OP LIVING ELEPHANTS 199 



tion, the operation whicli developes and hardens them. This is con- 

 founding two things essentially different, and giving, by ill-applied 

 names, false ideas which may even influence practice. 



But let us return to the molar teeth of the elephant. 



When aU the parts of the body of the tooth are formed and consoli- 

 dated, and that it proceeds from its alveolus, it experiences entirely 

 new changes. 



As the elephant is herbivorous, its teeth are used in masticating, as 

 are those of all the animals subjected to the same kind of food. It is 

 even known that it is necessary for their teeth to be used, that their 

 surface should be in a state of grinding the vegetable substances. This 

 general fact, put very recently in the clearest light by the works of M. 

 Tenon, might prove to him of itself, and independently of all those 

 which we are atter developing, that the teeth are not organized as 

 bones are. Who is not well aware to what consequences the latter 

 are exposed, when they are cut into, or only exposed ? 



The summits of the small dentuli (dentelures) of the lamellae will be 

 first used ; once used as far as the internal substance, each of these 

 summits will present a circular or oval disc of this substance, sur- 

 rounded by a circle of enamel and a circle of the cortical part ; and 

 there wUl be a range of these small circles for every lamella. 



If detrition penetrates to the bottom of the fissures which produce 

 the dentuli (dentelures), all these small circles will be united with a 

 single riband of bony substance, surrounded by a double line of ena- 

 mel, and the cortical substance will form all the round of the plane of 

 the tooth, and will occupy all the intervals of the ribands. Each riband 

 will be the section of one of the transverse lamellae which compose the 

 tooth. 



And if detrition could go as far as where the lamellae are united all 

 into one single base, the entire tooth would now present merely a very 

 large disc of osseous substance, surrounded on every side by a small 

 border of enamel, and another of the cortical part. 



But detrition can never go entirely so far, because it is never made 

 at the same time on aU the crown, just as the consolidation was not so 

 made there ; and here is the reason : — 



The tooth, by its rhomboidal form in the vertical direction, and by 

 its very oblique position, presents its anterior part to mastication much 

 sooner than its posterior portion. The plane or table produced by mas- 

 tication forms, then, with the common surface of the summits of all the 

 lamellae, an angle open behind; and thence it comes that when the la- 

 mellae before are cut into deeply and forn\ entire ribands, the inter- 

 mediate lamellae still present merely transverse rows of circles or ovals, 

 and those behind are entirely untouched, and present the summits of 

 their dentuli (dentelures) in the form of round nipples. 



The anterior lamellae are even altogether destroyed, before those 

 behind are cut much before, and thence results another phenomenon 

 which is also peculiar to the elephant ; it is this, that his teeth dimi- 

 nish in length at the same time that they diminish in height. 



Whilst the exterior part of the tooth is used and diminishes, the 

 portion of the root which corresponds to it is used in another manner, 

 which is more difficult to conceive. On examining what remains of it. 



