Dr CAMPS had not said that Dr Kidd found any fault with the report, but he merely stated that he thought Dr Kidd was not justified in affirming that local anesthesia was not produced by the local applicacation of chloroform.

THE CHAIRMAN said that the only difference of opinion was as to the production of anesthesia, whether local or general.

Mr BETTS stated that from his own experience of electricity, he was fully satisfied with the results arrived at by the committee; their labours had been extremely arduous, and the report was highly to be approved of for its honesty, and the straightforward manner in which the whole of the experiments seemed to have been carried out by the committee. [Hear.]

Mr PURLAND said that as a member of the committee he had signed the report, and that he perfectly agreed with its contents. But when he contrasted the experiments detailed in the report with his own actual practice he was bound to say that he reversed that judgment in toto, for instead of having at the rate of five successes to sixty failures, he had found that he did not have one in ten as a failure. He did not consider that there was any anesthesia in the matter, but he did believe that electricity alleviated the pain in a most remarkable degree; to a certain extent it removed the impression of pain and altered the condition of the patient altogether: there was something on the mind, and when that was diverted pain was insensibly manifested. He had extracted a great many teeth, as many as ten from one patient at a sitting, and it had been repeatedly declared to him that there was not the slightest pain. Although in some instances the convulsive motions of the patients had shown every indication of the most agonizing pain, yet when awakened out of the trance they had declared that they did not know that the tooth was extracted: therefore it was not quite true that the patients felt pain because their features expressed it. [Hear, hear.]

Dr KIDD wished to say one word as to whether small doses of chloroform produced anesthesia :-there was a law of providence with regard to chloroform; were there was excessive pain a very small amount of chloroform sufficed; and where there was the slightest pain more chloroform was required. If it was very defined pain a very small quantity of chloroform would do. That was the result of the experience of Dr Simpson and Dr Snow. The point was an interesting one, as bearing on the use of aconite and chloroform in these

cases.

Dr RICHARDSON said that Dr Purland and the College were not at issue in any respect; in fact there was no local anesthesia from the intermittent current, but a diversion of sensation. With regard to the application of aconite and chloroform, it had chloroform, it had a direct local effect wherever applied, but that was governed by the mode in which it was applied, and by the rapidity with which it was absorbed. The only use of electricity was that it produced a readier absorption, by the quickening of the capillary circulation.

Mr HARRY LOBB said that the Microscopic Society were aware of that result of the increase of the circulation by the application of the continuous current; and it was known that when the circulation was increased, absorption went on more quickly. Under the microscope this fact could be demonstrated upon a frog, but the intermittent current had precisely the opposite effect; it had the power of contracting the minute arteries and arresting the circulation, that was the difference between the two-the intermittent current arrested the G G

circulation, and the continuous current increased both the capillary and the arterial circulation.

The motion was then carried.

Mr PERKINS returned thanks on behalf of the committee.

The CHAIRMAN also, in rising to express his thanks, assured the members that the committee had been most anxious to do everything they could that might tend to the elucidation of facts. The council of the College had but one opinion, and their desire was to labour hand and heart to develope and exemplify whatever was laid before them. He would also state that the College was increasing in numbers, and indeed going on exceedingly well: the present season, now terminating, was a good augury of the forthcoming session. [Cheers.] There were four conversazione arranged, and an eminent lecturer was appointed to deliver a course of lectures similar to those of Dr Richardson. The school which had been formed would be in good working operation in October next, as its arrangements were well organised. He would also further observe that it was the intention of the College to grant dental certificates, and that examiners had been appointed among whom were some very eminent men, and he trusted that dental surgery would not be as it had been for a lengthened time, but that each and every one who felt an interest in the profession at large would unite, and let all petty differences cease, with one hand and one heart determined to go on. [Cheers.] He hoped that the end of this year would prove that there was but one wish amongst them, to exalt the status of the dental profession, and that all animosity would cease from the present moment. [Applause.]

Mr DOBIE begged to be allowed to express the gratification and high degree of pleasure which he had experienced in listening to the report of Dr Richardson, and also in hearing the satisfactory statement as to the prospects of the Society which had just fallen from the Chairman. He had come up to London for the express purpose of attending this meeting, and he should return to his practice in the country highly gratified and fully rewarded. He begged to move a vote of thanks to the Chairman.

Mr BETTS seconded the motion, which was then carried unanimously.

The CHAIRMAN.-I most humbly and most affectionately thank you for this mark of your respect. I am sure you will allow me to pay the meed of praise which is due to the other branches of the profession. We have many eminent physicians who have sent in their adhesion to us, offering their services to forward our views in every respect; and a great number of members of the College of Surgeons of England have assisted us, and are glad to find that we are going on well. This gives us encouragement to do our utmost night and day to carry on the College of Dentists of England. I am sure that I ought to pay that meed of praise which is due to them as well as to the other branches of the medical profession for helping us, they consider that we ought to be an independent body entirely; and such being their feelings, I hope the College of Dentists of England will live to become an entirely independent body. I thank you for your kind attention, this evening terminating the present session; and I hope we shall meet in health and strength to carry on the ensuing one.

The proceedings, which had been of a highly gratifying character throughout, were then brought to a close.

LECTURE IX.

[Delivered on February 8, 1859.]

ON DISEASES OF THE TEETH AND MAXILLARY BONES ARISING FROM THE EFFECTS OF MERCURY, PHOSPHORUS, LEAD, AND OTHER POISONS.

MR PRESIDENT AND GENTLEMEN,

In the present lecture I shall have to bring before you a subject relating to the special influence of certain poisons on the teeth and their neighbouring parts. I have noted in the syllabus three poisons, viz., mercury, phosphorus, and lead; but I shall not hesitate to refer to one or two more as the occasion may require. The poisons which we have now to consider, as they are tangible poisons, as their chemical combinations are well known, and as their effects on the body are in some measure understood, come before us now with much less of obscurity than certain other poisons which we have already considered. Yet we shall find, in regard to some of these, that on the very threshold of our inquiry difficulties are met; difficulties which experiment truly can solve, but which, up to this time, have not been solved, either by experimental inquiry, or by observation of diseases accidentally induced by the agency of the poisons.

One difficulty of this nature stands forward pre-eminently in regard to the two last-named poisons on my list, phosphorus and lead; viz., whether these poisons produce their injurious effects locally or generally; in other words, by simple application to the parts affected, or by a general influence exerted through the system. This difficulty suggested, a second arises in the inquiry as to the chemical combinations which occur between the poison and the disordered part; and so I might go on pointing out other obstacles to our knowledge which have yet to be overcome, though they are of minor importance.

The effects on animal bodies of the first of the poisons named on our list, viz., mercury, are best known. The action of this

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poison is local as well as general, but the local effect is always secondary, that is to say, is through the system. When mercury is applied to the body topically, its effects appear, but the effects are not confined to the part at which the application was made, they extend to the body at large, and when the spot at which the poison was applied is influenced, the result occurs as in other parts, from an empoisoned blood. The poison is taken up into the circulation, is borne into every structure, is made to lave every structure, and thus universally penetrating, enters into chemical combinations wherever it finds affinities, and produces a general and widely diffused effect.

Mercury, in one or other of its forms, is a poison which finds entrance into the system by any channel. Inhaled in fumes, it passes readily into the blood by the pulmonic circuit; rubbed into the skin it makes its way into the soft tissues, and either by lymphatic vessel or venous, enters the blood's highway. Taken by the mouth, the absorption is as by the skin, but with greater rapidity. Hence, mercury has been for centuries past exhibited as a medicine, and sometimes as a poison medicine, by all these three modes of introduction-by the stomach, in form of pill; by the skin, in form of ointment; by the lungs, in form of

vapour.

In like manner, mercury may be introduced into the body by any one of these means. Men who work in mercury, and who are of uncleanly habits, get the poison admixed with their food; or they absorb it from their hands. In some occupations, too, they inhale it by the lungs. Here the poison, as received by either process named, can hardly be said to be received accidentally; the men are aware of the exposure and its consequences.

Now and then, and perhaps more commonly than is supposed, the body is subjected to the poison in a way more insidious, and in a way purely accidental. Thus, I have an instance before me in which it is recorded that a hospital ward in France was fumigated with mercury for the purpose of destroying vermin. The ward was emptied of its inmates during the process; afterwards, when cleaned and refilled by its occupants, a new form of disease arose amongst them, which ended in the discovery that all of them were more or less poisoned by the inhalation of an air charged with mercury. Every inmate in the ward was salivated, and many weeks passed away before the cause of the distemper could be removed.

The condition of the system during the time when it is affected by the mercurial poison has not yet been sufficiently studied beyond the symptoms which are excited. The blood seems, however, to lose its power of healthy coagulation, it takes on a fœtid smell, and some new compounds are produced in it. The tissues are generally softened, and hæmorrhage from them is a common attendant when they are softened or injured. Ulceration is also

an occasional accompaniment, especially on the surface of the mucous membrane; the spongy parts, as the gums, swell; the action of the salivary glands is greatly excited; the bones are affected with pains, and all the fibrous structures are subjected to a low and spurious inflammatory process.

The effect of mercury upon the teeth varies according to the age at which the poison is exhibited. It is a curious as well as a fortunate circumstance, that young children exhibit a tolerance to this poison, which is possessed at no succeeding age. But infants are now and then, even in these enlightened times, subjected, either by ignorance or accident, to a mercurial course, which is lamentable in its results. If this is done before the cutting of the temporary teeth, the gums are subjected to widespread ulceration, and symptoms resembling cancrum oris are the result. When the period for cutting the teeth comes on, it is attended with much additional suffering, and the teeth evolved are dark, brittle, and notched, becoming speedily carious. I have several times seen children who were merely suffering from the irritation of dentition treated by mercury for some imaginary visceral inflammation, and with consequences to the teeth themselves little dreamt of. The practice of chemists who prescribe calomel to infants for any possible disease, on the kill-or-cure principle, is specially open to this ignorant accident. An infant six months old was once brought to me in my public practice, which well nigh lost its life from emaciation thus produced. The gums along the upper ridge presented a deep ulcerous line, the cheeks were ulcerated, the tongue on its under surface presented a deep, foul, ulcerous patch, and from the fact that pain prevented the introduction of proper nourishment, the body was reduced almost to the fact of dissolution. Under careful nursing, and by withdrawal of the poison, the recovery took place; but the teeth made their appearance in the dark semi-destroyed condition to which I have alluded, they decayed rapidly, and by the time the last molars were evolved the incisors were entirely lost. If I might use the expression, the teeth were shelled as soon as they were shed. After the occurrence of such accidents as these during the first dentition, the teeth of the second dentition not uncommonly suffer; suffer in a minor degree certainly, but in a sufficient degree to impair materially their after usefulness. The teeth thus modified by an interference with their nutrition in the early stages of their growth, are thrown out imperfectly developed. They are often small, dark in colour, brittle, and prone to decay. The pitting of teeth is, I believe, by no means an uncommon result from this cause.

On a previous occasion I referred to the theory held by Dr Harris and many other authors, that the pitting, and the carious tendency obvious in some permanent teeth, are due to the occurrence of the eruptive diseases during the period of the forma