DIVISION L 



i._ox tiip: oeigtn and development of the 



PULPS AND SACS OF THE HUMAN TEETH.— 

 Plate L 



" II est pen de sujets en niedecine sur lesquels on ait tant ccrit que sur les 

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

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

 matiere ait etc epuisee et qu'il ne reste plus lien a faire? Nullement. 

 L'Anatoniie n'a pas encore le dernier mot do la nature sur cet interessant 

 suji't et il resto encore, quoiqu'on en disc, quelques doutes a eclaircii- et 

 plus d'une difficulte a resoudre." — Blaxdin, Anat. du Systeme Dcntaire, 1836. 



Section I. — Examinations of the Dental Akciies at 



Different Ages. 



1. An embryo (Fig. 1), which measured 7i lines from tlie 

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

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

 and prepared for the purpose of examining the state )li ) 



It is difficult to determine the exact age of an embryo. The ^■J 



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 ])henoniena 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, Emhnjohfjic on Ovologic Hunuiinc ; lireschct, Etiuhs Anatomi- 

 qius, etc., (le I'auf dcnis ratjtccc Humainr : Soemmering, Iconcs Embnionum 

 Humanorum. 



B 



