This difficult and delicate operation cannot be practised in the infant, nor even in the young child. It should only be undertaken in adult age, about the age of eighteen or twenty, when the docility of the subjects may aid the surgeon in his manoeuvres, and in the treatment consecutive to the operation. Consequently, I shall no longer dwell on this subject, which belongs to the surgery of adults.

CHAPTER III.

ON THE PHYSIOLOGICAL PHENOMENA OF DENTITION, AND ON THE
SYMPTOMS WHICH ACCOMPANY THE DENTAL IRRUPTION.

The process of dentition was formerly considered as the almost
exclusive origin of the greater number of the diseases of children.
This is a serious mistake, one very extensively diffused, and especially
adopted; it will be as difficult to rectify it as most of the popular
medical prejudices, primarily sanctioned by the errors of physicians.
It is, then, necessary to study afresh the phenomena of dentition,
in order to establish from observation of the patients what is their
true influence on the development of diseases. This is what we shall
attempt in this chapter. As we shall see, there is but a very small
number of diseases which are really the result of the process of
dental irruption.

I shall first describe the physiological phenomena of the dental
irruption according to MM. Richerand and Bérard.

About towards the end of the seventh month the inferior middle incisor teeth pierce the tissue of the gums. (Shortly afterwards the corresponding incisors of the upper jaw appear, then the superior lateral incisors, and lastly, those of the lower jaw.) This order of irruption slightly differs from the order indicated by physiologists, who admit the irruption of the inferior lateral incisors before the appearance of the superior lateral. The above order is that of nature. I have very many times had the opportunity of observing it in the practice of M. Trousseau, who acquainted me with this disposition.

The first small molars, four in number, succeed the incisors, leaving between them and the incisors a space which at a later period the canines fill up, the irruption of which is generally more tedious and more difficult; the second small molars soon follow the canine; these small molars are larger than the corresponding teeth of second dentition. When towards the end of the second year these twenty teeth have appeared, the first dentition is accomplished; the life of the children is more assured; it was previously very uncertain, since the calculations

1

*

on the probability of human life prove that a third of the children who are born in a given period, die before having attained the age of twenty-three months. To these twenty teeth two new molars are added to each jaw when the child has arrived at the end of his fourth year. These last will finally form the first great molars; they differ from the preceding in that they should remain during the whole life, whereas the primitive or milk teeth fall at the seventh year, in the order according to which they appeared in the jaws, and are replaced by new, better formed teeth, larger (with the exception, however, that the small milk molars are always larger than those which replace them), and the fangs are longer and better developed. Towards the IL ninth year, two new large molars make their appearance beyond the first; the child has then twenty-eight teeth.) Dentition is sometimes complete from the eighteenth to the thirtieth year, and sometimes even much later. The late, or wisdom teeth, to the number of two on each jaw, appear at the most distant part of the alveolar border.

The order which is observed in the successive irruption of the teeth is by no means so invariable as not to be frequently disarranged. E The superior incisors are, in fact, very often observed to appear before the inferior incisors, and all the small molars present themselves before the canine, &c. As Richerand observes, with respect to dentition, like all the processes of the living economy, instability forms its principal character. An attentive examination will soon demonstrate with what irregularity these phenomena proceed, which, whether physiological or pathological, appear most subjected to certain calculable and determined periods.

This double row of teeth which follow each other, existed in the jaws of the fœtus. Each alveolus, at this period of life, enclosed two membranous follicles, one placed over the other. That which should form the primitive tooth first swells; a calcareous matter incrusts its surface, and forms the body of the tooth which thus invests the follicle by which the bony part is secreted, in such a manner that the development of the little bone being finished, the membranous vesicle in which the dental vessels and nerves ramify, is observed in the centre of its body, and adheres to the walls of its interior cavity. The tooth is then a calcareous substance secreted or rather excreted by the dental vesicle; vessels ramify in the walls of this vesicle, and prolong themselves into the osseous substance; this is at least what may be presumed from the intimate adhesion of the membrane to the bone. The primitive dental germs are attached to those from which the second Identition is to originate; a membranous prolongation unites them, and in order to be continued from the former to the latter, escapes by the small openings with which the alveolar border is pierced. It is by these small openings, of which Sabatier, Bichat, and Boyer make

сс

no mention, that the secondary teeth issue, the germs of which are behind the primitive teeth. Fallopius was aware of this communication of the dental germs and the small holes, foramina (Soemmerring), which allowed the teeth of the second dentition to pass. It is then a mistake to attribute their discovery to these latter times.

It is not a difficult matter to state why the irruption of the dental germs is successive; why, in the seventh year, the primitive teeth become detatched, and are replaced by others which have remained so long imprisoned in the thickness of the alveolar ridges. The jaws, and consequently the alveolar arches, increase in dimension with age; the arch enlarges, so that the primitive teeth would not be sufficient to furnish it if nature did not replace them by other larger and more numerous teeth. The guinea pig, the little animal so often made use of in our experiments, that it may be very reasonably termed the victim of physiologists, presents this singularity: the teeth are not renewed, but push forward, and proceed from the alveolus in increased size, in proportion as friction destroys them, so that they are sufficient to furnish the alveolar border. The same thing is observed in rabbits.

It is with dentition as with all the other phenomena of the animal economy; it presents an innumerable multitude of varieties with regard to its period, duration, &c. (Thus, the teeth have been observed to appear, for the third time, in people of very advanced age. Several cases are also related, but they are very rare, of children brought into the world with two incisor teeth in the upper jaw. Louis XIV was an instance of this. Bandelocque observes that the irruption of some of the teeth before birth is not always the consequence of an extraordinary development in the child, nor the presage of a better constitution, and proves it by several instances. Lastly, supernumerary teeth tend to establish the fact that the phenomena of dentition are subjected to the irregularities that most of the other phenomena of life are, whether physiological or pathological.*

The dental irruption is always modified by rachitis. When this alteration of nutrition makes its appearance before the sixth or seventh month, the period for the exit of the first teeth, their evolution is considerably retarded; when, on the contrary, this rachitis appears in the course of dentition, this process is arrested, and is not resumed until the rachitis has been cured. Nothing is better established than ... this fact, which serves daily for the diagnosis of rachitis before the occurrence of any other symptom.

OF THE SYMPTOMS OF DENTAL IRRUPTION.

It is not always an easy matter to determine the influence exercised * Richerand et Berard, Eléments de physiologie. Paris, 1832.

C. F. Burdach, Traité de

by the process of dentition on the development of diseases of children at the breast. It is evident that it is not sufficient to prove the appearance of a disease in the course of a dental evolution, and to conclude from thence that it is the cause of this morbid manifestation; we must further appreciate the relation which unites these two phenomenaren together, and to discover if their existence is the result of a coincidence,

or if, on the contrary, a relation of causality should be established between them.

Thus, all the diseases of children at the breast are developed at the time of dentition, since this process commences about the seventh month after birth, and terminates at the end of the second year. And are dildren at we then to say that all these diseases are the result of the dental evolution? Assuredly not; but there are a certain number of them the Fortest? which only appear at the time of the irruption of a tooth, and which reappear every time on the return of a similar occasion. These last may be regarded as truly symptomatic of dentition, and numerous facts appear to establish the reality of this coincidence.

The pneumonia which is developed in a young child about to cut a tooth has no relation with this phenomenon, since it is not reproduced each time that a fresh tooth is ready to pierce. Diarrhoea, convulsions, inflammations of the mouth, on the contrary, which, amongst some children, are observed each time that the inflammation of the gums 284, announces the dental irritation, are intimately allied to this physiological phenomenon.

The symptoms of dentition are local and general. The first are those Symptoms which are developed in the mouth as stomatitis, apthæ, membranous productions, &c. The general symptoms are certain diseases of the utilien skin, the intestine, and the brain. These are also termed sympathetic symptoms.

At the time of dentition, the gums are always red and swollen; but in some children this swelling is very considerable and accompanied by very acute pain. The examination of the interior of the mouth is sufficient to appreciate the redness and swelling of the mucous membrane; the pain manifests itself by the cries of the little patient Pai who is constantly weeping, and in some measure by the attack. There are no other alterations than those of the mouth which can explain t these cries. In these cases, the salivation is very considerable, the saliva running out of the mouth in abundance. Sometimes the children keep the mouth open, the lips forcibly separated, and they incessantly apply their hands to their gums, as if they would indicate the seat of their suffering. They labour under fever which is very irregular; it is either continued or intermittent; their sleep is much agitated, and often interrupted. Nothing will calm them, not even the nurse's breast, which they sometimes refuse, or pettishly leave it after having seized it. Talun

Proitation of child

When the stomatitis, consequent upon the dental irritation, is more considerable, apthæ are observed on the buccal mucous membrane, and on the lips ulcerations which are covered with membranous productions. These alterations do not differ from those described under the head of diseases of the mouth. The same treatment is suitable in these various circumstances.

When the children are observed in the position we have just described, the mouth should be washed with an emollient, mucilaginous liquid. The mucous membrane should be frequently touched by a piece of cotton wetted with a decoction of the root of marshmallow or with that of linseed. Neither poppy nor opium should enter into any of these preparations.

A piece of the root of marshmallow, or of that of liquorice, may be given to the children to bite. An emollient liquid after a little time escapes, which may calm the inflammation of the gums. Moreover, pressure on these parts favours the exit of the tooth, and slightly lessens the pain which the patients experience.

It is much better to make use of these substances which become soft on being moistened, as dry figs, a crust of bread, &c., than to recommend the use of ivory, glass, or coral. These hard bodies may, on the contrary, irritate the gums, probably harden their tissue, and rather retard than favour the irruption of the teeth.

If the fever is very high, and accompanied by congestion towards the head, irritant pediluvia, with mustard, or soap and water, sinapisms to the legs, and leeches to the ears, are the most suitable remedies to be employed.

Lastly, there are some cases in which the gum is so red and so swollen at the situation where the tooth is ready to pierce, that it is thought the tension of the parts might be remedied by a slight surgical operation. Lancing the gums has been recommended; this operation is practised ca with a small instrument made on purpose, or with a bistoury. It consists in a crucial incision, or in an elliptical incision which entirely removes a small slice of the gum from the place of exit of the tooth. Of these two, it is better to employ the last, for the other is often useless; the edges of the crucial incision unite again, and if cicatrization takes place, the irruption of the tooth is retarded, a result quite opposite to that we wished to obtain.

This operation has been very differently judged of by medical men; it is proscribed by some and adopted by others. It is seldom practised in France; but, on the contrary, it is in very common use in England.

It neither deserves the blame which some throw upon it, nor the praises which some bestow on it. It is a useful operation which may sometimes render great service. It remedies the extreme tension of the gums, occassions a slight loss of blood which is salutary; and lastly, leads to the irruption of the tooth.