a tooth caused erosion of adjacent tooth structure, and he inferred that galvanism was the responsible force, although it seems he offered no explanation of the polar quality which must have been exhibited by the tooth structure, holding it to be self-apparent. In his observation is the essence, unstated, of the hypothesis which both concedes and overthrows some of the older theories of dental caries.

In 1912 the writer observed a case similar to that described by Essig. Since then a difference in potential has been recognized in mouths where caries is active, but where no foreign bodies are present. This current was determined experimentally by means of the capillary electrometer," and with its detection came the promulgation of the hypothesis that as there is in mouths where active caries is present a noticeable difference of potential, there is a consequent electrolysis, and an action in progress upon the polar electrodes. The factors which determine the constancy of the presence and strength of the phenomenon are not concerned in recognition of the principles at work.

FACTORS IN THE INSTITUTION OR MODIFICATION OF ELECTROLYSIS IN THE MOUTH.

Under detailed consideration of the passage of such a current, whether a tooth is to be regarded as a whole as a positive pole (as its elements would indeed indicate it to be), whether the enamel is to be considered slightly more positive than the adjacent dentin through

5 A combination in circuit of a vertical glass tube drawn into a fine capillary and holding mercury, the lower end of the tube supported in a sulfuric acid (dil.) bath in the bottom of which vessel is a layer of mercury. The mercury is put in circuit through the sides of the two containers with the articles whose difference of potential is to be noted, and a microscope used to note the fluctuations. The mercury in the capillary moves in the direction of the current upon momentary contact. The string-galvanometer would probably be a preferable instrument, but the writer had none at his disposal.

a fissure or an abrasion, or the cementum slightly more negative than either, or vice versa, the point remains that there is in progress an electrobiolytic action. very largely responsive to obscure variations in mouth conditions.

The views held in the light of modern scientific philosophy relating to osmotic pressure, and ultimate diffusion against odds under prolonged sustenance of pressure, appear to coincide with the theory held regarding a constant action, however nearly infinitesimal, long continued.

The presence of galvanism holds still further significance when we consider the remarkable activity of colloidal substances in acidulated media, and the probable relation of the theory properly ascribed to Miller dealing with the activity of acids in caries to the principles of electrolysis and osmosis. It has many times been contended, even in the same discourse that lauded the work of Miller as a possible answer to the whole question, that his theories left something to be desired, and indeed it is a too improbable idea that the action of the mouth fluids alone might cause disintegration of the teeth. While the work of Miller and that of Michaels remains incontestable as to its actual data, it is in theorizing and the hope of discovering some one cause that there appeared an error, or at least a disposition to advance ideas not easily acceptable. Miller expressed in his later papers-before his death in 1907 he appeared to embrace

See footnote 3. It may be mentioned that it appears that substances which exert a definite osmotic pressure when in the body exhibit no such property when isolated, and Reid (Journal of Physiology, 1905) supposes that in the body proteins are closely allied with certain other unknown substances whose nature is either so obscure or so delicate that any attempt to isolate them would necessarily change their nature, and which themselves are indiffusible, but which, when existing normally with the proteins, render both capable of exerting feeble osmotic pressure. This is interesting to us chiefly because it shows the utter difficulty of setting up experimentally conditions similar to those in the mouth with any degree of surety of reproduction.

his theories for a time as proved-his belief in a course of operation of the features of the process of decay which entirely harmonizes with the theory under discussion, and these are the most rational of his papers, as it is possible to gain from them the clearest picture of an experienced practitioner's idea of dental caries, separate from his unproved theories. To Kirk, writing in the DENTAL COSMOS for January 1914, page 11, it was apparent that it was necessary to consider the etiology of caries "from a different angle of view from that which has characterized our mental attitude ever since the disease has been seriously studied at all." That the influence of secretions of the ductless glands has a profound effect upon the body metabolism is synonymous with the statement that they exert also a subtle influence upon the electrolytic qualities of the saliva-which, however changeful, are ever present and possibly an effect upon the teeth as electrodes.

In writing at that time Dr. Kirk appeared to find a reasonable position, and gave due credit for the valuable work hitherto done to discover causative factors, and his article practically summarized the ideas of value that had been put forth at that time. That much definite knowledge has been accumulated as to mouth conditions is a necessary point to bear in mind in the formulation of any explanation dependent upon new data.

There are no important difficulties in the advancement of the electrobiolytic theory of dental caries. Undoubtedly chemic and biochemic phenomena are advanced by the electrolytic changes that are constant in the presence of caries. It appears probable that in the light of peculiar conditions affecting the quality of the electrolyte, chemical factors will modify the operation of electrolytic changes in the mouth.

POSSIBLE COURSE OF THE PROCESS OF

ELECTROLYSIS IN THE MOUTH.

The ultimate definition of the status of the tooth structures in setting up different potentials, the location of the polar

8 See footnote 2.

charges, and the profound effect of the constituency as well as the reaction of the saliva on the presence and strength of electrolytic action, are points to be worked out. The early work of Jenner and of Pasteur is none the less logical on account of the exceedingly complex occupations and researches that have grown out of the older clinical work. The relation of the presence of various types of caries to further progress of electrolysis and the tendencies toward polarization, and the destruction of the poles as such through loss of their mineral content and the remainder of the endproducts10 of the process are under consideration.

Finally, among modifying factors study is being made of the influence of foreign bodies in the mouth-fillings, etc.--and of the possibilities of the introduction of correcting and nullifying measures11 for the attenuation and oblit

'The presence of a solution of one of its salts about the location of an electrode makes it non-polarizable, and it will be seen that this means of upsetting electrolysis in the mouth must be discarded, and the feature regarded as one disposing the scene to greater activity.

10 The work being done on the actual endproducts of the process of electrolysis in the mouth, and the nature of the matrix of cavity decay as refuse from the process, promises to be interesting in its results.

11 In connection with this theme Dr. Kirk referred the writer to the related literature

"growing out of the warfare which was waged by the so-called New-departurists in the late seventies of the nineteenth century, the chief exponent of the electrolytic theory at that time being Dr. S. B. Palmer of Syracuse," and directed attention "to the Transactions of the

Odontological Society of Pennsylvania for 1879 (published in the DENTAL COSMOS for 1879, page 623, and 1883, page 86), containing material by Bonwill, Register, Essig, Jack,

and others."

These pages are of great interest in that they indicate the probable value of clinical observation in the institution of a state which we may term insulation, and show the importance of consideration of all chance data for the possible determination of measures which will affect the process of electrolytic decomposition in the mouth.

Dr. Kirk's communication is quoted fur

eration of differences of electrical potential.

It is gratifying that the evidence in connection with this theory bears out the work of those advocates of the preparation of all tooth surfaces to a condition of irreproachable smoothness. This, it will be noted, is the condition of an inefficient electrode, and as we may never be able to obtain under the complex mouth conditions a state of polarization,

ther: "These references deal especially with the galvanic relations of gold or amalgam when in contact as fillings in the same or adjoining teeth. You may be interested in two personal observations relating to that matter. About 1882 or '83 I had occasion to examine the mouth of a woman who had applied to me for dental service, and I found very extensive amalgam fillings inserted on the approximal surfaces of her upper first and second molars in contact with large occlusal fillings of gold in the same teeth. The approximal cavities had been originally filled with gold, but recurrent decay had loosened the approximal fillings, which had been replaced by amalgam without disturbing the gold fillings in the occlusal surfaces. Extensive recession of the gum from gingival disease had occurred, and the amalgam reached almost to the bifurcation of the roots of the teeth. The margins were, however, absolutely perfect, and the fillings quite black. Nevertheless the entire operation was manifestly preserving the teeth, as the patient told me that the fillings had been inserted by the late Prof. James E. Garretson some fifteen years previously.

"As the combination of gold and amalgam in the same tooth in that way was at that time under serious condemnation by the best operators, I was struck by the success which had attended the use of amalgam and gold in this particular case, and was led thereafter to adopt the same method in similar cases, with equally good results. An interesting point in regard to the matter is that in all cases where the amalgam seemed to completely arrest recurrent decay its exposed surface quickly became quite black, so that the amalgam filling looked like an inlay of lignite or some other similar black material. In a few instances where the surface of the amalgam remained bright it became rapidly eroded, a condition which I attributed to the difference in salivary composition, the actual difference being that the saliva in these latter cases was found to be acid.

it appears probable that this measure will for all time constitute our sole preparation of the teeth to simulate a state of electrolytic inefficiency and consequent inactivity as electrodes.

The opportunities to explain in a reasonable manner all the known features of our clinical work dealing with caries and our accumulated knowledge of mouth conditions in their bearing upon the process of caries in alignment with

"The other case occurred in the practice of the late Dr. Isaac S. Fogg, with whom I was for a number of years associated as a partner. He had as a patient a lady of refined tastes and large wealth who when she first came to him as a patient had a lower left molar filled on its occlusal surface with amal

gam, which had turned black. This filling was the only one in that particular tooth. The rest of her teeth so far as they needed it were filled with gold. On several occasions this patient objected strenuously to the rather unsightly appearance of the dark amalgam surface, and requested Dr. Fogg to remove the amalgam and replace it by a gold filling. This he was reluctant to do, because the amalgam, which was well finished, was perfectly preserving the tooth. However, the patient still insisting, he acceded to her request, but compromised by cutting out about half of the amalgam filling, making a cavity of sufficient depth to hold a superimposed layer of gold. The operation was completed and thus consisted of a composite filling the under portion of which was amalgam and the exposed portion gold. The operation was finished in the late afternoon. The next morning the patient returned with a history of intolerable pain of a peculiar character, which from her description evidently arose from an irritated pulp from galvanic shock. I was called in consultation by my partner, and mainly for the purpose of testing the galvanic theory I suggested that a small hole be drilled through the center of the gold filling, the hole to be filled with amalgam so as to bring the two metals to the surface exposed to the action of the mouth fluids, my thought being that I would thus be able to switch the galvanic circuit from the pulp and confine it to the two metals. The procedure was carried out, and the moment that contact with the oral fluids was established with the amalgam through the hole drilled through the gold filling as above indicated, the pain ceased and did not return again."

this theory are numberless,12 and many must be left to further meditation and resolution to work out accurately those questions which the operation of these principles will bring to the minds of all observers.

If we consider a schematic case in which are existent all the hitherto supposed predisposing causes of caries, the presence of acids, bacterial growth, colloidal deposits (gelatinous plaques), mycoidal fermentation, various forms of systemic disease and altered body metabolism, the peculiar deviations in the functioning of the ductless glands, or any of the perplexing forms of caries. where there is no apparent cause aside from that under chief consideration, and where the mouth is kept scrupulously clean by every known artificial measure -that case will show the presence of differences of electrical potential; and

12 It would appear that the enamel, having 97 per cent. of earthy material, on account of its greater compactness offers greater resistance to electrolytic forces than the dentin, with 72 per cent. earthy material.

whether that alone is the causative agent (and its strength in some observed cases indicates that it well may be), or merely the correlative of other factors, it is not the task of a moment to discover.

It is not difficult to recognize that the definite laws of the behavior of electrical phenomena which are in operation in the mouth may offer a groundwork for investigation of those forces which, beset on every hand by modifiers which approach in complexity the secret of life itself, split up the normal tissues of the mouth.

It becomes necessary to investigate every chance means of elimination of an influence which, though at nearly all times bordering upon the infinitesimal, becomes by its cumulative effect a menace to the preservation of the teeth; and in the solution of its elimination is the hope of salvage of the teeth. The means will be simple, and the recognition of a means to alter this influence will bring benefit to the individual not so much as to the

race.

387 MAIN ST.

T

HE public advocacy of advanced ideas demands endless reiteration. The repetition must be so continuous, if possible varied, and long-maintained, that at last by the action of certain psychological sequences people begin to suppose that these ideas and arguments are their own, and that the advocate is a platitudinarian. It is only when, having long thought him mad, they think him dull, that he may congratulate himself on having done his work." (1)

I would be surprised if any member of this society should raise his voice in condemnation of the practice of logical asepsis in relation to any and every operation within the oral cavity; still I should meet with a surprise-no, two!-if 50 per cent. of those present do go through with a root-canal treatment and filling, maintaining a thorough asepsis, at the same time preserving the integrity of the surrounding vital tissues, with the methods and appliances now in use in the majority of offices.

I am not trying to hold my profession up to ridicule, for the dentist is as conscientious, capable, and thorough in his sterilization and general asepsis as other sections of medicine, excepting surgery; surgical practice stands upon asepsis as upon a rock, and it is for us to "observe, reflect, and record."

I do not call to mind a single operation in daily practice that does not call for surgical cleanliness. At the same. time I remember the scores of offices that I have visited; and when I examine the

various office appliances and equipments that are placed on exhibition by dental supply dealers and above all, when I remove the veil from my own eyes, or have it removed through the experience and observations of two years' service in and about the surgical pavilion of a large hospital, and study my own office and practice I have to admit that we have not kept pace with the growth and development of aseptic surgery.

S. Mark White, M.D., University of Minnesota, in a paper read during the Panama-Pacific Congress in San Francisco, said: "For the most part dental asepsis has not yet reached the perfection of the surgical operating rooms; it becomes apparent that the methods used are such as to invite rather than prevent infection. This is a question, however, for the dentist."

Again does another branch of the medical profession give us a truth that cannot be passed over lightly. Practically the same statement has been made over and over again by dentists, but do we as a profession make a whole-hearted effort to meet the situation? Suppose we examine our equipment and technique. With your consent let us analyze my own office and methods-for I myself have come up through all the phases of dental practice since 1877, and I have had, and still have, many things to learn.

In my own operating room the varnished walls are washed down once every week; the furniture is kept comparatively clean and free from dust; the linoleum floor is mopped every morning; no uphol