Licence: Public Domain Mark
Credit: A manual of dental anatomy : human and comparative / by Charles S. Tomes. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
29/614 (page 15)
![pattei'n found in the Manatee through that of the squirrel, dormouse, and the porcupine, we see how a ver}' definite arrangement, at first simple, becomes modified into some- thing a little more complex, till at last it reaches a degree of complexity that looks like mere disorder. No one un- familiar with the enamel of other rodents, looking at the enamel of the porcupine, would be able to unravel the very indefinite looking chaos of prisms before him; but had he studied forms in some degree transitional he could not doubt that the tortuous, curving course which he saw the prism to be pursuing was nevertheless perfectly definite and precise, and formed part of a regular pattern. It is very usual for the individual prisms, like dentinal tubes, to pursue a spiral course. In perfectly healthy human enamel the fibrillar arrange- ment is not so very strongly marked ; the prisms are solid, are apparently in absolute contact with one another, without visible intervening substance. But B/idecker, basing his conclusions upon the exami- nation of thin sections stained with chloride of gold, holds that enamel is Inult up of columns of calcified substance, between which minute spaces exist. These are filled l)y a material which takes the stain deeply, and is probably analogous to the cement substance of epithelial forma- tions. He states that it gives off exceeding fine thorns, which a])parently pierce the prisms at right angles to 'tbeir length, so that it forms a close network very intimately mixed uj) with the calcified ])ortion of the enamel. It is not of uniform thickness, but is beaded, and Biideckcr attributes to it a role of far greater importance than that of a mere cementing Hul)stance, for he regards it as being an active, protoplasmic network,' whicli renders the enamel niucli more alive than it has hitherto licen considered to be. lie believes it to become continuous with the soft](https://iiif.wellcomecollection.org/image/b21932025_0029.jp2/full/800%2C/0/default.jpg)
