Treatise on the natural history and diseases of the human teeth : explaining their structure, use, formation, growth, and diseases, in two parts / by John Hunter ; with notes by Thomas Bell.

  • Hunter, John, 1728-1793.
Date:
1839
Catalogue details

Licence: Public Domain Mark

Credit: Treatise on the natural history and diseases of the human teeth : explaining their structure, use, formation, growth, and diseases, in two parts / by John Hunter ; with notes by Thomas Bell. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    Of the Bony Part of a Tooth. The other substance of which a tooth is composed is bony, but much harder than the most compact part of bones in general. This substance makes the interior part of the body, the neck, and the whole of the root of a tooth. It is a mixture of two substances, viz. calcareous earth and an animal substance, which we might suppose to be organized and vascular. The earth is in very con- siderable quantity : it remains of the same shape after calcination, so that it is in some measure kept together by cohesion; and it is capable of being extracted by steeping in the muriatic and some other acids. The animal substance, when deprived of the earthy part by steeping in an acid, is more compact than the same sub- stance in other bones, but still is soft and flexible. That part of a tooth which is bony has nearly the same form as a complete tooth; and hence, when the enamel is removed, it has the same sort of edge or points as the enamel itself. We cannot by injection prove that the bony part of a tooth is vascular; but from some circumstances it would appear that it is so; for the fangs of teeth are liable to swellings, seemingly of the spina ven- tosa kind, like other bones, and they sometimes anchylose with the socket by bony and inflexible continuity, as all other contiguous bones are apt to do. But there may be a deception here, for the swelling may be an original formation, and the anchylosis may arise from the pulp, upon which the tooth is formed, being united with the socket. The following considerations would seem to show that the teeth are not vascular : first, I never saw them injected in any preparation, nor could I ever succeed in any attempt to inject them, either in young or old subjects, and therefore believe that there must have been some fallacy in the cases where they have been said to be injected. Secondly, we are not able to trace any vessels going from the pulp into the substance of a new-formed tooth ; and whatever part of a tooth is formed, it is always com- pletely formed which is not the case with other bones. But, rea- soning from analogy, we have a still more convincing proof in the effecfof madder. Take, for example, any young animal, as a pig, and feed it with madder for three or four weeks; then kill the animal, and upon examination you will find the following appear- ances : first, if this animal had some parts of its teeth formed before of the bony portion of the tooth with which their inner terminations are placed in contact. It is true that there is a trace of animal matter in this substance, according to the following analysis by Berzelius : Phosphate of lime 85*3 Fluate of lime 3*2 Carbonate of lime . 8- Phosphate of magnesia 1*5 Soda and muriate of soda 1* Animal matter and water 1' 100-]