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Note: This text has been automatically extracted via Optical Character Recognition (OCR) software. The text has not been manually corrected and should not be relied on to be an accurate representation of the item.
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Untitled Article
considerable portion of the tipper jaw . They form the greater part of the nose , a large portion c » f the roof of the mouth ; and a share of each orbit of the eye ; at their lower edge they afford a base and sockets for containing the sixteen
upper teeth . ( 5 ) Two palate bones placed at the back part of the palate or roof ok' the mouth , forming ' part of the palate , nostrils and orbits . ( 6 ) The spOiLgn-hones , though called two , are in fact two iu each nostril , so
named from their porous texture : they are covered with the membrane of the nose , which lines universally all the cavities of this organ : the points of the lower pair of these bones form those projections which may be felt by the finger , and from the improper but almost universal practice of picking the nose , very often the most
serious and fatal consequences follow ; and ( 7 ) The vomer , supposed to resemble a plough-share , is a thin flat bone that forms the lower and back parts of the division of the nose . This bone
divides the nostrils from each other , and like the spongy-bones enlarges the organ of smelling by affording greater space for the expansion of the membrane of the nose . The lower or inferior jaio consists
of only one moveable bone and sixteen teeth : the bone is nearly of the form of a crescent , serving as a frame for holding and -working * the lower teeth . The fore-part of this bone is termed the chin , from this its sides extend backwards to what are called
the angles of the lower jaw , here the bone bends upwards at right angles , to be articulated with the head . The lower jaw is capable of a great variety of motion , forwards and backwards and sideways . As the body grows ,
the jaw-bone slowly iu creases in length , and teeth are added in proportion , till the jaws acquire their full size , when the sockets are completely filled , the lips are extended , arid the mouth is said to be formed .
The teeth of an adult are generally sixteen in number above , and as many below , though some people have more and others not so many . The part appearing without the
socket , is called the base , or body , and those parts within , the roots or fangs . ICach tooth is composed of its enamel , and an internal bony substance : the enamel has no cavity for marrow , and is so extremely hard , that neither
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saws nor files will make any impres . sion upon it , but the internal hony part of the teeth is of the nature of the other bones - like them supplied with blood-vessels and nerves , and Hke them it is subject to the disorders of other vascular parts : heuce , > vhen
the enamel breaks or falls off , and the internal part becomes exposed to the air , it soon corrupts , and a carious tooth is produced , hollow within , and having only a very small hole externally . The vessels and nerves enter by a small opening placed a little to
the side of each root , and thence descend to be lodged in canals , formed in the middle of the teeth : here the arteries are employed in replacing the waste constantly made by attrition which they undergo in the act of eating .
The teeth are commonly divided into three classes , viz . the incisores , caniniy and molares or grinders . The incisores , so called from their use in cutting the food , are the four teeth in the fore part of the jaw : the caniui derive their name from their
resemblance to a dog ' s tusks : they are the longest of all the teeth , are plaeed on each side of the incisores , so that there are two canini in each jaw , intended not for dividing or grinding like the
other teeth , but for laying hold of substances : the grinders , of which there are ten in each jaw , are so named because from their shape and edge they are formed for grinding food . The structure and arrangement of all the teeth are evidences of a
wonderful degree of art guided by wisdom : to understand the business properly , it will be necessary to consider the under jaw as a kind of lever with its fixed points at the articulations of the skull : that this lever is worked by its muscles , and that the food taken into the mouth constitutes
the object of resistance to its elevation . In this case the grinders , from being placed nearest the centre of motion , and from their uneven surfaces are calculated to act as grinders , while the canini and incisores , being p laced farther from this point , from tlir those
sharpness of their edges , and overlapping each oiher , as the blades of seissars , are particularly adap ts to cut and tear the food . The first cutting of teeth to most children * attended with much pain and disease , and the symptoms are more or k ^
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436 Natural Theology . No * VII . — Mechanical Arrangement of the Bofy .
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Citation
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Monthly Repository (1806-1838) and Unitarian Chronicle (1832-1833), July 2, 1815, page 436, in the Nineteenth-Century Serials Edition (2008; 2018) ncse.ac.uk/periodicals/mruc/issues/vm2-ncseproduct1762/page/36/
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