( ^n ) 



tubuli otliers miglit notarife or branch forth ; but this part of nature's 

 work was infcrutable to me. My conje6hire refpe^ting the matter 

 however was, that each of the boney tubuh (proceeding from the 

 fmall cavity before mentioned) miglit be compofedof many folds or 

 coats, and thus not only be diipoi'ed to diverge or fpread into a 

 larger fpace, fo as to form the fubftance of the tooth, but alfo, by 

 this means, contribute to its ftrength. 



I alfo examined the teeth taken from young hogs, and found them 

 to be likewife formed of tubuli fpreading from the cavity m the cen- 

 ter, to the circumference. 



After this, I was defirous of examining the flru6lure of the hu- 

 man teeth, and having for that purpofe procured a number of the 

 large ones, called tlie grinders, I found them to be formed exadlly in 

 the manner before del'cribed, namely, of tubuli or little boney pipes, 

 clofely joined together, arifing at the cavity in the middle of the 

 tooth, and ending at the circumference or outfide. And in order to 

 explain this formation to the Reader as clearly as pofTible, 1 caufed 

 the following drawings to be made : 



In Plate V.fg. i, at A B C, is rcprefented a human tooth, on one 

 fide of which, with a file, I cut away almoft the half, not to difcover 

 the cavity thereiji, which is well known to moft perfons, but only to 

 fhew the manner how the tubuli, of which the boney part is compo- 

 fed, take their rife from the cavity in the center, and terminate at tlie 

 circumference. But it mufl be underftood, that tliefe tubuli are by 

 no means of the fize rcprefented by the lines in this figure, the fame 

 only denoting the order in which they lie, for the tubuli themfelves 

 are exceedingly fmall, and cannot be well difcerned without the help 

 of the very beR microfcopes. 



In the fame figure, at G H I, is reprefented another tooth, which 

 is filed down from the upper part of it as far as the before-menti- 

 oned cavity, in order to fliew how the tubuli do here alfo fpread 

 themfelves round about from the center. All the extremities of tlie 



