the enamel, the violation of nature in partaking of food producing dyspepsia, the acid eructations of this disease reacting upon the teeth, imperfect development of the teeth, fibrile conditions of the body, etc., etc.

The exciting causes are not so well understood. Many writers on this subject ascribe it to inflammation of the dentition; but if we must accept the usual accompaniments of inflammation--heat, redness, and pain-as the invariable results in other parts, the assumption would fail of support. Still we know that an inflamed part, when pressed upon, gives pain. We know, too, that when the decayed dentine is pressed upon by the excavator in shaping a cavity, pain is likewise experienced. Redness is not manifested, it is true, because the dentine is not so vascular as to admit an excessive flow of blood within its substance, as is the case with the soft tissues, nor can we judge if heat is present as in the soft tissues.

Prof. Tomes, in writing upon the subject, says: "In speaking of the predisposing and exciting causes of caries, allusion has yet to be made to those agents which may be regarded as capable of acting in the double capacity of depriving the dentine of its normal powers of resistance, and of producing its immediate decomposition.

"In considering the subject from this point of view, we must be prepared to admit that the dentine is possessed of vitality, and that that vitality must have been lost before the tissues undergo decomposition. If we take for example the effect produced on the skin by the application of caustic potash, the immediate result is the destruction of vitality in the part with which it comes in contact; and its secondary effect will be the disorganization of the part destroyed. But had the power exerted by the potash been incapable of destroying the skin of vitality,

the succeeding effect that of producing decomposition-would have been successfully resisted.

"In the case of a tooth, the application of potash would not produce conclusive results; but the use of mineral acids would be followed by consequences similar to those mentioned with respect to the skin. The vitality of the part would be destroye.. and decomposition would succeed the loss of life."

It may be said that agents of this active character are not applied to the teeth, but such as have sufficient power to destroy are applied, and it is by taking an extreme case that we are best able to examine the mode of action and the ensuing results.

Litmus paper applied within the cavity of a carious tooth almost invariably gives a strongly marked acid reaction, and thus furnishes evidence of the existence of an agent capable, if unresisted by the vitality of the dentine, of decomposing that tissue of its earthy constituents, leaving the gelatine to undergo gradual decomposition favored by heat and moisture of the mouth.

In examining the circumstances under which the decomposition of the dentine takes place, and under which it is resisted, apart from the influence of vitality, any one must be struck by the power that is exerted by the mere form of the surface involved. Supposing the disease to be situated in a deep fissure, or upon the side of a tooth against which another tooth is placed, the decomposition will go on with more or less rapidity, the rate being varied in accordance with the condition of the oral fluids. But if the cavity be superficial, and so placed that it is subject to friction during mastication, the process will be relatively slow; and if the low wall of such cavity be removed, the part will become polished by the act of mastication and by the motion of the tongue, and decomposition will be completely arrested quite independently of any power of resistance exercised by vital action.

Evidences of these kinds were quite forcibly brought to our attention during our late civil war. Being for a long time engaged at garrison duty we were called upon to practice dentistry to a considerable extent, for the officers and men in the immediate neighborhood where we were stationed. blockade every article, whether of necessity or luxury, rose to fabulous prices in the Confederate States, and dental materials were no exception. The last ounce of gold foil which I purchased while I was practicing in the army I paid $1500 for, and this was by no means its maximum price. All my tin foil was used up, and so with my amalgam; and silver quarters with which to make amalgams, were as scarce as green peas in January. Under these circumstances, wherever I met superficial caries on the masticating surfaces of the molars and bicuspids, I chiseled them out smooth, and this was the only treatment. This was readily accomplished; for, being in the artillery service, facility was afforded to shape, alter or make our chisels at the travelling forge connected with this arm of the

From the effects of the

service.

Again, let a tooth be placed under circumstances the opposite from the preceding. For example, take a bicuspid of the upper jaw, the distal surface of which is decayed, and remove the softened dentine; then let dry cotton wool be forced between the defective tooth and its neighbor, and renewed only once in three or four days; at the end of a fortnight, or three weeks, it will be found that the surface of the cavity, which was left hard

But where wool only is used, the secretions of the mouth are not only not excluded, but are held in constant apposition with the exposed dentine by the saturated wool.

Experiments of this character lead to the conclusion that within the mouth agents are present which, under favoring circumstances, are capable of decomposing the dental tissues, and the source of these agents becomes the next question which naturally suggests itself.

The secretion from the mucous membrane is ordinarily slightly acid, while the salivary fluid, when normal, is alkaline. The result of the admixture of these, if equally proportioned, would be a neutral fluid. In certain conditions of health even the saliva may be acid, and the mucus would then retain its original character after the mixture of the two fluids. Again, the degree of acidity of the mucus may be increased beyond the normal amount, and its tenacity may enable it to remain in certain situations unmixed, and consequently uninfluenced by the alkaline character of the salivary fluid. The quantity of mucus may be excessive, either from a local or a general cause. We not uncommonly find in mouths tenanted by numerous carious teeth, the gums thickened and vascular, and covered with a coating of thick adhesive mucus, capable of being drawn from the gum in long, ropy strings.

When this condition of the salivary fluids is observed, we notice a rapid destruction of the teeth, which leads us to the conclusion that the cause of decay exists in the condition of the oral fluids

that acids, whether from these or other causes, tend to the destruction of the teeth.

Whenever the fluids of the mouth are sluggish, inactive or stagnant, decay seems to be more active in the teeth. Thus in teeth with broad, flat crowns, which ap

proximate by a large surface of contact whereby the fluids of the mouth, or minute particles of animal food, are held in constant apposition with their proximate aspect, we find decay almost invariably present, but when such teeth are well separated, affording only a small point of contact, and permitting the free passage of the fluids of the mouth, as well as preventing the contact of particles of food from lodging and putrefying on these surfaces, we do not find decay to start again in these localities when once removed.

We once filed a semi-lunar notch on the mesial surface of a lower molar, where the second bicuspid was wanting, and, on examining this surface some nine years after the operation, we found that the superficial decay which we had thus treated had been entirely arrested, although the file marks had not been polished out of the dentine. We are therefore of opinion that the predisposing causes of decay are: close contact, irregular arrangement, structural development, febrile condition of the system, a scrofula diathesis, mercurial salivation, indigestion or dyspepsia, low, damp and miasmatic climates, etc.

As for the exciting cause or causes, we incline to the acid or chemical theory. It is true that this has been refuted by the statement that if there existed a superabundance of acid in the mouth which sought a neutralization with some alkali, there was an abundance of tartar generally to be found on the teeth, by which the excess of acid might be satiated; but we cannot consider this a refutation, for we know that the salivary calculus holds a very large percentage of animal matter as one of its constituents, and we know that acids do not combine readily with animal matter, but rather with alkali alone. All acids, too, have various affinities. Thus, sulphuric acid shows little preference for lead, but a great affinity for iron; nitric acid of full strength does not act on iron with as much intensity as if

largely diluted with water. The same acid readily dissolves silver, but will not affect gold, and so may the list be varied ad infinitum. ad infinitum. We know that nitric acid has a strong affinity for lime, and that lime forms a large constituent of the enamel. We know that white decay is most rapid in its action, and when white decay is observed the reaction is nitric acid. Professor Watt, writing on this subject, says: "Now, for the present, assume that white decay is immediately caused by nitric acid, and that this acid is formed by the oxidation of ammonia. As ammonia is composed of nitrogen and hydrogen, its oxidation results in nitric acid and water. Liebig and other authorities state that it is always thus oxidized in the presence of free oxygen. it was in Liebig's day, it is so now. Remember, too, that ammonia always results from the putrefaction of nitrogenous organic compounds."

And if

Now suppose a particle of food remaining between the teeth putrefies-as it will; nitric acid is the result of this putrefaction. This atom of nitric acid acts on the enamel. This action prepares the way for the lodgment of another particle of food larger than the first particle, to be in time converted into nitric acid, until the enamel is pierced, when the action is continued on the dentine-more rapidly on the line of this tissue than on the gelatine. Once the dentine is reached the action is more violent, for as the lime is dissolved away, the organic matter is left. The putrefaction of this gives off ammonia, which is oxidized into nitric acid, to dissolve more lime and to expose more organic material, which putrefying again gives more ammonia, to be again oxidized into more nitric acid, to dissolve more lime salts, and so to continne until the pulp is reached. This, gentlemen, seems to me to be the most plausible theory of dental decay, the parasite theory to the contrary notwithstanding.

GUTTA-PERCHA STOPPING.

CHAS. E. FRANCIS, D.D.S., NEW YORK.

[Note Frequent inquiries concerning the practical value of this material and the method of manipulating it, is the writer's excuse for printing the following communication.]

Among the various preparations for filling carious teeth, gutta-percha stopping holds an exceedingly important place. Cases are commonly presented where defective teeth can be better preserved if filled with this material, than with any other substance. Owing to its nice adaptability to the dentinal walls, together with its slightly expansive nature, it can be made to seal cavities in which it is packed with a remarkable degree of thoroughness.

For bucco-cervical cavities of second and third molars, it will stand for years, and prove exceedingly effective in preventing renewed decay.

It is frequently and advantageously used for packing against cervical walls of large buccal or approximal cavities, prior to introducing fillings of oxy-phosphate of zinc or amalgam; also for repairing large gold fillings with cervical borders slightly undermined.

As a stopping for deciduous teeth, it can be quickly introduced, and in most cases answers admirably; also for impoverished or poorly calcified teeth when attacked by caries, and is peculiarly well adapted in cases of white decay, or where the tooth structure is undergoing rapid decalcification.

As a temporary stopping for early decay in permanent teeth, nothing can surpass, or perhaps equal it, for safety. It holds good until the dentine becomes more dense, and the patient older and better able to tolerate the introduction of compact gold fillings.

In cases where the dental pulp is nearly or quite exposed, protection should be afforded by a covering of oxy-phosphate of zinc to prevent pulpitis, which might be

occasioned by the expansion and consequent pressure of gutta-percha stoppings. Similar care should also be observed where the enamel walls are so exceedingly frail as to become easily fractured.

Although these stoppings are liable to wear away when much exposed to attrition, the surrounding cavity walls usually remain well preserved. They are, moreover, easily repaired or renewed, and with no loss to the tooth structure.

For large stoppings, much exposed to wear, caps of gold plate can be fitted to cover them accurately, on the cavity surface of which may be soldered small loops or T shaped anchors. Such a cap, warmed over a spirit lamp, can be imbeded in or united with the fillings, leaving a firm gold surface on which to masticate.

With a degree of tact and experience, gutta-percha stopping can be manipulated readily and with comparatively little trouble. Cavities should be prepared as nicely as possible, and kept dry while filling is introduced.

Small pellets of the stopping heated to a plastic condition, can be carried to the cavity on the point of a small curved and flattened instrument. Gentle pressure against the walls packs it securely. The excess can be trimmed away with flat heated instruments, and the surface rubbed with burnishers. A bit of cotton or spunk moistened with chloroform, held with tweezers and passed over the filling, will also aid in smoothing it.

Great care is requisite to avoid overheating the material. If warmed over a spirit lamp it must be held considerably above the flame. It is safer to place bits of the stopping on of the stopping on a piece of heated porcelain, or a small covered vessel of boiling water, preparatory to use.

Gutta-percha stoppings, if well impacted in properly prepared cavities, seldom prove treacherous, but as a rule are exceedingly safe and reliable.-Independent

Practitioner.

The present number completes the first volume of THE DENTAL PRACTITIONER. With it all subscriptions which have not been renewed will terminate. We extend a cordial invitation to our old subscribers to continue with us another year, promising not to relax our efforts to make the journal readable and instructive.

To those not upon our lists we say, subscribe now!

We would like to see every dentist in the country subscribe for each of our home journals at least. Many of our most progressive men are doing this, and it is one reason why they are able to keep abreast of the times and be pointed out as progressive dentists.

While we recognize that ours is not the most powerful and influential dental journal extant, still THE DENTAL PRACTITIONER will fill its niche to the best of its ability, and whatever influence it does exert, will be for good and advancement.

In our salutatory occurs this statement: "We propose to add to its pages from time to time until it is as large as the largest and as good as the best."

As a

step towards the accomplishment of this purpose, eight pages will be added to the forthcoming numbers, and we shall spare no pains to make them better than the present.

So we hope to continue, step by step, until THE DENTAL PRACTITIONER shall take its place in the front ranks of dental literature.

It is not our present purpose, however, to extol Dr. How's method of pivoting, but to call attention to the usefulness of some of his appliances in another direction.

In restoring badly broken down and pulpless teeth to usefulness, it is frequently necessary, in order to secure proper anchorage for the filling material, to insert wires or screws in the root canals. Of the two methods, the screw is undoubtedly the best as affording the firmest and most certain support.

The screws we have heretofore used for this purpose were of the regulation pattern, i. e., with head and slot, and were inserted by means of a small screw-driver, often with much difficulty and annoyance, which the shape and size of Dr. How's instruments almost entirely overcome. The shortness of the sockets for holding the drill, tap and screw are so short that they may often be used entirely inside the mouth, thus enabling the operator to insert the screw on the axis line of any particular root, while it would