Tin: MO rrn. 355 



The follicle which develops these throe elements of the molar t > th. 

 - at the bottom an enormous papilla divided into several lobes, which 

 lie 1 1 Aether for their whole length; lodged in the internal dental cavity, it 

 gradually decreases, like the papilla in the other kinds of teeth, us the 

 cavity liecomes diminished by the formation of new d'-ntim-. ( )pposito to 

 it are two long papilla*, which occupy the enamelled infundibuli. 



It was believed for a long time that the molars of Solipeds were all 



pers; h. This error, founded on the authority of Aristotle, was so 



1 v rooted, that although Ruini, towards the end of the sixteenth century. 



had discovered the existence of two temporary molars, Bourgelat did not 



believe it when ho founded the French Veterinary Schools, and was only eon- 



d when Tenon had proved by specimens, in 1770, that the first three 



of each arcade are deciduous. 



" The replacement of these twelve molars is not at all like what happens 

 with the incisors. The molar of the adult grows immediately beneath the t< m- 

 porary one, and divides its two fangs into four, until its body is reduced to a 

 simple plate and falls off, allowing the contracted summit of the permanent to 

 appear ; and this Arrows up until it is soon on a level with the others in the row. 



The first replacing molar is always a little more elongated than that 

 which it succeeds, and it most frequently expels at the same time the sup- 

 plementary molar; so that if forty-four teeth be developed in the male 

 lb>r.-e. it i- very rare that they are all present at the same time." 



7. Tlie Mouth in General. 



Wo will now consider, as a whole, the cavity whose various parts have 

 studied in detail, and examine, successively, its general disposi'timi. 



ijun-ihj. and nun-nils nli'mlmm . 



Gem ml iL'xji-isition riml i-njim-ifi/ <>f tlic ntf>nth. The mouth being elon- 



_'ated in the direction of the head, offers a great antero-posterior diameter, 



aud two small diameters one vertical, the other transverse. The first 



Is tV- in the l>ase of the epiglottis to the anterior opening of the mouth ; 



the second, from the palate to the floor of the mouth; and the third, from 



one jaw to the other. When the jaws are in contact, the space includi d 



IICKC limits is divided into two regions: one central, the other 



peripheral. The first is circumscribed by the dental arches; the second 



is comprised between these arches on the one side, and the cheeks and 



inner aspect of the lips on the other. It may, then fore, be n-ma: 



that the. capacity of the mouth is almost null in these regions. The checks 



and lips, in reality, lie almost exactly against the alveolar arches, and the 



. in contact with the palate by its superior surface, almost entirely 



till.- the central region. If the jaws separate from one another, and the 



ch.-i-ks recede from the dental arcades, the cavity of the mouth becomes 



enlarged in proportion as these movements are extensive. It must bo 



i i-d that the separation of the jaws is effected in an angular manner. 



and that the dilatation produced in the mouth by this movement is greater 



B than Ix-hind, the opening of tho angle comprised bctwe.-n the t\\.> 



ug directed towards the entrance of the cavity. 



Mucous membrane. The walls of tho buccal cavity are covered by a 

 t< trniiK ntary membrane, which wo have hitherto only examined in parts in 

 th.- different regions it covers, but which, it is to IK; noted, forms here a 



inuous layer, the innmnx i,i< ntlinnn- <//// ,//<//<. 



'I'h.- m. bran - continuous with the external skin at the margin of the 



x 2 



