MEMOIRS. 



On the Development of the Enamel in the Teeth of 

 Mammals, as illustrated by the various Stages <t/ Growth 

 demonstrable in the Evolutiois of the Fourth Molar 

 of a young Elepha>t (Elephas indicus), and of the 

 Incisor Teeth in the F(etal Calf (Bos taurus). By 

 George Rolleston, M.D., F.R.S., Liuacre Professor of 

 Anatomy and Physiology, Oxford. ^ (With Plates VI 

 and VII.) 



A naked-eye examination of a spirit preparation of a 

 developing molar tooth of an elephant, such as is represented 

 in PL VI, appears to be sufficient to show that in development 

 the dentine takes precedence of the enamel in the tooth. In 

 such a tooth a certain number of the more anteriorly placed 

 denticles may be seen to be formed of caps of dentine, of a 

 yellowish colour, encrusted, for various distances from their 

 apices downwards, with opaque white deposits of enamel. 

 Posteriorly to the denticles of this composite character, we 

 see a few denticles consisting of dentine alone, upon which 

 no deposition of enamel has as yet taken place; and, most 

 posteriorly of all, we see processes of the dentinal pulp, 

 which, as yet, are devoid of any covering of dentine. 



If, in the second place, we proceed to take note of the 

 capsular processes in which the denticles are enclosed, we 

 shall observe that the inner (reflected) surfaces of certain of 

 these capsules are roughened over by deposit, in correspond- 

 ence with the enamel deposit already noticed on the denticles 

 which they surround. The deposit on the inner surface of 

 the capsule is soft, and consists of cylindriform cells packed 

 closely together, and forming, when their interior surfxce is 

 looked down upon, a mosaic arrangement by their apposition, 

 whilst in the immediate neighbourhood of their exterior 

 (their still attached) surface numerous blood-vessels are 

 seen ramifying. There can be no doubt that we have here 

 the often-described proximal and, as yet, but imperfectly 

 calcified ends of the enamel-cells, which have broken away 



1 Reprinted from the 'Transactions of the Odontological Society of Great 

 Britain,' by permission of the Council of the Society. 



vol. XII. NEW SEK. H 



