DIVISION I. 



I. ON THE OEIGIN AND DEVELOPMENT OF THE 

 PULPS AND SACS OF THE HUMAN TEETH. 

 PLATE I. 



"II est peu de sujets en medecine sur lesquels on ait tant ecrit que sur les 

 dents ; deux cent volumes contiendraient a peine tout ce qu'on en a imprime ! 

 Mais est-ce a dire que tout soit connu d cet egard ? Est-ce a dire que la 

 matiere ait ete epuisee et qu'il ne reste plus rien a faire? Nullement. 

 L'Anatomie n'a pas encore le dernier mot de la nature sur cet interessant 

 sujet et il reste encore, quoiqu'on en dise, quelques doutes a eclaircir et 

 plus d'une difficulte a resoudre." BLANDIN, Anat. du Systeme Dentaire, 1836. 



SECTION I. EXAMINATIONS OF THE DENTAL ARCHES AT 

 DIFFERENT AGES. 



1. An embryo (Fig. 1), which measured 7J lines from the 

 vertex to the point of the coccyx, weighed 15 grains, 

 and appeared to be about the sixth week,* was selected 

 and prepared for the purpose of examining the state 



* It is difficult to determine the exact age of an embryo. The 

 ages given in the text, therefore, must be considered as approxi- 

 mations, being probably rather under-rated. I have given a full-sized sketch 

 of the youngest subject in which I have observed any of the phenomena of 

 dentition, with the weight and measurements of a few of the others. In 

 researches of this kind, the sequences of phenomena are of more importance 

 than their periods of appearance. 



Velpeau, Embryologie ou Ovologie Humaine ; Breschet, Etudes Anatomi- 

 ques, etc., de I'oeuf dans Vcspece Humaine: Scemmering, Icones Embryonum 

 Humanorum. 



B 



