a languor, and a headache which can hardly be borne ; a stranger to the work cannot tolerate it at all. The drying, after the application of this solution, is done as before, in a large air-tight chamber heated to 130° or more. The workmen have often to enter this room and remain in it for several minutes for the purpose of removing dried skins and turning drying ones. The effort against absolute suffocation is tremendous during the performance of this duty.

It is but right to add that in some manufactories, as at Appold's, the principles of common sense in drying have prevailed, and that a ventilating shaft has been introduced into the heated chamber, through which the gases can escape. In smaller manufactories no such provision is made.

A third and serious mischief is produced by the inhalation of the dust during the beating of the dried skins which have been previously soaked in the copperas solution. The dust thus discharged produces constant irritating cough, and the teeth again are almost invariably affected by it; these organs are slowly rendered brittle, and generally carious. The grinding down of the colour stuffs from the crystalline to the pulverulent state leads to similar evil consequences.

I am sorry that I have not sufficient knowledge of the dental art to offer any definite opinion as to the use of arsenical stoppings for teeth, or as to the effects of arsenic in arresting or inducing caries. I think I can pretty safely state, if I have not done so already, that arsenic administered internally as a medicine, and continued for a long period, does no injury to the dental organs. But in regard to the act of filling the teeth with arsenic the dental profession must be the judges. I find much discrepancy of statement on the point amongst dental authors. Mr C. Barrow, in the fourth number of the Quarterly Journal of Dental Science,' maintains that arsenic exerts the same antiseptic properties on tooth structure as on other parts, and that it arrests caries. Mr Matthews, on the other hand, looks on arsenical filling with dread. He is convinced that arsenic sets up inflammation of the pulp and consequent destruction of the tooth structure.

The treatment of the teeth and their neighbouring parts, after the effects of the poisons which have been named, consists rather in the employment of general than of local remedies. In disease produced by the mercury, the local treatment cannot be too simple or too expectant: In all cases, whether occurring during the first dentition or in adult life, it is best to avoid as strictly as possible all attempts to remove the loosened teeth. It is extraordinary, how firmly teeth, which might almost be picked out of their sockets by the fingers during the period of salivation, will refix as the system gets clear of the poison. Above all things, it is advisable not to interfere with the gums. If you lance them they bleed copiously at first, and ulcerate

afterwards. If you leech them, the consequences are the same, or are even more severe. If you apply caustics, ulceration is

also secured.

Local applications in the way of astringent washes may, however, be employed with benefit; and for this intention alum solution is best; it is an astringent, and is not a caustic. I have sometimes added to this solution, when hæmorrhage has occurred, a little tincture of catechu, the active principle of which is the tannin it contains.

To remove the foetor arising from the ulcerated surfaces, charcoal is an efficient remedy. I found more relief from this simple measure than from any other in the last case of salivation I had under treatment. Two or three drams of charcoal were suspended by agitation in a tumbler of water, and the patient was made to gargle freely, and after retaining a portion of the gargle for a little time, to rinse the mouth with warm water simply, so as to remove the dark particles. This process was repeated several times in the day with great relief.

Medicinally, the iodide of potassium is now considered as the best remedy for mercurial poison. The medicine is given in doses of from three to five grains three times daily, in some simple bitter infusion. The theory as to the mode of action of this medicine is, that it eliminates the mercury by chemically combining with, and converting it into the iodide of mercury, a salt which is readily thrown off by the urine.

Hygienically, a great deal may be done. The room of the patient should be ventilated freely. The most sustaining foods should be supplied; wine may be given with advantage, and when the patient is able to leave his bed no delay should be offered. Care is required, however, to prevent exposure to heats and colds, for the mercurialized body is specially susceptible to congestion of visceral organs, and to the subsequent development of a low or adynamic inflammation.

The treatment in cases of poisoning by phosphorus is often made first to commence with extraction of the teeth. A very good illustration of this method of treatment will be found in a case recorded in the last number of the 'Quarterly Journal of Dental Science.' The extraction does no good; on the contrary, if the patient is still at his employment, extraction adds to the evil by increasing the exposure of the surface to the attacking agent. In doubtful cases, and when the patient is not employed at his dangerous business, the extraction of a tooth may be important in a diagnostic point of view. But the true remedial measure, the most speedy, as the most efficient, consists in removing the necrosed part altogether by the operation of excision. The steps of this formidable process are surgical purely, they require modification in different cases, and I must leave the history of these with the surgical authorities. All that the dental practitioner can do in true cases of phosphorous necrosis,

is to form an accurate diagnosis, and to recommend as he honestly may, the speedy performance of an operation for the removal of the diseased structure altogether.

At the same time it is the duty of us all, in so far as it is in our power, to recommend measures for the prevention of this manufactured disease. It seems that several very simple means exist for applying the amorphous or red phosphorus to the same purposes as the injurious white phosphorus. This subject has attracted much more attention on the continent than in this country. Recently MM. Chevalier and Poirier have published a report on this interesting topic, in which, after showing the dangers, accidental and criminal, accruing from our present methods of employing phosphorus in the arts, they suggest the interdiction of the fabrication of chemical matches out of ordinary phosphorus, and the substituting in its stead red phosphorus, either by employing the formula in which the latter substance enters into the constitution of the paste, or by making use of Lundstrom's Swedish process, of which the brothers Coignet are proprietors, and which consists in the preparation of a paste that cannot be inflamed except by friction on a small board covered with red phosphorus.

It is readily seen that matches thus prepared, having no phosphorus in their composition, but requiring friction on a slip covered with phosphorus, would cause a great diminution in a number of accidents. Independently of the removal of dangers arising from poisoning and fires, the employment of red phosphorus, on account of its harmlessness, presents yet another advantage, with reference to public hygiene. It would protect the unfortunate workmen employed in manufactories where phosphorous matches are prepared, from those attacks of necrosis of the maxillary bones, under which they succumb after having experienced sufferings of the most intense character.

MM. Chevallier and Poirier add that they could cite a large number of instances of these affections, which have been the subjects of interesting works by Heyfelder, Rousel, Strolh, Boys de Loury, Chevallier, Perry-Sedillot, Maisonneuve, and LaillerTrélat. These savants have successively determined that the effects of this disease are so much the more terrible, as they are too difficult to cure. According to their accounts, of sixty subjects attacked, more than half succumbed. This number is truly not exaggerted, for both in Paris and in the country there are many workmen who make chemical matches in the same place where their family sleep, eat, in a word, live. How many accidents, how many diseases, how many mysterious poisonings, result from this state of affairs, which would disappear by the employment of red phosphorus !

MM. Chevallier and Poirier consider that the slight difference in price has, up to this time, prevented the substitution of red for ordinary phosphorus; but this difference is so small, that it

cannot be placed in comparison with the danger which accompanies the employment of ordinary phosphorus; and they opine that this slight increase of price will not prevent the consumer from profiting by the advantages which red phosphorus presents as regards hygiene and public security.

No special local treatment is required for the gums in cases of lead poisoning, for the local disease passes away as the general cure is effected. As with mercury, the popular medicinal antidote for lead is the iodide of potassium. The action seems to be the same in both cases, a salt of iodide of lead is produced, and the elimination of the poison by the kidney is provided.

K K

LECTURE X.

[Delivered on February 15, 1859.]

ON DIET AND MODES OF LIFE IN THEIR INFLUENCE

ON THE ORGANS OF MASTICATION.

MR PRESIDENT AND GENTLEMEN,

THE effects of habits and modes of life in modifying the structure of the dental organs have been stated by various authors with so much variety of opinion and so much contradiction, that it would be impossible for the most candid and industrious exponent of the views of authors to offer any shade of independent opinion without finding himself in opposition at some one point or other.

With the fact, therefore, fully before me, that it is hopeless to attempt reconciliation of opinion, I shall strive rather to put the subject forward in my own way, collecting together such facts as experience and reading have placed before me, and commenting upon them in such manner as shall seem most in accordance with common observation and common sense.

In the preceding lectures, much of the groundwork of the present lecture has been occupied. We have in those lectures traced out the constitutional and many of the local causes of dental disorder, the narration of which has led us to notice many other points regarding diet and occupation. I shall therefore, on this occasion, have to supplement, merely, that which has gone before, and if omissions seem to have been made in a subject of such breadth as the one before us, I must intimate that the omissions are intentional, and are made for the sake of avoiding needless repetitions.

For indeed, in a strict sense, the meaning of all our labours lies enrolled in the correct understanding of diet and modes of life. We have urged that the causes of all diseases are external to us, and we to them; we take up the causes of diseases as we