485 



brass bullet has been imbedded, in a closed cavity with a smooth and entire 

 inner surface. 



The parietes of the cavity next the pulp-cavity, into which they project with a slight con- 

 vexity, are fully half an inch thick ; the outer parietes are fully an inch in thickness. There 

 was no outward indication of the presence of such foreign body. 



The following appears to be the explanation of this phenomenon : A ball aimed at the 

 head of an Elephant may penetrate the thin bony socket and the thinner ivory parietes 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. The pre- 

 sence of the foreign body exciting inflammation of the pulp, an irregular course of calcifica- 

 tion 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 osteodentine, together with the rest of the conical cavity into which that 

 mass projects, with layers of normal ivory, closing the breach in the thin parietes of the pulp- 

 cavity by which the ball entered ; and as the growth of the tusk proceeds, the ball, so in- 

 closed, is carried forwards into the solid exserted part of the tusk. 



Mas. Brit. 



2762. A section of the tusk of an Elephant, in which an iron ball is imbedded. 



The external wall of the cavity is scarcely two lines iu thickness, but shows no trace of the 

 entry of the bullet ; the inner wall appears to have been much thicker. 



Presented by Thomas Blizard, Esq., F.R.S. 



2763. A transverse section from near the base of the tusk of an Elephant, exposing 

 half of a leaden bullet imbedded in a mass of osteodentine which fills up a 

 great part of the pulp-cavity. 



In this section there are marks of external injury on opposite sides of the diseased part of 

 the tusk. 



Hunterian. 



2764. A section of the tusk of an Elephant, showing a cavity near the outer surface 

 in which a flattened leaden ball is fixed. 



The outer wall of the cavity appears to be formed by normal ivory, three lines in thickness : 

 the inner wall is formed of the irregular substance called osteodentine. 



Presented by William Clifi, Esq., F.R.S. 



2765. Two sections of the base of the tusk of an Elephant, into the pulp-cavity of 

 which the iron point of a javelin has penetrated, and has been broken. 



A mass of osteodentine surrounds this foreign body : the weapon has originally pierced the 

 thin wall of the socket and the vascular pulp, its point having been broken off and left there ; 



