APPOINTMENT.

MR. WILLIAM WILLIS, L.D.S.I., has been appointed Honorary Dental Surgeon to the Shibden Hall Industrial School, Halifax.

Obituary.

THE LATE MR. E. P. WARREN, OF BIRMINGHAM. WE regret to have to announce the death of Mr. Edward Pritchard Warren, L.D.S. Eng., of Old Square, Birmingham. Mr. Warren, who was sixty-three years of age, had been in practice in Birmingham for more than thirty years, and was widely known and respected in that neighbourhood.

Correspondence.

[We do not hold ourselves responsible for the opinions expressed by our Correspondents.]

THE ABUSE OF AMALGAM.

To the Editor of the British Journal of Dental Science.' SIR, I have noticed a letter in the last number of your Journal signed "Fair Play." The writer contradicts some statements made by Mr. J. J. Musgrave in a former number respecting the extraordinary use, and (I might say) abuse of amalgam in Liverpool. "Fair Play " tells us that he does not live in Liverpool. Now, Mr. Musgrave's remarks refer more particularly to that city, and as far as it is concerned, I am quite willing to corroborate them. I consider that Dental surgery proper, by which I mean the operative part, is at a very low ebb in Liverpool. There are hosts of second and third rate Dentists here, but the number of educated and qualified men is comparatively very small.

If " Fair Play" will look at the list of Dental licentiates for Liverpool in the Medical Directory, he will find but two mentioned who have the L.D.S. Eng. by curriculum. Fancy the second city in the Empire only possessing two men who have undergone a thorough Dental Education! The number of amalgam stoppings that are inserted here is

really incredible. In confirmation of this, refer to the statement which appears in the advertisement of Davis's amalgam at the end of your Journal, that "one Liverpool Dentist returns thirty-six ounces of waste at one time!" If these fillings were put in in a proper manner, and all of them carefully polished, such excessive use of amalgam might be defended; but I can safely assert that the contrary is the case. For of very many that have come under my notice, nearly all were quite guiltless of anything approaching a polish.

Dr. Waite of this city read a paper a short time ago before a Society of Dentists in America, and in it he attacked, in a very trenchant manner, the wholesale use of amalgam that goes on here. He evidently described the state of things as he had seen them in Liverpool; but I believe that his audience understood him to be describing the practice of English Dentists generally. Of course, if a Dentist finds that his patients are unwilling to repay him for his trouble in inserting a gold filling, he will have recourse to amalgam. And I am afraid that quackery and cheap Dentistry have so spread in our City of Liverpool that recourse to them has become second nature to her citizens. People, even of good position and means, grumble excessively if charged more than a guinea for contour gold fillings that have perhaps taken a couple of visits to perfect.

The only remedy for such a state of things that I can think of, would be for the qualified men to meet together and inaugurate a Dental Society similar to the Odontological Society of London. The Society might hold its meetings in the Dental Hospital, which is rather a good building.

With this suggestion I close my remarks upon the abuse of amalgam in Liverpool. Hoping that you will find space for I am, &c.,

their insertion.

DISINFECTION OF INSTRUMENTS.

Οδους.

To the Editor of the British Journal of Dental Science.' SIR,-In answer to Mr. Prager about guarding against the inoculation of syphilis through the agency of Dental instruments, I think the following plan will prove useful:— After each operation thoroughly cleanse the instruments in bot water, then dry them and smear over the points with the following:

Acid. Carbol., 3j ;
Ol. Olivæ, 3j.

Southampton.
VOL. XXIV.

I am, &c.,

W. H. C.

14

To Correspondents.

1. Communications intended for insertion in the ensuing number must be forwarded to the Editor, at the Office, 11, New Burlington Street, London, W. by the 8th and 23rd of the month, or they cannot be published in the ensuing issue; they must also be duly authenticated by the name and address of the writer.

2. We cannot undertake to return communications unless the necessary postage stamps are forwarded.

3. It is earnestly requested of our correspondents that their communications be written on one side of the sheet only; and we also beg to call particular attention to the importance of a carefully-penned signature and address. 4. All communications relative to subscriptions and advertisements are to be addressed to the Publishers, Messrs. J. and A. Churchill, 11, New Burlington Street, London, W.

5. The Journal will be supplied direct from the office on PREPAYMENT of subscriptions as under:

Twelve Months (post free)

14s. Od. Post-office Orders to be made payable at the Regent Street Office, to J. and A. Churchill, 11, New Burlington Street, W. A single number sent on receipt of seven (penny) stamps.

Communications have been received from Messrs. Chas. Sims (Birmingham); E. R. Showler (Crouch Hill); the Secretary of the Faculty of Physicians and Surgeons (Glasgow); W. C. J. Miller (London); "Odons;" "W. H. C.;" "Right and Justice;" &c.

BOOKS AND PAPERS RECEIVED.

'L'Odontologia.'

'Johnston's Miscellany.'

'Lancet.'

Medical Times.'

'British Medical Journal.'

'Missouri Dental Journal.'

'Correspondenz Blatt für Zahnarzte.'

'Journal of the Chemical Society.'

'Minutes of the General Medical Council,' &c.

NOTICE. We desire that it may be clearly understood that our pages are open to all for free expression of their views on matters connected with our profession. We only ask for terseness of expression and MODERATION IN TONE.

When otherwise unobjectionable, difference of political or other opinion will never be regarded by the Editor as a disqualification for the admission of any communication to the pages of the BRITISH JOURNAL OF DENTAL SCIENCE.

British Journal of Dental Science.

No. 315.

LONDON, MARCH 1, 1881. VOL. XXIV.

A COURSE OF LECTURES ON DENTAL ANATOMY AND

PHYSIOLOGY.

Delivered at the National Dental College during the Winter Session, 1880.

By THOMAS GADDES, L.D.S. Eng.

Lecturer also on the Elements of Histology; Assistant Dental Surgeon to the National Dental Hospital.

LECTURE III.

GENTLEMEN,-In my last lecture I pointed out the general structure and composition of bone in the higher vertebrates. That tissue, when compared with the bone of osseous fishes, presents very great differences; and when contrasted with the bony tissue of cartilaginous fishes there is little resemblance. The higher an animal stands in the scale of organisation, the more distinct and characteristic are not only its various organs, but also the different tissues which enter into their composition. This is a law which we shall find prevailing the animal kingdom. Instances of that law will ever and anon crop up before us in our study of odontology.

Cementum.

Cementum is the most external hard tooth-tissue. It forms a coating of variable thickness over the roots of teeth, and in some herbivorous animals, notably the elephant and ruminants, it also covers the enamel upon the crowns. The cementum is ordinarily said to be absent from the crowns of the teeth of Carnivora, but Mr. C. S. Tomes has observed it on the teeth of Primates, Carnivora, and Insectivora. In man it is present on the crowns of his teeth in a rudimentary condition, known as Nasmyth's membrane.

Cementum, both in structure and composition, is closely allied to bone. Indeed, it can be looked upon as a further differentiation of bone. This correspondence of the cementum with bone, which, when it exists in sufficient quantity, becomes almost identical with true bone, is illustrated by the varieties of microscopic structure which the cementum pre

VOL. XXIV.

15

sents in different classes of animals, and which always corresponds with the modifications of the osseous tissue of the skeleton in those animals. Thus the cementum in osseous fishes, in which the bone is not characterised by lacunæ, does not likewise contain lacunæ.

As cementum ordinarily exists upon the roots of human teeth, it is unvascular. It is only under exceptional circumstances, or where the tissue is thick, that it contains vascular canals, and in this respect resembles bone.

Seeing this relation between the structure of cementum and the structure of the bone of the same animal, and also the difference as to vascularity in cases where the cementum is of various thickness, it will be most expedient to describe cementum as found upon the human teeth.

Cementum consists of a calcified, laminated basis substance, containing lacunæ and canaliculi. According to the composition of the cementum-it containing about 67 per cent. of inorganic matter-it will be seen to be a harder tissue than bone which, as we have seen, contains about 66 per cent. The following table sets forth the chemical composition of the several substances named therein:

The lacunæ are very irregular in size, in form, and in their distribution. Some are comparatively large and others small; and there would appear to be no definite relation between, or arrangement of, the various sized lacunæ.