482 ORGANS OF DIGESTION. 



In the formation of a molar tooth, when the body is finished, 

 ossifications shoot from its brim, and proceed to the centre, 

 where, by their union, they form the commencement of two, 

 three, or even more roots. Mr. Hunter says, that also a dis- 

 tinct ossification is frequently found upon the centre of the base 

 of the pulp; and two or more processes according to the num- 

 ber of roots to be formed, proceed to join it from the circum- 

 ference of the tooth ; and in this way the fangs of the multiform 

 teeth begin. 



The secretion of enamel begins shortly after the external la- 

 minae of the bony matter commence being deposited. This 

 secretion, which has its mould always previously formed of the 

 bony part, comes from a pulpy substance adhering to the inter- 

 nal face of the internal capsule. The pulpy substance is placed 

 on the part of the capsule nearest to the gum, and faces the 

 pulp which secretes the bone; whatever eminences the one 

 pulp has, the other has the same, but reversed, so that they 

 exactly fit upon each other. This pulp is best seen in the foetus 

 of seven or eight months, and is not very vascular; it is much 

 thinner than the other, and decreases in size as the development 

 of the teeth advances. That which belongs to the incisor teeth 

 is in contact with their concave interior surface, but in the mo- 

 lar it is opposed to their biting surface.* 



" In the graminivorous animals, such as the horse, cow, &c., 

 whose teeth have the enamel intermixed with the bony part, 

 and whose teeth, when forming, have as many interstices as 

 there are continuations of the enamel, we find processes from 

 the pulp passing down into those interstices as far as the pulp 

 which the tooth is formed from, and there coming into contact 

 with it. 



" The enamel appears to be secreted from the pulp above 

 described, and perhaps from the capsula which encloses the 

 body of the tooth. That it is from the pulp and capsula,,seems 

 evident in the horse, ass, ox, sheep, &c.; therefore we have 

 little reason to doubt of it in the human species. It is a cal- 

 careous earth, probably dissolved in the juices of our body, and 

 thrown out from these parts, which act here as a gland. After 

 it is secreted, the earth is attracted by the bony part of the tooth, 

 which is already formed ; and upon that surface it crystallizes, 



* Hunter. 



