156 COGSWELL — ON THE HUMAN TEETH. 



Art. X. Comparative Anatomy and Pathology of the 

 Human Teeth. By A. C. Cogswell, D. D. S. 



{Read April 8, 1872.) 



Teeth are the prime organs of mastication, so essential for the 

 proper tritm^ation of food both in man as well as animals. In man 

 they have a secondary relation subservient to beauty and speech, 

 while with animals we find them used and adapted for seizing, tear- 

 in"", dividing, pounding or grinding the food, as well as formidable 

 weapons of offence and defence, aids in locomotion, means of 

 anchorage, instruments for uprooting or cutting down trees, as well 

 as carrying materials for building. Teeth are always intimately 

 related to the food and habits of the animal, and consequently 

 liio-hly interesting to the jjkysiologist, important to the naturalist in 

 the classification of animals, and as zoological characters, are 

 enhanced, by the durability of their tissues, being often the only 

 remains discoverable in the deposits of former periods of the earth's 

 history. Our purpose is not to go into a strict classification of 

 these organs, but merely to name some facts in relation to the 

 peculiar formation, modes of attachment, and singular growth and 

 appearance in many animals, comparing their density and indestruc- 

 tibility to those of man. 



In the Dental system of the fishes we find their number, form, 

 structure, substance, situation, or modes of attachment, present a 

 greater and more striking series of varieties than of any other class 

 of animals. The lancelet, sturgeon, and paddle fish are edentulous, 

 until the number vary and are multiplied in many fish, progressive- 

 Iv, finding the mouths of many crowded with countless teeth. The 

 moveability of the teeth of some fish is peculiar, as in the shark, and 

 the singular fish called the angles- — their base being tied by liga- 

 ments to the jaw, but they have no power of erecting or depressing 

 the teeth at will. In the wolf fish, *' Anarrhicas lupus," the power- 

 ful crushing teeth, made blunt by use, w^th the roof of the mouth 

 almost covered, presents a subject of interest to the anatomist. 

 The muscles of these fish have enormous power, from the constant 

 exercise in crushing lobsters, whelks and other shell fish on which 

 they live. 



