ORAL EQUIPMENTS. 49 



stronger, and more numerous to meet the requirements of 

 mastication of the more solid foods which form the aliment 

 of the adult. The latter set number thirty-two. An anato- 

 mical preparation of a child's jaws aged 5J years exhibiting 

 the succession of the permanent set of teeth in situ was here 

 shown. 



Commencing in the front of the mouth we have on each 

 side, in both jaws, two incisor or cutting teeth, one pointed 

 tooth called the canine or dog tooth (erroneously called the 

 eye tooth) then in the milk set come two molar or grinding 

 teeth. This completes the deciduous dentition of twenty. 

 In the adult jaws come two teeth which have replaced the 

 temporary molars, and are called by odontologists " premolars," 

 and by dentists (from the peculiar shape of the crowns of 

 these teeth in the human jaw) bicuspids, i.e., teeth with two 

 cusps or points ; and after these in order come three molar 

 teeth, the last one called the " wisdom tooth " or " dens 

 sapiential This makes up the requisite number of thirty- 

 two. I may here remark that the typical mammalian 

 dentition is forty-four as in the horse, but very few existing 

 mammals possess this number. 



As the consideration of the numerical differences of the 

 teeth of animals would lead us into the consideration of 

 dry detail unsuitable for the popular treatment of the 

 subject, this brief notice of the question must suffice for this 

 evening. 



We next saw that a human tooth consists of three 

 parts, viz., the crown, the neck, and the root or roots, and 

 that it is composed of a hard force-resistant substance called 

 "dentine" or ivory enclosing a soft living substance called 

 the "dental pulp" or formative and nutritive organ; and 

 invested on the crown by a hard flinty substance called 

 " enamel," and on the root by a hard substance analogous to 

 bone called the " cementum." 



We also saw that in most of the cold-blooded vertebrates 

 there is an endless succession of teeth ; that, for the most part 

 they are of a very simple kind ; and that they are generally 

 " ankilosed " or fixed directly to a " bone of attachment," 

 without any socket; and that in the Mammalia they are 

 implanted in a distinct socket, into which they are held by a 

 fibrous and vascular membrane called the "pericementum" 

 or " peridental membrane." 



We now see that the number is limited to not more than 

 forty-four generally, the dolphins and porpoises being an 

 exception, as they frequently have as many as 200, and these 



