Hand-book of dental anatomy and surgery for the use of students and practitioners / by John Smith.

  • Smith, John.
Date:
1864
Catalogue details

Licence: Public Domain Mark

Credit: Hand-book of dental anatomy and surgery for the use of students and practitioners / by John Smith. Source: Wellcome Collection.

Provider: This material has been provided by the University of Toronto, Harry A Abbott Dentistry Library, through the Medical Heritage Library. The original may be consulted at the Harry A Abbott Dentistry Library, University of Toronto.

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    of building in the beaver; of climbing and pro- gression in the walrus ; of digging in the extinct dinotherium ; of prehension in fishes ; of poison- ing in serpents; and of speech and appearance in man. Nothing like a common pattern or type of teeth, either in form or position, prevails among animals lower in the scale of being than the fishes. It is only when we rise to them,—be- longing as they do to the vertebrate or backboned animals,—that these organs can properly be recognised as a system. In some of the rotiferae or wheel animalcules, we have a teeth-like apparatus in the stomach. Among these minute animals the Brachionus urceolaris presents an apparatus of this kind, consisting of two little hammer-like teeth, work- ing upon another tooth or dental body, the whole acting like two hammers striking on one anvil, and in this way reducing the food to a proper consistence for subsequent digestion. In the echinus or sea urchin, again, an animal well known on our sea coasts, a somewhat com- plex form of jaws and teeth exists. Five bent and pointed teeth project from that part of the shell forming the mouth ; each of these five