The complete works of John Hunter, F.R.S (Volume 2).

  • John Hunter
Date:
1841
Catalogue details

Licence: Public Domain Mark

Credit: The complete works of John Hunter, F.R.S (Volume 2). 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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    the feeding with madder, those parts will be known by their remain- ing of the~natural colour; but such parts of the teeth as were formed while the animal was taking the madder will be found to be of a red colour. This shows that it is only those parts that were formed while the animal was taking the madder that are dyed; for what were already formed will not be found in the least tinged. This is different in all other bones, for we know that any part of a bone which is already formed is capable of being dyed with madder, though not so fast as the part that is forming; therefore, as we know that all other bones when formed are vascular, and are thence susceptible of the dye, we may readily suppose that the teeth are not vascular, because they are not susceptible of it after being once formed. But we shall carry this still further: if you feed a pig with madder for some time, and then leave it off for a considerable time before you kill the animal, you will find the above appearances still subsisting, with this addition, that all the parts of the teeth which were formed after leaving off feeding with the madder will be white. Here then in some teeth we shall have white, then red, and then white again ; and so we shall have the red and white colour alternately through the whole tooth. This experiment shows that the tooth, once tinged, does not lose its colour : now as all other bones that have not been tinged lose their colour in time, when the animal leaves off feeding with mad- der (though very slowly), and as that dye must be taken into the constitution by the absorbents, it would seem that the teeth are without absorbents as well as other vessels. This shows that the growth of the teeth is very different from that of other bones. Bones begin at a point, and shoot out at their surface, and the part that seems already formed is not in reality so, for it is forming every day by having new matter thrown into it, tdl the whole substance is complete ; and even then it is con- stantly changing its matter. Another circumstance in which teeth seem different from bone and a strong circumstance in support of their having no circulation in them, is, that they never change by age, and seem never to undergo any alteration when completely formed but by abrasion • they do not grow softer, like the other bones, as we find in some cases where the whole earthy matter of the bones has been taken into the constitution. tahe From these experiments it would appear that the teeth are to be considered as extraneous bodies, with resoect to * • V?- through their substance; but they have nos? certain]va ^ principle, by which means they make pan of the bodu , \ g capable of uniting with any part of Pa tbg body £ will Z explained hereafter. It is to be observed th?t VffZV c ?e whole body have less influence upon the teeth thnn f I °f the of the body. Thus, in children affected ^£^53.°^^ grow equally well as in health, though all th^trTont'a^m^h
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