ELEPHANT. 643 



supporting socket, and destined to be frequently applied in dealing 

 blows and thrusts. 



The central part of the tusk, especially near the base of such 

 as have reached their full size, is occupied by a slender cylin- 

 drical tract of modified ivory, perforated by a few vascular canals, 

 which is continued to the apex of the tusk. It is not uncom- 

 mon to find processes of osteo-dentine, or imperfect bone-like ivory, 

 projecting in a stalactitic form(l) into the interior of the pulp- 

 cavity, apparently the consequence of partial inflammation or mal- 

 formation of the vascular pulp. The musket-balls and other foreign 

 bodies which are occasionally found in ivory, are immediately sur- 

 rounded by osteo-dentine in greater or less quantity. It has long 

 ceased to be a matter of wonder how such bodies should become 

 completely imbedded in the substance of the tusk, sometimes without 

 any visible aperture, or how a leaden bullet may have become lodged 

 in the solid centre of a very large tusk without having been flattened. 

 Such a ball, aimed at the head of an Elephant, may penetrate 

 the thin bony socket and the thinner ivory parieties of the wide 

 conical pulp-cavity occupying the inserted base of the tusk ; if the 

 projectile force be then spent the ball gravitates to the opposite 

 and lower side of the pulp-cavity, as is indicated in PI. 146, 

 fig. 1.(2) The presence of the foreign body exciting inflammation 

 of the pulp, an irregular course of calcification ensues, which 

 results in the deposition around the ball of a certain thickness 

 of osteo-dentine. The pulp then resuming its healthy state and 

 functions, coats the surface of the inclosing mass of osteo-den- 

 tine, together with the rest of the conical cavity into w^hich 

 that mass projects, with' layers of normal ivory. (3) The ivory, 



(1) Haller seems to have been the first to notice these irregular internal deposits 

 in the pulp-cavity of the Elephant's tusk. 'Elementa Physiologise, torn, viii, p. 519. 



(2) Camper, ' Description Anatomique d'un Elephant Male' fol. p. 54. Cuvier, * Annales 

 du Museum, torn, viii, 1806, p, 115. 



(3) Cuvier, 'Annales du Museum,' torn. viii. p. 115, 1806. " Sur les defenses des 

 Elephans, la structure, I'accroissement les caracteres distinctifs de I'ivoire et sur les maladies," 

 first clearly stated that the ball or foreign body in the tusk of the Elephant was immediately 

 surrounded by a substance different from the regular ivory. The great Anatomist observes, 

 " Touts la portion d'ivoire en dehors de la balle est semblable au reste ; il n'y a que ce qui 

 I'entoure immediatement qui soit irregulier." Mr. Goodsir has confirmed this statement hy 



T T 2 



