40 CLAIMS TO DISCOVERY. 



is made by little depressions in the form of a crescent 

 upon the inside of the mouth of each of the milk folli- 

 cles. These depressions Goodsir called "cavities of 

 reserve," furnishing delicate mucous membrane for the 

 future formation of the pulps and sacs of the ten an- 

 terior permanent teeth — incisor, canine, and bicuspid. 

 The sacs in which the six posterior (superadded) per- 

 manent teeth, or the three permanent molars on each 

 side, which arise from successive extensions of the dental 

 groove carried backwards in the jaw posterior to themilk- 

 teeth are developed, Goodsir named "posterior cavities of 

 reserve," the wisdom tooth being the final development. 



Goodsir looked upon his follicular stage, from the 

 first appearance of the dental groove and papillae, till 

 the latter became completely hid by the closure of the 

 mouths of their follicles, and of the groove itself, as a 

 hitherto unknown stage of dentition. He was the first 

 to point out the peculiar development and character of 

 the anterior permanent molar — the most remarkable 

 tooth in man, as it forms a transition between the milk 

 and permanent teeth : if considered anatomically, it is 

 decidedly a milk-tooth ; if physiologically, a permanent 

 one. No observer had noticed the peculiarity of the 

 anterior molars that Goodsir established ; he did not 

 fail to mark the practical bearing of the growth with 

 the decay of the said teeth. 



The careful investigation of the whole process of 

 dentition in man, and the clear illustrations given of 

 the text, fully justified Goodsir in the conclusions he 

 drew from his researches. The milk or deciduous teeth 



