356 Memoir upon living and fossil Elephants. 



was an old id a maintained by Pausanias *, refuted by Phi- 

 lostratus, and which no pi-rsou adopted a'lv U)nger. 



On the contrary, the greatest part of the anatomists who 

 think that teeth grow Uke common bones, by a kind of in- 

 tus-susception, take their proofs from ivory, its diseases and 

 its accidents. 



Nevertheless, ivory is formed, like the other teeth, from 

 successive layers being transuded by tlie pu'py nucleus. 



1 opened the alveolus and the bare of a tusk in a recent 

 carcase of an elephant ; and here I saw evidently a pulpy 

 Ducleus of enormous size, and entirely dtprived of all or- 

 ganical union with the tusk, which it had nevertheless se- 

 creted. Alihough the carcase was periecily fresh, I could 

 not see the least adherence between the tusk and Uie nu- 

 cleus j not the least fibre, nor the smallest vessel ; no celiu- 

 losity tied them togithtr. The nucleus was in the cavity of 

 the tusk, like a sword in its scabbard, and only adhered by 

 itself to the bottom of its alveolus. 



The tusk is therefore in its alveoHis like a nail driven into 

 a plank. Nothing leiains it there except the elasticity of 

 the parts which enclose it; we may therefore chanjic its di- 

 rection by gentle pressure. This is an experiment which 

 succeeded with our second elephant : its tusks were brought 

 so close together as to constrain the motion of its proboscis; 

 "we separated them by means of a bar of iron, the middle of 

 which was in the form of a vice, and we could thus lengthen 

 it at pleasure. Every one knows that dentists do the same 

 thing, upon a small scale, with wires, with such teeth as 

 have only one root. 



The successive layers of which the ivory is composed 

 leave but few traces upon the section of a fresh tusk; but 

 here the fossil teeth assist us in better ascertaining the struc- 

 ture of the parts. Those tusks which have been decomposed 

 and altered by their being under-ground, are split into coni- 

 cal and thin laminae, all enveloped within each other, and 

 thereby show what has been their origin. 



• Vita Apollonii, lib. ii. cap. 13. 



No 



