bridge work scientifically adapted should be confined to small fixtures involving the replacement of one, two, three, or at most four teeth, and when the reconstructive and restorative requirements demand the replacement of more than this number, then some type of removable structure or partial denture is invariably indicated. As a means of differentiation between removable bridge work and partial removable dentures he submits that "partial removable dentures" include that type of fixture where the sustaining (retaining) support of the fixture is obtained only, or at least mainly, by means of contact with the contiguous soft tissues; and that where any form of attachment to either the crowns or roots of the remaining natural teeth is utilized, and acts as a means of retaining the fixture and of precluding any great degree of subsequent settlement of it, thus relieving the soft tissues of the entire responsibility of supporting the fixture, it may be properly classified as a "removable bridge," irrespective of whether the body be made of metal or vulcanite.

Whenever the position of the supporting teeth is favorable, two attachments will usually be all that will be required, though as the number of missing teeth to be supplied increases, and the position of the supporting teeth becomes more unfavorable, it may possibly become necessary to use three. More than two are rarely ever necessary, and only add to the difficulty of obtaining parallelism, and this in turn increases the strain thrown upon those so used.

When a concrete problem arises, and we must make decision of the fixture to be used, the first consideration incident to such selection is the inherent strength of the appliance. To secure this maximum of strength Goslee resorts to the use of "assembled abutments" or "alveolar bars." Abutment pieces in the form of gold or porcelain crowns may often be attached together with a 14-gage round iridio-platinum or clasp-metal wire lying just in contact with the immediate summit of the ridge. This method is especially useful when it is desirable or becomes necessary to use such naturally weak teeth or roots as third molars or second incisors, though it may be found useful when other teeth are involved, and in either arch, and more especially in those so-called "long span" cases where sev

eral teeth are missing between those to be used for abutments.

Goslee's present purpose is to call attention mainly to, and to discuss but one particular form of the many removable attachments now in common use the clasp.

Clasps have been much abused, but Goslee has seen many teeth supporting clasps in which the pulps were still alive after ten years, even though dental caries may have necessitated fillings.

The anatomy of the teeth indicates that clasps are mainly suitable for premolars and molars. The shapes of the crowns in the incisors and canines are usually not favorable to the grasping and self-engaging properties of clasps.

To be successful it is required that a clasp shall (1) possess both inherent strength and resilience; (2) be well adapted to the supporting tooth; (3) must encircle three angles of the circumference of the tooth in order to grasp it firmly and remain in correct position thereon; (4) must be provided with some form of occlusal rest as a means of minimizing abrasive influence and of precluding subsequent settling of the fixture, which would alter its position on the tooth and thus render the clasp useless or perhaps even injurious; (5) must not impinge upon the soft tissues or interfere with occlusion; and (6) it must be securely attached to the supporting structure. It is not clear what Goslee means by the last requirement. If he means the tooth by the "supporting structure," as seems most logical, then it is not obvious wherein this requirement differs from the second, third, and fourth. If by "supporting structure" he means the base of the prosthetic appliance, it is strange that he does not take exception, in the discussion which followed his paper, to the idea of movable clasps.

The occlusal rest is an essential part of a clasp in all cases and at all times. The type of clasp which Goslee has found to be most useful and least injurious to the supporting tooth is made in the form of a double loop of 17- or 18-gage round iridio-platinum or high-fusing clasp-metal wire. This wire is adapted and adjusted to a fusible metal model of the tooth. When this has been accomplished, the clasps are properly fitted in the mouth, and then, and not until then, the

full impression, with the clasps in position on the teeth, should be taken in plaster, and the model made. Thus the original model will have the clasps, the form and shape of which are not to be subsequently altered, in position upon it. The base of the denture may now be made in metal or vulcanite. The attachment of the clasp to the base is an extremely important consideration, and must be done so as to secure adequate strength, and at the same time permit of an unrestricted freedom in the springiness of both ends of the clasp.

The discussion which followed the reading of Goslee's paper is thoroughly practical. It is particularly interesting because it developed a subject which has not as yet received general recognition, viz, the desirability of allowing some freedom of motion between the prosthetic appliance on the one hand and the abutment on the other. Norman Essig described a considerable number of movable clasps, designed to accomplish this purpose. His technique cannot be abbreviated, and should be consulted in the original, where clear drawings facilitate one's grasping his ideas. Ottolengui described a movable clasp, which is attached to the base by means of an oval upright post and an oval tube, in place of the round upright post and round tube mentioned by Essig. The oval nature of the post and tube permits sufficient play without allowing the clasps to get out of alignment when removing and replacing the piece.

The central thought of Gormsen's paper is the desirability of allowing some freedom of motion between the prosthetic appliance and the abutment.

He introduces the term mobile bridges, because it expresses the thought that bridges should have a certain mobility, so that their abutments may not be strained more than is absolutely necessary. He emphasizes that mobile, not merely removable bridge work, is in every case to be preferred to fixed work. Gormsen's appliances are not to be mobile to the extent that their mobility is noticeable to the patient, or that the bridge should fall off. At this time we can note that partial dentures well meet this requirement of mobility.

Most of the existing systems for removable bridges can readily be adapted to meet Gorm

sen's requirement. He personally is attached to Peeso's method. In this form of bridge, the mobility can easily be produced when the bridge is finished, by grinding or polishing the telescope caps and split pins so much that they become very loose, so loose that when one has the inner cap of the telescope crown in the bridge, it can be pushed off with a touch of the hand. It is absolutely essential that the abutments be exactly parallel, otherwise the desired mobility cannot be obtained. Gormsen believes that by his method one can make use of abutments which ordinarily would be considered too weak to bear their load. This principle he illustrates by reference to cases in practice.

[La Stomatologia, Milano, March 1918.] Note upon Mottled Teeth. BY PIERGILI.

This note was called forth by the elaborate studies of Black and McKay in the DENTAL COSMOS for February, May, June, July, and August 1916. To these authors the etiology apparently was most obscure, although there was some evidence that there was some correlation, more than pure coincidence, between the pathological condition and the drinkingwater supply.

Piergili quite positively advances his views. The qualitative chemical analysis of the water gives no result, but the quantitative analysis has revealed a common characteristic in the waters of the regions wherein this dental lesion is endemic; a minimum content of mineral salts in general, and of the salts of calcium in particular. This minimum content of calcium salts is the cause of the condition which produces mottled teeth. Chemically, water with its dissolved carbon dioxid has affinity for calcium carbonate. Unless this affinity be satisfied before the water be taken into the mouth, it will (unless the teeth have reached a certain maturity of hardness) dissolve out from the teeth this latter salt.

[Journal of the California State Dental Association, San Francisco, March and April, 1918.]

An Investigation of the Methods of Dis= infection Carried Out in Dental Offices. BY ADAH ROBERTA HOLMES.

This extensive and voluminous report comprises one of the most valuable contributions to the subject. The objects of the author

were (1) to point out the dangers of careless methods of disinfection; (2) to demonstrate positively that such methods are at present practiced by many of the profession, and hence the pressing need for their remedy; and (3) when in any way possible, to recommend a standard inexpensive and efficient technique for dental offices.

In reality the paper is an elaborate compilation of data furnished by seventy questionnaires, supplemented to a relatively small extent by personal visits to dental offices. The first two objects may be accepted as unquestionably attained, although some of the remarks would lead one to conclude that the writer is more or less unfamiliar with the exigencies of dental practice. The third object, which is urgently needed, is left for report at some future time. This must be waited for with great interest. We must not forget that such a ponderous, laborious, and minute statement as this present report is of great worth as a logical and necessary prerequisite to the future report, of immediately practical bearing, on the standardization of an inexpensive and efficient technique for dental offices.

[Lancet, London, March 30, 1918.] On Bone-Grafting in Gunshot Wounds of the Mandible. BY HARRY PLATT, GEORGE G. CAMPION, AND BARRON J. RODWAY. During the past two years more than 500 cases of injuries of the lower jaw have been under treatment in the hospital at which the authors are stationed. The operation of bone-grafting has been performed nine times out of this number. They have found that two distinct types of fracture exist in which the autogeneous bone-graft can be used—(a) where there has been a considerable loss of bony tissue with a resulting gap, and (b) where with comparatively close apposition of the fragments an unstable fibrous union has developed in spite of long-continued fixation by splints. In (a) the function of the graft is to restore continuity; in (b) to bridge over the small gap entailed in any refreshening operation (a refreshening of the healed bone ends). The authors briefly describe eight of their cases. They used grafts from rib, scapula, and tibia, prefering the rib. In fixing the graft, they carefully avoided all foreign materials. Where it has been possible they

maintained immobility by splintage for some time after the operation. The Claude Martin flange-splint has proved of great value, especially where the smaller fragment is edentulous. The 11 roentgenograms which accompany this article demonstrate the mechanical and physiological functions of the graft.

[Journal of the American Medical Association, April 13, 1918.]

The Treatment of Cancer of the Lip by Radium: A Report of Twenty-four Cases. By HENRY H. JANEWAY.

Epi

This brief summary, the result of much work, is both concise and convincing. thelioma of the lip offers favorable conditions for successful treatment, whether by operation or by radium, more frequently than the majority of other forms of epidermoid carcinoma. The reason for this is, not be cause of less malignant tendencies, but rather because of the exposed position of cancer of the lip. Janeway concludes that the degree of success obtained in the treatment of operable cancer of the lip by radium in the series of cases here reported, and the maintenance to date with such regularity of the healed condition in the earlier cases treated, justifies a continuation of the use of radium in operable cancer of the lip. He recommends the application of radium emanation embedded in molds of dental compound, and filtered through the thinnest material, for the most superficial lesions. The use of emanation instead of radium element facilitates uniform distribution over the lesion, and provision for uniform distribution is the most important factor in obtaining a successful result. The superior adaptability of radium emanation for the treatment of cancer makes the use of the element itself obsolete, and for the vast majority of cancers it is inefficient.

[La Restauration Maxillo-faciale, Paris, Février 1918.]

Ionization Applied to the Treatment of Facial Cicatrices. BY HOLLANDE.

Hollande employs a constant current of 220 volts. The strength of the current should be very weak-10 m.a. The passage of the solution of the electrolyte produces its effect upon the cicatricial tissues in proportion to the weakness of the current. He uses potassium

iodid (KI) 1 part in 100 parts of distilled water.

The electrode is generally 5 by 4 cm. Nevertheless its dimension varies according to the extent of the scar. For the face, the electrodes are very near each other. The negative pole is placed upon the cicatrix to be treated; the positive pole, being the farthest, is generally placed under the chin. The positive pole is saturated with the solution of KI. The sittings are given every day for 20 to 25 minutes, during three weeks at least, or about a month. However, in the case of obstinate cicatrices, it may be necessary to prolong this treatment during many months before obtaining appreciable results. Hollande gives the following conclusions: (1) The influence of KI plays a certain rôle in the softening of cicatricial tissue; the scar progressively loses its peculiar characters— color, stiffness, and adherence and consequently permits the play of the underlying muscles; the circulation resumes its course. (2) Adherence to osseous tissue disappears as well as the trophic disturbances. (3) Ionization renders a real service to the surgeon for the repair of scars already freed from the subjacent tissues.

[American Journal of Surgery, April 1918. Quarterly Supplement of Anesthesia and Analgesia.]

Changes Produced in the Blood by Nitrous Oxid-Oxygen Anesthesia. BY THEODORE D. CASTO.

This is an extension of the researches reported in the DENTAL COSMOS, vol. lvii, 1915, p. 881; also vol. lix, 1917, p. 415. The animals used in the present series of experiments were albino rats (Mus norvegicus, var. albinus). The erythrocytes were decreased in number after anesthetization with nitrous oxid and oxygen for from thirty minutes to one hour, the maximum decrease in the twenty animals studied being 70 per cent.. the minimum 1 per cent., with an average of 25 per cent. The leucocytes did not show any change in actual number that was constant throughout the series of experiments. A differential count, however, showed a marked tendency on the part of the poly

morphonuclear neutrophiles to decrease and of the lymphocytes to increase. The hydrogen-ion concentration of the blood was slightly greater in anesthesia than under normal conditions. The alkali reserve of the blood was depleted during anesthesia. This decrease was comparable to that of a mild acidosis in man. Histological preparations were made to determine the rôle of the spleen in the blood changes under anesthesia. In general, it may be said that no evidence was developed to show any profound or even slight pathological conditions existing. There appear to be no radical changes which take place in the tissue of the splenic pulps, the cells, nor in the Malpighian corpuscles of the spleens of those rats which were given a continuous dose of nitrous oxid-oxygen until death supervened.

[Lancet, London, April 13, 1918.] Unilateral Hypertrophy of the Mandible. BY H. P. PICKERILL.

Pickerill has had 3 cases of (apparent) unilateral hypertrophy of the mandible resulting from gunshot wounds. In all 3 cases the injury has been a small piece of shrapnel (about the size of a pea) lodged in the pterygo-maxillary fossa. In none of these cases has there been any sign whatever of infection-the wounds have healed by "first intention." There has been no pain, no paralysis, no anesthesia, no fracture, practically no loss of function, and X-ray examination has in each case been negative. Yet in each case there has been an obviously increasing asymmetry of the face, the chin deviated away from the side of the lesion, and there was marked bulging both above and below the zygoma. The only "positive" sign has been a slight hyperemia of the side of the lesion. Pickerill attributes the asymmetry to vasomotor disturbance due to injury in the pterygo-maxillary fossa, and in one of the cases there was evidence of a deep hematoma due to wounding of the internal maxillary artery.

This note was called forth by a case of the same title recorded by William Edmond in the March 30, 1918, Lancet. In Edmond's case there was no history of injury, and the pathogenesis was entirely obscure.

Matrix. A celluloid strip cut to shape, with two holes punched at the ends, and held in place by the ivory matrix retainer, makes a very good substitute for the metal band. One has the advantage of watching the cervical margin also.-R. McCLINTON, Commonwealth Dental Review.

To Remove Mercury Stain From Gold Crown. If you chance to have your gold crown or bridge discolored by coming in contact with mercury before being cemented to place, heat it to drive off the mercury, and, if necessary, restore the polish with your finest abrasive.-O. V. CALKINS, Dental Review.

After-pain Following Operation.—There is one preparation which will give great satisfaction, and that is a solution of guaiacyl and glycerin. This has been found to be the best preparation for the relief of pain. Orthoform is of service also, but guaiacyl and glycerin in equal parts is an almost unfailing agent for the prevention of after-pain. -L. M. S. MINER, Journ. N. D. A.

Die and Counter-die for Swaging Saddles. After making an impression, take Melotte's moldine, place it around where you want your saddles, and flow it up with Melotte's metal, thereby working your counter-die first; repeat the process with your moldine and make your die in the same manner. Allow this to cool and your gold saddle can be swaged out immediately.— Minneapolis District Dental Journal.

Bismuth-Iodoform-Paraffin Paste.-Bismuth-iodoform-paraffin paste, or "bipp," as it is called, has now many advocates. Its use in wound treatment has spread considerably during the year. The paste consists of bismuth subnitrate 1 part, iodoform 2 parts, liquid paraffin 1 part, and it is applied freely to the wound, which is entirely filled with the paste and dressed, with sterile gauze. In preparing "bipp" great care must be taken to insure freedom from grit.-Amer. Journ. of Pharmacy.

Lysol.-Lysol is a brown, oily looking, clear liquid, with a creasote-like odor. It is made by dissolving the fraction of tar oil which boils between 190° C. and 200° C. in fat, and subsequent saponifying by the addition of alkali in the presence of alcohol. It contains 50 per cent. cresol, is miscible in water, forming a clear, frothy liquid. It is a more powerful germicide than phenol.ADAH ROBERTA HOLMES, Journ. Calif. State Dental Association.

To Desensitize Teeth that Are Sensitive to Scaling. Dry the sensitive part thoroughly. Apply for four or five minutes a hot saturated solution of potassium carbonate in glycerin on a pellet of cotton. Dry the part with warm air. Repeat the application, leaving the cotton in place until the patient notices a burning sensation in the tooth, when the scaling may be continued painlessly. This solution will not cause discoloration.-A. DE VRIES, Dental Review.

To Clean a Blocked Hypodermic Needle. -To unblock long hypodermic needles, screw the needles on the syringe tightly, put distilled water in the barrel, hold the needle in the flame, and apply pressure with the piston. Steam is thus created in the immediate vicinity of the flame, which exerts pressure sufficient to unblock the needle. Bear in mind that passing through the flame removes the temper, and care should be taken in its use.-H. M. HALPERON, Dental Review.

Large Amalgam Fillings in Doubtful Teeth. Sometimes it is expedient to provide for the possibility of having to remove the filling to obtain re-access to canals, and yet to provide a hard filling, or at any rate a filling hard on the surface. The difficulty is met by filling the bulk of the cavity with an amalgam in which tin predominates, and covering with an amalgam in which silver predominates. This filling will be as useful as an all-hard filling, but if it has to be removed it will be easy to do so after having cut through the casing of hard amalgam.— HUGH PATERSON, Commonwealth Dental Review.