; the gallinaceous bird a muscular gizzard; the ruminant quadruped has the faculty of regurgitation and mastication at leisure. No such provision is made in our case, and we may rest assured that the penalty of impaired health must inevitably follow our neglect of so important a function as that of the thorough mastication of our food. A curious and interesting subject of inquiry presents itself in the indefinable variety of expres- sion arising from the undue prominence, or from the absence, of certain teeth, although we may not give our assent to Lavater's ingenious but fanciful theory of physiognomy, which he carried out to a really absurd extent. We may not admit that mental qualities are indicated by the form and position of the teeth, but no one can doubt that the expression of the face is powerfully influenced by their condition and arrangement. For example, if the upper canines are large and prominent, or approximate, through absence of the lateral incisors, too nearly to the centre of the mouth, a somewhat harsh and even fierce expression is the result ; and, on 2 a 354 STRUCTURE AND ADAPTATION OF TRETII the other hand, if the canines are actually want- ing, an opposite lack of force of character, or a vacant aspect, is given to the face. We have seen in the carnivorous, gnawing, and graminivorous animals, that the canines, incisors, and molars respectively attain their highest de- velopment. In man each of these classes of teeth is represented in a modified degree, unitedly forming a symmetrical arrangement. A denti- tion exhibiting a medium between the extremes, would appear to be adapted to an omnivorous diet, and a comparison with the more robust development of the teeth in the Quadrumana shows the human teeth to be unfitted for the division and comminution of the hard and tough uncooked food on which those animals principally subsist. But the divine gift of reason more than com- pensates for the comparative feebleness of man's physical endowments ; and he alone possesses the intelligence to employ fire in the preparation of his food. The most degraded savage can procure fire at his will ; the most cunning beast has not the sense even to maintain the hunter's deserted fire, although deriving enjoyment fi:'om its genial warmth. Man, therefore, is the only cooking animal, and consequently the only true cosmopo- lite. His mastery over the powers of nature enables him to traverse the globe from the tropics to the poles, and his digestive organs are adapted, equally with his teeth, for the utmost IN THE LOWER ANIMALS, ETC. 355 variety in diet. In the warmer latitudes, he can maintain a healthy existence on rice, fruits, or roots ; but in the Arctic regions he can live exclu- sively on animal food, and that of the most oleaginous kind ; thus supporting vital combus- tion in the respiratory process, and maintaining the temperature of the body amidst the most in- tense cold. I was informed by Dr. Walker, the able natural- ist and surgeon of Lady Franklin's expedition, that as he approached the colder latitudes on the outward voyage, he felt obliged to live almost entirely on animal food ; as the temperature dimi- nished, he was compelled to select the fat portions exclusively ; until, when within the Arctic circle, he could subsist on blubber, finding it necessary for the supply of an adequate amount of animal heat. Having examined a large number of skulls of various animals while engaged in preparing this paper, I embraced the opportunity of ascertaining to what extent disease occurred in their teeth. I found several examples of injury arising from mechanical causes, as in the case of teeth splin- tered by shot, or the canines of the Carnivora fractured by the animal's violent use of them, and in other instances severe alveolar abscess conse- quent upon the dislocation of otherwise sound teeth. So far, however, as my own observation extended, I could not find a single instance of 2 A 2 356 STRUCTURE AND ABAPTATTON OF TEETH dental caries. It has been so often affirmed that the monkeys in the Zoological Society's Grardens were subject to diseased teeth, that I fully ex- pected to find that those poor animals were vic- tims of this human malady, as they undeniably are of that scourge of our race, consumption, which too often terminates their existence within a limited period. To my surprise, however, after careful scrutiny of many skulls of monkeys which had died in the Society's menagerie, I failed to detect a solitary example of a carious tooth, either in the crowns of the molars or in the approximal surfaces of the teeth, although I found several instances in which they had been split or dislo- cated, by the violence the animals had used in seizing the iron bars of the cage. My statement is supported by Mr. Bartlett, superintendent of the gardens, who assures me he has never known an instance of a truly carious tooth in any of the animals, although a few rare instances of caries have been recorded by other observers. May we not, however, reasonably suppose, that were a race of captive monkeys established, the indications of dental disease would be found at the second or third descent, in animals whose health necessarily suffers from the highly artificial conditions of their existence ? The wild horse and the rough mountain pony, the shepherd's dog and the wild boar, are exempt from disease in the teeth, while the artificially- IN THE LOWEU ANIMALS, ETC. 357 reared racehorse, the pampered lapdog, and the domesticated hog are all subjected to caries. We know, on reliable authority, that disease of the teeth frequently occurred among the ancient Egyptians, the Greeks, and the Romans ; and we are but too well convinced of its accelerated pro- gress in the highly artificial state of civilized nations in the present day. On the other hand, if we examine the teeth found in the ancient tumuli scattered over our hills, which form almost the sole remaining link between the present generation and the aboriginal races of this island, we find the teeth sound, although, as in the examples before you (taken from a barrow on the Kentish Downs), the whole of the tubercles are worn down, and in some of the teeth the entire covering of enamel has been abraded from the grinding surface of the molars ; and we may find abundant parallels amongst the savage races of our own day ; as, for example, in the Papuan and Caffre skulls on the table. It therefore appears reasonable to conclude that dental caries is the result of the artificial condi- tions of life, by deteriorating the race in succes- sive generations, rather than in a prejudicial in- fluence on the teeth of the individual. A point of so much practical importance de- mands more particular investigation ; and I hope, ere long, to present to your notice some detailed results of my inquiries relative to the existence 358 STKUCTURE AND ADAPTATION OF TEETH of caries in the various races of men and ani- mals. Altliougli my paper has far exceeded the limits I had originally proposed, we have only been able to examine in a very cursory manner a few of the points of interest comprised in so extensive a subject. It has been my aim to condense within mode- rate limits a general view of the typical forms and special adaptations of the teeth to the struc- ture and requirements of each animal ; and I have refrained from more extended observation upon many sections of our subject, each of which would demand our undivided attention did time permit. Conscious that the task has been most imper- fectly executed, I yet hope that some hints may have been given which may stimulate others to cultivate these deeply interesting studies, so emi- nently suggestive of profitable trains of thought to every reflecting mind. On reviewing the entire subject of this paper, we arrive at the conclusion that man's supe- riority, as compared with the irrational mam- malia, is one of kind rather than of degree ; consisting not in the mere strength of bone and sinew, or in those instincts in which he resembles the brute, but in a rational and moral nature. For him, throughout the long series of geologic changes, the earth was gradually being prepared, until the time when he should come to take his :]59 place at the head of creation. To quote the eloquent language of Professor Sedgewick, in his discourse on the studies of Cambridge, " Man stands by himself, the despotic lord of the living- world ; not so great in organic strength as many of the despots that went before him in nature's chronicle, but raised far above them all by a higher development of the brain, by a framework that fits him for the operation of mechanical skill ; by superadded reason ; by a social instinct of combination ; by a prescience that tells him to act prospectively; by a conscience that makes him amenable to law ; by conceptions that tran- scend the narrow limits of his vision ; by hopes that have no full fruition here; by an inborn capacity of rising from individual facts to the apprehension of general laws ; by a conception of a cause for all the phenomena of sense ; and by a consequent belief in a God of nature." Note. — Since my paper was read, I have been favoured by my friend, Professor Quekett, with the result of his investigations. He has ex- amined a very large number of aucient British skulls without detecting a trace of dental caries; but in several skulls which are known to have been those of Romanized Britons, he has shown me examples of true dental caries, occurring on the grinding surface of the molars, and also on the approximal surfaces of the molares and bicuspides. GENERAL MONTHLY MEETING. Monday, November 5, 1860. W. A. HARRISON, Esq., President, in the Chair. The following Gentlemen were proposed for the Membership of the Society : — Mr. D. CoRBETT, M.R.C.S., L.D.S. Eng. ...Dublin. Mr. Alfred Hill, L.D.S., R.C.S. Eng Euston Square. Mr. J. K. Devonshire, L.D.S., R.C.S. Eng., Great Coram Street. Dr. M*QuiLLEN, of Philadelphia, U.S., presented to the Museum a east of the head of a Troglodytes Gorilla; also, two magnified casts of bicuspid Teeth, showing Dr. M'Quillen's mode of stopping approximal cavities ; preserving a greater extent of masticating surface than when done on the ordinary method. Mr. Thomas Bell, F.R.S., P.L.S., &c., presented to the Museum some models illustrative of the eruption of Teeth at a very advanced period of life. Mr. Palmer presented to the Museum a model, in which an upper canine Tooth occupied a space in the alveolar arch, between the first and second molars. Mr. Vaxderpant presented to the Museum a preparation showing six incisors in the upper jaw. Messrs. Ash exhibited some improved mineral Teeth for the vulcanite base. Mr. Hallam exhibited some flexible rose drills. Mr. Hennett exhibited an improved Flask for vulcanizing, and made the following communication : — Permit me to call the attention of the mem- bers to a means of producing vulcanite plates by a simple method, so as to insure uniformity 362 IMPROVED FLASK FOR VULCANIZINCI. of thickness, reproducing at the same time on the lingual surface the exact form of the palate. The small piece which I will pass round, was my first trial ; and will show, perhaps, in its un- finished state, better than any explanation I can give, the effect produced by this process. The second specimen, which is a fractured one, shows the object clear enough in its finished state. This method is especially advantageous for suc- tion-pieces, and cases of fissure or imperfection in the palate, when a thin substance is most desirable. The flask used for the purpose is one introduced by Messrs. Bell & Turner. It is slightly modi- fied for my purpose by the substitution of round guide-pins for the flat lips in the upper part of the body of the flask. The method of preparing the model piece is somewhat the same as usual; that is, the way the teeth are mounted in wax, gutta percha, or the like : but instead of placing wax on the palate, this part is left exposed. In just those parts required thicker than the palate, I place a suitable quantity of wax. Instead of pouring plaster on the waxed palate, as usual, to form the plug, it is poured directly on to the plaster cast, which has been prepared with oil, or some non- adhesive material (that supplied by the Messrs. Ash I find the best). After the plaster has set sufficient time, the parts are separated and the IMPKOVED FLASK FOE VULCANIZING. 863 wax removed, as in ordinary cases. Should the plaster plug be pressed down in its present state, it would come directly on to the palate of the cast ; but this is prevented by means of a plate of brass or other metal of this form, and used in this manner (method shown). The piece is packed in the usual way ; rubber is placed on the palate, the pieces of the flask put together, one of the metal plates of the required thickness being placed between the upper and lower parts of the body of the flask ; the ring is then put on, and the whole screwed together. When in this condition, the two parts of the body of the flask are closed as nearly as the gauge-plate will permit, and that gauge-plate gives the thickness that the palate will be. These plates may be of various thicknesses, but that which I have found most useful is No. 16 of the Birmingham wire-gauge. /'\ om>o* A. A metal plate put between this division of the fiusk before screu-ing it vp in the ring, to prevent the mould coming close together ; so that a corresponding space is left hetiveen the palate and the plug, which, whenjilled up with vulcanite, forms am outer surface corresponding to the inequalities of the palate. 304 OPERATION OF RlSODONTRYrf. Mr. T. A. Rogers read the following paper from J. Bellisario, D.U.S.:— 147, Philip Street, Sydney, N.S.W., July 20, 1860. Mr. President and Gentlemen, — I wish to direct the attention of the society to the value of the late Dr. HuUihen's operation of risodontrypy in the treatment of the dental pulp in certain stages. It is particularly applicable to those cases in which the pulp has been under treatment, capped, and permanently filled; and I have selected from my note-book one of many inter- esting cases to illustrate the practice. I was consulted by a gentleman on the 8th of January, 1859, about an anterior lower molar; it was diseased on the posterior approximating sur- face, the pulp exposed at a point, and he had experienced two or three slight attacks of tooth- ache. I removed perfectly the carious parts of the sides of the cavity, leaving that in contiguity to the pulp undisturbed ; filled the cavity with cotton wool, for the purpose of seeing in what condition the pulp was, and directed the patient to see me the following day. On removing the cotton, it was much dis- coloured on that part which came in contact with the pulp cavity, and slightly offensive. I used astringents and stimulants for five weeks, three times a day, before getting the discharge under; OPERATION OF RISODONTRYPY. 865 at the expiration of that period I again filled the tooth with wool, but this time densely, and left it for forty-eight hours : on removal, it was perfectly colourless and free from all odour. I now proceeded to fill the tooth. I first intro- duced a strip of gutta-percha, the size of the bottom of the cavity, as a non-conductor, then fitted very perfectly a gold cap. I commenced the filling with a tolerably close pellet of un- adhesive gold, somewhat larger than the cavity, and which required some slight force to insert it ; so that the whole cavity was filled, but not very solidly. I now forced a small plugging instru- ment on one side of it, enlarged the opening thus made without disturbing the body of the gold, and filled densely with adhesive foil. I repeated this process to the other three sides, then con- densed the gold in the centre, and finished the filling at this point. I had very great difficulty in making this filling ; the flow of saliva was excessive, and frequently threatened to submerge the gold : however, by one way and another, I accomplished it. There was hardly any incon- venience produced during the operation, and the patient left perfectly satisfied. I directed him, if he had the slightest uneasiness, not to let it run into absolute pain, but to come to me at once. So far so good. The case did well until April 4th. I then had a visit from my patient. He 366 OPERATION OF RISODONTEYPY. said he had not felt any pain until the previous day ; and then, to use his own words, he " was sensible the tooth was there.'' He had lately recovered from influenza, coupled with some stomach disturbance, which, no doubt, induced the pulp to take on an irritable action. We all know how mortifying, both to patient and operator, it is, after a tooth has been under treatment for some time, and filled to all appear- ance successfully, for such a state of things to arise. I prescribed three leeches to the gum, and an aperient of Pil. Hydrarg., Ext. Hyoscyam., and Ext. Oolocynth. comp., and dismissed him until the following day. April 5th. — Both leeches and pills did their duty well, but without ameliorating the symp- toms ; the tooth was now tender on pressure, combined with slight but constant uneasiness. I now saw clearly that if something was not done promptly to relieve the tension of the pulp, it would suppurate, and the tooth would be lost. I was disinclined to remove the filling, as it was perfect. Under these circumstances, I determined to perform the late Dr. Hullihen's operation of risodontrypy. At the terminal line of enamel at the neck of the tooth, 1 entered a spear-like drill, and carefully drilled through its substance until I reached the pulp cavity, which I knew from the OPERATION OF RISOPONTRYPY. 367 slight start that the patient gave ; on withdrawing the instrument, it was very slightly tinged with blood. I applied a little cotton wool with chlo- roform a slight distance within the cavity, and dismissed the patient until the next day. He did not come near me for three days ; he had been much engaged, and said that all pain in the tooth had ceased the day following the ope- ration, and that he now could use the tooth as well as any he had in his mouth. By great persuasion I got him to call on me every other day for three weeks, to apply fresh cotton, saturated with tanate of lead. At the ex- piration of that time there was no discharge on the cotton or uneasiness in the tooth. I now filled with Hill's stopping, to about half the length of the cavity, and sent him away for two months, providing no pain supervened. I did not see him again until the end of November. He had been to Melbourne, and was on his return, and had merely called in to express how grati- fied he was at the result. He was very loath to allow me to remove the gutta-percha stopping ; however, he did. I cautiously introduced a drill into the cavity, which came in contact with solid substance, without producing the slightest un- easiness on pressure, clearly indicating the pulp had calcified. After introducing a non-conductor, I filled the cavity with adhesive gold. June 2nd, 1860. — I again saw the patient ; he 368 OPERATION OF RISODONTRYPY. had not had any pain since the last operation. The tooth was perfect in colour and usefulness, and a period of six months having elapsed since all treatment ceased, I think I may fairly conclude the operation has been successful. I do not think the profession attach sufficient importance to this operation ; and I am sure if members, when cases adapted for it present them- selves, would try it, they would be gratified with the result. I do not mean to state that I have not failed occasionally; but I attribute my failures, in a great measure, in my early practice of it, to a want of caution in manipulating and in severing the pulp, instead of slightly wounding or touching it ; also inattention to the state of health of the patient at the time. So valuable do I consider this operation, from extended experience of it, that in all cases of deep-seated caries, if cases will admit, or where there is a probability of the pulp taking on an irritable action, after filling the tooth, I perform the operation at the time, subsequently filling the cavity thus made, and I seldom have had cause to regret it. I think, from reference to my note- book, the average of failures are two out of four- teen cases. It is also useful in general inflammation of the pulp of a sound tooth; and, if performed suffi- ciently early, is usually successful. OPERATION OF RISODONTRYPY. 369 In conclusion, I have only to add, that this operation, emanating from so high an authority on dental matters as the late Dr. Hullihen, is deserving (and I am sure members will agree with me) of a more extended trial than has yet been awarded to it. John Bellisario, D.D.S. 2 B GENERAL MONTHLY MEETING. Monday^ December 3, 1860. W. A. HA.RRISON, Esq., President, in tub Chaie. The following Gentlemen were duly elected Members of the Society : — Mr. Joseph Walker, M.R.C.S. Eng London. Mr. Martin Magor, L.D.S., R.C.S. Eng .Penzance. Mr. Joseph Calorie Jamaica. Mr. Adolphus Hart, M.R.C.S. Eng London. Mr. S. J. A. Salter, M.B., M.R.C.S. Eng., L.D.S., London. Mr. C. Bygbave 3,RueLaffitte Paris. The following Gentlemen were proposed as Members of the Society : — Dr. Dunning New York, U.S. Mr. Frederick Rogers Sackville Street, London. Mr. I. Sheffield and Mr. W. D. Saunder were appointed to audit the Treasurer's accounts. Mr. John T. Edmonds presented to the Museum a curious Prench instrument for extracting molar teeth, and a curious key-instrument. Mr. Fletcher presented to the Museum a preparation of a Second Molar, showing extensive absorption from pressure of the Third Molar. Mr. Bridgman presented to the Museum a fine specimen of a Shark's Jaws, and also several models of cases of irregularity, with the teeth extracted in each case ; and made the following communication : — A YOUNG lady, about eigliteen or nineteen years of age at the time I extracted the accompanying tooth, had been to me a year or so previously, and had it stopped on the buccal surface. Find- ing it deformed, and very sensitive, I wished to 2 B 2 372 APPLICATION OF HYDEAULIC PRESS remove it as I suspected what would follow; but I could not obtain ber consent, so I merely filled it witb amalgam. The point on wbicb I wish to have the opinion of tbe Society is tbis : — Is tbe extracted tootb a dens sapientice, or a second molar ? I bope to obtain another cast of the mouth when tbe coming tootb has attained its maturity, which will be necessary to complete the case. The following oommunication was read from Mr. Fox, of Gloucester, *' 0?i the application of an Hydraulic Press for swaging Gold Plates :^' — Gentlemen, — For a long time past I have been convinced that the practice now in use among dentists for obtaining a correct plate is open to many objections. The ordinary practice of striking up by a sudden blow frequently injures the die, whether of zinc or of any other material now in use, and also cracks the gold. To show this is the case : in all other branches of manufacture in which a plate is driven up between two dies, squeezing has been substituted for striking. This squeezing is sometimes per- formed through the means of a powerful screw, but now more usually obtained by the wonderful ease of the hydraulic press. To mention a familiar example : the beauti- fully raised curtain-plates, and the finger-plates for doors, are all stamped by pressure and not by a sudden strike. FOR SWAGING GOLD PLATES. 373 It occurred to me some years since, to sub- stitute squeezing for striking, but the introduc- tion of the vulcanite for a time set my notion aside. From two to three years' experience with the vulcanite has enabled dentists to un- derstand its capabilities, its great use for under- gums and for upper palates where the gums have much receded ; still I believe it has brought most to see the vast superiority of a correct gold plate for the upper denture, where it can Ibe used. "With this view I proposed to the manufac- turers of the improved patent hydraulic press, that they should make me a small press, of at least ten tons' pressure ; and, after forwarding a de- sign of such machine, it has been made and been in use in my workroom for some weeks. Our experience fully justifies the anticipations formed of it. It is quite an addition to the capa- bilities of a workshop, taking up but little room. A child four years of age can exert a pressure of from five to six tons, — ^it has been used to ten or twelve. We have made several large plates, which fit weU. The ordinary pressure of a four-pound hammer, as struck by a dentist, varies from 80 pounds to 150 pounds; but that struck by a blacksmith might reach two hundredweight. We have found it for single teeth of very little advantage, and in some cases prefer the hammer to the press. It is very simple in its work, takes but little 374 METHOD OF TREATING THE DENTAL PULP time — ^in some cases no more tlian the old method — and where it does occupy more time it is quite worth it, for the ease with which it produces a good plate. After beating up the plate in the ordinary way with the wooden mallet, it is an- nealed and squeezed gently, then cut to shape, annealed again, and the final pressure used. When clasps have to be attached, the pressure may have to be repeated, first before the clasps are attached,'' and then after soldering them to the plate, according to the individual practice of the dentist. Any further information I would gladly give, if you think the subject deserving your conside- ration. The price, £12. 10s., brings it within the reach of most practitioners, and the makers are Tangye Brothers and Price, Cornwall Works, Birmingham. Yours very respectfully, Geoege Feedeeic Fox. Spa, Gloucester. Mr. Coleman read the following paper : — On a Method of Treating the Dental Pulp, when Suppurating, or in other Stages of Inflammation, with a vieiv to produce Calcification. Me. Peesident and Gentlemen, — It is not the object of this short paper to advocate any ncAv method of treating the dental pulp when exposed WHEN SUPPURATING, ETC. 3r O by caries or accident; it has resulted from an interesting question raised at the last meeting of this Society by Mr. Cartwright, viz., "as to whether a dental pulp that has been in a suppu- rating condition can ever take on a healthy action and become calcified." My own opinion was, and I found my practice upon it, that the same conditions might exist in the dental pulp that we find in other struc- tures of the body, and that healthy action might be set up and secondary dentine formed in a tooth the pulp of which had been in that state of inflam- mation termed the suppurative. The truth of this opinion I never had the opportunity of veri- fying, satisfactorily, until a week or two ago, which was since the last meeting ; and as I keep notes of most of my cases, I am enabled to bring one under your notice which, I think, will prove that my previous opinions were not incorrect. Mr. T — , 88t. about 43, came to me on the 28th of October of last year, ha^dng the first upper bicuspid of the left side considerably decayed on its anterior surface ; and as the second bicuspid of the same side had been removed, and there was a space between the first bicuspid and the canine tooth, a very good view of the cavity could be obtained. The patient informed me that he suf- fered a good deal of pain in it at various times, and complained of an unpleasant taste arising from it. 376 METHOD OF TREATING THE DENTAL PULP After removing as mucli of the softened dentine as I deemed prudent, and having cleansed the cavity, I introduced a small piece of dry cotton, and over this a piece of cotton steeped in a solu- tion of mastic, and directed him to call in a few days. Nov. 1st, I have this note : " Cotton- wool stained and very offensive ; applied a strong solu- tion of tannin in ether, and over this cotton and mastic." 8th. — " Tooth has ached a little ; cotton- wool removed very offensive, directed to apply a strong solution of tannin in ether, viz. thirty grains to a drachm of the latter two or three times a day." As I was doing some mechanical work for him, I was enabled to see him occasionally, but did not alter the treatment until the 28th of the same month, when I lanced the gum around the tooth freely, it being red and congested, and had given him some discomfort. Dec. 8.— Again tried mastic and clean cotton. 16th. — ^A little discharge, so directed to con- tinue the ether and tannin. Jan. 19th, 1860. — Patient fancied the dis- charge had ceased, so again tried mastic over clean cotton. 26th. — Removed cotton wool from cavity, which was dry and free from unpleasant smell. Tooth filled with gutta percha. Feb. 23rd. — " Gutta percha removed and amal- WHEN SUPPURATING, ETC. 377 gam substituted ; walls of tooth too thin to bear gold/' Nov. 13. — The patient called in consequence of the filling having come out, owing to a large portion of the masticating surface of the tooth having broken away. I thought I might now venture to cut away the tooth in the direction of the pulp-cavity. After removing a substance of the consistency of leather, and more resembling it than anything else, the outline of the pulp- cavity was exposed, which was filled with a mass of fawn-coloured dentine, of a consistence some- what harder than horn. The plan of treatment adopted in this case is the one I almost universally pursue, theoretically, upon the following grounds. I believe a tooth, in both its modes of nutrition, considerably re- sembles a long bone, at least that portion between its epiphyses. If by accident an oblique fracture divides and cuts off the nutrient artery from such a bone, its periosteal supply of blood is insuffi- cient to maintain its vitality, and the bone becomes necrosed ; and so, I believe, a tooth suddenly cut off from the supply of blood which enters it through its fangs is also liable to become necrosed, and a series of troublesome abscesses to result. I therefore deem it of great importance to pre- serve as much of the dental pulp as possible, which, I think, will render periostitis less liable to occur ; for, though much of the pulp may even- 378 METHOD OF TEEATING THE DENTAL PULP tually become calcified, yet this process, as in the case of teeth worn down by mastication, is a healthy process ; and as it takes place very gradu- ally, provision is doubtless made by an increased supply of blood through the periosteal vessels for the loss by the nutrient vessels. My practice does not, I apprehend, differ much from that adopted by other dentists ; only I, per- haps, almost universally pursue a plan which all occasionally are in the habit of employing. The solution of tannin in ether used is a very strong one ; it is prepared by dissolving as much tannin in ether as this solvent will take up in the cold, filtering the fluid and allowing a portion of the ether to evaporate at the ordinary tempera- ture of the atmosphere. A piece of cotton-wool immersed in this fluid may be placed under a mastic stopping, should you be able to see your patient in about a week ; or under gutta percha should a longer period be desired. But I have generally obtained the best results from the patients applying the solution themselves, twice, or, if possible, three times a day ; for though the fluids of the mouth must soon dissolve it out of the cotton, yet I beheve it is better than allowing the wool saturated with the discharge to remain long in the cavity of the tooth.. Patients at first usually complain of the exces- sive bitterness of this application, but soon seem to get accustomed to it, and, in some eases, even WHEN SUPPURATING, ETC. 379 to like it, so greatly is it the fashion in the present day to exalt bitter beverages. The effect of the solution upon the decalcified dentine of the tooth is to form a sort of leather, I believe, a true tannate of gelatine or analogous substance; and in cases where the pulp has not been actually exposed, although pain may have been experienced in the tooth, a covering is formed, under which calcification of the pulp seems to take place very readily. In cases where the pulp has been completely disorganized and has suppurated away, the solu- tion is still valuable in subduing the discharge. I will give a good case to illustrate this. Mr. D — , ast. 19, called upon me on 13th March, 1860, to have a right, lower, wisdom tooth re- moved, on account of the pain he believed he had suffered in it. On examining his mouth, I found the wisdom tooth decayed to the level of the surrounding gum, which was quite healthy, while the gum about the neck and fangs of the second molar of the same side, which was decayed on its masticating surface, and somewhat loose and tender on pressure, was red and inflamed. In removing the softened dentine from the latter tooth, which I suspected to be the source of the pain, the cavity of the interior fang was exposed, and a quantity of pus welled up from it. This almost imme- diately gave him relief. I'he ether and tannin was applied twice, and 380 METHOD OF TREATING THE DENTAL PULP the tootli afterwards filled with gutta percha, and eventually permanently stopped. I frequently employ gutta percha as a temporary filling, in cases where I feel pretty certain there is no discharge from the pulp, on account of its being readily removed should pain come on in the tooth, and because it very often allows a gold filling to be employed when a cement stopping could only be borne at the time the patient is first seen. Its excellent quality of being a non-conductor of heat renders it very valuable. There is, I think, little doubt but that calcifi- cation of the pulp takes place more rapidly under an amalgam filling than under any other; what this is due to I have not been able to ascertain. It may be due to its being a good conductor of heat, and by this means acts moderately as an irritant, and thus excites calcification. The diffi- culty of removing it readily from a tooth, and also the circumstance of changes of temperature being readily conveyed through it to a sensitive pulp, prevent its frequent use as a temporary filling. As a rule, I have met with the least success when employing this plan where a pulp has been exposed in excavating a carious tooth, and where capping the pulp seems to be the proper mode of treatment. I know it would be very useful to give a per- centage of the teeth saved by this process of WHEN SUPPURATING, ETC. 381 treatment, but I feel it would be of little value unless tbe exact conditions of tbe teeth at the time of the first application were also correctly stated. Now, a patient often applies to you whose suffering is more of a constitutional than of a local nature ; and this, like any other topical remedy, fails to afford relief. Or a patient appHes to you having a tooth which you feel satisfied is beyond the range of your conservative powers, yet, unwilling to part with it, you yield to his solicitations, and make an effort to save it, which proves fruitless. But in cases where there is a fair chance of success, I believe the method I have described will be found at least equal to any other; and has not, as in operations for destroying the pulp, the drawback of being, at times, an intensely painful process. In applying it, however, I am willing to admit there are several disadvantages. It demands a larger amount of time and attention, both on the part of the operator and patient, though very rarely so much as in the first case I have reported. Then, again, where the apphcation is left to the patient, you have no means of ascertaining that it is regularly employed; and then, after the tooth has received the gutta percha, your patient, per- fectly comfortable, forgets his appointment at the end of the month, or puts it off from time to time till the gutta percha has come out, pain has again been experienced, and he is compelled to seek 382 METHOD OF TREATINC^ DENTAL PULP, ETC. your assistance. This, I regret to say, has too often occurred to me : in one case on three occa- sions had I to repeat the whole process over again ; and, finally I removed the tooth after failing in the fourth attempt. Each time there was a discharge from the pulp, which was sub- dued, and the gutta percha borne ; but instead of seeing my patient at the end of a month, it was each time nearer the end of a year — the gutta percha having come out, and pain having re- curred. But looking to the results of the various pro- cesses that have been employed to render a carious tooth capable of receiving a stopping, and con- tinuing in a healthy condition after it has received that stopping, if one plan promises more success than another, I think we are bound to adopt it, even though we are compelled to devote a larger portion of our time to the object, and even though our efforts are liable to be defeated through the negligence of our patients. The responsibility of the latter rests with them, though the failure may to us be a source of disappointment. INDEX Aeriform bodies expand by increase of temperature, 194. Aged patient, models of his teeth, 123. AUcard, G., elected a member, 181. Aluminium, use of in casting beds and palates, 75 ; peculiarly adapted for artificial teeth, 76. Alveolar arch, anchylosis of the, 264. Alveolar process, cases of injury to the, 27, 28. Alveolus, on the re-union of teeth with the, 64 et seq. ; pressure of the tongue upon the, 173. Anchylosis of the jaw, case of, 260 et seq. Anderson, J., elected a member, 79. Animals, lower, dentition of the, 223 et seq. ; 311 et seq. ; 338 et seq. Antrum, adult, on its form and size, 31 ; graphic illustrations of the, 31 et seq. ; occasionally extends into the body of the malar bone, 34 ; various phases of the, 34, 35 ; fossae formed in various parts of its cavity, 36 ; fossa) extend- ing along the upper part of the ante- rior wall, 37 ; accidents and diseases to which this part is liable, ib. ; dilated by morbid growths, 40 ^ inflammation of the lining membrane, 40, 42, 45 ; causes, symptoms, and treatment, 41 — 46 ; part of the floor attached to the fangs of a molar tooth, 41 ; character of the morbid fluid of the lining mem- brane, 42 ; dropsy of the, 43 ; abscess of the, ib. Ape, dentition of the, 340, Arsenic, its use in dentistry, 120. Arthur, Dr., his employment of the ore of cobalt, 117. Arthur, R., elected a corresponding member, 159. Artificial teeth, mode of casting be«l» and palates for, 76. Ash, G., elected a member, 61. Babyroussa, dentition of the, 251. Badger, dentition of the, 239 ; skull of the, 240. Baker, J. A., elected a member, 139. Ballard, Dr., elected a corresponding member, 207. Ballard, W. R., elected a member, 207. Bartlett, E. B., elected a member, 123. Bartlett, G. , elected a member, 139. Bate's method of constructing lower plates, 139. Beaver, skull of the, 326, 327 ; enamel of its teeth, 327 ; ravages of the, by its incisor teeth, 328 ; country and habits of the, 334, 335. Beds and palates for artificial teeth, mode of casting, 75. Bell, Professor, his remarks on lateral pressm*e, 164 ; one of our first natural- ists, 336. Bell, J., elected a member, 255. Bell, T., elected a member, 311. Bellisario, Dr. J., elected a correspond- ing member, 269 ; his commxmication on the operation of Risodontrypy, 364 et seq. ; his applications and prescrip- tions, 366 et seq. Bennett, W. G., elected a member, 139; his communication on an improved flask for vulcanizing, 361. Betjeman, Messrs., their exhibition of an improved dental chair, &c., 6. Blandy, Dr., on the cheoplastic method 384 INDEX. of mounting artificial teeth, 129 et seq. Boa constrictor, dentinal tubuli of the, 227. Boiler for generating steam, 212. Bond, T. E., elected a corresponding member, 159. Brae, A., elected a member, 23. Brand, E. E., elected a member, 61. Bridgman, Mr., on lateral pressure, 160; his communication on an extracted tooth, 371. British skulls, ancient, exempt from den- tal caries, 359 (note). Brown, W., elected a member, 159. Burridge, L. S., elected a corresponding member, 159. Bygravo, C, elected a member, 371. Calcification, method of producing, in the treatment of dental pulp, when suppu- rating, &c. 374 ; cases of, 375, 377. Caldcleugh, J., elected a member, 181. Calorie, J., elected a member, 371. Canine teeth of the lower animals, 231. Capybara, molar teeth of the, 330, 332 ; skull of the, 331 ; jaws of the, 332, 333. Carnivorous tribes, teeth of the, 229 ; their organs of destruction, 231. Cartwright, S., elected an honorary mem- ber, 61. Cat tribe, teeth of the, 232 et seq. Cattlin, Mr., on the extraction of an upper molar, 15 ; on the adult antrum, 31 ; on a case of ulceration arising from a wisdom tooth, 93 ; his exhibition of models representing the teeth of an aged patient, 123. Cattlin, W., Jun., elected a member. 111. Caustics, used in dental surgery, 113 et seq. ; nitrate of silver, 118 ; arsenic, 120. Cautery, application of in dental surgery, 118. Cementum of the human teeth, 243. Cheoplastic method of mounting artifi- cial teeth, 129 et seq. ; its great advan- tages, 134. Childs' exhibition of a vulcanizing appa- ratus, and description, 159, 160 ; his communication on superheated steam, 181 et seq. ; his vulcanizer applied to the hardening of India-rubber, 199, 200. Child's mouth, model of, exhibited, 23. Chimpanzee, dentition of the, 341 ; skulls of the, 342, 343. Chisholm, J. K., elected a member, 139. Chlorate of potash, application of, 297. Cleft-palate, on taking impressions of cases of, 5. Cobalt, ore of, 117. Cookings, W. S. , elected a member, 337. Coleman, Mr., his new forceps for re- moving the stumps of upper molars, 62, 63 ; his communication on heredi- tary syphilis, as illustrated by the teeth, 103, 258. Council, election of in 1858, 13 ; in 1859, 111 ; in 1860, 256. Crab, the, has powerful apparatus of cal- careous gastric teeth, 353. Cranium of the elephant, 321. Cushman, Dr., cases of the re-union of teeth recorded by, 68. Cutting of teeth in old age, 124, 125. Cyst, osseous, containing a loose tooth, 38. De Lessert, C. G., elected a member, 61. Dental arch, different forms of the, 169. Dental caries, examples of, in Romanized Britons, 359 (notes). Dental operations, on the employment of electricity in, 80 et seq. Dental pulp, method of treating when suppurating, &c. 374 ; cases of, 375, 377. Dental surgery, on caustics used in, 113 et seq. Dentinal tubuli, application of the micro- scope to the, 226 ; arrangement of the, ib. ; of man, ib. ; of the dolphin, the boa constrictor, and dog fish, 227. Dentistry, cases of, in Middlesex Hospi- tal, 26 ; vulcanite base applied to, 140 et seq. Dentists, on the materials used by, 1. Dentition, first period of, in hereditary syphilis, 103 ; of various lower animals, IXDKX. 385 232 et seq. ; rolations of their teeth to those of man, 223 et soq., 311 et seq. 338 et sofi. ; of the elephant, 311 ; of the quadrumana, 338 et seq. Doiitz, Simon N., elected honorary mem- ber, 1. Dowar, Dr. H. A., elected a member, 299. Dowar, Mr., on a self-packing vulcanite apparatus, 300. Diseases of the teeth in animals, 355, 356. Dog-fish, dentinal tubuli of the, 227. Dolphin, dentinal tubuli of the, 227. Donations presented to the society, 18. Drill, a new one exhibited, 181. Duff, Mr., his communication on mate- rials used by dentists, 1. Dunn, C. W., elected hon. member, 5. Elections of ofi&cers and council in 1858, 13 ; in 1859, 111 ; in 1860, 256. Electricity, employment of, in dental operations, 80 et seq. Elephant, dentition of the, 311 ; its tusks, and their enormous weight, 312 ; de- struction of one at Exeter 'Change, 314 ; its skeleton set up at the Hun- terian Museum, 315 ; its molar teeth, ib. ; Professor Owen's description of its molar teeth, 315, 316 ; section of the skull of an Asiatic one, 322. Elephants, different descriptions of, 321 — 323 (note) ; numerous in Siberia, ib. ; carcass of an enormous one found in Siberia, 324, 325. Elephas primigenius, teeth of the, found scattered throughout the whole of Eu- rope, 323. Elliott, J. W., elected a member, 337. Epulis, occurrence of, in the antnun, 40. Ether and tannin, its application, 378, 379. Evans, T. W., elected a corresponding member, 159. Expansion, increase of, by heat, .191, 194 ; rate of, 194. Face, injury of the, through the bursting of a gim, 48 ; its treatment, 48 et seq. ; surgical operation on the, 50 ; breech of !i gun extracted from the, 51 . Finnie, J., elected a oorreeponding mem- ber, 181. Flask employed in the self-packing appa- ratus, 303, 304 ; an improved on© for vulcanizing, 361. Fletcher's commimication on the mecha- nical appliances for reducing irregu- larity in the growth of teeth, 213 — 222. Food of different animals, 354, 355. Forceps for removing the stumps of upper molars, 62. Forsyth, W. F., elected a member, 257. Fossils, the medals of creation, 225 ; a guide to the form of extinct races, ib. ; remains of, 238. Fox, Mr., his commimication on the ap- plication of an hydraulic press for swaging gold plates, 372. Eraser, Dr., his communication on an injury of the face, 47 et seq. Gallinaceous bird possesses a muscular gizzard, 353. Ghrimes, S., elected a member, 139. Gill, S. , elected a member, 207. Gold, its use in the manufacture of arti- ficial teeth, 1. Gold plates, application of the hydraulic press for swaging, 372. Goodyear's experiments on vulcanite, 141, 142. Gorilla, dentition of the, 341 ; habits of the, ib. Graminivoi'ous mammals, teeth of, 243 ; their teeth equivalent to a self-dressing millstone, 244. Gregson, G., elected a member, 5. Gutta-percha, use of, in dentistry, 3 ; employment of, in cases of cleft palate, 11 ; does not change when exposed to a vulcanizing heat, 151 ; employment of, as a temporary filling, 380. Haemorrhage, cases of, from the dental periosteum, 26, 27. Hampson, C, elected a member, 113. Harris, C, elected a corrcsponding mem- ber, 159. C 386 INDEX. Harrison, W. A,, V.P., Chairman, 13, 223 ; his mode of reducing irregularity in the growth of the teeth, 219, 220 ; elected president, 256, Hart, A., elected a member, 371. Harwood, Dr., elected a member, 223. Hawkins, T., elected a member, 257. Hoarder, J. N., on the employment of electricity in dental operations, 80 et seq. Heat, excess of, gives a dark colour to the vulcanite base, 153. Hepburn, David, elected a member, 139. Hepb\im, D. D., elected a member, 139 ; his presents, 257. Hepburn, E., elected a member, 139. Herbivorous tribes, teeth of the, 229. High-pressure saturated steam, 183. Highmore's description of the antrum, 31. Hippopotamus, tusk of the, used for dental purposes, 1, 2 ; skull of one pre- sented, 181 ; dentition of the, 251, Hog tribe, dentition of the, 251. Holden's description of the antrum, 31. Horse, dentition and skull of the, 246, 249. Hugo, H. R., elected a member, 79. Hugo, S. G., elected a member, 61. Hullihen, Dr., his operation of risodon- trypy in the treatment of dental pulp, 364 et seq. Hutchins, Mr., his communication upon deposition of tartar upon teeth, 127. Hutchinson, Mr. J., on the influence of hereditary syphilis on the teeth, 95. Hydraulic press, application of the, for swaging gold plates, 372. Hyena, dentition of the, 237. Idiot, skull of the, 350. Incisor teeth of rodents, 325, 326 ; of beavers, 326, 327 ; their occasional misgrowth, 329; in the family Lepo- ridae, 330. India-rubber, application of preparations of, 300 ; (see Rubber.) Inflammation of the lining membrane of the antrum, 40, 41 ; its causes, symp- toms, and treatment, 40 — 46: of the dental pulp, and method of treatment, 374 ; cases of, 375, 377. Inverted tooth, description of one con- sidered in relation to certain forms of tumours in the jaw, 54 et seq. Iodide of potassium, unfavovu-able effects produced by its exhibition, 287. Iodine, employment of, 286. Irregularity in the growth of permanent teeth, and mechanical appliances for reducing, 213—222. Jameson, W, E., elected a member, 93. Jaw, anchylosis of the, 260 et seq. Jaws, contraction of the, found to follow the extraction of a tooth, 170. Jaws of man, development of the roots of, graphically illustrated, 329. Jordan, H., elected a corresponding member, 269. Keene, J. J., elected a corresponding member, 337. Kemp, C. G., elected a member, 257. Keratitis, chronic, case of, 100. Kolliter, P. A., elected a corresponding- member, 299. Kyan, J. H., elected a member, 225. Lateral pressure, Mr. Bridgman's trea- tise on, 160 et seq. ; causes of, 161 ; diagrams illustrative of, 162, 166, 167 ; Professor BelFs remarks on, 164. Lemurs, dentition of the, 338. Leporidaj, incisors of the, 330. Levison, Dr., on anchylosis of the jaw, 260 et seq. Lindsay, J. B., elected a member, 13. Littlewood, J., elected a member. 111. Lowe, E., elected a member, 255. Lower jaw, teeth removed from, 24, 25. Macintosh and Co., the eminent manu- facturers of India-rubber, 206. Maclean, M., elected an honorary mem- ber, 207. M'Quillen, J. H., elected a corresponding member, 207. Major, M., elected a member, 371. Mammoth, tusks of the, found in the British Channel, 323; molar teeth of INDEX, 387 the, found in Kent, and other parts of Europe, 324. Man possesses the divine gift of reason, which compensates for the feebleness of his physical endowments, 354 ; the only cooking animal, ib. ; his supe- riority over the irrational mammalia one of kind rather than of degree, 358 ; The despotic lord of the living world, 359. Man ton, J. N., his statistical account of the removal of 1,500 permanent teeth, 23 et seq. Manton, J. N. , comparison between his cases and those of Tomes' s dental sur- gery, 24 ; J. N., elected a member, 47. Mather's communication on the soldering apparatus, 176. Maxilla, superior, case of its removal from a child, 126. Maxillary Sinus, the, 31 . May, W. H., elected a member, 337. Meetings, general monthly, Nov. 1857, 1 ; Dec. 5 ; Jan. 1858, 13 ; elec- tion of officers, Feb., 15 ; March, 23 ; April, 47 ; May, 61 ; June, 73 ; Nov., 79 ; Dec, 93 ; Jan., 1859, 111; Feb., 113; March, 123; April, 139 ; May, 159 ; June, 181 ; Nov. 207 ; Dec, 223; Jan. 1860,255; Feb., 257; March, 269 ; April, 299 ; May, 311 ; June, 337 ; Nov., 361 ; Dec, 371. Members, monthly elections of (see Meet- ings). Membrane of the antrum, inflammation of the, 40—46. Mercury, vises of, in a vulcanizing heat, 152. Middlesex hospital, list of cases in the dental department of the, 26. Mineml teeth, introduction of, 2 ; im- provements in, 75 ; specimens of ex- hibited, 181. Molar, upper, case of extracting the, 15 ; the difl&culties of extracting, ib. Molar bone, antrum occasionally extends into the, 34. Molar teeth, absence of in cases of cleft palate, 10 ; of the lower animals, 231 ; of sheep, 245 ; of the elephant, 315 ; their development described by Pro- fessor Owen, 315, 316 ; of the Indian elephant, 317 ; enamel of the, 318 ; of the African elephant, 320. Molar tooth, antrum attached to the fangs of a, 41 ; hajmorrhage caused by their removal, 26, 27 ; new forceps for removing the stumps, 62, 63; of the monkey tribe, 341. Monkey, dentition of the, 338, 346, 347 J skull of the, 346. Moore, R. H., elected a member, 159. Morbid growths, dilate the antnun, 40. Motmting artificial teeth, cheoplastic method of, 129 et seq. Mouth, taking impressions of the, 5 ; on inflammation in the tissues of the, and its treatment, 269 et seq. ; periostitis, 274 ; stomatitis, 290. Mvunmery, Mr., on the structure and adaptation of the teeth in the lower animals, 223, 311 et seq., 338 et seq. Murphy, J., elected a member, 139. Nitrate of silver, its use in dentistry, 118. Norman, Robert, elected a member, 13. Odontological Society, general monthly meetings of, and presents made to the, 1, 5, 13, 15, 23, 47, 61, 73, 79, 93, 113, 123, 139, 159, 181, 207, 223, 255, 257, 269, 299, 311, 337, 361 (see Meetings). Ofiicers and Council, election of in 1858, 13 ; in 1859, 111 ; in 1860, 256. Old age, cutting of teeth in, 124, 125. Ollive, A. E., elected a member, 269. O'Meara, A., elected a member, 123. Operating chair, new form of adjusting, 107. Oral cavity, peculiarities of the, 171. Orang-outang, dentition of the, 340 ; skulls of the, 342, 343. Orphoot, Peter, elected a member. 111. Orrock, J., elected a member, 139. Osteoplastic base, 212, Owen, G., elected a member, 73. Owen's new fonu of adjusting operating chair, 107. 388 INDEX. Oxley, Mrs., her case of cutting teeth in old age, 125. Packing, Dr. Dewar's apparatus for, 300, 308 ; methods of, 301 ; his machine for, 308. Palate, different forms of the, 169. Palate, cleft, on taking impressions of cases of,*j5. Palates for artificial teeth, mode of casting, 75. Palmer, J. E., elected a member. 111. Parkinson, G., elected a member, 255. Parkinson, J. H., V.P., chairman, 5; elected president, 13. Parks, W. J., elected a member, 257. Parmly, E., elected a corresponding member, 159. Patents, remarks on, objections to the law of, 205. Periostitis, 274 ; symptoms of, 275 ; treat- ment of, 276 ; cases of, 277 et seq. Pigott, A. S., elected a corresponding member, 159, Pilling, R. E., elected a member, 255. Plaster of Paris becomes changed by the vulcanizer, 202. Plate-casting, Mr. Statham's paper on, 18 ; cast by Mr. Corbett, 19. Plates, striking up, 73, 74. Plates, lower, Bate's method for construc- ting, 139. Platina, its use in the manufacture of ar- tificial teeth, 1. Pratt, R. J. H., elected a member, 123. Presentations to the Society, 13, 79, 181, 207, 223, 255, 257, 269, 311, 337, 361, 371. Presents to the Society, at each monthly meeting — see Meetings. President, election of, in 1858, 13; in 1859, 111 ; in 1860, 256. Pressure, mode of producing in the vul- canizing machine, 209. Putnam, Mr,, on the vulcanitej base as applied to dentistry, 140 et seq, ; his viilcanizing flasks, 143. Quadrumana, dentition of the, 338 ; skulls of the, 339. Randell, E. B., elected a member, lit. Ransome, R., elected a member, 47. Rats, molar teeth of the, 330. Regulator for the vulcanizing machine, 210. Risodontrypy, operation of, 364 et seq. Roberts, C. D., elected a member, 139. Roberts, W., case of, 47 ; injury to the face sustained by, from the bursting of a gun, 47—52. Roberts, W. A., elected a member. 111, Rodents, remarkable for the great deve- lopment of their incisor teeth, 325, 326 ; dentition of the, 230. Rod way, C. A., elected a member, 337. Rogers, Arnold, V.P., chairman, 1; his exhibition of teeth, 73 ; elected presi- dent, 111, Rogers, J., elected a member, 123. Rogers, S. A., elected a member, 255. Rogers, T. A., on caustics used in dental surgery, 113 et seq. Rubber (India) not liable to change in a vulcanizing heat, 151 ; chemical for- mation of, and its change, from being hardened by heat, 196 ; effects of car- rying the heat too far, 198 ; results of impurities or adulterations in, 198 ; the various modes of hardening, 198, 199 ; Childs' vulcanizer applied to the hard- ening of, 199, 200 ; adulterations prac- tised with, 205 ; necessity of obtaining it in purity, 206 ; expiration of Mr. Goodyear's patent, ib. Ruminants, dentition of the, 330 ; possess the faculty of regurgitation and mas- tication, 353. Ruminating process of herbivorous ani- mals, 245. Ryan, J. H., elected a member, 223. Salter, S. J. A,, elected a meiTiber, 371. Sass, F. A., elected a member, 93. Secretaries, honorar}', election of, in 1858, 13 ; in 1859, 111 ; in 1860, 256. Self-packing vulcanite apparatus, 300. Sercombe, Mr, E., his exhibition of ir- regular development of teeth, 1 ; paper on taking impressions of cases of cleft palate, 6 ; communication INDEX. 380 respecting a case of trismus, 63 ; ex- hibition of a child's superior maxilla, 126 ; instruments for reducing irregu- larity of teeth, 218 ; paper on in- flammation in the tissues of the mouth, 269 ot seq. ; his communication on the destruction of bone which follows ul- cerative stomatitis, 299. Shark's jaw, specimen of the, 371. Sheep, skull of the, 240, 241 ; molar teeth of the, 245 ; ruminating process of, 245. Sherwin, J,, elected a member, 207. Siberia, tusks of elephants found in, 324 ; carcass of an enormous elephant found in, 324, 325. Silver, its use in the manufacture of arti- ficial teeth, 1, Skull of an elephant, 322 ; of the bieaver, 326, 327, 334 ; of the hare, 334 ; of the quadrumana, 339 ; of the chimpanzee, and orang-outang, 342, 343. Skull of man, 348, 349 ; striking features in the, 350 ; varieties of the, 351 ; Aus- tralian and Caucasian, ib. Smee's exciting battery, 84. Smith, G. W., elected a member, 61. Snape, J., elected a member, 93. Soldering apparatus, 176 ; graphic repre- sentation of the, 179. • Spider monkeys, dentition of the, 338. Statham, J. N., on plate-casting, 18. Steam, superheated, Mr. Childs' paper on, 181 et seq. ; in contact with water^ 185 ; table of atmospheres, pressure, and corresponding temperature, 185 ; table of expansion and temperature, 191 ; graphic illustrations of, 192, 193 ; laws of expansion, 194 ; various modes of heating, ib. ; patents connected with, 204, 205. Steam baths attached to the vulcanizing machine, 212. Steam-boiler likened to a man's digester, 188. Steam-boilers, use of prohibited in France before testing, 149 ; considerations on, 183. Steam-heat, use of a certain degree of, 153. Stent, Mr., his introduction of a new ma- terial for taking impressions in cases of cleft palate, 12. Stevenson, N. , elected a member, 61. Stokes, C, elected a member, 139. Stomatitis, 290 ; symptoms and causes, ib. ; treatment, 291 ; ulcerative, 293, 299. Stopping of carious teeth, 380, 382. Sulphur not changed in a vulcanizing heat, 150 ; effects of produced by the vulcanizer, 202. Suppuration of the dental pulp, method of treating, 374 ; cases of, 376, 377. Swainson, W. B., elected a member, 255. SyphiUs, hereditary, its influence on the teeth, 95 et seq. ; Mr. Coleman's obser- vations on, 103 ; period of the first den- tition, ib. ; form of the permanent teeth, ib. ; their colour, 104 ; figures illustrative of Mr. Hutchinson's report on, 105 ; its diagnosis made entirely through the teeth, 258. Talma, A. J. L., elected a corresponding member, 169. Tannin, solution of, and its application, 378, 379. Tartar, deposition of upon teeth, 127. Teeth, artificial, materials used in the manufacture of, 1, 2 ; statistical ac- count of the removal of 1,500 perma- nent ones, 23 et seq. ; tables of the dififerent kinds of, 24, 25 ; removal of 1,500 temporary ones in twelve months, 25 ; removal of temporary to give room for permanent ones, ib. ; extraction of supernumerary ones, 28, 29 ; loose ones found in solid and encysted tumours, 38 ; instruments for extracting them, 39 ; on the reunion of, with the alveolus, 64 et seq. ; influence of hereditary syphilis on the, 95 et seq. ; form of the permanent ones in hereditary syphilis, 103 ; syphilitic malformations of the, 105, 106 ; of aged patients, 123, 126 ; deposition of tartar upon, 127 J Cheo- plastic method of mounting, 129 et seq. ; their proper antagonism of the 390 INDEX. utmost importance, 176 ; mechanical appliances for reducing irregularity in the growth of, 213, 222 ; on their structure and adaptation in the lower ' animals, and their relation to human dentition, 223 et seq., 311 et seq., 338 et seq. ; furnish a guide to the forms of extinct races, 225 ; determine the nature of the food of animals, 229 ; of the herbivorous and carnivorous tribes of animals, ib. ; of the tiger, 232 ; human cementum of the, 243 ; of the horse, 247^-249 ; diagnosis of hereditary syphilis made through the, . 258 ; of the elephant, 311 ; of the rodents, 325 ; of the beaver, 326, 327 ; Dr. Hunter's remarks on the preserva- tion of, 352 ; their value and import- ance, 353 ; expressive of mentality, 353 ; diseases of the, 355, 356 (see Tooth). Temperature, increase of, by heat, 185, 191 ; aeriform bodies expanded by in- crease of, 194, Thermometers, their use when applied to vulcanizers, 204. Thompson, R., his exhibition of an appa- ratus for making spiral springs, 5 ; his communication on "striking-up plates," 73, 74. Tiger, skull and teeth of the, 231 et seq. Tomes, Mr., 1,500 cases from his "Den- tal Surgery," 24 ; his communication on the forms of dental instruments, 47 ; his description of an inverted tooth, 54 et seq. ; his case of pressure of the wisdom tooth, 61, 62. Tongue, pressure of the, on the alveolus, 173. Tooth, case of a persistent temporary one, 29 ; inverted one described, 54 et seq. ; operation on the, 58 ; treat- ment for replacing a dislocated one, 70 ; its extraction, followed by the contrac- tion of the jaws, 170 ; removal of one to make room for , another, ib. (see Teeth). Tray, form of the, 7 ; employment of the, 8,9. Treasurer, election of, in 1858, 13 ; in 1859, 111 ; in 1860, 256. Trismus, case of, 63 ; treatment and cure of, 53, 54. Troglodytes, dentition of, 341. Tubbs, C. F., elected a member, 337. Tucker, J., elected a corresponding mem- ber, 159. Tumour, cast of one exhibited, 181. Tusks of the elephant, 312 ; their enor- mous weight, ib. ; shedding of, 313 ; of the Mammoth found in the tertiary beds of the British Channel, 323 ; of the European elephant, 324. Ulceration, case of, arising from a wisdom tooth, 93. Ulcerative stomatitis, 293 ; symptoms, 294 ; causes and treatment, 295 ; on the destruction of bone which follows, 299. Underwood, T,, elected a member, 123. Upper jaw, teeth removed from, 24, 25. Vermilion, not liable to change in a vulcanizing heat, 151. Vice-presidents, election of, in 1858, 13 ; in 1859, 111 ; in 1860, 256. Vulcanite, coloured exhibitions of, 207 ; self-packing, 300 ; apparatus for; with graphic illustrations, 304, 305. Vulcanite base as applied to dentistry, 140 et seq. ; a self-circulating and self- regulating machine for working, 147, 148 ; on changing it so as to make it approximate to the natural colour of the gums, 150, 151 ; on its exposure to the atmosphere, and effects thereby produced, 152, 153 ; will the material shrink ? 154, 155. Vulcanization, process of extremely sim- ple, 209. Vulcanizer, Childs', applied to the har- dening of India-rubber, 199, 200 ; its general application, 202, 203. Vulcanizing, an improved flask for, 361. Vulcanizing apparatus, exhibition and description of, 159, 160. Vulcanizing machine, with dry heat, treatise on, 207 et seq ; patented by Mr. Patrick, 208 ; its utility, 211 ; boiler for genei'ating steam, attached to. 212. INDEX. 391 Walker, J., elected a member, 371. Walrus, tusk of the, used for dental pur- poses, 2. Water, a wonderful and mighty agent, 184 ; its vast expansive powere, ib. ; . saturated steam in contact with, 185 ; impurity of, and its effects, 188. Watt, J., elected a member, 139. Wax, uses of, in taking impressions of cleft palate, 8, 9. Whale teeth, used for dental purposes, 2. White, J. D., elected a corresponding member, 159. Wisdom tooth, case of pressure of the, 61, 62 ; in which necrosis and absorp- tion of the fang had taken place, 73. Wood, compressed, its use in reducing in-egularity in the growth of teeth, 219, 221. Woodhouse, Mr., onthere-tmion of teeth with the alveolus, 64. Woolfryes, U. A., elected a member. 111. TIIK KM). Cox iSl WVMAN, PRINTEB8, GBKAT QFEEN STREET, LONDOW.