BH 



////: IHtiKSTIVK M'l'All.lTUB IN UAMM I I.I.I 



stitnting tlic root, and separated from one another by a very marked constriction the 

 n.K-k. This arn\iigcment gives to the tooth tin- form" of a shovel, tin- root representing 

 Hi,- handle (tig- I- 



"The free portion, flattened above and below, and thinnest and widest townr-1 

 anterior extremity, presents two faces an inferior or external, tin other -up. ; 

 internal ; with three borders, an anterior and two lateral. 



The external face, slightly convex, and milk-whit- in colour. N eo\, n d with tine. 



Fig. 163. 



border ; 

 i".r.k-r; 

 border ; 



undulating, longitudinal stria-, which disap- 

 with age, and leave the surface beautifully 



polished iL'. !;:{, a). 



"The internal face, Hatter than the pre- 

 ceding, presents in its middle a slight conical 

 eminence, whose base widens and is termii 

 near the free extremity of the tooth, while its 

 sides are circumscribed towards each border by 

 a well-defined groove (fig. 103, a'). 



"The two lateral borders (the internal 

 slightly convex in its length, the external 

 slightly concave in the same direction) make 

 the free portion appear as if thrown emtw 

 The anterior border is sharp, and slightly > 

 vex from one side to the oilier; it is the lir.-t 

 part of the tooth destroyed by wear. 



"The root is rounded, slightly conical, and 

 implanted in an alveolus of the same form; in 

 youth, it shows at its extremity an opening 

 communicating with an internal cavity analo- 



Portion, external face, outer p^ to that in the teeth ..fS.lipeds. and pn,- 

 '<,', Ibid, internal face, outer |W* '^ *" mtcriOT f ^ G * P" rtl " 

 b. Root ; c, Neck ; /, Anterior <- L OJ \ -K . . 



(i a' Inner border * vir ln to th, the enamel forms around 



the free portion a continuous layer, thinnest on 

 the internal surface, and extending very scantily over a part of the root. 



"The dentine composes the remainder of the organ, and the (pulp) cavity, which 



is originally a large space of the same form as the tooth, is tilled, us the animal grows 



old, by new dentin -, which, as in the Horse, hasa yellower tint than the primitive ivory. 



" When the c.ivity is completely filled, the tooth ceases to grow, and is not pushed 



beyond the alveolus during wear, like the teeth of the Horse. 



' The incisor tooth has scarcely arrived at its perfect envelopment before it begins to 

 be worn. Its horizontal position, and its coming in contact with the pad on the upper 

 jaw, exposes the anterior border and superior lace to friction, and consequent wear 

 from before to behind. The wear, therefore, chiefly affects this upper face, which n ally 

 forms the table of the tooth, and which Girard designated the nrnli: When use- has 

 worn away the conical eminence and the grooves bordering it, the tooth is /< << ll< /. 



"As wear goes on, there appears at first, and at the extremity of the tooth, a yellow- 

 band, which is the dentine denuded of its enamel; and later, in this ivory a yellower 

 transverse band shows itself. With increase of wear, this contracts, then widens, anel. 

 linishc.s by forming a mark nearly square, and then round, which is nothing c!s-- than 

 the recently-formed dentine that fills the pulp cavity of the tooth. It is a veiilahle 

 dent il star, analogous to that in the Horse's tooth, and varying in form according to the 

 incisor iu which it appears. 



" In proportion as the teeth are used, they seem to separate from one an 

 alth .ugh they .-till remain in the same places. This i> t . < HIM tl.. -.-e t. < th, in ymith. 

 only touch) el ca'-h other by their extremities, and as they l>ecaiiie worn they dccn-as. d in 

 Width, aiul necessarily Ix-came separated to an extent varying with their degree of 



Finally, when the tooth I as reached its last stage of wear, then- only remains (he- 

 ro i. tin- in p r pr.rti'in of whie-h. becoming apparent by the retreat of the gum, stands as 

 a ve-11 )w stump, very distant from theise which form with it the re-mains of the incisive 

 arcaele. 



"The first incisors (or milJt-teeth) of the Ox. like those ofthe Heirse, are all deeidnoiH. 

 ami differ from those which replace them by their smaller veilume, h-s width, the 

 transparency of th'-ir enamel, anel th.-ir bein.r mon- curved outward-. Their re.; 

 iniii-h shorter, and nr- i by the succeeding teeth. The two temporary pinoeM 



nre alway.- : by a marked inte-rval. eli pending em the lldckm.-- of tia tihro- 



eartiliL'- in the m:ixi!lar\ Bymphynt during yovth." 



